000
FXUS63 KLSX 201137
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
537 AM CST TUE JAN 20 2009
.DISCUSSION...
/331 AM CST TUE JAN 20 2009/
LOOKS LIKE A PRETTY TRANQUIL PD OF WX BGNG TDA AND CONTG INTO THE
EARLY PART OF THE WEEKEND WITH TEMPERATURES THE MAIN FCST CONCERN.
THE MAIN N-NWLY FLOW SHRTWV TROF WILL PUSH S-SE OF THE CWA BY 12Z
TUE ALTHOUGH THERE WILL BE PLENTY OF REMAINING LOW LVL CLOUDS
ESPECIALLY OVER THE SRN-SWRN PTN OF THE CWA THIS MRNG ALONG WITH
SOME LINGERING FLURRIES POSSIBLE OVER THE SRN PTN OF THE CWA AS
WELL THIS MRNG. ALTHOUGH THE SATELLITE IMAGES WERE SHOWING AT
LEAST PARTIAL CLRG OVER THE NRN AND ERN PTNS OF THE CWA ATTM...MDL
RH FCSTS STILL DEPICT PLENTY OF LOW LVL RH ACRS MUCH OF THE CWA
THIS MRNG. MAY SEE SOME DIURNAL CUMULUS OR STRATOCUMULUS CLOUDS
DVLP SHORTLY AFTER SUNRISE THIS MRNG. THIS LOW LVL CLOUD CVR
SHOULD DISSIPATE LTR THIS AFTN AS THE SFC RDG ACRS THE PLAINS BLDS
SEWD INTO THE CWA WITH INCRSG SUBSIDENCE. LOOKS LIKE THERE WILL ONLY
BE SCT MID-HI LVL CLOUDS TGT. COLD TEMPERATURES SHOULD CONT FOR
THE CWA TDA AND TGT WITH THE CONTD N-NWLY MID-UPR LVL FLOW ON THE
WRN SIDE OF THE ERN US MID-UPR LVL TROF...AND CONTD NWLY SFC WNDS
TDA AND A LGT SFC WND TGT. MAX TEMPS TDA SHOULD BE SIMILAR TO
YESTERDAYS HIGHS WITH THE MDLS ONLY FCSTG 850 MB TEMPERATURES OF
-11 TO -13 DGRS C ACRS MOST OF THE CWA AT 18Z TUE. THERE WILL BE
GOOD RADIATIONAL COOLING TGT WITH ONLY SCT MID-HI LVL CLOUDS...LGT
SFC WNDS...AND SFC DWPTS ONLY IN THE TEENS. THE WARMUP SHOULD BGN
ON WED AS THE MID-UPR LVL HEIGHTS BGN TO RISE AS THE MAIN MID-UPR
LVL TROF MOVES EWD TWRDS THE ATLANTIC SEABOARD AND THE SFC WNDS
BCM SWLY WED MRNG AHD OF A WK APPROACHING 850 MB/SFC TROF. MDLS
WERE DEPICTING STG LOW LVL WAA AHD OF THE 850 MB TROF ON WED WITH
THE 850 MB TEMPS WRMG TO 2 TO 8 DGRS C PER THE NAM MDL FCST BY 00Z
THU...NOT QUITE THIS WRM PER THE GFS MDL 850 MB TEMP FCST AT THE
SAME TIME BUT IT STILL DEPICTED A SIGNIFICANT WRMG TREND. ALSO
THERE SHOULD BE PLENTY OF SOLAR INSOLATION ON WED WITH LTL CLOUDS
EXPECTED. THE WK SFC TROF WILL LOSE ITS IDENTITY AS IT MOVES SEWD
THRU THE CWA WED AFTN WITH INCRSG SWLY SFC WNDS ON THU AND EVEN
WARMER AIR OVER THE CWA. BOTH THE NAM AND GFS MDLS BRING THE 8
DGR C 850 MB ISOTHERM NEWD TO NR STL BY THU AFTN. HIGH TEMPS ON
THU SHOULD MAKE IT AT LEAST INTO THE LWR 50S ACRS THE SWRN PTN OF
THE CWA. A STG CDFNT WILL MOVE SEWD THRU THE CWA LT THU NGT AND
FRI MRNG ENDING THIS WRMG TREND. DO NOT SEE MUCH MID-UPR LVL FRCG
OVER MO IL WITH THIS CDFNT...PLUS IT APRS THAT THE LOW LVL
MOISTURE ALONG AND JUST AHD OF THIS FNT WILL BE LIMITED...SO
EXPECTING LTL IF ANY PCPN WITH THIS FRONTAL PASSAGE. THE MAIN
EFFECT WILL BE MUCH COLDER TEMPERATURES ON FRI AND FRI NGT AS A
STG SFC RDG BLDS SEWD INTO THE CWA BHND THE CDFNT WITH LOW LVL
NWLY WNDS BRINGING MUCH COLDER AIR BACK INTO THE REGION.
GKS
&&
.AVIATION...
/524 AM CST TUE JAN 20 2009/
FOR THE 12Z TAFS...
DEEP NORTHERLY FLOW PERSISTS ACROSS THE AREA EARLY THIS MORNING
AND THIS IS MAINTAINING QUITE A BIT OF STRATUS ACROSS THE REGION.
IT SEEMS JUST ABOUT ANY CLOUD IS PRODUCING EITHER LIGHT SNOW OR
FLURRIES. THE NORTHERN AND EASTERN EDGES OF THE STRATUS ARE NOT
COMPLETELY SOLID WHICH MEANS MAKES THE CLEARING TREND A LITTLE MORE
DIFFICULT TO EXTRAPOLATE. I THINK SOME OF THE BREAKS WILL ALSO
FILL IN AFTER SUNRISE. OVERALL HOWEVER THERE SHOULD A GENERAL
DIMINISHING TREND TO SCT STRATOCU FROM THE NORTH DURING THE
MORNING. MID AND HI CLOUDS WILL BEGIN SPREADING INTO THE REGION
THIS EVENING AS WAA ADVECTION COMMENCES ALOFT. SURFACE WINDS WILL
GRADUALLY BACK TO SOUTHERLY TONIGHT AS THE HIGH PRESSURE SLIDES
SOUTHEAST OF THE REGION AND INTO THE DEEP SOUTH.
