000
FXUS63 KSGF 200431
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1131 PM CDT FRI SEP 19 2008

...UPDATE TO AVIATION...


.DISCUSSION...

ISOLATED/WIDELY SCATTERED CONVECTION HAS DEVELOPED ON THE EASTERN
PERIPHERY OF A WEAK UPPER LEVEL LOW CENTERED OVER NORTHWEST AR.
DIURNALLY DRIVEN MODEST MLCAPES IN THE NEIGHBORHOOD OF 500-700
J/KG (DEPICTED BY THE SREF) MAY ALLOW SOME CONVECTION TO FURTHER
DEVELOP THIS AFTERNOON CLOSER TO THE UPPER LOW CENTER ALONG THE
MO/AR BORDER. COVERAGE SHOULD FAIRLY MINIMAL.

THE UPPER LOW IS EXPECTED SLOWLY SHIFT ENE INTO SOUTHEAST MO ON
SATURDAY...AND EXPECT MORE OF THE SAME...JUST FARTHER EAST. A
LITTLE MORE OF A SOUTHEAST FETCH WILL INTRODUCE INCREASED LOW
LEVEL MOISTURE TO THE AREA LATER TODAY AND INTO THE WEEKEND.
SHOWERS SHOULD BE MORE NUMEROUS...ESPECIALLY ON SATURDAY OVER THE
EASTERN CWFA. MAINTAINED SIMILAR POPS TO THE PREVIOUS FORECAST AND
CURRENT AVAILABLE MOS GUIDANCE.

TEMPERATURES WILL BE SOMEWHAT TRICKY OVER THE WEEKEND. LOW
STRATUS/FOG MAY BE FAIRLY WIDESPREAD...ESPECIALLY ALONG AND SOUTH
OF THE MO OZARK PLATEAU BOTH SAT AND SUN MORNING. THE LOW CLOUDS
COUPLED WITH CLOUDS/RAIN CHANCES SHOULD KEEP TEMPERATURES DOWN
OVER THE EASTERN CWFA. AGAIN...I WON`T BE DEVIATING TOO MUCH FROM
GUIDANCE AND THE PREVIOUS FORECAST...WHICH HAS MAX TEMPERATURES
WELL DOWN INTO THE 70S AT WEST PLAINS AND ROLLA/VICHY. THE WESTERN
CWFA WITH MORE SUNSHINE IS EXPECTED TO BE IN THE 80S. THE
PERSISTENCE OF THE LOW CLOUD COVER WILL DICTATE HIGHS THIS
WEEKEND. MOS GUIDANCE LOWS ALSO SEEM A LITTLE COOL GIVEN THE
INCREASED CLOUDS AND LOW LEVEL MOISTURE AND MAY SHADE THEM UP A
BIT.

THE UPPER LOW EXITS THE REGION SUNDAY NIGHT...BEING REPLACED BY A
WEAK UPPER RIDGE EARLY IN THE WORK WEEK. THE AREA REMAINS SOUTH
OF THE MAIN BELT OF UPPER WESTERLIES EARLY IN THE WEEK...BUT THE
WESTERLIES TAKE A BIT OF A DIP TOWARD MIDWEEK WITH A STRONG TROUGH
MOVING INTO WESTERN CANADA AND NORTHWEST CONUS/NORTHERN ROCKIES. A
COLD FRONT IS EXPECTED TO APPROACH THE REGION WED/THU...BUT WEAK
TO NIL GULF MOISTURE FETCH AND WEAKENING CONVERGENCE ALONG THE
FRONT DOES NOT LOOK GOOD FOR RAIN CHANCES. FOLLOWED FAIRLY CLOSE
TO HPC GUIDANCE WHICH HAS SLIGHT AND LOW END CHANCE POPS FOR THE
WED/THU PERIOD. DSA


&&

.AVIATION...

FOR THE 06Z TAFS...A FEW LINGERING SHOWERS CONTINUE OVER SOUTH
CENTRAL MO...HOWEVER MOST OF THE CONVECTION HAS ENDED FROM EARLIER
IN THE EVENING. SATELLITE SHOWS AREA OF STRATUS DEVELOPING OVER
SOUTH CENTRAL MISSOURI AND SPREADING NORTHWEST. THIS WILL LIKELY
AFFECT THE SGF TERMINAL LOCATION OVERNIGHT AND HAVE GONE WITH
CEILINGS FROM 1500 TO 2500 AND VISIBILITIES IN THE MVFR CATEGORY.
JLN ALREADY AT 6SM AND A NEARLY CLEAR SKY. WILL LIKELY SEE MORE OF
A RADIATIONAL FOG DEVELOPMENT THERE OVERNIGHT AND HAVE DROPPED
VISIBILITIES DOWN TO AROUND 2SM OVERNIGHT.

LINDENBERG

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KLSX 200408
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1108 PM CDT FRI SEP 19 2008

.DISCUSSION...
/152 PM CDT FRI SEP 19 2008/
THE ELONGATED MID/UPPER LOW THAT IS SLOWLY SPINNING INTO SOUTHERN
MISSOURI WILL BRING SCATTERED SHOWERS/THUNDERSTORMS TO THE CWA
THIS WEEKEND. AS EXPECTED THE DEWPOINTS HAVE INCREASED INTO THE
LOWER 60S...AND THROUGH THE NUMEROUS BREAKS OF THE CIRRUS CLOUD
COVER...TEMPERATURES HAVE WARMED INTO THE LOWER 80S. CURRENT
SURFACE BASED CAPES UNDERNEATH THE UPPER LOW ARE AROUND 1000 J/KG
AND SCATTERED SHOWERS/THUNDERSTORMS ARE BEING OBSERVED ACROSS FAR
SOUTHERN MISSOURI AND ARKANSAS.

TONIGHT...
THE AREA OF SHOWERS/THUNDERSTORMS ADVECTING NORTH/NORTHWEST
FROM EASTERN ARKANSAS IS ASSOCIATED WITH THE FIRST LOBE OF VORTICITY
ROTATING COUNTERCLOCKWISE AROUND THE UPPER LOW. RAINFALL WITH THIS
FEATURE SHOULD REMAIN FAIRLY LIGHT AND DIMINISH AS IT HEADS NORTH
INTO THE CWA THIS EVENING AND OVERNIGHT. IT WILL CERTAINLY HELP TO
MOISTEN THE LOWER LAYERS OF THE ATMOSPHERE...BUT DON`T EXPECT MUCH
MORE THAN ISOLATED/SCATTERED SHOWERS TO AFFECT THE SOUTHERN HALF
OF THE CWA. TEMPERATURES WILL BE WARMER AS CLOUD COVER AND HIGHER
DEWPOINTS WILL KEEP MOST LOCATIONS FROM DROPPING BELOW 60 DEGREES.

SATURDAY AND SUNDAY...
NOT UNLIKE TODAY...EXPECT MOST OF THE PRECIPITATION TO BE DRIVEN BY
DAYTIME INSTABILITY AND REMAIN SCATTERED GIVEN THE LACK OF ANY
FEATURE TO FOCUS THE CONVECTION. LACK OF ANY WIND SHEAR WILL KEEP
STORMS FROM BEING SEVERE...BUT SLOW MOVING NATURE COULD LEAD TO A
FEW LOCALIZED HEAVY RAINFALL REPORTS. HIGH TEMPERATURES WILL BE A
FEW DEGREES COOLER WHERE THE MOST PERSISTENT CLOUD COVER AND
RAINFALL OCCURS. THIS LOOKS TO BE ESPECIALLY TRUE ACROSS THE
SOUTHWEST PORTION OF THE CWA WHERE THE CORE OF THE UPPER LOW IS
ANTICIPATED TO RESIDE...AND THE BEST PROBABILITY OF PRECIPITATION IS
FORECAST.

MONDAY AND BEYOND...
ANOTHER PERIOD OF DRY WEATHER IS EXPECTED MONDAY THROUGH THE MIDDLE
OF NEXT WEEK AS THE UPPER LOW PULLS EAST AND HEIGHTS BEGIN TO RISE.
A SMALL WARMING TREND IN TEMPERATURES IS EXPECTED EACH DAY WITH THE
NEXT CHANCE OF PRECIPITATION ARRIVING BY WEEKS END AS A COLD FRONT
TRIES TO MOVE ACROSS THE FORECAST AREA. STILL SOME TIMING
DIFFERENCES IN THE MODEL GUIDANCE...SO THE EXTENDED FORECAST
REMAINS DRY.

CVKING

&&

.AVIATION...
/1035 PM CDT FRI SEP 19 2008/
FOR THE 06Z TAFS...MID-UPR LVL LOW CURRENTLY CNTRD OVER S CNTRL MO WILL
BRING MID-HI LVL CLOUDINESS TO THE TAF SITES LT TGT. IT APRS THAT
THE SHRA/TSRA ACTIVITY WILL REMAIN S OF THE TAF SITES LT TGT.
MAINLY LGT SELY SFC WNDS FOR LT TGT...THEN A WK E-SELY SFC WND ON
SAT ON THE WRN PERIPHERY OF SFC RDG. WITH THE MID-UPR LVL LOW
OVER THE AREA ON SAT THERE SHOULD BE SCT-BKN DIURNALLY DRIVEN
CUMULUS CLOUDS ALONG WITH SCT SHRA/TSRA DURING THE LT MRNG AND
AFTN HRS. LOOKING AT MDL QPF FCSTS THE STL METRO AREA MAY HAVE THE
BEST SHRA/TSRA COVERAGE OF THE TAF LOCATIONS. MUCH OF THE SHRA/TSRA
ACTIVITY ALONG WITH THE CUMULUS CLOUDS SHOULD DISSIPATE SAT EVNG
WITH LOSS OF DAYTIME HTG.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KEAX 192357
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
657 PM CDT FRI SEP 19 2008

...UPDATED AVIATION DISCUSSION...

.DISCUSSION...
/ISSUED 347 PM CDT FRI SEP 19 2008/
SHORT RANGE (TONIGHT THROUGH SUNDAY NIGHT)...

WEAK UPPER LEVEL SHORT WAVE SHOWING UP ON WATER VAPOR OVER NORTH
CENTRAL ARKANSAS. THIS WAVE HAS SPAWNED SOME THUNDERSTORMS OVER THE
OZARKS AND INTO THE MISSOURI BOOTHEEL...KIND OF FORETELLING OUR
WEATHER OVER THE WEEKEND. FOR THE FORECAST AREA...SOME LOW LEVEL
MOISTURE WRAPPING AROUND THIS SHORT WAVE CIRCULATION WAS PRODUCING
AN EXTENSIVE SCATTERED CU FIELD...BUT VERTICAL DEVELOPMENT HAS BEEN
LIMITED DUE TO A WEAK CAP AROUND 750 MB. ON SATURDAY...WITH THE WEAK
CUT OFF LOW SITTING IN THE BOOTHEEL...AND MOISTURE CONTINUING TO
WRAP INTO THE FORECAST AREA...LACK OF CAP MAY LEAD TO SCATTERED
STORMS DEVELOPING INTO CENTRAL MISSOURI WHERE BETTER MOISTURE WILL
BE FOUND. WILL INTRODUCE SOME LOW CHANCE POPS IN EXTREME
SOUTHEASTERN AREAS WHERE SLIGHTLY BETTER MID LEVEL LAPSE RATES WILL
RESIDE. FOR SUNDAY...MODELS SHOWING WEAKENING SHORT WAVE LIFTING TO
THE NORTH WITH STILL A MOISTURE AXIS ACROSS EASTERN HALF OF
MISSOURI.  WOULD EXPECT WITH AFTERNOON HEATING...MORE INSTABILITY
TYPE CONVECTION WILL OCCUR...AND WILL LEAVE LOW CHANCE POPS IN
EXTREME EASTERN AREAS.

REGARDING TEMPERATURES...WITH EXPECTED SCATTERED TO BROKEN CLOUD
DECK AND DEWPOINTS REMAINING AT OR SLIGHTLY HIGHER THAN CURRENT
LEVELS...SEE LITTLE REASON TO DEVIATE FROM GUIDANCE WHICH SHOWS
BASICALLY A PERSISTENT FORECAST. FOR TONIGHT...MAY SEE SOME VALLEY
FOG AGAIN NEAR RIVER SOURCES WITH TEMPERATURES DIPPING TOWARD THE
DEWPOINTS AS WINDS BENEATH THE INVERSION GO LIGHT.

PC

MEDIUM RANGE (MON-FRI)...

A BROAD UPPER LEVEL TROUGH WILL BE IN PLACE BY THE BEGINNING OF THE
WEEK ACROSS THE WESTERN US WITH GENERAL WEST TO SOUTHWEST FLOW ALOFT
ACROSS THE CENTRAL PLAINS. LEE SIDE TROUGHING WILL RESULT BY MONDAY
WITH AREAS OF SCATTERED SHOWERS ACROSS THE PLAINS AS WAA TAKES SHAPE
AND ISENTROPIC ASCENT COMMENCES. IN ADDITION...OPERATIONAL MODELS
INDICATE AN UPPER IMPULSE TO TRAVERSE THE PLAINS INTO THE MIDWEST
DURING THE DAY MONDAY. NOT COMPLETELY SOLD ON THIS IDEA JUST YET
WITH AN OVERALL LACK OF SFC FOCUS AND HAVE ONLY INCLUDED SLIGHT CHC
POPS ATTM ACROSS THE NORTHERN PORTIONS OF THE CWA.

A MORE VIGOROUS SHORT WAVE TROUGH IS PROGGED TO EMERGE INTO THE
PLAINS BY MIDWEEK. 12Z OPERATIONAL GFS IS MUCH FASTER WITH THIS
FEATURE AND PREFER TO REMAIN CLOSER TO THE OPERATIONAL ECMWF AS IT
MORE CLOSELY RESEMBLES THE ENSEMBLE MEAN OUTPUT. ACCOMPANYING SFC
FRONT IS EXPECTED TO APPROACH THE AREA BY WEDNESDAY AND HAVE KEPT
POPS FROM WEDNESDAY THROUGH THURSDAY TO ACCOUNT. FRONT IS EXPECTED
TO SLOW AS IT PUSHES ACROSS THE CWA AND MAY LINGER LONGER THAN
EXPECTED. WILL KEEP DAYS 7 AND 8 DRY FOR THE TIME BEING WITH LOW
CONFIDENCE IN THE FRONTAL POSITION BY THIS TIME.

DEROCHE

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH A FEW
DIURNAL CU AND CIRRUS ASSOCIATED WITH WEAK UPPER LOW. ONLY EXCEPTION
IS PSBL GROUND FOG WITH VSBY 1/2-1SM AROUND DAYBREAK AT KSTJ. WITHIN
BROAD SURFACE HIGH PRESSURE ZONE...WINDS WILL BE LIGHT/VARIABLE.

BOOKBINDER

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.

$$

000
FXUS63 KLSX 192339
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
639 PM CDT FRI SEP 19 2008

.DISCUSSION...
/152 PM CDT FRI SEP 19 2008/
THE ELONGATED MID/UPPER LOW THAT IS SLOWLY SPINNING INTO SOUTHERN
MISSOURI WILL BRING SCATTERED SHOWERS/THUNDERSTORMS TO THE CWA
THIS WEEKEND. AS EXPECTED THE DEWPOINTS HAVE INCREASED INTO THE
LOWER 60S...AND THROUGH THE NUMEROUS BREAKS OF THE CIRRUS CLOUD
COVER...TEMPERATURES HAVE WARMED INTO THE LOWER 80S. CURRENT
SURFACE BASED CAPES UNDERNEATH THE UPPER LOW ARE AROUND 1000 J/KG
AND SCATTERED SHOWERS/THUNDERSTORMS ARE BEING OBSERVED ACROSS FAR
SOUTHERN MISSOURI AND ARKANSAS.

TONIGHT...
THE AREA OF SHOWERS/THUNDERSTORMS ADVECTING NORTH/NORTHWEST
FROM EASTERN ARKANSAS IS ASSOCIATED WITH THE FIRST LOBE OF VORTICITY
ROTATING COUNTERCLOCKWISE AROUND THE UPPER LOW. RAINFALL WITH THIS
FEATURE SHOULD REMAIN FAIRLY LIGHT AND DIMINISH AS IT HEADS NORTH
INTO THE CWA THIS EVENING AND OVERNIGHT. IT WILL CERTAINLY HELP TO
MOISTEN THE LOWER LAYERS OF THE ATMOSPHERE...BUT DON`T EXPECT MUCH
MORE THAN ISOLATED/SCATTERED SHOWERS TO AFFECT THE SOUTHERN HALF
OF THE CWA. TEMPERATURES WILL BE WARMER AS CLOUD COVER AND HIGHER
DEWPOINTS WILL KEEP MOST LOCATIONS FROM DROPPING BELOW 60 DEGREES.

SATURDAY AND SUNDAY...
NOT UNLIKE TODAY...EXPECT MOST OF THE PRECIPITATION TO BE DRIVEN BY
DAYTIME INSTABILITY AND REMAIN SCATTERED GIVEN THE LACK OF ANY
FEATURE TO FOCUS THE CONVECTION. LACK OF ANY WIND SHEAR WILL KEEP
STORMS FROM BEING SEVERE...BUT SLOW MOVING NATURE COULD LEAD TO A
FEW LOCALIZED HEAVY RAINFALL REPORTS. HIGH TEMPERATURES WILL BE A
FEW DEGREES COOLER WHERE THE MOST PERSISTENT CLOUD COVER AND
RAINFALL OCCURS. THIS LOOKS TO BE ESPECIALLY TRUE ACROSS THE
SOUTHWEST PORTION OF THE CWA WHERE THE CORE OF THE UPPER LOW IS
ANTICIPATED TO RESIDE...AND THE BEST PROBABILITY OF PRECIPITATION IS
FORECAST.