GLASS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 200944
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
344 AM CST TUE JAN 20 2009
.DISCUSSION...
/331 AM CST TUE JAN 20 2009/
LOOKS LIKE A PRETTY TRANQUIL PD OF WX BGNG TDA AND CONTG INTO THE
EARLY PART OF THE WEEKEND WITH TEMPERATURES THE MAIN FCST CONCERN.
THE MAIN N-NWLY FLOW SHRTWV TROF WILL PUSH S-SE OF THE CWA BY 12Z
TUE ALTHOUGH THERE WILL BE PLENTY OF REMAINING LOW LVL CLOUDS
ESPECIALLY OVER THE SRN-SWRN PTN OF THE CWA THIS MRNG ALONG WITH
SOME LINGERING FLURRIES POSSIBLE OVER THE SRN PTN OF THE CWA AS
WELL THIS MRNG. ALTHOUGH THE SATELLITE IMAGES WERE SHOWING AT
LEAST PARTIAL CLRG OVER THE NRN AND ERN PTNS OF THE CWA ATTM...MDL
RH FCSTS STILL DEPICT PLENTY OF LOW LVL RH ACRS MUCH OF THE CWA
THIS MRNG. MAY SEE SOME DIURNAL CUMULUS OR STRATOCUMULUS CLOUDS
DVLP SHORTLY AFTER SUNRISE THIS MRNG. THIS LOW LVL CLOUD CVR
SHOULD DISSIPATE LTR THIS AFTN AS THE SFC RDG ACRS THE PLAINS BLDS
SEWD INTO THE CWA WITH INCRSG SUBSIDENCE. LOOKS LIKE THERE WILL ONLY
BE SCT MID-HI LVL CLOUDS TGT. COLD TEMPERATURES SHOULD CONT FOR
THE CWA TDA AND TGT WITH THE CONTD N-NWLY MID-UPR LVL FLOW ON THE
WRN SIDE OF THE ERN US MID-UPR LVL TROF...AND CONTD NWLY SFC WNDS
TDA AND A LGT SFC WND TGT. MAX TEMPS TDA SHOULD BE SIMILAR TO
YESTERDAYS HIGHS WITH THE MDLS ONLY FCSTG 850 MB TEMPERATURES OF
-11 TO -13 DGRS C ACRS MOST OF THE CWA AT 18Z TUE. THERE WILL BE
GOOD RADIATIONAL COOLING TGT WITH ONLY SCT MID-HI LVL CLOUDS...LGT
SFC WNDS...AND SFC DWPTS ONLY IN THE TEENS. THE WARMUP SHOULD BGN
ON WED AS THE MID-UPR LVL HEIGHTS BGN TO RISE AS THE MAIN MID-UPR
LVL TROF MOVES EWD TWRDS THE ATLANTIC SEABOARD AND THE SFC WNDS
BCM SWLY WED MRNG AHD OF A WK APPROACHING 850 MB/SFC TROF. MDLS
WERE DEPICTING STG LOW LVL WAA AHD OF THE 850 MB TROF ON WED WITH
THE 850 MB TEMPS WRMG TO 2 TO 8 DGRS C PER THE NAM MDL FCST BY 00Z
THU...NOT QUITE THIS WRM PER THE GFS MDL 850 MB TEMP FCST AT THE
SAME TIME BUT IT STILL DEPICTED A SIGNIFICANT WRMG TREND. ALSO
THERE SHOULD BE PLENTY OF SOLAR INSOLATION ON WED WITH LTL CLOUDS
EXPECTED. THE WK SFC TROF WILL LOSE ITS IDENTITY AS IT MOVES SEWD
THRU THE CWA WED AFTN WITH INCRSG SWLY SFC WNDS ON THU AND EVEN
WARMER AIR OVER THE CWA. BOTH THE NAM AND GFS MDLS BRING THE 8
DGR C 850 MB ISOTHERM NEWD TO NR STL BY THU AFTN. HIGH TEMPS ON
THU SHOULD MAKE IT AT LEAST INTO THE LWR 50S ACRS THE SWRN PTN OF
THE CWA. A STG CDFNT WILL MOVE SEWD THRU THE CWA LT THU NGT AND
FRI MRNG ENDING THIS WRMG TREND. DO NOT SEE MUCH MID-UPR LVL FRCG
OVER MO IL WITH THIS CDFNT...PLUS IT APRS THAT THE LOW LVL
MOISTURE ALONG AND JUST AHD OF THIS FNT WILL BE LIMITED...SO
EXPECTING LTL IF ANY PCPN WITH THIS FRONTAL PASSAGE. THE MAIN
EFFECT WILL BE MUCH COLDER TEMPERATURES ON FRI AND FRI NGT AS A
STG SFC RDG BLDS SEWD INTO THE CWA BHND THE CDFNT WITH LOW LVL
NWLY WNDS BRINGING MUCH COLDER AIR BACK INTO THE REGION.
GKS
&&
.AVIATION...
/1144 PM CST MON JAN 19 2009/
FOR THE 06Z TAFS...
CIGS REMAIN THE CHALLENGE OF THE FORECAST. THERE`S A CORRIDOR OF
VFR OVER THE BI-STATE SANDWICHED BETWEEN TO AREAS OF MVFR OVER
SOUTHERN ILLINOIS AND WESTERN MISSOURI. THINK THIS GENERAL PATTERN
WILL CONTINUE THROUGH THE REST OF THE NIGHT...WITH AN INTERMITTENT
PERIOD OF LIGHT SNOW WHICH WILL BRING CONDITIONS DOWN TO MVFR BRIEFLY.
AFTER THE UPPER LEVEL SYSTEM WHICH IS BRINGING US THIS WEATHER
MOVES SOUTH OF THE AREA TUESDAY MORNING...CIGS SHOULD REMAIN
VFR...SCATTERING OUT IN THE LATE AFTERNOON OR EARLY EVENING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 200549
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1149 PM CST MON JAN 19 2009
.UPDATE...
/854 PM CST MON JAN 19 2009/
UPDATED FORECAST TO CONFINE LIKELY POPS THROUGH 08Z OVER IL. THIS
LINES UP WELL WITH N-S ORIENTED BAND OF -SN ALREADY EXTENDING
FROM S CNTRL IL BACK UP INTO S CNTRL WI. THIS BAND WILL LIE ON THE
EAST SIDE OF VORT MAX CURRENTLY MOVING QUICKLY SOUTH OVER ERN IA.
HAVE LOWERERED POPS OVER MO GOING WITH JUST ISOLD/SCT -SNSH TO
ACCOUNT FOR SNOW OVER CENTRAL IA. SPEED OF VORT SUGGESTS THAT IT
SHOULD MOVE SOUTH OF THE CWA BY 08Z...SO HAVE LOW CHANCE OR JUST
FLURRIES AFTER THAT.
INCREASE CLOUD COVER THROUGH 18Z TUESDAY AS RUC/NAM IS SHOWING
ABUNDANT LOW LEVEL MOISTURE WITH CYCLONIC FLOW. FLOW THEN TURNS
ANTICYCLONIC AND MOISTURE BECOMES SHALLOWER IN THE AFTERNOON SO
STILL HAVE PARTLY CLOUDY GOING.
TEMPERATURES HAVE BEEN ADJUSTED SLIGHTLY LOWER IN THE MORNING TO
ACCOUNT FOR MORE CLOUDS...BUT GOING LOW TONIGHT AND HIGH TOMORROW
STILL LOOKS GOOD.
BRITT
&&
.DISCUSSION...
/135 PM CST MON JAN 19 2009/
MODELS IN GOOD AGREEMENT ON MASS FIELDS THRU THE NEXT FEW DAYS...
ADVERTISING HIGHLY AMPLIFIED FLOW TO MODERATE SIGNIFICANTLY OVER THE
NEXT FEW DAYS. THE REGIME THAT IS PRETTY TYPICAL OF WINTER AND HAS
BEEN ELEVATED TO NEW HEIGHTS IN THE PAST WEEK OR SO WITH A LONGWAVE
RIDGE OVER THE WRN CONUS AND TROF OVER THE ERN CONUS WILL TRANSITION
DURING MID WEEK TO A SPLIT FLOW REGIME OVER THE WRN CONUS AND A MUCH
MORE PROGRESSIVE FLOW PATTERN FOR AREAS DOWNSTREAM OVER THE CNTRL
AND ERN CONUS. TWO SHORTWAVES OF NOTE THRU THURSDAY...THE FIRST WILL
PASS THRU TONIGHT...MAINLY THIS EVENING...AND THE SECOND ON
WEDNESDAY. AT THE SURFACE...NW-N FLOW TONIGHT WILL CONTINUE INTO
TUESDAY UNTIL A WEAK RIDGE PASSES THRU LATE TUESDAY AND EARLY
TUESDAY NIGHT. THIS RIDGE WILL PASS TO THE E TUESDAY NIGHT AND BEGIN
A MODERATING SLY FLOW THAT WILL MORE-OR-LESS CONTINUE UNINTERRUPTED
THRU LATE THURSDAY.
THE FIRST SHORTWAVE DOESN/T CARRY MUCH MOISTURE...BUT DOES PACK
QUITE A PUNCH WITH LIFT...AND SO GIVEN A COLUMN THAT IS AOB NORMAL
FOR MID JANUARY...SHOULD RESULT IN REASONABLY HI PROBS FOR PCPN BUT
AMOUNTS WILL BE ON THE LO SIDE. HAVE BUMPED POPS TO LIKELY OVER MUCH
OF THE AREA...NAMELY THE NRN TWO-THIRDS OF THE FA NEAR AND E OF THE
MS RIVER. WE EXPECT A LIGHT DUSTING AS WITH PREVIOUS FCSTS...WITH
SOME LOCNS SEEING AS MUCH AS A HALF INCH. LEANED ON THE WARM SIDE
WITH MOS WITH THE NEXT WAVE OF CLOUDS EXPECTED.
FOR TUESDAY...DECENT SUBSIDENCE SHOULD END ANY THREAT FOR
ACCUMULATING SNOW...BUT STRAGGLER SC DECK THAT WILL BE SLOW TO CLEAR
OUT MAY STILL RESULT IN A FEW FLURRIES AS WE SAW TODAY IN SOME
SPOTS. HAVE LEFT THE FLURRY MENTION IN THERE FOR THE MORNING HOURS.
OTHERWISE...SHOULD SEE SUN BY AFTERNOON.
PREFER THE WARMER MOS TUESDAY NIGHT WITH SLY FLOW...AND WENT ABOVE
MOS TEMPS ON WEDNESDAY WITH DECENT SUNSHINE EXPECTED AND SW-W
FLOW...AS MOS HAS STUGGLED A BIT LATELY IN KEEPING PACE WITH
INTRUSIONS OF WARM AIR ALBEIT BRIEF. CONTINUED THE MILD STRING THRU
THURSDAY AS TEMPS EDGE INTO THE 50S.
FOR THE EXTENDED PERIOD (THURSDAY NIGHT - MONDAY)...THE MILD SPELL
WILL COME TO AN END EARLY IN THE PERIOD WITH A STRONG CDFNT MOVING
THRU ON FRIDAY. LARGE AND COLD HI PRES WILL THEN BUILD IN BEHIND
IT...DOMINATING THE WX THRU SATURDAY AND SUNDAY AND WENT ON THE COLD
END OF MOS...IF NOT BELOW...THRU THIS PERIOD. THE NEXT CHANCE FOR
PCPN...AND FIRST SINCE TONIGHT...WILL COME PERHAPS SUNDAY NIGHT AND
MONDAY AS A PAC SYSTEM APPROACHES FROM THE W. FOR NOW HAVE ONLY
PLACED IN SLIGHT CHANCES AND WAIT AND SEE HOW MODELS WILL HANDLE
THIS OVER THE NEXT DAY OR TWO. EARLY INDICATIONS ARE THAT IT MAY
BEGIN AS WINTRY MIXED PCPN AND THEN TRANSITION TO RAIN BEFORE ENDING
BRIEFLY AS A LITTLE SNOW WITH PASSAGE OF ANOTHER CDFNT. LOTS OF TIME
TO WATCH THOUGH.