MONDAY AND BEYOND...
ANOTHER PERIOD OF DRY WEATHER IS EXPECTED MONDAY THROUGH THE MIDDLE
OF NEXT WEEK AS THE UPPER LOW PULLS EAST AND HEIGHTS BEGIN TO RISE.
A SMALL WARMING TREND IN TEMPERATURES IS EXPECTED EACH DAY WITH THE
NEXT CHANCE OF PRECIPITATION ARRIVING BY WEEKS END AS A COLD FRONT
TRIES TO MOVE ACROSS THE FORECAST AREA. STILL SOME TIMING
DIFFERENCES IN THE MODEL GUIDANCE...SO THE EXTENDED FORECAST
REMAINS DRY.

CVKING

&&

.AVIATION...
/435 PM CDT FRI SEP 19 2008/
FOR THE 00Z TAFS...MID-UPR LVL LOW CURRENTLY CNTRD OVER S CNTRL MO WILL
BRING MID-HI LVL CLOUDINESS TO THE TAF SITES TGT. IT APRS THAT THE
SHRA/TSRA ACTIVITY WILL REMAIN S OF THE TAF SITES TGT. LGT SFC
WNDS CAN BE EXPECTED TGT...THEN A WK E-SELY SFC WND ON SAT ON THE
WRN PERIPHERY OF A SFC RDG. WITH THE MID-UPR LVL LOW OVER THE
AREA ON SAT THERE SHOULD BE SCT-BKN DIURNALLY DRIVEN CUMULUS
CLOUDS ALONG WITH SCT SHRA/TSRA DURING THE LT MRNG AND AFTN HRS.
LOOKING AT MDL QPF FCSTS THE STL METRO AREA MAY HAVE THE BEST SHRA/TSRA
COVERAGE OF THE TAF LOCATIONS.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KSGF 192321
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
621 PM CDT FRI SEP 19 2008

...UPDATE TO AVIATION...

...MESOSCALE CONVECTIVE DISCUSSION...

.UPDATE...

SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP IN ADVANCE OF UPPER
LOW OVER SOUTHWEST MISSOURI. MOST STORMS REMAINING BELOW SEVERE
LIMITS BUT HAVE HAD A FEW DEVELOP WITH 50 TO 34KFT WHICH PROMPTED
A SEVERE WARNING. STORMS HAVE BEEN QUICK TO DEVELOP AND DIMINISH
THIS EVENING AND THIS TREND IS EXPECTED. STORMS SHOULD BEGIN TO
DIMINISH AFTER SUNSET WITH LOSS OF DAYTIME HEATING.


&&

.DISCUSSION...

ISOLATED/WIDELY SCATTERED CONVECTION HAS DEVELOPED ON THE EASTERN
PERIPHERY OF A WEAK UPPER LEVEL LOW CENTERED OVER NORTHWEST AR.
DIURNALLY DRIVEN MODEST MLCAPES IN THE NEIGHBORHOOD OF 500-700
J/KG (DEPICTED BY THE SREF) MAY ALLOW SOME CONVECTION TO FURTHER
DEVELOP THIS AFTERNOON CLOSER TO THE UPPER LOW CENTER ALONG THE
MO/AR BORDER. COVERAGE SHOULD FAIRLY MINIMAL.

THE UPPER LOW IS EXPECTED SLOWLY SHIFT ENE INTO SOUTHEAST MO ON
SATURDAY...AND EXPECT MORE OF THE SAME...JUST FARTHER EAST. A
LITTLE MORE OF A SOUTHEAST FETCH WILL INTRODUCE INCREASED LOW
LEVEL MOISTURE TO THE AREA LATER TODAY AND INTO THE WEEKEND.
SHOWERS SHOULD BE MORE NUMEROUS...ESPECIALLY ON SATURDAY OVER THE
EASTERN CWFA. MAINTAINED SIMILAR POPS TO THE PREVIOUS FORECAST AND
CURRENT AVAILABLE MOS GUIDANCE.

TEMPERATURES WILL BE SOMEWHAT TRICKY OVER THE WEEKEND. LOW
STRATUS/FOG MAY BE FAIRLY WIDESPREAD...ESPECIALLY ALONG AND SOUTH
OF THE MO OZARK PLATEAU BOTH SAT AND SUN MORNING. THE LOW CLOUDS
COUPLED WITH CLOUDS/RAIN CHANCES SHOULD KEEP TEMPERATURES DOWN
OVER THE EASTERN CWFA. AGAIN...I WON`T BE DEVIATING TOO MUCH FROM
GUIDANCE AND THE PREVIOUS FORECAST...WHICH HAS MAX TEMPERATURES
WELL DOWN INTO THE 70S AT WEST PLAINS AND ROLLA/VICHY. THE WESTERN
CWFA WITH MORE SUNSHINE IS EXPECTED TO BE IN THE 80S. THE
PERSISTENCE OF THE LOW CLOUD COVER WILL DICTATE HIGHS THIS
WEEKEND. MOS GUIDANCE LOWS ALSO SEEM A LITTLE COOL GIVEN THE
INCREASED CLOUDS AND LOW LEVEL MOISTURE AND MAY SHADE THEM UP A
BIT.

THE UPPER LOW EXITS THE REGION SUNDAY NIGHT...BEING REPLACED BY A
WEAK UPPER RIDGE EARLY IN THE WORK WEEK. THE AREA REMAINS SOUTH
OF THE MAIN BELT OF UPPER WESTERLIES EARLY IN THE WEEK...BUT THE
WESTERLIES TAKE A BIT OF A DIP TOWARD MIDWEEK WITH A STRONG TROUGH
MOVING INTO WESTERN CANADA AND NORTHWEST CONUS/NORTHERN ROCKIES. A
COLD FRONT IS EXPECTED TO APPROACH THE REGION WED/THU...BUT WEAK
TO NIL GULF MOISTURE FETCH AND WEAKENING CONVERGENCE ALONG THE
FRONT DOES NOT LOOK GOOD FOR RAIN CHANCES. FOLLOWED FAIRLY CLOSE
TO HPC GUIDANCE WHICH HAS SLIGHT AND LOW END CHANCE POPS FOR THE
WED/THU PERIOD. DSA


&&

.AVIATION...

FOR THE 00Z TAFS...STORM WHICH AFFECTED THE SGF TERMINAL LOCATION
LAST HOUR HAS FALLEN APART AND DOESNT APPEAR THAT ADDITIONAL
CONVECTION WILL OCCUR AT JLN/SGF THIS EVENING. SO HAVE LEFT OUT
TSRA FROM THE TAFS AT THIS TIME. COULD SEE SOME FOG DEVELOP
TONIGHT...MAINLY IN THE MVFR CATEGORY AFTER MIDNIGHT AT JLN AND SGF.

LINDENBERG

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KEAX 192047
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
347 PM CDT FRI SEP 19 2008

.DISCUSSION...
SHORT RANGE (TONIGHT THROUGH SUNDAY NIGHT)...

WEAK UPPER LEVEL SHORT WAVE SHOWING UP ON WATER VAPOR OVER NORTH
CENTRAL ARKANSAS. THIS WAVE HAS SPAWNED SOME THUNDERSTORMS OVER THE
OZARKS AND INTO THE MISSOURI BOOTHEEL...KIND OF FORETELLING OUR
WEATHER OVER THE WEEKEND. FOR THE FORECAST AREA...SOME LOW LEVEL
MOISTURE WRAPPING AROUND THIS SHORT WAVE CIRCULATION WAS PRODUCING
AN EXTENSIVE SCATTERED CU FIELD...BUT VERTICAL DEVELOPMENT HAS BEEN
LIMITED DUE TO A WEAK CAP AROUND 750 MB. ON SATURDAY...WITH THE WEAK
CUT OFF LOW SITTING IN THE BOOTHEEL...AND MOISTURE CONTINUING TO
WRAP INTO THE FORECAST AREA...LACK OF CAP MAY LEAD TO SCATTERED
STORMS DEVELOPING INTO CENTRAL MISSOURI WHERE BETTER MOISTURE WILL
BE FOUND. WILL INTRODUCE SOME LOW CHANCE POPS IN EXTREME
SOUTHEASTERN AREAS WHERE SLIGHTLY BETTER MID LEVEL LAPSE RATES WILL
RESIDE. FOR SUNDAY...MODELS SHOWING WEAKENING SHORT WAVE LIFTING TO
THE NORTH WITH STILL A MOISTURE AXIS ACROSS EASTERN HALF OF
MISSOURI.  WOULD EXPECT WITH AFTERNOON HEATING...MORE INSTABILITY
TYPE CONVECTION WILL OCCUR...AND WILL LEAVE LOW CHANCE POPS IN
EXTREME EASTERN AREAS.

REGARDING TEMPERATURES...WITH EXPECTED SCATTERED TO BROKEN CLOUD
DECK AND DEWPOINTS REMAINING AT OR SLIGHTLY HIGHER THAN CURRENT
LEVELS...SEE LITTLE REASON TO DEVIATE FROM GUIDANCE WHICH SHOWS
BASICALLY A PERSISTENT FORECAST. FOR TONIGHT...MAY SEE SOME VALLEY
FOG AGAIN NEAR RIVER SOURCES WITH TEMPERATURES DIPPING TOWARD THE
DEWPOINTS AS WINDS BENEATH THE INVERSION GO LIGHT.

PC

MEDIUM RANGE (MON-FRI)...

A BROAD UPPER LEVEL TROUGH WILL BE IN PLACE BY THE BEGINNING OF THE
WEEK ACROSS THE WESTERN US WITH GENERAL WEST TO SOUTHWEST FLOW ALOFT
ACROSS THE CENTRAL PLAINS. LEE SIDE TROUGHING WILL RESULT BY MONDAY
WITH AREAS OF SCATTERED SHOWERS ACROSS THE PLAINS AS WAA TAKES SHAPE
AND ISENTROPIC ASCENT COMMENCES. IN ADDITION...OPERATIONAL MODELS
INDICATE AN UPPER IMPULSE TO TRAVERSE THE PLAINS INTO THE MIDWEST
DURING THE DAY MONDAY. NOT COMPLETELY SOLD ON THIS IDEA JUST YET
WITH AN OVERALL LACK OF SFC FOCUS AND HAVE ONLY INCLUDED SLIGHT CHC
POPS ATTM ACROSS THE NORTHERN PORTIONS OF THE CWA.

A MORE VIGOROUS SHORT WAVE TROUGH IS PROGGED TO EMERGE INTO THE
PLAINS BY MIDWEEK. 12Z OPERATIONAL GFS IS MUCH FASTER WITH THIS
FEATURE AND PREFER TO REMAIN CLOSER TO THE OPERATIONAL ECMWF AS IT
MORE CLOSELY RESEMBLES THE ENSEMBLE MEAN OUTPUT. ACCOMPANYING SFC
FRONT IS EXPECTED TO APPROACH THE AREA BY WEDNESDAY AND HAVE KEPT
POPS FROM WEDNESDAY THROUGH THURSDAY TO ACCOUNT. FRONT IS EXPECTED
TO SLOW AS IT PUSHES ACROSS THE CWA AND MAY LINGER LONGER THAN
EXPECTED. WILL KEEP DAYS 7 AND 8 DRY FOR THE TIME BEING WITH LOW
CONFIDENCE IN THE FRONTAL POSITION BY THIS TIME.

DEROCHE

&&

.AVIATION...
/1230 PM CDT FRI SEP 19 2008/
VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. ONLY EXCEPTION
IS PSBL GROUND FOG WITH VSBY 1/2-1SM DURING LATE TONIGHT AND EARLY
SATURDAY MORNING AT STJ.

PC

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.

$$

000
FXUS63 KLSX 191916
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
216 PM CDT FRI SEP 19 2008

.DISCUSSION...
/152 PM CDT FRI SEP 19 2008/
THE ELONGATED MID/UPPER LOW THAT IS SLOWLY SPINNING INTO SOUTHERN
MISSOURI WILL BRING SCATTERED SHOWERS/THUNDERSTORMS TO THE CWA
THIS WEEKEND. AS EXPECTED THE DEWPOINTS HAVE INCREASED INTO THE
LOWER 60S...AND THROUGH THE NUMEROUS BREAKS OF THE CIRRUS CLOUD
COVER...TEMPERATURES HAVE WARMED INTO THE LOWER 80S. CURRENT
SURFACE BASED CAPES UNDERNEATH THE UPPER LOW ARE AROUND 1000 J/KG
AND SCATTERED SHOWERS/THUNDERSTORMS ARE BEING OBSERVED ACROSS FAR
SOUTHERN MISSOURI AND ARKANSAS.

TONIGHT...
THE AREA OF SHOWERS/THUNDERSTORMS ADVECTING NORTH/NORTHWEST
FROM EASTERN ARKANSAS IS ASSOCIATED WITH THE FIRST LOBE OF VORTICITY
ROTATING COUNTERCLOCKWISE AROUND THE UPPER LOW. RAINFALL WITH THIS
FEATURE SHOULD REMAIN FAIRLY LIGHT AND DIMINISH AS IT HEADS NORTH
INTO THE CWA THIS EVENING AND OVERNIGHT. IT WILL CERTAINLY HELP TO
MOISTEN THE LOWER LAYERS OF THE ATMOSPHERE...BUT DON`T EXPECT MUCH
MORE THAN ISOLATED/SCATTERED SHOWERS TO AFFECT THE SOUTHERN HALF
OF THE CWA. TEMPERATURES WILL BE WARMER AS CLOUD COVER AND HIGHER
DEWPOINTS WILL KEEP MOST LOCATIONS FROM DROPPING BELOW 60 DEGREES.

SATURDAY AND SUNDAY...
NOT UNLIKE TODAY...EXPECT MOST OF THE PRECIPITATION TO BE DRIVEN BY
DAYTIME INSTABILITY AND REMAIN SCATTERED GIVEN THE LACK OF ANY
FEATURE TO FOCUS THE CONVECTION. LACK OF ANY WIND SHEAR WILL KEEP
STORMS FROM BEING SEVERE...BUT SLOW MOVING NATURE COULD LEAD TO A
FEW LOCALIZED HEAVY RAINFALL REPORTS. HIGH TEMPERATURES WILL BE A
FEW DEGREES COOLER WHERE THE MOST PERSISTENT CLOUD COVER AND
RAINFALL OCCURS. THIS LOOKS TO BE ESPECIALLY TRUE ACROSS THE
SOUTHWEST PORTION OF THE CWA WHERE THE CORE OF THE UPPER LOW IS
ANTICIPATED TO RESIDE...AND THE BEST PROBABILITY OF PRECIPITATION IS
FORECAST.

MONDAY AND BEYOND...
ANOTHER PERIOD OF DRY WEATHER IS EXPECTED MONDAY THROUGH THE MIDDLE
OF NEXT WEEK AS THE UPPER LOW PULLS EAST AND HEIGHTS BEGIN TO RISE.
A SMALL WARMING TREND IN TEMPERATURES IS EXPECTED EACH DAY WITH THE
NEXT CHANCE OF PRECIPITATION ARRIVING BY WEEKS END AS A COLD FRONT
TRIES TO MOVE ACROSS THE FORECAST AREA. STILL SOME TIMING
DIFFERENCES IN THE MODEL GUIDANCE...SO THE EXTENDED FORECAST
REMAINS DRY.

CVKING

&&

.AVIATION...
/1219 PM CDT FRI SEP 19 2008/
FOR THE 18Z TAFS...FOR THE SHORT-TERM HV REMAINED PERSISTENT WITH
PREV FCST. WNDS WL RMN LGT AND OUT OF THE EAST WITH BKN250 AND VFR
CONDITIONS OVRNGT. HI PRES WL CONTINUALLY SLIDE EWD THROUGH NEW
ENGLAND. MAIN CONCERN IS WITH THE LATER PD AS UPR LVL LOW PRESENTLY
SPINS ACRS ERN OK AND WRN AK. BY 12Z LOW SHLD MV EWD AND CENTER
ACRS SE MO DURING WHICH TIME LWR CIGS ARE TO BE EXPECTED FOR
POINTS ALONG AND SOUTH OF THE I-70 COORIDOR. HV LEFT TAFS DRY AND
ABOVE MVFR CONDITIONS. BETTER ISENTROPIC LIFT...MOISTURE
CONTENT...AND UPR LVL SUPPORT SEEMS FAVORABLE THROUGH SE MO AND
DOWN THE LWR MS VLY. STILL CAN NOT RULE OUT CHC PRECIP OVR STL AND
SUS DURING THE LATE PORTION OF THE PD. VSBYS WL REMAING P6SM WITH
EAST TO SE WNDS ACRS ALL LOCATIONS.

SIPPRELL

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KSGF 191823
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
123 PM CDT FRI SEP 19 2008

.DISCUSSION...

ISOLATED/WIDELY SCATTERED CONVECTION HAS DEVELOPED ON THE EASTERN
PERIPHERY OF A WEAK UPPER LEVEL LOW CENTERED OVER NORTHWEST AR.
DIURNALLY DRIVEN MODEST MLCAPES IN THE NEIGHBORHOOD OF 500-700
J/KG (DEPICTED BY THE SREF) MAY ALLOW SOME CONVECTION TO FURTHER
DEVELOP THIS AFTERNOON CLOSER TO THE UPPER LOW CENTER ALONG THE
MO/AR BORDER. COVERAGE SHOULD FAIRLY MINIMAL.

THE UPPER LOW IS EXPECTED SLOWLY SHIFT ENE INTO SOUTHEAST MO ON
SATURDAY...AND EXPECT MORE OF THE SAME...JUST FARTHER EAST. A
LITTLE MORE OF A SOUTHEAST FETCH WILL INTRODUCE INCREASED LOW
LEVEL MOISTURE TO THE AREA LATER TODAY AND INTO THE WEEKEND.
SHOWERS SHOULD BE MORE NUMEROUS...ESPECIALLY ON SATURDAY OVER THE
EASTERN CWFA. MAINTAINED SIMILAR POPS TO THE PREVIOUS FORECAST AND
CURRENT AVAILABLE MOS GUIDANCE.

TEMPERATURES WILL BE SOMEWHAT TRICKY OVER THE WEEKEND. LOW
STRATUS/FOG MAY BE FAIRLY WIDESPREAD...ESPECIALLY ALONG AND SOUTH
OF THE MO OZARK PLATEAU BOTH SAT AND SUN MORNING. THE LOW CLOUDS
COUPLED WITH CLOUDS/RAIN CHANCES SHOULD KEEP TEMPERATURES DOWN
OVER THE EASTERN CWFA. AGAIN...I WON`T BE DEVIATING TOO MUCH FROM
GUIDANCE AND THE PREVIOUS FORECAST...WHICH HAS MAX TEMPERATURES
WELL DOWN INTO THE 70S AT WEST PLAINS AND ROLLA/VICHY. THE WESTERN
CWFA WITH MORE SUNSHINE IS EXPECTED TO BE IN THE 80S. THE
PERSISTENCE OF THE LOW CLOUD COVER WILL DICTATE HIGHS THIS
WEEKEND. MOS GUIDANCE LOWS ALSO SEEM A LITTLE COOL GIVEN THE
INCREASED CLOUDS AND LOW LEVEL MOISTURE AND MAY SHADE THEM UP A
BIT.

THE UPPER LOW EXITS THE REGION SUNDAY NIGHT...BEING REPLACED BY A
WEAK UPPER RIDGE EARLY IN THE WORK WEEK. THE AREA REMAINS SOUTH
OF THE MAIN BELT OF UPPER WESTERLIES EARLY IN THE WEEK...BUT THE
WESTERLIES TAKE A BIT OF A DIP TOWARD MIDWEEK WITH A STRONG TROUGH
MOVING INTO WESTERN CANADA AND NORTHWEST CONUS/NORTHERN ROCKIES. A
COLD FRONT IS EXPECTED TO APPROACH THE REGION WED/THU...BUT WEAK
TO NIL GULF MOISTURE FETCH AND WEAKENING CONVERGENCE ALONG THE
FRONT DOES NOT LOOK GOOD FOR RAIN CHANCES. FOLLOWED FAIRLY CLOSE
TO HPC GUIDANCE WHICH HAS SLIGHT AND LOW END CHANCE POPS FOR THE
WED/THU PERIOD. DSA

&&

.AVIATION...

FOR THE 18Z TAFS...HAVE SOME CONCERNS ABOUT FOG POTENTIAL LATE
TONIGHT. FORECAST MODEL SOUNDINGS AND MOS OUTPUT FROM THE NAM AND
GFS DO NOT AGREE ON FOG DEVELOPMENT...WITH THE GFS DROPPING THE
AIRPORTS TO 1/2 MILE OR LESS AND THE NAM GOING MVFR. FOR NOW WILL
LEAN MORE TOWARD THE NAM WITH LESS THAN IDEAL RADIATIONAL COOLING
AND LACK OF STRONG LOW LEVEL MOISTURE ADVECTION OR WET GROUND. MAY
HAVE A BETTER SHOT AT FOG TOMORROW NIGHT WITH CLEARING SKIES AND
SLIGHTLY INCREASING DEW POINT TEMPS.

TERRY


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KLSX 191732
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1232 PM CDT FRI SEP 19 2008

.DISCUSSION...
/407 AM CDT FRI SEP 19 2008/
MID AND HIGH CLOUDS CONTINUE TO STREAM NORTHWARD ACROSS REGION AHEAD
OF UPPER LOW THAT IS CURRENTLY OVER WESTERN ARKANSAS. SO IN THE
SHORT TERM...THE MAIN FORECAST ISSUE IS THIS UPPER LOW AND HOW IT
WILL AFFECT THE WEATHER FOR THIS WEEKEND.

MODEL GUIDANCE CONTINUES TO BE IN FAIRLY GOOD AGREEMENT ON MID AND
UPPER LEVEL MOISTURE INCREASING ACROSS THE FORECAST AREA TODAY AS
THE UPPER LOW EDGES NORTHEAST. BY SATURDAY MORNING THE UPPER LOW
SHOULD BE PARKED DIRECTLY OVER THE OZARKS AND REMAIN NEARLY
STATIONARY THROUGH THE WEEKEND.

LOW LEVEL MOISTURE FOR THIS UPPER LEVEL DISTURBANCE REMAINS IN
QUESTION. HOWEVER...THE GFS HAS NOW COME IN LINE WITH THE OTHER
MODELS AND PRODUCES SOME QPF OVER THE REGION FOR SATURDAY AND
SUNDAY. SO HAVE LOW CHANCE POPS FAR SOUTH TONIGHT AND FOR MOST OF
THE AREA ON SATURDAY. RAIN CHANCES LET UP A LITTLE SATURDAY
NIGHT...THEN SEE ADDITIONAL DEVELOPMENT ON SUNDAY...THOUGH NOT REAL
CONFIDENT ON MOISTURE THAT DAY...SO KEPT SILENT 20 POPS IN FOR NOW.
THEN UPPER LEVEL SYSTEM WEAKENS AND EXITS THE REGION BY THE
BEGINNING OF THE WORK WEEK. BEYOND THAT...NO MAJOR CHANGES TO THE
FORECAST.

ON THE TEMPERATURE FRONT...HAVE LOWERED TEMPS IN THE WEST A DEGREE
OR SO TODAY DUE TO AN INCREASE IN THE MID AND HIGH CLOUDS. SAME GOES
FOR SATURDAY DUE TO CLOUDS AND PRECIPITATION...WITH COOLEST TEMPS IN
THE SOUTHERN SECTIONS OF THE FORECAST AREA. ALSO...LOWERED HIGHS ON
SUNDAY A FEW DEGREES. OTHERWISE...ONLY MINOR ADJUSTMENTS MADE BEYOND
SUNDAY.

BYRD

&&

.AVIATION...
/1219 PM CDT FRI SEP 19 2008/
FOR THE 18Z TAFS...FOR THE SHORT-TERM HV REMAINED PERSISTENT WITH
PREV FCST. WNDS WL RMN LGT AND OUT OF THE EAST WITH BKN250 AND VFR
CONDITIONS OVRNGT. HI PRES WL CONTINUALLY SLIDE EWD THROUGH NEW
ENGLAND. MAIN CONCERN IS WITH THE LATER PD AS UPR LVL LOW PRESENTLY
SPINS ACRS ERN OK AND WRN AK. BY 12Z LOW SHLD MV EWD AND CENTER
ACRS SE MO DURING WHICH TIME LWR CIGS ARE TO BE EXPECTED FOR
POINTS ALONG AND SOUTH OF THE I-70 COORIDOR. HV LEFT TAFS DRY AND
ABOVE MVFR CONDITIONS. BETTER ISENTROPIC LIFT...MOISTURE
CONTENT...AND UPR LVL SUPPORT SEEMS FAVORABLE THROUGH SE MO AND
DOWN THE LWR MS VLY. STILL CAN NOT RULE OUT CHC PRECIP OVR STL AND
SUS DURING THE LATE PORTION OF THE PD. VSBYS WL REMAING P6SM WITH
EAST TO SE WNDS ACRS ALL LOCATIONS.

SIPPRELL

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KEAX 191730
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1230 PM CDT FRI SEP 19 2008

...UPDATED AVIATION...

.DISCUSSION...

/250 AM CDT FRI SEP 19 2008/
EARLY MORNING WV IMAGERY SHOWS TWO AREAS OF WEAK UPPER LEVEL
CIRCULATIONS...ONE OVER NWRN OKLAHOMA AND A SECOND OVER CNTRL
ARKANSAS. THESE FEATURES ARE ASSOCIATED WITH A BROAD...AND NEARLY
CUTOFF WEAKNESS IN THE CNTRL CONUS HEIGHT FIELD. CURRENTLY...THE
ONLY IMPACT WITH THIS CIRCULATION IS AN EXPANSIVE CIRRUS
SHIELD...WITH A MIDLEVEL DECK ONLY RELEGATED TO THE LOW CENTER OVER
ARKANSAS. PRIMARY LIMITING FACTOR TO PRECIPITIVE PROCESSES IS THE
LACK OF LOW AND MID LEVEL MOISTURE...AS SFC PRESSURE RIDGING HAS
TRAPPED QUALITY MOISTURE IN THE NRN GULF OF MEXICO. BOUNDARY LAYER
THETA-E WILL SLOWLY INCREASE THROUGH THE WEEKEND...LEADING TO
SLIGHTLY BETTER PRECIP CHANCES...HOWEVER LIKELY REMAINING CLOSELY
COLLOCATED WITH THE MIDLEVEL CIRCULATION AND WEAK CORE COLD ALOFT.
HAVE CONTINUED WITH SLGT CHANCE MENTION FOR SERN HALF OF THE CWA
DURING THE AFTERNOON HOURS FOR SPOTTY SHRA/TSTMS.

REGARDING TEMPERATURES...SEE LITTLE REASON TO DEVIATE FAR FROM
PERSISTENCE WITH RESPECT TO HIGH TEMPS THROUGH SATURDAY...WITH ONLY
A SLIGHT BUMP TO PERSISTENCE FOR LOW TEMPS. BOUNDARY LAYER WIND
SPEEDS AND TRAJECTORIES STILL DO NOT SUGGEST DEEP MECHANICAL
MIXING...AND ANY SMALL INCREASE IN H9 TEMPS SHOULD BE OFFSET
SOMEWHAT BY INCREASED HIGHER CLOUD COVER. HAVE CUT HIGHS FOR SUNDAY
JUST A BIT...AS INCREASED SFC MOISTURE ADVECTION ON ELY FLOW LOOKS
TO INCREASE CLOUD COVER ENOUGH TO MORE SIGNIFICANTLY HINDER
INSOLATION.

BY EARLY NEXT WEEK...CUTOFF SYSTEM IS FORECAST TO BECOME ABSORBED IN
THE MAIN NLY STREAM OFF THE ERN SEABOARD...WHILE MUCH STRONGER JET
ENERGY DIGS A MEAN TROUGH THROUGH THE NRN ROCKIES. AS A RESULT...SFC
LEE PRESSURE FALLS WILL COMMENCE BY MONDAY MORNING...BRINGING AN
INCREASED 30-40KT LLJ AXIS FROM THE SRN PLAINS TO UPPER
MIDWEST...GRADUALLY PULLING BETTER GULF MOISTURE NWD. TO A VARYING
EXTENT...ALL FORECAST MODELS INDICATE AGGRESSIVE THETA-E ADVECTION
AND ISENTROPIC LIFT MONDAY MORNING IN AN AREA RESEMBLING A NWD
RETREATING SFC WARM FRONT. WHILE THESE PROCESSES ARE FAVORED IN THIS
EVOLVING FLOW PATTERN...EXACT PLACEMENT OF PRECIP FIELDS THIS FAR IN
THE FUTURE REMAINS TENUOUS AT BEST...AND HAVE JUST INTRODUCED SLGT
CHANCE POPS FOR THE TIME BEING. OTHERWISE...A BETTER DEFINED COLD
FRONT AND FORCING ENTERS THE FORECAST AREA IN THE WED/THURS TIME
FRAME...AND WILL WAIT FOR MORE MODEL CONSISTENCY BEFORE INCREASING
POPS HERE.

21

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. ONLY EXCEPTION
IS PSBL GROUND FOG WITH VSBY 1/2-1SM DURING LATE TONIGHT AND EARLY
SATURDAY MORNING AT STJ.

PC

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.

$$

000
FXUS63 KSGF 191721
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1221 PM CDT FRI SEP 19 2008

.UPDATE...

WENT AHEAD AND EXPANDED 20 PERCENT POP ACROSS MUCH OF SOUTHERN
MISSOURI WITH CIRCULATION OF UPPER LOW OVER THE AREA AND
TEMPERATURES WARMING SUFFICIENTLY TO RAISE CAPES TO AROUND 900
J/KG....BASED ON MODIFICATION OF KSGF 12Z SOUNDING FOR CURRENT
CONDITIONS. GOING TEMPERATURES/WINDS ARE PRETTY MUCH ON TRACK.

TERRY

&&

.DISCUSSION...

THE FORECAST CHALLENGE IS RAIN CHANCES ASSOCIATED WITH AN UPPER
LEVEL LOW THAT WILL TRACK THROUGH THE SOUTHERN PLAINS INTO THE
OZARKS. WATER VAPOR IMAGERY AND THE WIND PROFILER NETWORK DEPICT
A WEAK UPPER LEVEL LOW OVER SOUTHWEST KANSAS. AHEAD OF THIS
LOW...MID AND HIGH CLOUDS HAVE SPREAD OVER THE OZARKS.
OVERNIGHT....TEMPERATURES HAVE FALLEN TO THE UPPER 50S AND LOWER
60S WITH DEWPOINTS IN THE MIDDLE AND UPPER 50S WITH A WEAK
SOUTHEAST WIND.

GFS/ECMWF/NAM/UKMET ALL PROG THIS UPPER LEVEL LOW MOVING INTO THE
OZARKS TONIGHT. THIS LOW WILL BE SLOW TO MOVE THROUGH THE REGION
OVER THE WEEKEND WITH THE FEATURE CUTOFF FROM THE MAIN BELT OF
WESTERLIES TO THE NORTH. MOISTURE WILL BE LIMITED INITIALLY WITH
THE 00Z KSGF SOUNDING DEPICTING A SIGNIFICANT DRY LAYER ABOVE
800MB. ISENTROPIC UPGLIDE WILL INCREASE THROUGH THE WEEKEND
ALONG THE 305K SURFACE WHICH WILL BRING CHANCES FOR SCATTERED
LIGHT RAIN SHOWERS. THE BEST RAIN CHANCES LOOK TO BE EAST OF THE
HIGHWAY 65 CORRIDOR WHERE THE STRONGEST LIFT IS EXPECTED WITH THE
LOW. AN ISOLATED THUNDERSTORM CAN NOT BE RULED OUT BUT
INSTABILITY WILL BE LIMITED. BELOW NORMAL HIGH TEMPERATURES WILL
BE POSSIBLE SATURDAY ACROSS SOUTH CENTRAL MISSOURI DUE TO
EXTENSIVE CLOUD COVER AND SCATTERED SHOWERS.

DRY AND WARMER WEATHER RETURN EARLY NEXT WEEK AS AN UPPER LEVEL
RIDGE BUILDS INTO THE CENTRAL CONUS. MODELS DEPICT A COLD FRONT
MOVING THROUGH THE PLAINS WEDNESDAY AND THURSDAY ASSOCIATED WITH
AN UPPER LEVEL TROUGH AND HEIGHT FALLS ACROSS THE NORTHERN
PLAINS. THIS FRONT COULD BRING ADDITIONAL CHANCES FOR SHOWERS AND
THUNDERSTORMS TO THE OZARKS LATE IN THE WEEK.

ANGLE


&&

.AVIATION...

FOR THE 18Z TAFS...HAVE SOME CONCERNS ABOUT FOG POTENTIAL LATE
TONIGHT. FORECAST MODEL SOUNDINGS AND MOS OUTPUT FROM THE NAM AND
GFS DO NOT AGREE ON FOG DEVELOPMENT...WITH THE GFS DROPPING THE
AIRPORTS TO 1/2 MILE OR LESS AND THE NAM GOING MVFR. FOR NOW WILL
LEAN MORE TOWARD THE NAM WITH LESS THAN IDEAL RADIATIONAL COOLING
AND LACK OF STRONG LOW LEVEL MOISTURE ADVECTION OR WET GROUND. MAY
HAVE A BETTER SHOT AT FOG TOMORROW NIGHT WITH CLEARING SKIES AND
SLIGHTLY INCREASING DEWPOINT TEMPS.

TERRY
&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KEAX 191153
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
653 AM CDT FRI SEP 19 2008

...UPDATED AVIATION...

.DISCUSSION...