TES
&&
.AVIATION...
/1144 PM CST MON JAN 19 2009/
FOR THE 06Z TAFS...
CIGS REMAIN THE CHALLENGE OF THE FORECAST. THERE`S A CORRIDOR OF
VFR OVER THE BI-STATE SANDWICHED BETWEEN TO AREAS OF MVFR OVER
SOUTHERN ILLINOIS AND WESTERN MISSOURI. THINK THIS GENERAL PATTERN
WILL CONTINUE THROUGH THE REST OF THE NIGHT...WITH AN INTERMITTENT
PERIOD OF LIGHT SNOW WHICH WILL BRING CONDITIONS DOWN TO MVFR BRIEFLY.
AFTER THE UPPER LEVEL SYSTEM WHICH IS BRINGING US THIS WEATHER
MOVES SOUTH OF THE AREA TUESDAY MORNING...CIGS SHOULD REMAIN
VFR...SCATTERING OUT IN THE LATE AFTERNOON OR EARLY EVENING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 200315
AFDLSX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ST LOUIS MO
915 PM CST MON JAN 19 2009
.UPDATE...
/854 PM CST MON JAN 19 2009/
UPDATED FORECAST TO CONFINE LIKELY POPS THROUGH 08Z OVER IL. THIS
LINES UP WELL WITH N-S ORIENTED BAND OF -SN ALREADY EXTENDING
FROM S CNTRL IL BACK UP INTO S CNTRL WI. THIS BAND WILL LIE ON THE
EAST SIDE OF VORT MAX CURRENTLY MOVING QUICKLY SOUTH OVER ERN IA.
HAVE LOWERERED POPS OVER MO GOING WITH JUST ISOLD/SCT -SNSH TO
ACCOUNT FOR SNOW OVER CENTRAL IA. SPEED OF VORT SUGGESTS THAT IT
SHOULD MOVE SOUTH OF THE CWA BY 08Z...SO HAVE LOW CHANCE OR JUST
FLURRIES AFTER THAT.
INCREASE CLOUD COVER THROUGH 18Z TUESDAY AS RUC/NAM IS SHOWING
ABUNDANT LOW LEVEL MOISTURE WITH CYCLONIC FLOW. FLOW THEN TURNS
ANTICYCLONIC AND MOISTURE BECOMES SHALLOWER IN THE AFTERNOON SO
STILL HAVE PARTLY CLOUDY GOING.
TEMPERATURES HAVE BEEN ADJUSTED SLIGHTLY LOWER IN THE MORNING TO
ACCOUNT FOR MORE CLOUDS...BUT GOING LOW TONIGHT AND HIGH TOMORROW
STILL LOOKS GOOD.
BRITT
&&
.DISCUSSION...
/135 PM CST MON JAN 19 2009/
MODELS IN GOOD AGREEMENT ON MASS FIELDS THRU THE NEXT FEW DAYS...
ADVERTISING HIGHLY AMPLIFIED FLOW TO MODERATE SIGNIFICANTLY OVER THE
NEXT FEW DAYS. THE REGIME THAT IS PRETTY TYPICAL OF WINTER AND HAS
BEEN ELEVATED TO NEW HEIGHTS IN THE PAST WEEK OR SO WITH A LONGWAVE
RIDGE OVER THE WRN CONUS AND TROF OVER THE ERN CONUS WILL TRANSITION
DURING MID WEEK TO A SPLIT FLOW REGIME OVER THE WRN CONUS AND A MUCH
MORE PROGRESSIVE FLOW PATTERN FOR AREAS DOWNSTREAM OVER THE CNTRL
AND ERN CONUS. TWO SHORTWAVES OF NOTE THRU THURSDAY...THE FIRST WILL
PASS THRU TONIGHT...MAINLY THIS EVENING...AND THE SECOND ON
WEDNESDAY. AT THE SURFACE...NW-N FLOW TONIGHT WILL CONTINUE INTO
TUESDAY UNTIL A WEAK RIDGE PASSES THRU LATE TUESDAY AND EARLY
TUESDAY NIGHT. THIS RIDGE WILL PASS TO THE E TUESDAY NIGHT AND BEGIN
A MODERATING SLY FLOW THAT WILL MORE-OR-LESS CONTINUE UNINTERRUPTED
THRU LATE THURSDAY.
THE FIRST SHORTWAVE DOESN/T CARRY MUCH MOISTURE...BUT DOES PACK
QUITE A PUNCH WITH LIFT...AND SO GIVEN A COLUMN THAT IS AOB NORMAL
FOR MID JANUARY...SHOULD RESULT IN REASONABLY HI PROBS FOR PCPN BUT
AMOUNTS WILL BE ON THE LO SIDE. HAVE BUMPED POPS TO LIKELY OVER MUCH
OF THE AREA...NAMELY THE NRN TWO-THIRDS OF THE FA NEAR AND E OF THE
MS RIVER. WE EXPECT A LIGHT DUSTING AS WITH PREVIOUS FCSTS...WITH
SOME LOCNS SEEING AS MUCH AS A HALF INCH. LEANED ON THE WARM SIDE
WITH MOS WITH THE NEXT WAVE OF CLOUDS EXPECTED.
FOR TUESDAY...DECENT SUBSIDENCE SHOULD END ANY THREAT FOR
ACCUMULATING SNOW...BUT STRAGGLER SC DECK THAT WILL BE SLOW TO CLEAR
OUT MAY STILL RESULT IN A FEW FLURRIES AS WE SAW TODAY IN SOME
SPOTS. HAVE LEFT THE FLURRY MENTION IN THERE FOR THE MORNING HOURS.
OTHERWISE...SHOULD SEE SUN BY AFTERNOON.