/250 AM CDT FRI SEP 19 2008/
EARLY MORNING WV IMAGERY SHOWS TWO AREAS OF WEAK UPPER LEVEL
CIRCULATIONS...ONE OVER NWRN OKLAHOMA AND A SECOND OVER CNTRL
ARKANSAS. THESE FEATURES ARE ASSOCIATED WITH A BROAD...AND NEARLY
CUTOFF WEAKNESS IN THE CNTRL CONUS HEIGHT FIELD. CURRENTLY...THE
ONLY IMPACT WITH THIS CIRCULATION IS AN EXPANSIVE CIRRUS
SHIELD...WITH A MIDLEVEL DECK ONLY RELEGATED TO THE LOW CENTER OVER
ARKANSAS. PRIMARY LIMITING FACTOR TO PRECIPITIVE PROCESSES IS THE
LACK OF LOW AND MID LEVEL MOISTURE...AS SFC PRESSURE RIDGING HAS
TRAPPED QUALITY MOISTURE IN THE NRN GULF OF MEXICO. BOUNDARY LAYER
THETA-E WILL SLOWLY INCREASE THROUGH THE WEEKEND...LEADING TO
SLIGHTLY BETTER PRECIP CHANCES...HOWEVER LIKELY REMAINING CLOSELY
COLLOCATED WITH THE MIDLEVEL CIRCULATION AND WEAK CORE COLD ALOFT.
HAVE CONTINUED WITH SLGT CHANCE MENTION FOR SERN HALF OF THE CWA
DURING THE AFTERNOON HOURS FOR SPOTTY SHRA/TSTMS.

REGARDING TEMPERATURES...SEE LITTLE REASON TO DEVIATE FAR FROM
PERSISTENCE WITH RESPECT TO HIGH TEMPS THROUGH SATURDAY...WITH ONLY
A SLIGHT BUMP TO PERSISTENCE FOR LOW TEMPS. BOUNDARY LAYER WIND
SPEEDS AND TRAJECTORIES STILL DO NOT SUGGEST DEEP MECHANICAL
MIXING...AND ANY SMALL INCREASE IN H9 TEMPS SHOULD BE OFFSET
SOMEWHAT BY INCREASED HIGHER CLOUD COVER. HAVE CUT HIGHS FOR SUNDAY
JUST A BIT...AS INCREASED SFC MOISTURE ADVECTION ON ELY FLOW LOOKS
TO INCREASE CLOUD COVER ENOUGH TO MORE SIGNIFICANTLY HINDER
INSOLATION.

BY EARLY NEXT WEEK...CUTOFF SYSTEM IS FORECAST TO BECOME ABSORBED IN
THE MAIN NLY STREAM OFF THE ERN SEABOARD...WHILE MUCH STRONGER JET
ENERGY DIGS A MEAN TROUGH THROUGH THE NRN ROCKIES. AS A RESULT...SFC
LEE PRESSURE FALLS WILL COMMENCE BY MONDAY MORNING...BRINGING AN
INCREASED 30-40KT LLJ AXIS FROM THE SRN PLAINS TO UPPER
MIDWEST...GRADUALLY PULLING BETTER GULF MOISTURE NWD. TO A VARYING
EXTENT...ALL FORECAST MODELS INDICATE AGGRESSIVE THETA-E ADVECTION
AND ISENTROPIC LIFT MONDAY MORNING IN AN AREA RESEMBLING A NWD
RETREATING SFC WARM FRONT. WHILE THESE PROCESSES ARE FAVORED IN THIS
EVOLVING FLOW PATTERN...EXACT PLACEMENT OF PRECIP FIELDS THIS FAR IN
THE FUTURE REMAINS TENUOUS AT BEST...AND HAVE JUST INTRODUCED SLGT
CHANCE POPS FOR THE TIME BEING. OTHERWISE...A BETTER DEFINED COLD
FRONT AND FORCING ENTERS THE FORECAST AREA IN THE WED/THURS TIME
FRAME...AND WILL WAIT FOR MORE MODEL CONSISTENCY BEFORE INCREASING
POPS HERE.

21

&&

.AVIATION...

VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD. ONLY EXCEPTION
IS PSBL GROUND FOG WITH VSBY 1/2-1SM DURING THE EARLY MORNING HOURS
AT STJ.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.

$$

000
FXUS63 KLSX 191144
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
644 AM CDT FRI SEP 19 2008

.DISCUSSION...
/407 AM CDT FRI SEP 19 2008/
MID AND HIGH CLOUDS CONTINUE TO STREAM NORTHWARD ACROSS REGION AHEAD
OF UPPER LOW THAT IS CURRENTLY OVER WESTERN ARKANSAS. SO IN THE
SHORT TERM...THE MAIN FORECAST ISSUE IS THIS UPPER LOW AND HOW IT
WILL AFFECT THE WEATHER FOR THIS WEEKEND.

MODEL GUIDANCE CONTINUES TO BE IN FAIRLY GOOD AGREEMENT ON MID AND
UPPER LEVEL MOISTURE INCREASING ACROSS THE FORECAST AREA TODAY AS
THE UPPER LOW EDGES NORTHEAST. BY SATURDAY MORNING THE UPPER LOW
SHOULD BE PARKED DIRECTLY OVER THE OZARKS AND REMAIN NEARLY
STATIONARY THROUGH THE WEEKEND.

LOW LEVEL MOISTURE FOR THIS UPPER LEVEL DISTURBANCE REMAINS IN
QUESTION. HOWEVER...THE GFS HAS NOW COME IN LINE WITH THE OTHER
MODELS AND PRODUCES SOME QPF OVER THE REGION FOR SATURDAY AND
SUNDAY. SO HAVE LOW CHANCE POPS FAR SOUTH TONIGHT AND FOR MOST OF
THE AREA ON SATURDAY. RAIN CHANCES LET UP A LITTLE SATURDAY
NIGHT...THEN SEE ADDITIONAL DEVELOPMENT ON SUNDAY...THOUGH NOT REAL
CONFIDENT ON MOISTURE THAT DAY...SO KEPT SILENT 20 POPS IN FOR NOW.
THEN UPPER LEVEL SYSTEM WEAKENS AND EXITS THE REGION BY THE
BEGINNING OF THE WORK WEEK. BEYOND THAT...NO MAJOR CHANGES TO THE
FORECAST.

ON THE TEMPERATURE FRONT...HAVE LOWERED TEMPS IN THE WEST A DEGREE
OR SO TODAY DUE TO AN INCREASE IN THE MID AND HIGH CLOUDS. SAME GOES
FOR SATURDAY DUE TO CLOUDS AND PRECIPITATION...WITH COOLEST TEMPS IN
THE SOUTHERN SECTIONS OF THE FORECAST AREA. ALSO...LOWERED HIGHS ON
SUNDAY A FEW DEGREES. OTHERWISE...ONLY MINOR ADJUSTMENTS MADE BEYOND
SUNDAY.

BYRD

&&

.AVIATION...
/640 AM CDT FRI SEP 19 2008/
FOR THE 12Z TAFS...
FOG PERSISTS AT KSUS AT THIS TIME WITH THE OTHER TAF SITES VFR.
EXPECT THE FOG TO DISSIPATE BY 13Z WITH VFR WEATHER THEN EXPECTED
THROUGH TONIGHT. UPPER LOW IS FORECAST TO MOVE INTO SOUTHERN MO
THIS EVENING. SYSTEM WILL KEEP WIDESPREAD HIGH CLOUDS ABOVE 10K
FEET ACROSS THE AREA THROUGH TONIGHT.

TPS
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KSGF 191134
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
634 AM CDT FRI SEP 19 2008

.DISCUSSION...

THE FORECAST CHALLENGE IS RAIN CHANCES ASSOCIATED WITH AN UPPER
LEVEL LOW THAT WILL TRACK THROUGH THE SOUTHERN PLAINS INTO THE
OZARKS. WATER VAPOR IMAGERY AND THE WIND PROFILER NETWORK DEPICT
A WEAK UPPER LEVEL LOW OVER SOUTHWEST KANSAS. AHEAD OF THIS
LOW...MID AND HIGH CLOUDS HAVE SPREAD OVER THE OZARKS.
OVERNIGHT....TEMPERATURES HAVE FALLEN TO THE UPPER 50S AND LOWER
60S WITH DEWPOINTS IN THE MIDDLE AND UPPER 50S WITH A WEAK
SOUTHEAST WIND.

GFS/ECMWF/NAM/UKMET ALL PROG THIS UPPER LEVEL LOW MOVING INTO THE
OZARKS TONIGHT. THIS LOW WILL BE SLOW TO MOVE THROUGH THE REGION
OVER THE WEEKEND WITH THE FEATURE CUTOFF FROM THE MAIN BELT OF
WESTERLIES TO THE NORTH. MOISTURE WILL BE LIMITED INITIALLY WITH
THE 00Z KSGF SOUNDING DEPICTING A SIGNIFICANT DRY LAYER ABOVE
800MB. ISENTROPIC UPGLIDE WILL INCREASE THROUGH THE WEEKEND
ALONG THE 305K SURFACE WHICH WILL BRING CHANCES FOR SCATTERED
LIGHT RAIN SHOWERS. THE BEST RAIN CHANCES LOOK TO BE EAST OF THE
HIGHWAY 65 CORRIDOR WHERE THE STRONGEST LIFT IS EXPECTED WITH THE
LOW. AN ISOLATED THUNDERSTORM CAN NOT BE RULED OUT BUT
INSTABILITY WILL BE LIMITED. BELOW NORMAL HIGH TEMPERATURES WILL
BE POSSIBLE SATURDAY ACROSS SOUTH CENTRAL MISSOURI DUE TO
EXTENSIVE CLOUD COVER AND SCATTERED SHOWERS.

DRY AND WARMER WEATHER RETURN EARLY NEXT WEEK AS AN UPPER LEVEL
RIDGE BUILDS INTO THE CENTRAL CONUS. MODELS DEPICT A COLD FRONT
MOVING THROUGH THE PLAINS WEDNESDAY AND THURSDAY ASSOCIATED WITH
AN UPPER LEVEL TROUGH AND HEIGHT FALLS ACROSS THE NORTHERN
PLAINS. THIS FRONT COULD BRING ADDITIONAL CHANCES FOR SHOWERS AND
THUNDERSTORMS TO THE OZARKS LATE IN THE WEEK.

ANGLE


&&

.AVIATION...

VFR CONDITIONS WILL BE THE RULE AT THE SPRINGFIED AND JOPLIN
TERMINALS THROUGH TONIGHT. A VEIL OF HIGH CLOUDINESS WILL AFFECT
MUCH OF THE REGION AS AN UPPER LEVEL LOW PRESSURE MOVES SLOWLY
ACROSS THE REGION. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 5
TO 10 KTS.

FOSTER


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KLSX 190909
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
409 AM CDT FRI SEP 19 2008

.DISCUSSION...
/407 AM CDT FRI SEP 19 2008/
MID AND HIGH CLOUDS CONTINUE TO STREAM NORTHWARD ACROSS REGION AHEAD
OF UPPER LOW THAT IS CURRENTLY OVER WESTERN ARKANSAS. SO IN THE
SHORT TERM...THE MAIN FORECAST ISSUE IS THIS UPPER LOW AND HOW IT
WILL AFFECT THE WEATHER FOR THIS WEEKEND.

MODEL GUIDANCE CONTINUES TO BE IN FAIRLY GOOD AGREEMENT ON MID AND
UPPER LEVEL MOISTURE INCREASING ACROSS THE FORECAST AREA TODAY AS
THE UPPER LOW EDGES NORTHEAST. BY SATURDAY MORNING THE UPPER LOW
SHOULD BE PARKED DIRECTLY OVER THE OZARKS AND REMAIN NEARLY
STATIONARY THROUGH THE WEEKEND.

LOW LEVEL MOISTURE FOR THIS UPPER LEVEL DISTURBANCE REMAINS IN
QUESTION. HOWEVER...THE GFS HAS NOW COME IN LINE WITH THE OTHER
MODELS AND PRODUCES SOME QPF OVER THE REGION FOR SATURDAY AND
SUNDAY. SO HAVE LOW CHANCE POPS FAR SOUTH TONIGHT AND FOR MOST OF
THE AREA ON SATURDAY. RAIN CHANCES LET UP A LITTLE SATURDAY
NIGHT...THEN SEE ADDITIONAL DEVELOPMENT ON SUNDAY...THOUGH NOT REAL
CONFIDENT ON MOISTURE THAT DAY...SO KEPT SILENT 20 POPS IN FOR NOW.
THEN UPPER LEVEL SYSTEM WEAKENS AND EXITS THE REGION BY THE
BEGINNING OF THE WORK WEEK. BEYOND THAT...NO MAJOR CHANGES TO THE
FORECAST.

ON THE TEMPERATURE FRONT...HAVE LOWERED TEMPS IN THE WEST A DEGREE
OR SO TODAY DUE TO AN INCREASE IN THE MID AND HIGH CLOUDS. SAME GOES
FOR SATURDAY DUE TO CLOUDS AND PRECIPITATION...WITH COOLEST TEMPS IN
THE SOUTHERN SECTIONS OF THE FORECAST AREA. ALSO...LOWERED HIGHS ON
SUNDAY A FEW DEGREES. OTHERWISE...ONLY MINOR ADJUSTMENTS MADE BEYOND
SUNDAY.

BYRD
&&

.AVIATION...
/1105 PM CDT THU SEP 18 2008/
FOR THE 06Z TAFS...LGT SFC WNDS LT TGT ON THE WRN PERIPHERY OF THE
SFC RDG EXTDG FM MI SW THRU NERN MO ATTM. SFC WNDS SHOULD BE
MAINLY SELY ON FRI AND RELATIVELY WK. CIRRUS CLOUDS WILL CONT TO
STREAM NEWD THRU THE CWA LT TGT AHD OF A MID-UPR LVL LOW CURRENTLY
OVER NERN TX. WILL KEEP FOG IN ALL THE TAF FCSTS EXCEPT STL FOR LT
TGT AND EARLY FRI MRNG. CIRRUS CLOUDS MAY LIMIT RADIATIONAL
COOLING SLIGHTLY LT TGT SO THE VSBYS MAY NOT BE QUITE AS LOW AS
THEY WERE EARLY THU MRNG. THE LOWEST VSBYS SHOULD OCCUR AT SUS NR
THE RVR VALLEY...WITH AT LEAST LGT FOG IN COU AND POSSIBLY ALSO AT
UIN ALTHOUGH UIN STILL HAD A PRETTY GOOD TEMP/DWPT SPREAD ATTM
SIMILAR TO STL. SHOULD BE MAINLY CIRRUS CLOUDS ON FRI WITH A FEW
DAYTIME CUMULUS POSSIBLE. IT APRS THAT THE PCPN SHOULD REMAIN S OF
THE TAF SITES AT LEAST THRU FRI.

GKS
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$
WFO LSX

000
FXUS63 KSGF 190819
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
319 AM CDT FRI SEP 19 2008

.DISCUSSION...

THE FORECAST CHALLENGE IS RAIN CHANCES ASSOCIATED WITH AN UPPER
LEVEL LOW THAT WILL TRACK THROUGH THE SOUTHERN PLAINS INTO THE
OZARKS. WATER VAPOR IMAGERY AND THE WIND PROFILER NETWORK DEPICT
A WEAK UPPER LEVEL LOW OVER SOUTHWEST KANSAS. AHEAD OF THIS
LOW...MID AND HIGH CLOUDS HAVE SPREAD OVER THE OZARKS.
OVERNIGHT....TEMPERATURES HAVE FALLEN TO THE UPPER 50S AND LOWER
60S WITH DEWPOINTS IN THE MIDDLE AND UPPER 50S WITH A WEAK
SOUTHEAST WIND.

GFS/ECMWF/NAM/UKMET ALL PROG THIS UPPER LEVEL LOW MOVING INTO THE
OZARKS TONIGHT. THIS LOW WILL BE SLOW TO MOVE THROUGH THE REGION
OVER THE WEEKEND WITH THE FEATURE CUTOFF FROM THE MAIN BELT OF
WESTERLIES TO THE NORTH. MOISTURE WILL BE LIMITED INITIALLY WITH
THE 00Z KSGF SOUNDING DEPICTING A SIGNIFICANT DRY LAYER ABOVE
800MB. ISENTROPIC UPGLIDE WILL INCREASE THROUGH THE WEEKEND
ALONG THE 305K SURFACE WHICH WILL BRING CHANCES FOR SCATTERED
LIGHT RAIN SHOWERS. THE BEST RAIN CHANCES LOOK TO BE EAST OF THE
HIGHWAY 65 CORRIDOR WHERE THE STRONGEST LIFT IS EXPECTED WITH THE
LOW. AN ISOLATED THUNDERSTORM CAN NOT BE RULED OUT BUT
INSTABILITY WILL BE LIMITED. BELOW NORMAL HIGH TEMPERATURES WILL
BE POSSIBLE SATURDAY ACROSS SOUTH CENTRAL MISSOURI DUE TO
EXTENSIVE CLOUD COVER AND SCATTERED SHOWERS.

DRY AND WARMER WEATHER RETURN EARLY NEXT WEEK AS AN UPPER LEVEL
RIDGE BUILDS INTO THE CENTRAL CONUS. MODELS DEPICT A COLD FRONT
MOVING THROUGH THE PLAINS WEDNESDAY AND THURSDAY ASSOCIATED WITH
AN UPPER LEVEL TROUGH AND HEIGHT FALLS ACROSS THE NORTHERN
PLAINS. THIS FRONT COULD BRING ADDITIONAL CHANCES FOR SHOWERS AND
THUNDERSTORMS TO THE OZARKS LATE IN THE WEEK.

ANGLE

&&

.AVIATION...

FOR THE 06Z TAFS...FOR THE MOST PART HAVE GONE VFR FOR THE
FORECAST. ONLY CAVEAT...JLN CURRENTLY AS OF 05Z AT 6SM BR AND HAVE
GONE WITH SOME MVFR VISIBILITIES OVERNIGHT THERE. CLOUDS SHOULD
REMAIN FAIRLY HIGH LEVEL AND COULD SEE SOME CUMULUS DEVELOP DURING
THE AFTERNOON HOURS ON FRIDAY.

LINDENBERG


&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KEAX 190751
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
250 AM CDT FRI SEP 19 2008

.DISCUSSION...

EARLY MORNING WV IMAGERY SHOWS TWO AREAS OF WEAK UPPER LEVEL
CIRCULATIONS...ONE OVER NWRN OKLAHOMA AND A SECOND OVER CNTRL
ARKANSAS. THESE FEATURES ARE ASSOCIATED WITH A BROAD...AND NEARLY
CUTOFF WEAKNESS IN THE CNTRL CONUS HEIGHT FIELD. CURRENTLY...THE
ONLY IMPACT WITH THIS CIRCULATION IS AN EXPANSIVE CIRRUS
SHIELD...WITH A MIDLEVEL DECK ONLY RELEGATED TO THE LOW CENTER OVER
ARKANSAS. PRIMARY LIMITING FACTOR TO PRECIPITIVE PROCESSES IS THE
LACK OF LOW AND MID LEVEL MOISTURE...AS SFC PRESSURE RIDGING HAS
TRAPPED QUALITY MOISTURE IN THE NRN GULF OF MEXICO. BOUNDARY LAYER
THETA-E WILL SLOWLY INCREASE THROUGH THE WEEKEND...LEADING TO
SLIGHTLY BETTER PRECIP CHANCES...HOWEVER LIKELY REMAINING CLOSELY
COLLOCATED WITH THE MIDLEVEL CIRCULATION AND WEAK CORE COLD ALOFT.
HAVE CONTINUED WITH SLGT CHANCE MENTION FOR SERN HALF OF THE CWA
DURING THE AFTERNOON HOURS FOR SPOTTY SHRA/TSTMS.

REGARDING TEMPERATURES...SEE LITTLE REASON TO DEVIATE FAR FROM
PERSISTENCE WITH RESPECT TO HIGH TEMPS THROUGH SATURDAY...WITH ONLY
A SLIGHT BUMP TO PERSISTENCE FOR LOW TEMPS. BOUNDARY LAYER WIND
SPEEDS AND TRAJECTORIES STILL DO NOT SUGGEST DEEP MECHANICAL
MIXING...AND ANY SMALL INCREASE IN H9 TEMPS SHOULD BE OFFSET
SOMEWHAT BY INCREASED HIGHER CLOUD COVER. HAVE CUT HIGHS FOR SUNDAY
JUST A BIT...AS INCREASED SFC MOISTURE ADVECTION ON ELY FLOW LOOKS
TO INCREASE CLOUD COVER ENOUGH TO MORE SIGNIFICANTLY HINDER
INSOLATION.

BY EARLY NEXT WEEK...CUTOFF SYSTEM IS FORECAST TO BECOME ABSORBED IN
THE MAIN NLY STREAM OFF THE ERN SEABOARD...WHILE MUCH STRONGER JET
ENERGY DIGS A MEAN TROUGH THROUGH THE NRN ROCKIES. AS A RESULT...SFC
LEE PRESSURE FALLS WILL COMMENCE BY MONDAY MORNING...BRINGING AN
INCREASED 30-40KT LLJ AXIS FROM THE SRN PLAINS TO UPPER
MIDWEST...GRADUALLY PULLING BETTER GULF MOISTURE NWD. TO A VARYING
EXTENT...ALL FORECAST MODELS INDICATE AGGRESSIVE THETA-E ADVECTION
AND ISENTROPIC LIFT MONDAY MORNING IN AN AREA RESEMBLING A NWD
RETREATING SFC WARM FRONT. WHILE THESE PROCESSES ARE FAVORED IN THIS
EVOLVING FLOW PATTERN...EXACT PLACEMENT OF PRECIP FIELDS THIS FAR IN
THE FUTURE REMAINS TENUOUS AT BEST...AND HAVE JUST INTRODUCED SLGT
CHANCE POPS FOR THE TIME BEING. OTHERWISE...A BETTER DEFINED COLD
FRONT AND FORCING ENTERS THE FORECAST AREA IN THE WED/THURS TIME
FRAME...AND WILL WAIT FOR MORE MODEL CONSISTENCY BEFORE INCREASING
POPS HERE.

21

&&

.AVIATION...

FOR THE 00Z TAFS...PATCHY/BROKEN CIRRUS WILL OVERSPREAD THE AREA
THIS EVENING AHEAD OF A WEAK UPPER LOW CENTERED OVER SW KANSAS. THIS
REALLY IS THE ONLY HINDRANCE TO AN OTHERWISE CONTINUATION OF VFR
CONDITIONS EXPECTED ACROSS THE KANSAS CITY TERMINALS THROUGH THE
PERIOD. WINDS WILL BE LIGHT FROM THE SOUTH TO SOUTHEAST.

DESPITE SOME CIRRUS...DO NOT THINK IT WILL BE ENOUGH TO PREVENT THE
REDEVELOPMENT OF STEAM FOG AT KSTJ ONCE AGAIN. SO BANKING ON FOUR
NIGHTS OF PERSISTENCE...WILL CONTINUE WITH VSBY 1/2-2SM DURING THE
PREDAWN HOURS TO JUST AFTER SUNRISE.

BOOKBINDER

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.

$$

000
FXUS63 KSGF 190441
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1141 PM CDT THU SEP 18 2008

...UPDATE TO AVIATION...

.DISCUSSION...

COMFORTABLE WEATHER WAS OBSERVED ACROSS THE REGION TODAY.  SUNSHINE
WAS PLENTIFUL WHILE SOUTHERLY BREEZES RANGED FROM 5 TO 15 MPH...AND
AFTERNOON TEMPERATURES WERE GENERALLY IN THE 70S.  THESE BENIGN
CONDITIONS RESULTED FROM A DOME OF HIGH PRESSURE
OVERHEAD...ANCHORING A CANADIAN AIRMASS OVER MUCH OF THE STATE OF
MISSOURI.

FURTHER WEST...AN UPPER LEVEL LOW WAS PROGRESSING ACROSS SOUTHWEST
KANSAS.  THIS FEATURE MAY PROVIDE THE REGION WITH SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS AS WE HEAD INTO THE WEEKEND.  AS A MATTER
OF FACT...A FEW SHOWERS WILL BE POSSIBLE AS EARLY AS FRIDAY
AFTERNOON. POINT FORECAST SOUNDINGS INDICATE AN UNCAPPED AIRMASS
WITH MODEST INSTABILITY DEVELOPING.  FORCING WILL BE AIDED BY THE
RISES IN POTENTIAL TEMPERATURE SURFACES AS THE UPPER COLD CORE
APPROACHES.

MOISTURE LEVELS WILL REMAIN LOW THROUGH THE WEEKEND...THEREFORE LOOK
FOR SHOWERS TO BE SCATTERED IN NATURE...AND OCCUR MOSTLY DURING THE
DAYTIME HOURS.  SATURDAY AND SUNDAY AFTERNOONS WILL ALSO BE
FAVORABLE FOR SCATTERED SHOWERS.  LOW INSTABILITY AND SHEAR WILL
LIMIT THUNDERSTORM INTENSITIES BELOW SEVERE LIMITS.  GIVEN THE
SCATTERED AND ISOLATED NATURE OF THESE SHOWERS...SOME LOCATIONS WILL
REMAIN DRY THROUGH THE WEEKEND.

HEADING INTO NEXT WORK WEEK...A WARMING TREND WILL BE UNDERWAY AS
UPPER RIDGING BUILDS OVER THE NATIONS MID SECTION.  DRY CONDITIONS
WITH TEMPERATURES IN THE 80S ARE A GOOD BET THROUGH WEDNESDAY.  BOTH
THE ECMWF AND GFS INDICATE A FRONT IMPACTING THE CWA BY WEDNESDAY
NIGHT INTO THURSDAY.  THIS FRONTAL SYSTEM COULD PROVIDE THE AREA
WITH A GLANCING BLOW OF SHOWERS AND THUNDERSTORMS.

CRAMER


&&

.AVIATION...

FOR THE 06Z TAFS...FOR THE MOST PART HAVE GONE VFR FOR THE
FORECAST. ONLY CAVEAT...JLN CURRENTLY AS OF 05Z AT 6SM BR AND HAVE
GONE WITH SOME MVFR VISIBILITIES OVERNIGHT THERE. CLOUDS SHOULD
REMAIN FAIRLY HIGH LEVEL AND COULD SEE SOME CUMULUS DEVELOP DURING
THE AFTERNOON HOURS ON FRIDAY.

LINDENBERG

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KLSX 190420
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1120 PM CDT THU SEP 18 2008

.DISCUSSION...
/116 PM CDT THU SEP 18 2008/
THE FOCUS FOR THIS AFTERNOONS FORECAST DISCUSSION IS THE UPPER LOW
CURRENTLY SPINNING ACROSS THE CENTRAL PLAINS AND ITS EVENTUAL IMPACT
ON SENSIBLE WEATHER ACROSS THE FORECAST AREA THIS WEEKEND.

MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON MID AND UPPER LEVEL
MOISTURE INCREASING ACROSS THE FORECAST AREA TOMORROW AS THE UPPER
LOW EDGES EAST. BY SATURDAY MORNING THE UPPER LOW SHOULD BE PARKED
DIRECTLY OVER THE OZARKS AND REMAIN NEARLY STATIONARY THROUGH THE
WEEKEND.

AS ELUDED TO IN THE PREVIOUS DISCUSSION...LOW LEVEL MOISTURE FOR
THIS UPPER LEVEL DISTURBANCE IS IN QUESTION. THE GFS IS MUCH DRIER
WHEN COMPARED TO THE OTHER MODELS AND THEREFORE DOESN`T PRODUCE MUCH
IN THE WAY OF QPF THIS WEEKEND. IN STARK CONTRAST THE ECWMF...WHOSE
PERFORMANCE HAS BEEN STELLAR THESE PAST FEW WEEKS...CONTINUES TO
PRINT OUT QPF ACROSS THE FORECAST AREA BOTH SATURDAY AND SUNDAY.

ASSUMING THAT THERE WILL BE AT LEAST LOWER 60 DEWPOINTS IN THE AREA
AS THE ECWMF SUGGESTS AND CURRENT OBSERVATIONS SUPPORT...MODEL
SOUNDINGS SUGGEST THAT THERE COULD BE AS MUCH AS 1000 J/KG OF
SURFACE BASED CAPE SATURDAY AND SUNDAY AFTERNOON UNDERNEATH THE
UPPER LEVEL LOW.

I BELIEVE IT IS PRUDENT AT THIS TIME TO INCREASE CLOUD COVER ACROSS
THE BOARD AND ADD CHANCES FOR SHOWERS/THUNDERSTORMS TO THE
SOUTHWESTERN HALF OF THE FORECAST AREA ON SATURDAY. I AM LIMITED TO
SLIGHT CHANCES OF PRECIPITATION SUNDAY DUE TO COLLABORATION
LIMITS...BUT I WOULD NOT BE SURPRISED TO SEE SCATTERED COVERAGE OF
CONVECTION BOTH DAYS THIS WEEKEND UNDERNEATH THE UPPER LOW. BY NO
MEANS DO I THINK IT WILL BE A RAIN OUT...BUT CERTAINLY DIFFERENT
THAN WHAT WE HAVE BEEN ADVERTISING UP TO THIS POINT.

ANOTHER PERIOD OF DRY WEATHER IS EXPECTED MONDAY THROUGH THE MIDDLE
OF NEXT WEEK AS THE UPPER LOW FINALLY PULLS EAST AND HEIGHTS BEGIN
TO RISE. A SMALL WARMING TREND IN TEMPERATURES IS EXPECTED EACH DAY
WITH THE NEXT CHANCE OF PRECIPITATION ARRIVING BY THE END OF NEXT
WEEK. TIMING DIFFERENCES WITH THE COLD FRONT ARE STILL AN
ISSUE...SO THE EXTENDED FORECAST REMAINS DRY FOR NOW.

CVKING

&&

.AVIATION...
/1105 PM CDT THU SEP 18 2008/
FOR THE 06Z TAFS...LGT SFC WNDS LT TGT ON THE WRN PERIPHERY OF THE
SFC RDG EXTDG FM MI SW THRU NERN MO ATTM. SFC WNDS SHOULD BE
MAINLY SELY ON FRI AND RELATIVELY WK. CIRRUS CLOUDS WILL CONT TO
STREAM NEWD THRU THE CWA LT TGT AHD OF A MID-UPR LVL LOW CURRENTLY
OVER NERN TX. WILL KEEP FOG IN ALL THE TAF FCSTS EXCEPT STL FOR LT
TGT AND EARLY FRI MRNG. CIRRUS CLOUDS MAY LIMIT RADIATIONAL
COOLING SLIGHTLY LT TGT SO THE VSBYS MAY NOT BE QUITE AS LOW AS
THEY WERE EARLY THU MRNG. THE LOWEST VSBYS SHOULD OCCUR AT SUS NR
THE RVR VALLEY...WITH AT LEAST LGT FOG IN COU AND POSSIBLY ALSO AT
UIN ALTHOUGH UIN STILL HAD A PRETTY GOOD TEMP/DWPT SPREAD ATTM
SIMILAR TO STL. SHOULD BE MAINLY CIRRUS CLOUDS ON FRI WITH A FEW
DAYTIME CUMULUS POSSIBLE. IT APRS THAT THE PCPN SHOULD REMAIN S OF
THE TAF SITES AT LEAST THRU FRI.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KEAX 182358
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
655 PM CDT THU SEP 18 2008

...UPDATED AVIATION DISCUSSION...

.DISCUSSION...
/ISSUED 352 PM CDT THU SEP 18 2008/
SEASONAL TEMPERATURES ARE ON TAP FOR THE REGION WITH A GRADUAL
RETURN OF PRECIPITATION CHANCES TO THE FORECAST.

WATER VAPOR IMAGERY ACROSS THE CONUS SHOWS A RATHER DIRTY NORTHWEST
FLOW PREVAILING OVER THE CENTRAL PLAINS. THIS WILL ADJUST TO THE
SOUTHWEST OVER THE WEEKEND AS THE WEST CONUS RIDGE MOVES EAST MAKING
ROOM FOR A WEST CONUS TROUGH. OF NOTE FOR THE NEXT FEW DAYS WILL BE
A WEAK UPPER LEVEL LOW WHIRLING THROUGH THE PANHANDLES OF TEXAS AND
OKLAHOMA...AND A SHORTWAVE MOVING EAST INTO THE PACIFIC NORTHWEST.
CLOSER TO THE SURFACE...MODEST MOISTURE RETURN IS NOTED MOVING NORTH
THROUGH THE SOUTHERN PLAINS AS 60 DEGREE DEW POINTS HAVE TOWARDS THE
RED RIVER VALLEY AND A DIURNAL CU FIELD IS NOTED ON SATELLITE
IMAGERY.

THE UPPER LEVEL LOW OVER THE PAN-HANDLES WILL CONTINUE TO MOVE EAST
NORTHEAST OVER THE NEXT COUPLE OF DAYS...EVENTUALLY MOVING THROUGH
SOUTHERN MISSOURI SATURDAY. MODEL SOUNDING INDICATE THAT WHILE LAPSE
RATES WILL STEEPEN AS THE LOW MOVES IN...MOISTURE WILL STILL BE A
LITTLE SPARSE. DID ADD SLIGHT CHANCE POPS TO THE SOUTHERN HALF OT HE
CWA FOR SATURDAY THOUGH...ALONG WITH INCREASING THE CLOUD COVER.

NEXT POTENTIAL SHOT AT CONVECTION WILL FOLLOW QUICKLY SUNDAY AS THE
PACIFIC NORTHWEST TROUGH SWINGS NORTHEAST THROUGH THE NORTHERN
PLAINS. MOISTURE WILL HAVE HAD A BIT MORE TIME TO MOVE NORTH...BUT
EXPECTATIONS ARE THAT BEST CHANCE FOR ACTIVITY WILL BE LOCATED
CLOSER TO THE UPPER LEVEL DYNAMICS TO OUR WEST AND NORTH.
STILL...INCLUDED A SILENT SLIGHT CHANCE POP FOR SUNDAY DUE TO
POTENTIAL WARM AIR ADVECTION ACTIVITY WHICH WILL BE ADVECTING IN
HIGHER VALUE THETA-E AIR DURING THE AFTERNOON PEEK HEATING HOURS.