PREFER THE WARMER MOS TUESDAY NIGHT WITH SLY FLOW...AND WENT ABOVE
MOS TEMPS ON WEDNESDAY WITH DECENT SUNSHINE EXPECTED AND SW-W
FLOW...AS MOS HAS STUGGLED A BIT LATELY IN KEEPING PACE WITH
INTRUSIONS OF WARM AIR ALBEIT BRIEF. CONTINUED THE MILD STRING THRU
THURSDAY AS TEMPS EDGE INTO THE 50S.
FOR THE EXTENDED PERIOD (THURSDAY NIGHT - MONDAY)...THE MILD SPELL
WILL COME TO AN END EARLY IN THE PERIOD WITH A STRONG CDFNT MOVING
THRU ON FRIDAY. LARGE AND COLD HI PRES WILL THEN BUILD IN BEHIND
IT...DOMINATING THE WX THRU SATURDAY AND SUNDAY AND WENT ON THE COLD
END OF MOS...IF NOT BELOW...THRU THIS PERIOD. THE NEXT CHANCE FOR
PCPN...AND FIRST SINCE TONIGHT...WILL COME PERHAPS SUNDAY NIGHT AND
MONDAY AS A PAC SYSTEM APPROACHES FROM THE W. FOR NOW HAVE ONLY
PLACED IN SLIGHT CHANCES AND WAIT AND SEE HOW MODELS WILL HANDLE
THIS OVER THE NEXT DAY OR TWO. EARLY INDICATIONS ARE THAT IT MAY
BEGIN AS WINTRY MIXED PCPN AND THEN TRANSITION TO RAIN BEFORE ENDING
BRIEFLY AS A LITTLE SNOW WITH PASSAGE OF ANOTHER CDFNT. LOTS OF TIME
TO WATCH THOUGH.
TES
&&
.AVIATION...
/540 PM CST MON JAN 19 2009/
FOR THE 00Z TAFS...
PRIMARY CONCERN FOR AVIATORS TONIGHT...AS HAS BEEN THE PAST FEW
NIGHTS...WILL BE CIGS AND POSSIBILITY OF SNOW SHOWERS AS AN UPPER
LEVEL WAVE ROTATES ACROSS THE AREA. CIGS OVER IOWA AND NORTHERN
ILLINOIS ARE IN THE MVFR RANGE...WITH SOME SPOTTY IFR IN PLACES
WHERE THE SNOW IS FALLING. THERE`S A LARGE GAP IN THESE LOWER CIGS
IN EASTERN IOWA AND WEST CENTRAL ILLINOIS. MODELS ARE INDICATING
THAT THIS GAP WILL FILL IN DURING THE EVENING AS THE WAVE MOVES
SOUTH INTO THE AREA. HOWEVER...I HAVE MY DOUBTS. MODEL PERFORMANCE
HAS BEEN POOR THE PAST FEW DAYS WITH RESPECT TO CIGS...SO I THINK
PREVAILING CIGS WILL BE AOA 2000FT AND COULD BE AOA 3000FT...STILL
CAN`T RULE OUT SOME PATCHY LOWER CIGS IN SNOW SHOWERS THO...SO
HAVE LEFT TEMPOS FOR 1500-2000FT CIGS IN TERMINALS. AFTER WAVE
EXITS THE REGION TUESDAY MORNING CIGS SHOULD LIFT TO VFR RANGE AND
SCATTER OUT IN THE LATE AFTERNOON OR EARLY EVENING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 200000
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
600 PM CST MON JAN 19 2009
.DISCUSSION...
/135 PM CST MON JAN 19 2009/
MODELS IN GOOD AGREEMENT ON MASS FIELDS THRU THE NEXT FEW DAYS...
ADVERTISING HIGHLY AMPLIFIED FLOW TO MODERATE SIGNIFICANTLY OVER THE
NEXT FEW DAYS. THE REGIME THAT IS PRETTY TYPICAL OF WINTER AND HAS
BEEN ELEVATED TO NEW HEIGHTS IN THE PAST WEEK OR SO WITH A LONGWAVE
RIDGE OVER THE WRN CONUS AND TROF OVER THE ERN CONUS WILL TRANSITION
DURING MID WEEK TO A SPLIT FLOW REGIME OVER THE WRN CONUS AND A MUCH
MORE PROGRESSIVE FLOW PATTERN FOR AREAS DOWNSTREAM OVER THE CNTRL
AND ERN CONUS. TWO SHORTWAVES OF NOTE THRU THURSDAY...THE FIRST WILL
PASS THRU TONIGHT...MAINLY THIS EVENING...AND THE SECOND ON
WEDNESDAY. AT THE SURFACE...NW-N FLOW TONIGHT WILL CONTINUE INTO
TUESDAY UNTIL A WEAK RIDGE PASSES THRU LATE TUESDAY AND EARLY
TUESDAY NIGHT. THIS RIDGE WILL PASS TO THE E TUESDAY NIGHT AND BEGIN
A MODERATING SLY FLOW THAT WILL MORE-OR-LESS CONTINUE UNINTERRUPTED
THRU LATE THURSDAY.
THE FIRST SHORTWAVE DOESN/T CARRY MUCH MOISTURE...BUT DOES PACK
QUITE A PUNCH WITH LIFT...AND SO GIVEN A COLUMN THAT IS AOB NORMAL
FOR MID JANUARY...SHOULD RESULT IN REASONABLY HI PROBS FOR PCPN BUT
AMOUNTS WILL BE ON THE LO SIDE. HAVE BUMPED POPS TO LIKELY OVER MUCH
OF THE AREA...NAMELY THE NRN TWO-THIRDS OF THE FA NEAR AND E OF THE
MS RIVER. WE EXPECT A LIGHT DUSTING AS WITH PREVIOUS FCSTS...WITH
SOME LOCNS SEEING AS MUCH AS A HALF INCH. LEANED ON THE WARM SIDE
WITH MOS WITH THE NEXT WAVE OF CLOUDS EXPECTED.