LOOKING INTO THE NEXT WORK WEEK...THIS WEEKENDS PACIFIC NORTHWEST
SHORTWAVE WILL HERALD THE ARRIVAL OF A MORE TRADITIONAL PROGRESSIVE
WEST TO EAST MOVING TROUGH. OPERATIONAL GFS AND ECMWF HAD BEEN IN
FAIR AGREEMENT ON THE PROGRESSION OF THE TROUGH THROUGH THE CONUS IN
PREVIOUS RUNS...BUT THE LATEST SOLUTIONS ARE DIVERGING AS THE ECMWF
DEAMPLIFY`S THE TROUGH SOME AND WEAKENS THE ASSOCIATED SURFACE
FRONT. HOWEVER...PREFERENCE IS FOR NEITHER AND INSTEAD WITH THE
ENSEMBLE GFS WHICH IS MUCH SLOWER WITH THE TROUGH AND FRONTS
PROGRESS THROUGH THE PLAINS. HAVE SKEWED THE FORECAST IN THAT
DIRECTION AS A RESULT BY GOING WITH CHANCE POPS ARE RESTRICTED TO
THE IOWA BORDER REGION FOR THE WEDNESDAY THROUGH THURSDAY TIME
PERIOD FOR THE ASSOCIATED PRECIPITATION CHANCE IN THE PRE-FRONTAL
AND FRONTAL ENVIRONMENTS.

OTHERWISE...ONLY MODEST ADJUSTMENTS WERE MADE TO THE REST OF THE
GOING FORECAST PARAMETERS.

CUTTER

&&

.AVIATION...

FOR THE 00Z TAFS...PATCHY/BROKEN CIRRUS WILL OVERSPREAD THE AREA
THIS EVENING AHEAD OF A WEAK UPPER LOW CENTERED OVER SW KANSAS. THIS
REALLY IS THE ONLY HINDRANCE TO AN OTHERWISE CONTINUATION OF VFR
CONDITIONS EXPECTED ACROSS THE KANSAS CITY TERMINALS THROUGH THE
PERIOD. WINDS WILL BE LIGHT FROM THE SOUTH TO SOUTHEAST.

DESPITE SOME CIRRUS...DO NOT THINK IT WILL BE ENOUGH TO PREVENT THE
REDEVELOPMENT OF STEAM FOG AT KSTJ ONCE AGAIN. SO BANKING ON FOUR
NIGHTS OF PERSISTENCE...WILL CONTINUE WITH VSBY 1/2-2SM DURING THE
PREDAWN HOURS TO JUST AFTER SUNRISE.

BOOKBINDER

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.

$$

000
FXUS63 KLSX 182344
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
644 PM CDT THU SEP 18 2008

.DISCUSSION...
/116 PM CDT THU SEP 18 2008/
THE FOCUS FOR THIS AFTERNOONS FORECAST DISCUSSION IS THE UPPER LOW
CURRENTLY SPINNING ACROSS THE CENTRAL PLAINS AND ITS EVENTUAL IMPACT
ON SENSIBLE WEATHER ACROSS THE FORECAST AREA THIS WEEKEND.

MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON MID AND UPPER LEVEL
MOISTURE INCREASING ACROSS THE FORECAST AREA TOMORROW AS THE UPPER
LOW EDGES EAST. BY SATURDAY MORNING THE UPPER LOW SHOULD BE PARKED
DIRECTLY OVER THE OZARKS AND REMAIN NEARLY STATIONARY THROUGH THE
WEEKEND.

AS ELUDED TO IN THE PREVIOUS DISCUSSION...LOW LEVEL MOISTURE FOR
THIS UPPER LEVEL DISTURBANCE IS IN QUESTION. THE GFS IS MUCH DRIER
WHEN COMPARED TO THE OTHER MODELS AND THEREFORE DOESN`T PRODUCE MUCH
IN THE WAY OF QPF THIS WEEKEND. IN STARK CONTRAST THE ECWMF...WHOSE
PERFORMANCE HAS BEEN STELLAR THESE PAST FEW WEEKS...CONTINUES TO
PRINT OUT QPF ACROSS THE FORECAST AREA BOTH SATURDAY AND SUNDAY.

ASSUMING THAT THERE WILL BE AT LEAST LOWER 60 DEWPOINTS IN THE AREA
AS THE ECWMF SUGGESTS AND CURRENT OBSERVATIONS SUPPORT...MODEL
SOUNDINGS SUGGEST THAT THERE COULD BE AS MUCH AS 1000 J/KG OF
SURFACE BASED CAPE SATURDAY AND SUNDAY AFTERNOON UNDERNEATH THE
UPPER LEVEL LOW.

I BELIEVE IT IS PRUDENT AT THIS TIME TO INCREASE CLOUD COVER ACROSS
THE BOARD AND ADD CHANCES FOR SHOWERS/THUNDERSTORMS TO THE
SOUTHWESTERN HALF OF THE FORECAST AREA ON SATURDAY. I AM LIMITED TO
SLIGHT CHANCES OF PRECIPITATION SUNDAY DUE TO COLLABORATION
LIMITS...BUT I WOULD NOT BE SURPRISED TO SEE SCATTERED COVERAGE OF
CONVECTION BOTH DAYS THIS WEEKEND UNDERNEATH THE UPPER LOW. BY NO
MEANS DO I THINK IT WILL BE A RAIN OUT...BUT CERTAINLY DIFFERENT
THAN WHAT WE HAVE BEEN ADVERTISING UP TO THIS POINT.

ANOTHER PERIOD OF DRY WEATHER IS EXPECTED MONDAY THROUGH THE MIDDLE
OF NEXT WEEK AS THE UPPER LOW FINALLY PULLS EAST AND HEIGHTS BEGIN
TO RISE. A SMALL WARMING TREND IN TEMPERATURES IS EXPECTED EACH DAY
WITH THE NEXT CHANCE OF PRECIPITATION ARRIVING BY THE END OF NEXT
WEEK. TIMING DIFFERENCES WITH THE COLD FRONT ARE STILL AN
ISSUE...SO THE EXTENDED FORECAST REMAINS DRY FOR NOW.

CVKING

&&

.AVIATION...
/627 PM CDT THU SEP 18 2008/
FOR THE 00Z TAFS...LGT SFC WNDS TGT ON THE WRN PERIPHERY OF THE
SFC RDG EXTDG FM MI SW THRU NERN MO ATTM. SFC WNDS SHOULD BE
MAINLY SELY ON FRI AND RELATIVELY WK. CIRRUS CLOUDS WILL CONT TO
STREAM NEWD THRU THE CWA TGT AHD OF UPR LVL LOW CURRENTLY OVER
NERN TX. WILL KEEP FOG IN THE ALL THE TAF FCSTS EXCEPT STL FOR LT
TGT AND EARLY FRI MRNG. CIRRUS CLOUDS MAY LIMIT RADIATIONAL COOLING
SLIGHTLY TGT SO THE VSBYS MAY NOT BE QUITE AS LOW AS THEY WERE THU
MRNG. THE LOWEST VSBYS SHOULD OCCUR AT SUS NR THE RVR VALLEY.

GKS

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KSGF 182256
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
556 PM CDT THU SEP 18 2008

...UPDATE TO AVIATION...

.DISCUSSION...

COMFORTABLE WEATHER WAS OBSERVED ACROSS THE REGION TODAY.  SUNSHINE
WAS PLENTIFUL WHILE SOUTHERLY BREEZES RANGED FROM 5 TO 15 MPH...AND
AFTERNOON TEMPERATURES WERE GENERALLY IN THE 70S.  THESE BENIGN
CONDITIONS RESULTED FROM A DOME OF HIGH PRESSURE
OVERHEAD...ANCHORING A CANADIAN AIRMASS OVER MUCH OF THE STATE OF
MISSOURI.

FURTHER WEST...AN UPPER LEVEL LOW WAS PROGRESSING ACROSS SOUTHWEST
KANSAS.  THIS FEATURE MAY PROVIDE THE REGION WITH SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS AS WE HEAD INTO THE WEEKEND.  AS A MATTER
OF FACT...A FEW SHOWERS WILL BE POSSIBLE AS EARLY AS FRIDAY
AFTERNOON. POINT FORECAST SOUNDINGS INDICATE AN UNCAPPED AIRMASS
WITH MODEST INSTABILITY DEVELOPING.  FORCING WILL BE AIDED BY THE
RISES IN POTENTIAL TEMPERATURE SURFACES AS THE UPPER COLD CORE
APPROACHES.

MOISTURE LEVELS WILL REMAIN LOW THROUGH THE WEEKEND...THEREFORE LOOK
FOR SHOWERS TO BE SCATTERED IN NATURE...AND OCCUR MOSTLY DURING THE
DAYTIME HOURS.  SATURDAY AND SUNDAY AFTERNOONS WILL ALSO BE
FAVORABLE FOR SCATTERED SHOWERS.  LOW INSTABILITY AND SHEAR WILL
LIMIT THUNDERSTORM INTENSITIES BELOW SEVERE LIMITS.  GIVEN THE
SCATTERED AND ISOLATED NATURE OF THESE SHOWERS...SOME LOCATIONS WILL
REMAIN DRY THROUGH THE WEEKEND.

HEADING INTO NEXT WORK WEEK...A WARMING TREND WILL BE UNDERWAY AS
UPPER RIDGING BUILDS OVER THE NATIONS MID SECTION.  DRY CONDITIONS
WITH TEMPERATURES IN THE 80S ARE A GOOD BET THROUGH WEDNESDAY.  BOTH
THE ECMWF AND GFS INDICATE A FRONT IMPACTING THE CWA BY WEDNESDAY
NIGHT INTO THURSDAY.  THIS FRONTAL SYSTEM COULD PROVIDE THE AREA
WITH A GLANCING BLOW OF SHOWERS AND THUNDERSTORMS.

CRAMER


&&

.AVIATION...

FOR THE 00Z TAFS...VFR CONDITIONS EXPECTED THROUGH THE PERIOD.
WILL SEE CONTINUED BROKEN HIGH LEVEL CEILINGS IN ADVANCE OF THE
UPPER LOW WHICH WILL TRACK INTO THE AREA ON FRIDAY.

LINDENBERG

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KEAX 182052
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
352 PM CDT THU SEP 18 2008


.DISCUSSION...

SEASONAL TEMPERATURES ARE ON TAP FOR THE REGION WITH A GRADUAL
RETURN OF PRECIPITATION CHANCES TO THE FORECAST.

WATER VAPOR IMAGERY ACROSS THE CONUS SHOWS A RATHER DIRTY NORTHWEST
FLOW PREVAILING OVER THE CENTRAL PLAINS. THIS WILL ADJUST TO THE
SOUTHWEST OVER THE WEEKEND AS THE WEST CONUS RIDGE MOVES EAST MAKING
ROOM FOR A WEST CONUS TROUGH. OF NOTE FOR THE NEXT FEW DAYS WILL BE
A WEAK UPPER LEVEL LOW WHIRLING THROUGH THE PANHANDLES OF TEXAS AND
OKLAHOMA...AND A SHORTWAVE MOVING EAST INTO THE PACIFIC NORTHWEST.
CLOSER TO THE SURFACE...MODEST MOISTURE RETURN IS NOTED MOVING NORTH
THROUGH THE SOUTHERN PLAINS AS 60 DEGREE DEW POINTS HAVE TOWARDS THE
RED RIVER VALLEY AND A DIURNAL CU FIELD IS NOTED ON SATELLITE
IMAGERY.

THE UPPER LEVEL LOW OVER THE PAN-HANDLES WILL CONTINUE TO MOVE EAST
NORTHEAST OVER THE NEXT COUPLE OF DAYS...EVENTUALLY MOVING THROUGH
SOUTHERN MISSOURI SATURDAY. MODEL SOUNDING INDICATE THAT WHILE LAPSE
RATES WILL STEEPEN AS THE LOW MOVES IN...MOISTURE WILL STILL BE A
LITTLE SPARSE. DID ADD SLIGHT CHANCE POPS TO THE SOUTHERN HALF OT HE
CWA FOR SATURDAY THOUGH...ALONG WITH INCREASING THE CLOUD COVER.

NEXT POTENTIAL SHOT AT CONVECTION WILL FOLLOW QUICKLY SUNDAY AS THE
PACIFIC NORTHWEST TROUGH SWINGS NORTHEAST THROUGH THE NORTHERN
PLAINS. MOISTURE WILL HAVE HAD A BIT MORE TIME TO MOVE NORTH...BUT
EXPECTATIONS ARE THAT BEST CHANCE FOR ACTIVITY WILL BE LOCATED
CLOSER TO THE UPPER LEVEL DYNAMICS TO OUR WEST AND NORTH.
STILL...INCLUDED A SILENT SLIGHT CHANCE POP FOR SUNDAY DUE TO
POTENTIAL WARM AIR ADVECTION ACTIVITY WHICH WILL BE ADVECTING IN
HIGHER VALUE THETA-E AIR DURING THE AFTERNOON PEEK HEATING HOURS.

LOOKING INTO THE NEXT WORK WEEK...THIS WEEKENDS PACIFIC NORTHWEST
SHORTWAVE WILL HERALD THE ARRIVAL OF A MORE TRADITIONAL PROGRESSIVE
WEST TO EAST MOVING TROUGH. OPERATIONAL GFS AND ECMWF HAD BEEN IN
FAIR AGREEMENT ON THE PROGRESSION OF THE TROUGH THROUGH THE CONUS IN
PREVIOUS RUNS...BUT THE LATEST SOLUTIONS ARE DIVERGING AS THE ECMWF
DEAMPLIFY`S THE TROUGH SOME AND WEAKENS THE ASSOCIATED SURFACE
FRONT. HOWEVER...PREFERENCE IS FOR NEITHER AND INSTEAD WITH THE
ENSEMBLE GFS WHICH IS MUCH SLOWER WITH THE TROUGH AND FRONTS
PROGRESS THROUGH THE PLAINS. HAVE SKEWED THE FORECAST IN THAT
DIRECTION AS A RESULT BY GOING WITH CHANCE POPS ARE RESTRICTED TO
THE IOWA BORDER REGION FOR THE WEDNESDAY THROUGH THURSDAY TIME
PERIOD FOR THE ASSOCIATED PRECIPITATION CHANCE IN THE PRE-FRONTAL
AND FRONTAL ENVIRONMENTS.

OTHERWISE...ONLY MODEST ADJUSTMENTS WERE MADE TO THE REST OF THE
GOING FORECAST PARAMETERS.

CUTTER

&&

.AVIATION...

FOR THE 18Z TAFS...HIGH PRESSURE STILL IN CONTROL OF THE WEATHER
ACROSS THE TERMINALS...THEREFORE VFR CONDITIONS EXPECTED OVER THE
NEXT 24 HOURS. ONLY EXCEPTION IS SOME GROUND FOG WITH VSBY 1/2-1SM
DURING THE EARLY MORNING HOURS AT KSTJ.

CUTTER

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
$$

000
FXUS63 KLSX 181818
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
118 PM CDT THU SEP 18 2008

.DISCUSSION...
/116 PM CDT THU SEP 18 2008/
THE FOCUS FOR THIS AFTERNOONS FORECAST DISCUSSION IS THE UPPER LOW
CURRENTLY SPINNING ACROSS THE CENTRAL PLAINS AND ITS EVENTUAL IMPACT
ON SENSIBLE WEATHER ACROSS THE FORECAST AREA THIS WEEKEND.

MODEL GUIDANCE IS IN FAIRLY GOOD AGREEMENT ON MID AND UPPER LEVEL
MOISTURE INCREASING ACROSS THE FORECAST AREA TOMORROW AS THE UPPER
LOW EDGES EAST. BY SATURDAY MORNING THE UPPER LOW SHOULD BE PARKED
DIRECTLY OVER THE OZARKS AND REMAIN NEARLY STATIONARY THROUGH THE
WEEKEND.

AS ELUDED TO IN THE PREVIOUS DISCUSSION...LOW LEVEL MOISTURE FOR
THIS UPPER LEVEL DISTURBANCE IS IN QUESTION. THE GFS IS MUCH DRIER
WHEN COMPARED TO THE OTHER MODELS AND THEREFORE DOESN`T PRODUCE MUCH
IN THE WAY OF QPF THIS WEEKEND. IN STARK CONTRAST THE ECWMF...WHOSE
PERFORMANCE HAS BEEN STELLAR THESE PAST FEW WEEKS...CONTINUES TO
PRINT OUT QPF ACROSS THE FORECAST AREA BOTH SATURDAY AND SUNDAY.

ASSUMING THAT THERE WILL BE AT LEAST LOWER 60 DEWPOINTS IN THE AREA
AS THE ECWMF SUGGESTS AND CURRENT OBSERVATIONS SUPPORT...MODEL
SOUNDINGS SUGGEST THAT THERE COULD BE AS MUCH AS 1000 J/KG OF
SURFACE BASED CAPE SATURDAY AND SUNDAY AFTERNOON UNDERNEATH THE
UPPER LEVEL LOW.

I BELIEVE IT IS PRUDENT AT THIS TIME TO INCREASE CLOUD COVER ACROSS
THE BOARD AND ADD CHANCES FOR SHOWERS/THUNDERSTORMS TO THE
SOUTHWESTERN HALF OF THE FORECAST AREA ON SATURDAY. I AM LIMITED TO
SLIGHT CHANCES OF PRECIPITATION SUNDAY DUE TO COLLABORATION
LIMITS...BUT I WOULD NOT BE SURPRISED TO SEE SCATTERED COVERAGE OF
CONVECTION BOTH DAYS THIS WEEKEND UNDERNEATH THE UPPER LOW. BY NO
MEANS DO I THINK IT WILL BE A RAIN OUT...BUT CERTAINLY DIFFERENT
THAN WHAT WE HAVE BEEN ADVERTISING UP TO THIS POINT.