FOR TUESDAY...DECENT SUBSIDENCE SHOULD END ANY THREAT FOR
ACCUMULATING SNOW...BUT STRAGGLER SC DECK THAT WILL BE SLOW TO CLEAR
OUT MAY STILL RESULT IN A FEW FLURRIES AS WE SAW TODAY IN SOME
SPOTS. HAVE LEFT THE FLURRY MENTION IN THERE FOR THE MORNING HOURS.
OTHERWISE...SHOULD SEE SUN BY AFTERNOON.
PREFER THE WARMER MOS TUESDAY NIGHT WITH SLY FLOW...AND WENT ABOVE
MOS TEMPS ON WEDNESDAY WITH DECENT SUNSHINE EXPECTED AND SW-W
FLOW...AS MOS HAS STUGGLED A BIT LATELY IN KEEPING PACE WITH
INTRUSIONS OF WARM AIR ALBEIT BRIEF. CONTINUED THE MILD STRING THRU
THURSDAY AS TEMPS EDGE INTO THE 50S.
FOR THE EXTENDED PERIOD (THURSDAY NIGHT - MONDAY)...THE MILD SPELL
WILL COME TO AN END EARLY IN THE PERIOD WITH A STRONG CDFNT MOVING
THRU ON FRIDAY. LARGE AND COLD HI PRES WILL THEN BUILD IN BEHIND
IT...DOMINATING THE WX THRU SATURDAY AND SUNDAY AND WENT ON THE COLD
END OF MOS...IF NOT BELOW...THRU THIS PERIOD. THE NEXT CHANCE FOR
PCPN...AND FIRST SINCE TONIGHT...WILL COME PERHAPS SUNDAY NIGHT AND
MONDAY AS A PAC SYSTEM APPROACHES FROM THE W. FOR NOW HAVE ONLY
PLACED IN SLIGHT CHANCES AND WAIT AND SEE HOW MODELS WILL HANDLE
THIS OVER THE NEXT DAY OR TWO. EARLY INDICATIONS ARE THAT IT MAY
BEGIN AS WINTRY MIXED PCPN AND THEN TRANSITION TO RAIN BEFORE ENDING
BRIEFLY AS A LITTLE SNOW WITH PASSAGE OF ANOTHER CDFNT. LOTS OF TIME
TO WATCH THOUGH.
TES
&&
.AVIATION...
/540 PM CST MON JAN 19 2009/
FOR THE 00Z TAFS...
PRIMARY CONCERN FOR AVIATORS TONIGHT...AS HAS BEEN THE PAST FEW
NIGHTS...WILL BE CIGS AND POSSIBILITY OF SNOW SHOWERS AS AN UPPER
LEVEL WAVE ROTATES ACROSS THE AREA. CIGS OVER IOWA AND NORTHERN
ILLINOIS ARE IN THE MVFR RANGE...WITH SOME SPOTTY IFR IN PLACES
WHERE THE SNOW IS FALLING. THERE`S A LARGE GAP IN THESE LOWER CIGS
IN EASTERN IOWA AND WEST CENTRAL ILLINOIS. MODELS ARE INDICATING
THAT THIS GAP WILL FILL IN DURING THE EVENING AS THE WAVE MOVES
SOUTH INTO THE AREA. HOWEVER...I HAVE MY DOUBTS. MODEL PERFORMANCE
HAS BEEN POOR THE PAST FEW DAYS WITH RESPECT TO CIGS...SO I THINK
PREVAILING CIGS WILL BE AOA 2000FT AND COULD BE AOA 3000FT...STILL
CAN`T RULE OUT SOME PATCHY LOWER CIGS IN SNOW SHOWERS THO...SO
HAVE LEFT TEMPOS FOR 1500-2000FT CIGS IN TERMINALS. AFTER WAVE
EXITS THE REGION TUESDAY MORNING CIGS SHOULD LIFT TO VFR RANGE AND
SCATTER OUT IN THE LATE AFTERNOON OR EARLY EVENING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 191935
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
135 PM CST MON JAN 19 2009
.DISCUSSION...
/135 PM CST MON JAN 19 2009/
MODELS IN GOOD AGREEMENT ON MASS FIELDS THRU THE NEXT FEW DAYS...
ADVERTISING HIGHLY AMPLIFIED FLOW TO MODERATE SIGNIFICANTLY OVER THE
NEXT FEW DAYS. THE REGIME THAT IS PRETTY TYPICAL OF WINTER AND HAS
BEEN ELEVATED TO NEW HEIGHTS IN THE PAST WEEK OR SO WITH A LONGWAVE
RIDGE OVER THE WRN CONUS AND TROF OVER THE ERN CONUS WILL TRANSITION
DURING MID WEEK TO A SPLIT FLOW REGIME OVER THE WRN CONUS AND A MUCH
MORE PROGRESSIVE FLOW PATTERN FOR AREAS DOWNSTREAM OVER THE CNTRL
AND ERN CONUS. TWO SHORTWAVES OF NOTE THRU THURSDAY...THE FIRST WILL
PASS THRU TONIGHT...MAINLY THIS EVENING...AND THE SECOND ON
WEDNESDAY. AT THE SURFACE...NW-N FLOW TONIGHT WILL CONTINUE INTO
TUESDAY UNTIL A WEAK RIDGE PASSES THRU LATE TUESDAY AND EARLY
TUESDAY NIGHT. THIS RIDGE WILL PASS TO THE E TUESDAY NIGHT AND BEGIN
A MODERATING SLY FLOW THAT WILL MORE-OR-LESS CONTINUE UNINTERRUPTED
THRU LATE THURSDAY.
THE FIRST SHORTWAVE DOESN/T CARRY MUCH MOISTURE...BUT DOES PACK
QUITE A PUNCH WITH LIFT...AND SO GIVEN A COLUMN THAT IS AOB NORMAL
FOR MID JANUARY...SHOULD RESULT IN REASONABLY HI PROBS FOR PCPN BUT
AMOUNTS WILL BE ON THE LO SIDE. HAVE BUMPED POPS TO LIKELY OVER MUCH
OF THE AREA...NAMELY THE NRN TWO-THIRDS OF THE FA NEAR AND E OF THE
MS RIVER. WE EXPECT A LIGHT DUSTING AS WITH PREVIOUS FCSTS...WITH
SOME LOCNS SEEING AS MUCH AS A HALF INCH. LEANED ON THE WARM SIDE
WITH MOS WITH THE NEXT WAVE OF CLOUDS EXPECTED.
FOR TUESDAY...DECENT SUBSIDENCE SHOULD END ANY THREAT FOR
ACCUMULATING SNOW...BUT STRAGGLER SC DECK THAT WILL BE SLOW TO CLEAR
OUT MAY STILL RESULT IN A FEW FLURRIES AS WE SAW TODAY IN SOME
SPOTS. HAVE LEFT THE FLURRY MENTION IN THERE FOR THE MORNING HOURS.
OTHERWISE...SHOULD SEE SUN BY AFTERNOON.
PREFER THE WARMER MOS TUESDAY NIGHT WITH SLY FLOW...AND WENT ABOVE
MOS TEMPS ON WEDNESDAY WITH DECENT SUNSHINE EXPECTED AND SW-W
FLOW...AS MOS HAS STUGGLED A BIT LATELY IN KEEPING PACE WITH
INTRUSIONS OF WARM AIR ALBEIT BRIEF. CONTINUED THE MILD STRING THRU
THURSDAY AS TEMPS EDGE INTO THE 50S.
FOR THE EXTENDED PERIOD (THURSDAY NIGHT - MONDAY)...THE MILD SPELL
WILL COME TO AN END EARLY IN THE PERIOD WITH A STRONG CDFNT MOVING
THRU ON FRIDAY. LARGE AND COLD HI PRES WILL THEN BUILD IN BEHIND
IT...DOMINATING THE WX THRU SATURDAY AND SUNDAY AND WENT ON THE COLD
END OF MOS...IF NOT BELOW...THRU THIS PERIOD. THE NEXT CHANCE FOR
PCPN...AND FIRST SINCE TONIGHT...WILL COME PERHAPS SUNDAY NIGHT AND
MONDAY AS A PAC SYSTEM APPROACHES FROM THE W. FOR NOW HAVE ONLY
PLACED IN SLIGHT CHANCES AND WAIT AND SEE HOW MODELS WILL HANDLE
THIS OVER THE NEXT DAY OR TWO. EARLY INDICATIONS ARE THAT IT MAY
BEGIN AS WINTRY MIXED PCPN AND THEN TRANSITION TO RAIN BEFORE ENDING
BRIEFLY AS A LITTLE SNOW WITH PASSAGE OF ANOTHER CDFNT. LOTS OF TIME
TO WATCH THOUGH.
TES
&&
.AVIATION...
/1138 AM CST MON JAN 19 2009/
FOR THE 18Z TAFS...MID CLOUDS OVER IA WILL DRIFT S THIS AFTERNOON.
CIGS WILL GRADUALLY LOWER THIS EVENING AS ANOTHER POTENT SHORTWAVE
MOVES S ACROSS THE REGION. THIS SHORTWAVE WILL BRING A CHANCE OF
SNOW TO THE TAF SITES LATE THIS EVENING. CIGS WILL GRADUALLY LIFT
TUES MORNING AS THE SYSTEM PULLS OUT OF THE AREA. CIGS ARE
EXPECTED TO REMAIN MVFR LONGER AT UIN AS LOWER CLOUDS MOVE OFF OF
THE SNOW FIELD IN IA. WINDS WILL LIGHTEN LATE TUES MORNING.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 191748
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1148 AM CST MON JAN 19 2009
.DISCUSSION...
/228 AM CST MON JAN 19 2009/
THE SHRTWV TROF PUSHING SOUTH THROUGH THE ERN OH VLY AND MID MS
VLY HAS PRODUCED A FRAGMENTED ARCING BAND OF LIGHT SNOW. A DUSTING
SEEMS TO BE ABOUT THE BEST IT HAS GENERATED WITHIN THE CWA INCLUDING
HERE AT THE WFO. THE MAIN CLEARING LINE WASN`T TOO FAR BEHIND THE
BACK EDGE OF ANY SNOW ALTHOUGH THERE WAS A LITTLE FRAGMENTED
STRATUS LINGERING BEHIND THIS AS WELL. SOME DECENT CAA WAS ALSO
UNDERWAY WITH NORTHERLY WINDS IN THE WAKE OF THE ASSOCIATED SFC
SYSTEM. EXTRAPOLATION OF THE CLEARING LINE WOULD SUGGEST THAT
THE GREATEST CLOUD COVER WILL BE CONFINED TO CENTRAL AND SE MO
AND SRN IL AT DAYBREAK WITH AN ATTENDANT THREAT OF SCT FLURRIES.
THESE LOW CLOUDS SHOULD CONT PUSHING SOUTH DURING THE FIRST PART
OF THE MORNING. THERE WILL LIKELY BE SOME HIGH CLOUDS SKIRTING
ACROSS THE AREA DURING THE DAY...BUT THE NEXT BIG THRUST OF CLOUD
COVER SHOULDN`T BE UNTIL THE LATER PART OF THE AFTERNOON WHEN THE
SHRTWV NOW OVER MANITOBA BEGINS TO IMPACT THE REGION. THIS LATER
AND FAIRLY STRONG SHORT WAVE WILL QUICKLY DIG SSEWD ACROSS THE
REGION TONIGHT...A BIT FURTHER WEST THAN THE CURRENT ONE. THE
MODELS CONTINUE TO DEPICT SOME GOOD FORCING AND ASCENT WITH THIS
TROF...AND IT WILL LIKELY PRODUCE A BAND OF LIGHT SNOW. THE
QUESTION IS HOW MUCH OF THIS WILL BE MEASURABLE. I THINK MOST
LOCATIONS WILL SET YET ANOTHER DUSTING...LOCALLY PERHAPS A TAD
MORE. THE POPS TONIGHT REFLECT THE UNCERTAINTY IN THE MEASURABLE
COMPONENT TO THE SNOWFALL. THIS SHORT WAVE WILL ALSO BRING A
REFORCING SHOT OF COLD AIR TO THE COLD BLAST INFILTRATING THE CWA
ATTM. TEMPERATURES FOR THE NEXT FEW DAYS SHOULD BE ON AVERAGE 10
DEGS OR SO COLDER THAN YDA. IT STILL LOOKS LIKE THE TEMPERATURE
MODERATION SHOULD GET UNDERWAY MIDWEEK WITH WAA ALREADY DEVELOPING
ON TUESDAY NIGHT AND HEIGHTS ALOFT RISING AS THE UPPER TROF
DEPARTS EWD.