ANOTHER PERIOD OF DRY WEATHER IS EXPECTED MONDAY THROUGH THE MIDDLE
OF NEXT WEEK AS THE UPPER LOW FINALLY PULLS EAST AND HEIGHTS BEGIN
TO RISE. A SMALL WARMING TREND IN TEMPERATURES IS EXPECTED EACH DAY
WITH THE NEXT CHANCE OF PRECIPITATION ARRIVING BY THE END OF NEXT
WEEK. TIMING DIFFERENCES WITH THE COLD FRONT ARE STILL AN
ISSUE...SO THE EXTENDED FORECAST REMAINS DRY FOR NOW.

CVKING

&&

.AVIATION...
/1219 PM CDT THU SEP 18 2008/
FOR THE 18Z TAFS...HI PRES IN CONTROL FOR THE AFTN AND EVNG HRS.
SHLD SEE SOME SLGT CU IN VICINITY OF ALL TAF LOCATIONS THRU 00Z
CLEARING THEREAFTER. BELIEVE SIMILAR TRENDS OF ERLY MRNG ARE TO BE
ANTICIPATED ONCE AGAIN THRU THE 09Z TO 12Z HRS. KEEPING PERSISTENT
WITH PREV TAF FCSTS WITH RESPECT TO THE POSSIBILITY OF FG OVRNGT
AT KUIN AND KCOU...MOST ESPECIALLY AT KSUS DUE TO ITS PROXIMITY TO
THE MO RVR VLY. WNDS WL RMN LGT OUT OF ESE. ANTICIPATE SCT HI
CLOUD IN CONJUNCTION WITH UPR LVL LOW CURRENTLY CENTERED OVER THE
OK PANHANDLE AFTER 12Z.

SIPPRELL

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KSGF 181809
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
113 PM CDT THU SEP 18 2008

.DISCUSSION...

COMFORTABLE WEATHER WAS OBSERVED ACROSS THE REGION TODAY.  SUNSHINE
WAS PLENTIFUL WHILE SOUTHERLY BREEZES RANGED FROM 5 TO 15 MPH...AND
AFTERNOON TEMPERATURES WERE GENERALLY IN THE 70S.  THESE BENIGN
CONDITIONS RESULTED FROM A DOME OF HIGH PRESSURE
OVERHEAD...ANCHORING A CANADIAN AIRMASS OVER MUCH OF THE STATE OF
MISSOURI.

FURTHER WEST...AN UPPER LEVEL LOW WAS PROGRESSING ACROSS SOUTHWEST
KANSAS.  THIS FEATURE MAY PROVIDE THE REGION WITH SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS AS WE HEAD INTO THE WEEKEND.  AS A MATTER
OF FACT...A FEW SHOWERS WILL BE POSSIBLE AS EARLY AS FRIDAY
AFTERNOON. POINT FORECAST SOUNDINGS INDICATE AN UNCAPPED AIRMASS
WITH MODEST INSTABILITY DEVELOPING.  FORCING WILL BE AIDED BY THE
RISES IN POTENTIAL TEMPERATURE SURFACES AS THE UPPER COLD CORE
APPROACHES.

MOISTURE LEVELS WILL REMAIN LOW THROUGH THE WEEKEND...THEREFORE LOOK
FOR SHOWERS TO BE SCATTERED IN NATURE...AND OCCUR MOSTLY DURING THE
DAYTIME HOURS.  SATURDAY AND SUNDAY AFTERNOONS WILL ALSO BE
FAVORABLE FOR SCATTERED SHOWERS.  LOW INSTABILITY AND SHEAR WILL
LIMIT THUNDERSTORM INTENSITIES BELOW SEVERE LIMITS.  GIVEN THE
SCATTERED AND ISOLATED NATURE OF THESE SHOWERS...SOME LOCATIONS WILL
REMAIN DRY THROUGH THE WEEKEND.

HEADING INTO NEXT WORK WEEK...A WARMING TREND WILL BE UNDERWAY AS
UPPER RIDGING BUILDS OVER THE NATIONS MID SECTION.  DRY CONDITIONS
WITH TEMPERATURES IN THE 80S ARE A GOOD BET THROUGH WEDNESDAY.  BOTH
THE ECMWF AND GFS INDICATE A FRONT IMPACTING THE CWA BY WEDNESDAY
NIGHT INTO THURSDAY.  THIS FRONTAL SYSTEM COULD PROVIDE THE AREA
WITH A GLANCING BLOW OF SHOWERS AND THUNDERSTORMS.

CRAMER

&&

.AVIATION...

FOR THE 1800 UTC KSGF/KJLN TAFS...VFR CONDITIONS ARE EXPECTED
THROUGH FRI MORNING. HIGH CLOUDS WILL INCREASE WITH THE APPROACH
OF AN UPPER LEVEL DISTURBANCE. DSA

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KSGF 181734
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
1234 PM CDT THU SEP 18 2008

...UPDATE TO AVIATION...

.DISCUSSION...

CURRENTLY...CLEAR...CALM AND SEASONABLY COOL CONDITIONS CONTINUE
ACROSS THE AREA AS HIGH PRESSURE HAS A FIRM GRASP ON OUR WEATHER
REGIME. TEMPERATURES ARE A FEW DEGREES WARMER THAN THE PAST FEW
NIGHTS WITH READINGS IN THE LOWER TO MIDDLE 50S.

HIGH PRESSURE AT THE SFC AND ALOFT WILL CONTINUE TODAY. LITTLE
CHANGE IN 925/850MB TEMPS ARE PROGGED AND PERSISTENCE TEMPS PLUS A
DEGREE OR TWO ARE EXPECTED. A MAINLY CLEAR SKY WILL PERSIST
THROUGH TONIGHT AND LOWS WILL ONCE AGAIN FALL INTO THE 50S.

A MINOR WEAKNESS WILL DEVELOP ALOFT FRIDAY AS A DISTURBANCE
SLIDES NORTHEASTWARD OUT OF CENTRAL TEXAS. COMPARED TO THE LAST
COUPLE OF NIGHTS OF MODEL RUNS...THERE IS A LITTLE MORE IN THE WAY
OF MID AND UPPER LEVEL MOISTURE PROGGED FOR FRI/SAT AND WE SHOULD
SEE MORE CLOUDS THAN THE PAST FEW DAYS. QUESTIONS STILL REMAIN
THOUGH AS TO THE EXTENT AND QUALITY OF MOISTURE THAT WILL BE
AVAILABLE IN THE LOWER LEVELS OF THE ATMOSPHERE. THE GFS IS DRIER
COMPARED TO THE NAM/ECMWF/UKMET...BOTH IN LOW LEVEL MOISTURE AND
POPS. THE NAM/ECMWF/UKMET SUGGEST THAT SFC DEW POINTS WILL BE WELL
INTO THE 60S...WHILE THE GFS MAINTAINS 50S DEW POINTS. WITH LOW
LEVEL FLOW REMAINING RATHER WEAK...AND MAINLY FROM THE EAST TO
SOUTHEAST AT THE SFC...I AM A LITTLE SKEPTICAL THAT DEW POINTS WILL
MAKE IT WELL INTO THE 60S. NEVERTHELESS...WEAK ISENTROPIC UPGLIDE
IN THE 300-310K LAYER AND MARGINAL OMEGA FIELDS SUGGEST THAT A
PERIOD OR TWO OF -SHRA ARE POSSIBLE. PLUS...THE ECMWF HAS BEEN
CONSISTENT IN BREAKING OUT SOME SEMBLANCE OF QPF ACROSS THE
AREA...AND TO SAY THE LEAST THIS MODEL HAS BEEN ON A ROLL FOR THE
PAST FEW WEEKS. THUS...HAVE KEPT LOW POPS FOR -SHRA ON SATURDAY.
TEMPERATURES WILL REMAIN NORMAL FOR THIS TIME OF YEAR.

ANOTHER PERIOD OF DRY WEATHER IS IN THE OFFING FOR SUNDAY INTO
EARLY NEXT WEEK. THE MED RANGE MODELS ARE A LITTLE SLOWER IN
EVOLVING THE UPPER PATTER TO A TROUGH WEST/RIDGE EAST STRUCTURE.
VERY LITTLE VARIANCE IN 925/850MB TEMPS ARE PROGGED AND HIGHS
AROUND 80 AND LOWS IN THE 50S/LOWER 60S WILL CONTINUE.

GAGAN


&&

.AVIATION...

FOR THE 1800 UTC KSGF/KJLN TAFS...VFR CONDITIONS ARE EXPECTED
THROUGH FRI MORNING. HIGH CLOUDS WILL INCREASE WITH THE APPROACH
OF AN UPPER LEVEL DISTURBANCE. DSA

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KLSX 181730
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1230 PM CDT THU SEP 18 2008

.DISCUSSION...
/258 AM CDT THU SEP 18 2008/
SURFACE RIDGE TO REMAIN IN PLACE OVER REGION THROUGH THE FORECAST
PERIOD.  HOWEVER...THE GFS AND ECMWF ARE SIMILAR IN FORECASTING A
CLOSED UPPER LOW THAT WILL DEVELOP ACROSS THE REGION OVER THE
WEEKEND. MOISTURE IS FORECAST TO BE LIMITED AND LITTLE OR NO RAIN
EXPECTED OVER THE WEEKEND. OTHERWISE...TEMPS WILL BE AROUND NORMAL
NEXT SEVERAL DAYS WITH DRIER AIR ACROSS THE REGION AND LIGHT WINDS
UNDER SURFACE HIGH.

ONE ISSUE IN THE SHORT TERM IS THE PATCHY DENSE FOG THAT HAS
DEVELOPED ONCE AGAIN...MAINLY ALONG RIVER VALLEYS...FEEL THAT IT
WILL REMAIN PATCHY ENOUGH...SO FOG ADVISORY NOT NEEDED AT THIS TIME.
WILL KEEP IN GRIDS FOR A FEW HOURS THIS MORNING BEFORE IT BURNS OFF.

BEYOND THAT...NO MAJOR CHANGES TO THE FORECAST.

BYRD

&&

.AVIATION...
/1219 PM CDT THU SEP 18 2008/
FOR THE 18Z TAFS...HI PRES IN CONTROL FOR THE AFTN AND EVNG HRS.
SHLD SEE SOME SLGT CU IN VICINITY OF ALL TAF LOCATIONS THRU 00Z
CLEARING THEREAFTER. BELIEVE SIMILAR TRENDS OF ERLY MRNG ARE TO BE
ANTICIPATED ONCE AGAIN THRU THE 09Z TO 12Z HRS. KEEPING PERSISTENT
WITH PREV TAF FCSTS WITH RESPECT TO THE POSSIBILITY OF FG OVRNGT
AT KUIN AND KCOU...MOST ESPECIALLY AT KSUS DUE TO ITS PROXIMITY TO
THE MO RVR VLY. WNDS WL RMN LGT OUT OF ESE. ANTICIPATE SCT HI
CLOUD IN CONJUNCTION WITH UPR LVL LOW CURRENTLY CENTERED OVER THE
OK PANHANDLE AFTER 12Z.

SIPPRELL

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KEAX 181712
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
1212 PM CDT THU SEP 18 2008

...UPDATED AVIATION...

.DISCUSSION...

/218 AM CDT THU SEP 18 2008/
IN THE SHORT TERM...YET ANOTHER CARBON COPY DAY CAN BE EXPECTED
TODAY AS OVERALL SYNOPTIC SETUP HAS CHANGED LITTLE SINCE YESTERDAY.
TEMPERATURES WILL REMAIN VERY CONSTANT THROUGH THE REMAINDER OF THE
WEEK...WITH NO CHANGES MADE TO THE EXISTING TEMPERATURE FORECAST.
HAVE MADE A SLIGHT ADJUSTMENT TO OVERNIGHT DEW POINTS FOR TONIGHT AS
WE HAVE UNDERESTIMATED THE AMOUNT OF BOUNDARY LAYER MOISTURE AS OF
LATE.  THIS IS ONLY A MINOR 2-3 DEGREE ADJUSTMENT UPWARDS.

OTHERWISE...WATER VAPOR IMAGERY THIS MORNING SHOWS A SERIES OF WEAK
UPR LVL CIRCULATIONS ACROSS THE PANHANDLE OF OKLAHOMA AND FURTHER NW
INTO COLORADO...WHICH SPUN OFF THE SHEERED OUT UPR LOW IN NORTHERN
CA.  THESE UPR WAVES ARE EXPECTED TO SLOWLY MEANDER EASTWARD UNDER
THE MID-LVL RIDGE AND BY SATURDAY LIKELY FIND THEMSELVES IN SOUTHERN
MISSOURI.  IF ONE VORT MAX BECOMES MORE ORGANIZED IT HAS THE
POTENTIAL DEPENDING ON WHERE IT DRIFTS TO PRODUCE SCATTERED
TSRA/SHRA SAT AFTN AND AGAIN ON SUN.  HOWEVER...CLOSER INSPECTION OF
SOUNDINGS REVEALS AN OVERALL LACK OF MOISTURE RETURN AND A WEAK
LOW-LVL CAP.  WITH THE BEST FORCING TO THE SOUTH OF THE AREA WILL
REMOVE THE SLIGHT CHC POPS CURRENTLY IN THE FORECAST AND INCREASE
CLOUD COVER IN THE SOUTHERN CWA.

APPEARS PLEASANT WEATHER WILL CONTINUE THROUGH MONDAY...BEFORE NEXT
UP SYSTEM TRIES TO LIFT THROUGH THE NORTHERN PLAINS ON MONDAY.
SYSTEM WILL LIKELY SPAWN AN MCS SOMEWHERE...WITH ALL SIGNALS
POINTING NORTHWEST OF THE CWA.  NEXT BEST CHC FOR RAIN WOULD ARRIVE
WITH COLD FRONT PASSAGE ON WED/THU...HOWEVER THIS IS A LITTLE OUT OF
MY TIMEFRAME AND CURRENT FORECAST LOOKS REASONABLE.  TEMPERATURES
INTO NEXT WEEK WON`T CHANGE MUCH AS FLOW ALOFT REMAINS RATHER STALE.

DUX

&&

.AVIATION...

FOR THE 18Z TAFS...HIGH PRESSURE STILL IN CONTROL OF THE WEATHER
ACROSS THE TERMINALS...THEREFORE VFR CONDITIONS EXPECTED OVER THE
NEXT 24 HOURS. ONLY EXCEPTION IS SOME GROUND FOG WITH VSBY 1/2-1SM
DURING THE EARLY MORNING HOURS AT KSTJ.

CUTTER

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
$$

000
FXUS63 KLSX 181149
AFDLSX

AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
649 AM CDT THU SEP 18 2008

.DISCUSSION...
/258 AM CDT THU SEP 18 2008/
SURFACE RIDGE TO REMAIN IN PLACE OVER REGION THROUGH THE FORECAST
PERIOD.  HOWEVER...THE GFS AND ECMWF ARE SIMILAR IN FORECASTING A
CLOSED UPPER LOW THAT WILL DEVELOP ACROSS THE REGION OVER THE
WEEKEND. MOISTURE IS FORECAST TO BE LIMITED AND LITTLE OR NO RAIN
EXPECTED OVER THE WEEKEND. OTHERWISE...TEMPS WILL BE AROUND NORMAL
NEXT SEVERAL DAYS WITH DRIER AIR ACROSS THE REGION AND LIGHT WINDS
UNDER SURFACE HIGH.

ONE ISSUE IN THE SHORT TERM IS THE PATCHY DENSE FOG THAT HAS
DEVELOPED ONCE AGAIN...MAINLY ALONG RIVER VALLEYS...FEEL THAT IT
WILL REMAIN PATCHY ENOUGH...SO FOG ADVISORY NOT NEEDED AT THIS TIME.
WILL KEEP IN GRIDS FOR A FEW HOURS THIS MORNING BEFORE IT BURNS OFF.

BEYOND THAT...NO MAJOR CHANGES TO THE FORECAST.

BYRD

&&

.AVIATION...
/640 AM CDT THU SEP 18 2008/
FOR THE 12Z TAFS...
DENSE FOG IN RIVER VALLEYS DISSIPATED BY 14Z YESTERDAY AND EXPECT
THE SAME TODAY...INCLUDING AT KSUS. OTHERWISE...HIGH PRESSURE HAS
MOVED OFF A BIT TO THE EAST TODAY...SO HAVE LIGHT E-SELY WINDS
GOING THROUGH THE PERIOD. HAVE FOG MOVING BACK INTO KSUS AFTER 08Z
TONIGHT BECAUSE I EXPECT THE REDEVLOPMENT OF STEAM FOG ALONG THE
MO RIVER.

BRITT

&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$

WFO LSX

000
FXUS63 KEAX 181142
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
642 AM CDT THU SEP 18 2008

...UPDATED AVIATION...

.DISCUSSION...

/218 AM CDT THU SEP 18 2008/
IN THE SHORT TERM...YET ANOTHER CARBON COPY DAY CAN BE EXPECTED
TODAY AS OVERALL SYNOPTIC SETUP HAS CHANGED LITTLE SINCE YESTERDAY.
TEMPERATURES WILL REMAIN VERY CONSTANT THROUGH THE REMAINDER OF THE
WEEK...WITH NO CHANGES MADE TO THE EXISTING TEMPERATURE FORECAST.
HAVE MADE A SLIGHT ADJUSTMENT TO OVERNIGHT DEW POINTS FOR TONIGHT AS
WE HAVE UNDERESTIMATED THE AMOUNT OF BOUNDARY LAYER MOISTURE AS OF
LATE.  THIS IS ONLY A MINOR 2-3 DEGREE ADJUSTMENT UPWARDS.

OTHERWISE...WATER VAPOR IMAGERY THIS MORNING SHOWS A SERIES OF WEAK
UPR LVL CIRCULATIONS ACROSS THE PANHANDLE OF OKLAHOMA AND FURTHER NW
INTO COLORADO...WHICH SPUN OFF THE SHEERED OUT UPR LOW IN NORTHERN
CA.  THESE UPR WAVES ARE EXPECTED TO SLOWLY MEANDER EASTWARD UNDER
THE MID-LVL RIDGE AND BY SATURDAY LIKELY FIND THEMSELVES IN SOUTHERN
MISSOURI.  IF ONE VORT MAX BECOMES MORE ORGANIZED IT HAS THE
POTENTIAL DEPENDING ON WHERE IT DRIFTS TO PRODUCE SCATTERED
TSRA/SHRA SAT AFTN AND AGAIN ON SUN.  HOWEVER...CLOSER INSPECTION OF
SOUNDINGS REVEALS AN OVERALL LACK OF MOISTURE RETURN AND A WEAK
LOW-LVL CAP.  WITH THE BEST FORCING TO THE SOUTH OF THE AREA WILL
REMOVE THE SLIGHT CHC POPS CURRENTLY IN THE FORECAST AND INCREASE
CLOUD COVER IN THE SOUTHERN CWA.

APPEARS PLEASANT WEATHER WILL CONTINUE THROUGH MONDAY...BEFORE NEXT
UP SYSTEM TRIES TO LIFT THROUGH THE NORTHERN PLAINS ON MONDAY.
SYSTEM WILL LIKELY SPAWN AN MCS SOMEWHERE...WITH ALL SIGNALS
POINTING NORTHWEST OF THE CWA.  NEXT BEST CHC FOR RAIN WOULD ARRIVE
WITH COLD FRONT PASSAGE ON WED/THU...HOWEVER THIS IS A LITTLE OUT OF
MY TIMEFRAME AND CURRENT FORECAST LOOKS REASONABLE.  TEMPERATURES
INTO NEXT WEEK WON`T CHANGE MUCH AS FLOW ALOFT REMAINS RATHER STALE.

DUX

&&

.AVIATION...

HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE
REGION...WITH VFR CONDITIONS PREVAILING. ONLY EXCEPTION IS SOME
GROUND FOG WITH VSBY 1/2-1SM DURING THE EARLY MORNING HOURS AT STJ.

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
$$

000
FXUS63 KSGF 181141
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
641 AM CDT THU SEP 18 2008

...UPDATE TO AVIATION...

.DISCUSSION...

CURRENTLY...CLEAR...CALM AND SEASONABLY COOL CONDITIONS CONTINUE
ACROSS THE AREA AS HIGH PRESSURE HAS A FIRM GRASP ON OUR WEATHER
REGIME. TEMPERATURES ARE A FEW DEGREES WARMER THAN THE PAST FEW
NIGHTS WITH READINGS IN THE LOWER TO MIDDLE 50S.

HIGH PRESSURE AT THE SFC AND ALOFT WILL CONTINUE TODAY. LITTLE
CHANGE IN 925/850MB TEMPS ARE PROGGED AND PERSISTENCE TEMPS PLUS A
DEGREE OR TWO ARE EXPECTED. A MAINLY CLEAR SKY WILL PERSIST
THROUGH TONIGHT AND LOWS WILL ONCE AGAIN FALL INTO THE 50S.

A MINOR WEAKNESS WILL DEVELOP ALOFT FRIDAY AS A DISTURBANCE
SLIDES NORTHEASTWARD OUT OF CENTRAL TEXAS. COMPARED TO THE LAST
COUPLE OF NIGHTS OF MODEL RUNS...THERE IS A LITTLE MORE IN THE WAY
OF MID AND UPPER LEVEL MOISTURE PROGGED FOR FRI/SAT AND WE SHOULD
SEE MORE CLOUDS THAN THE PAST FEW DAYS. QUESTIONS STILL REMAIN
THOUGH AS TO THE EXTENT AND QUALITY OF MOISTURE THAT WILL BE
AVAILABLE IN THE LOWER LEVELS OF THE ATMOSPHERE. THE GFS IS DRIER
COMPARED TO THE NAM/ECMWF/UKMET...BOTH IN LOW LEVEL MOISTURE AND
POPS. THE NAM/ECMWF/UKMET SUGGEST THAT SFC DEWPOINTS WILL BE WELL
INTO THE 60S...WHILE THE GFS MAINTAINS 50S DEWPOINTS. WITH LOW
LEVEL FLOW REMAINING RATHER WEAK...AND MAINLY FROM THE EAST TO
SOUTHEAST AT THE SFC...I AM A LITTLE SKEPTICAL THAT DEWPOINTS WILL
MAKE IT WELL INTO THE 60S. NEVERTHELESS...WEAK ISENTROPIC UPGLIDE
IN THE 300-310K LAYER AND MARGINAL OMEGA FIELDS SUGGEST THAT A
PERIOD OR TWO OF -SHRA ARE POSSIBLE. PLUS...THE ECMWF HAS BEEN
CONSISTENT IN BREAKING OUT SOME SEMBLANCE OF QPF ACROSS THE
AREA...AND TO SAY THE LEAST THIS MODEL HAS BEEN ON A ROLL FOR THE
PAST FEW WEEKS. THUS...HAVE KEPT LOW POPS FOR -SHRA ON SATURDAY.
TEMPERATURES WILL REMAIN NORMAL FOR THIS TIME OF YEAR.

ANOTHER PERIOD OF DRY WEATHER IS IN THE OFFING FOR SUNDAY INTO
EARLY NEXT WEEK. THE MED RANGE MODELS ARE A LITTLE SLOWER IN
EVOLVING THE UPPER PATTER TO A TROUGH WEST/RIDGE EAST STRUCTURE.
VERY LITTLE VARIANCE IN 925/850MB TEMPS ARE PROGGED AND HIGHS
AROUND 80 AND LOWS IN THE 50S/LOWER 60S WILL CONTINUE.

GAGAN


&&

.AVIATION...

FOR THE 12Z TAF PACKAGE...VFR CONDITIONS WILL CONTINUE. A SURFACE
RIDGE EXTENDING ACROSS THE OZARKS WILL BRING A SOUTHEAST
COMPONENT TO THE WIND WITH SPEEDS REMAINING UNDER 8 KNOTS. A
CIRRUS SHIELD ASSOCIATED WITH A WEAK DISTURBANCE IN THE OKLAHOMA
AND TEXAS PANHANDLES WILL GRADUALLY SPREAD EAST.

ANGLE

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KLSX 180758
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
258 AM CDT THU SEP 18 2008

.DISCUSSION...
/258 AM CDT THU SEP 18 2008/
SURFACE RIDGE TO REMAIN IN PLACE OVER REGION THROUGH THE FORECAST
PERIOD.  HOWEVER...THE GFS AND ECMWF ARE SIMILAR IN FORECASTING A
CLOSED UPPER LOW THAT WILL DEVELOP ACROSS THE REGION OVER THE
WEEKEND. MOISTURE IS FORECAST TO BE LIMITED AND LITTLE OR NO RAIN
EXPECTED OVER THE WEEKEND. OTHERWISE...TEMPS WILL BE AROUND NORMAL
NEXT SEVERAL DAYS WITH DRIER AIR ACROSS THE REGION AND LIGHT WINDS
UNDER SURFACE HIGH.

ONE ISSUE IN THE SHORT TERM IS THE PATCHY DENSE FOG THAT HAS
DEVELOPED ONCE AGAIN...MAINLY ALONG RIVER VALLEYS...FEEL THAT IT
WILL REMAIN PATCHY ENOUGH...SO FOG ADVISORY NOT NEEDED AT THIS TIME.
WILL KEEP IN GRIDS FOR A FEW HOURS THIS MORNING BEFORE IT BURNS OFF.

BEYOND THAT...NO MAJOR CHANGES TO THE FORECAST.

BYRD
&&

.AVIATION...
/1121 PM CDT WED SEP 17 2008/
FOR THE 06Z TAFS...SIMILAR THINKING CONTINUES WITH PREV FCST.
REDUCED VSBYS ARE STILL PSBL FOR KCOU AND KUIN THRU ERLY MRNG HRS
BUT BETTER CHANCES LIE WITH KSUS AS THERE IS THE POTENTIAL FOR FOG
TO SPREAD OUTWARDS FROM THE MO RVR VLY INTO THE CHESTERFIELD
VLY...WHICH IN AND OF ITSELF HAS SUBSTANTIAL SURFACE SOIL MOISTURE
FROM REMNANTS OF IKE. BUT OF COURSE THERE IS SUBSTANTIAL DRY AIR
AT ALL LVLS OF THE ATMOS MAKING THE FCST TRICKY. THEREFORE WILL
CONTINUE WITH TEMPOS IN THE FCST. CENTER OF HI PRES ANTICIPATED TO
DRIFT NEWD THRU 06Z TOMORROW RESULTING IN LGT EWD FLOW ACRS ALL
TAF LOCALES.

SIPPRELL
&&

.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&

$$
WFO LSX

000
FXUS63 KSGF 180743
AFDSGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
243 AM CDT THU SEP 18 2008

.DISCUSSION...

CURRENTLY...CLEAR...CALM AND SEASONABLY COOL CONDITIONS CONTINUE
ACROSS THE AREA AS HIGH PRESSURE HAS A FIRM GRASP ON OUR WEATHER
REGIME. TEMPERATURES ARE A FEW DEGREES WARMER THAN THE PAST FEW
NIGHTS WITH READINGS IN THE LOWER TO MIDDLE 50S.

HIGH PRESSURE AT THE SFC AND ALOFT WILL CONTINUE TODAY. LITTLE
CHANGE IN 925/850MB TEMPS ARE PROGGED AND PERSISTENCE TEMPS PLUS A
DEGREE OR TWO ARE EXPECTED. A MAINLY CLEAR SKY WILL PERSIST
THROUGH TONIGHT AND LOWS WILL ONCE AGAIN FALL INTO THE 50S.

A MINOR WEAKNESS WILL DEVELOP ALOFT FRIDAY AS A DISTURBANCE
SLIDES NORTHEASTWARD OUT OF CENTRAL TEXAS. COMPARED TO THE LAST
COUPLE OF NIGHTS OF MODEL RUNS...THERE IS A LITTLE MORE IN THE WAY
OF MID AND UPPER LEVEL MOISTURE PROGGED FOR FRI/SAT AND WE SHOULD
SEE MORE CLOUDS THAN THE PAST FEW DAYS. QUESTIONS STILL REMAIN
THOUGH AS TO THE EXTENT AND QUALITY OF MOISTURE THAT WILL BE
AVAILABLE IN THE LOWER LEVELS OF THE ATMOSPHERE. THE GFS IS DRIER
COMPARED TO THE NAM/ECMWF/UKMET...BOTH IN LOW LEVEL MOISTURE AND
POPS. THE NAM/ECMWF/UKMET SUGGEST THAT SFC DEWPOINTS WILL BE WELL
INTO THE 60S...WHILE THE GFS MAINTAINS 50S DEWPOINTS. WITH LOW
LEVEL FLOW REMAINING RATHER WEAK...AND MAINLY FROM THE EAST TO
SOUTHEAST AT THE SFC...I AM A LITTLE SKEPTICAL THAT DEWPOINTS WILL
MAKE IT WELL INTO THE 60S. NEVERTHELESS...WEAK ISENTROPIC UPGLIDE
IN THE 300-310K LAYER AND MARGINAL OMEGA FIELDS SUGGEST THAT A
PERIOD OR TWO OF -SHRA ARE POSSIBLE. PLUS...THE ECMWF HAS BEEN
CONSISTENT IN BREAKING OUT SOME SEMBLANCE OF QPF ACROSS THE
AREA...AND TO SAY THE LEAST THIS MODEL HAS BEEN ON A ROLL FOR THE
PAST FEW WEEKS. THUS...HAVE KEPT LOW POPS FOR -SHRA ON SATURDAY.
TEMPERATURES WILL REMAIN NORMAL FOR THIS TIME OF YEAR.

ANOTHER PERIOD OF DRY WEATHER IS IN THE OFFING FOR SUNDAY INTO
EARLY NEXT WEEK. THE MED RANGE MODELS ARE A LITTLE SLOWER IN
EVOLVING THE UPPER PATTER TO A TROUGH WEST/RIDGE EAST STRUCTURE.
VERY LITTLE VARIANCE IN 925/850MB TEMPS ARE PROGGED AND HIGHS
AROUND 80 AND LOWS IN THE 50S/LOWER 60S WILL CONTINUE.

GAGAN

&&

.AVIATION...

FOR THE 06Z TAFS...VFR CONDITIONS EXPECTED THROUGH THE PERIOD WITH
GENERALLY LIGHT AND VARIABLE SURFACE WINDS. DURING THE DAY
THURSDAY LIGHT 5-8 KT WINDS EXPECTED FROM THE ESE.

LINDENBERG

&&

.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&

$$

000
FXUS63 KEAX 180722
AFDEAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
218 AM CDT THU SEP 18 2008

.DISCUSSION...

IN THE SHORT TERM...YET ANOTHER CARBON COPY DAY CAN BE EXPECTED
TODAY AS OVERALL SYNOPTIC SETUP HAS CHANGED LITTLE SINCE YESTERDAY.
TEMPERATURES WILL REMAIN VERY CONSTANT THROUGH THE REMAINDER OF THE
WEEK...WITH NO CHANGES MADE TO THE EXISTING TEMPERATURE FORECAST.
HAVE MADE A SLIGHT ADJUSTMENT TO OVERNIGHT DEW POINTS FOR TONIGHT AS
WE HAVE UNDERESTIMATED THE AMOUNT OF BOUNDARY LAYER MOISTURE AS OF
LATE.  THIS IS ONLY A MINOR 2-3 DEGREE ADJUSTMENT UPWARDS.

OTHERWISE...WATER VAPOR IMAGERY THIS MORNING SHOWS A SERIES OF WEAK
UPR LVL CIRCULATIONS ACROSS THE PANHANDLE OF OKLAHOMA AND FURTHER NW
INTO COLORADO...WHICH SPUN OFF THE SHEERED OUT UPR LOW IN NORTHERN
CA.  THESE UPR WAVES ARE EXPECTED TO SLOWLY MEANDER EASTWARD UNDER
THE MID-LVL RIDGE AND BY SATURDAY LIKELY FIND THEMSELVES IN SOUTHERN
MISSOURI.  IF ONE VORT MAX BECOMES MORE ORGANIZED IT HAS THE
POTENTIAL DEPENDING ON WHERE IT DRIFTS TO PRODUCE SCATTERED
TSRA/SHRA SAT AFTN AND AGAIN ON SUN.  HOWEVER...CLOSER INSPECTION OF
SOUNDINGS REVEALS AN OVERALL LACK OF MOISTURE RETURN AND A WEAK
LOW-LVL CAP.  WITH THE BEST FORCING TO THE SOUTH OF THE AREA WILL
REMOVE THE SLIGHT CHC POPS CURRENTLY IN THE FORECAST AND INCREASE
CLOUD COVER IN THE SOUTHERN CWA.

APPEARS PLEASANT WEATHER WILL CONTINUE THROUGH MONDAY...BEFORE NEXT
UP SYSTEM TRIES TO LIFT THROUGH THE NORTHERN PLAINS ON MONDAY.
SYSTEM WILL LIKELY SPAWN AN MCS SOMEWHERE...WITH ALL SIGNALS
POINTING NORTHWEST OF THE CWA.  NEXT BEST CHC FOR RAIN WOULD ARRIVE
WITH COLD FRONT PASSAGE ON WED/THU...HOWEVER THIS IS A LITTLE OUT OF
MY TIMEFRAME AND CURRENT FORECAST LOOKS REASONABLE.  TEMPERATURES
INTO NEXT WEEK WON`T CHANGE MUCH AS FLOW ALOFT REMAINS RATHER STALE.

DUX

&&

.AVIATION...

PERSISTENCE FORECAST APPEARS A LOCK FOR THE 00Z TAFS AS HIGH
PRESSURE REMAINS IN FIRM CONTROL. ONCE AGAIN...OPTIMAL RADIATIONAL
COOLING SHOULD ALLOW TEMPERATURES TO FALL BELOW CURRENT DEWPOINTS
OVER NORTHERN MISSOURI...WITH A LARGE WATER TO AIR TEMPERATURE
DIFFERENTIAL PROMOTING STEAM FOG DEVELOPMENT ALONG THE MISSOURI
RIVER TOWARD DAYBREAK. MVFR TO LOCALLY LIFR CONDITIONS ARE
THEREFORE AGAIN EXPECTED AT KSTJ...PRIMARILY BETWEEN 09 AND 13Z.

BOOKBINDER

&&

.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
$$