GLASS
&&
.AVIATION...
/1138 AM CST MON JAN 19 2009/
FOR THE 18Z TAFS...MID CLOUDS OVER IA WILL DRIFT S THIS AFTERNOON.
CIGS WILL GRADUALLY LOWER THIS EVENING AS ANOTHER POTENT SHORTWAVE
MOVES S ACROSS THE REGION. THIS SHORTWAVE WILL BRING A CHANCE OF
SNOW TO THE TAF SITES LATE THIS EVENING. CIGS WILL GRADUALLY LIFT
TUES MORNING AS THE SYSTEM PULLS OUT OF THE AREA. CIGS ARE
EXPECTED TO REMAIN MVFR LONGER AT UIN AS LOWER CLOUDS MOVE OFF OF
THE SNOW FIELD IN IA. WINDS WILL LIGHTEN LATE TUES MORNING.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 190840
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
240 AM CST MON JAN 19 2009
.DISCUSSION...
/228 AM CST MON JAN 19 2009/
THE SHRTWV TROF PUSHING SOUTH THROUGH THE ERN OH VLY AND MID MS
VLY HAS PRODUCED A FRAGMENTED ARCING BAND OF LIGHT SNOW. A DUSTING
SEEMS TO BE ABOUT THE BEST IT HAS GENERATED WITHIN THE CWA INCLUDING
HERE AT THE WFO. THE MAIN CLEARING LINE WASN`T TOO FAR BEHIND THE
BACK EDGE OF ANY SNOW ALTHOUGH THERE WAS A LITTLE FRAGMENTED
STRATUS LINGERING BEHIND THIS AS WELL. SOME DECENT CAA WAS ALSO
UNDERWAY WITH NORTHERLY WINDS IN THE WAKE OF THE ASSOCIATED SFC
SYSTEM. EXTRAPOLATION OF THE CLEARING LINE WOULD SUGGEST THAT
THE GREATEST CLOUD COVER WILL BE CONFINED TO CENTRAL AND SE MO
AND SRN IL AT DAYBREAK WITH AN ATTENDANT THREAT OF SCT FLURRIES.
THESE LOW CLOUDS SHOULD CONT PUSHING SOUTH DURING THE FIRST PART
OF THE MORNING. THERE WILL LIKELY BE SOME HIGH CLOUDS SKIRTING
ACROSS THE AREA DURING THE DAY...BUT THE NEXT BIG THRUST OF CLOUD
COVER SHOULDN`T BE UNTIL THE LATER PART OF THE AFTERNOON WHEN THE
SHRTWV NOW OVER MANITOBA BEGINS TO IMPACT THE REGION. THIS LATER
AND FAIRLY STRONG SHORT WAVE WILL QUICKLY DIG SSEWD ACROSS THE
REGION TONIGHT...A BIT FURTHER WEST THAN THE CURRENT ONE. THE
MODELS CONTINUE TO DEPICT SOME GOOD FORCING AND ASCENT WITH THIS
TROF...AND IT WILL LIKELY PRODUCE A BAND OF LIGHT SNOW. THE
QUESTION IS HOW MUCH OF THIS WILL BE MEASURABLE. I THINK MOST
LOCATIONS WILL SET YET ANOTHER DUSTING...LOCALLY PERHAPS A TAD
MORE. THE POPS TONIGHT REFLECT THE UNCERTAINTY IN THE MEASURABLE
COMPONENT TO THE SNOWFALL. THIS SHORT WAVE WILL ALSO BRING A
REFORCING SHOT OF COLD AIR TO THE COLD BLAST INFILTRATING THE CWA
ATTM. TEMPERATURES FOR THE NEXT FEW DAYS SHOULD BE ON AVERAGE 10
DEGS OR SO COLDER THAN YDA. IT STILL LOOKS LIKE THE TEMPERATURE
MODERATION SHOULD GET UNDERWAY MIDWEEK WITH WAA ALREADY DEVELOPING
ON TUESDAY NIGHT AND HEIGHTS ALOFT RISING AS THE UPPER TROF
DEPARTS EWD.
GLASS
&&
.AVIATION...
/1126 PM CST SUN JAN 18 2009/
FOR THE 06Z TAFS...
MVFR CIGS CONTINUE TO BE THE PRIMARY CONCERN FOR AVIATORS ACROSS
THE BI-STATE REGION. ALSO...SOME VERY LIGHT SNOW...REDUCING THE
VISIBILITY TO MVFR IN SOME SPOTS WILL AFFECT AREAS ALONG AND EAST
OF THE MISSISSIPPI FOR THE NEXT FEW HOURS. ANY ACCUMULATIONS
SHOULD BE MINIMAL...BUT RUNWAYS AND RAMPS COULD GET SLICK IF LEFT
UNTREATED. THINK PATCHY MVFR CIGS WILL PLAGUE THE REGION THROUGH
SUNRISE...AND LIFT INTO A VFR DECK WITH DAYTIME HEATING. NEXT
UPPER LEVEL WAVE STILL LOOKS TO MOVE OVERHEAD MONDAY EVENING AND
THIS COULD SPREAD SOME MORE WIDESPREAD LIGHT SNOW WITH CIGS BLO
2000FT...AND VSBYS PROBABLY IN THE MVFR RANGE.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 190530
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1130 PM CST SUN JAN 18 2009
.DISCUSSION...
/311 PM CST SUN JAN 18 2009/
ONLY CONCERN IS CHANCES OF LIGHT SNOW THE NEXT TWO NIGHTS. PREFER
THE GFS OVER THAN NAM AS IT HAS BETTER CONTINUITY WITH SHORTWAVE
MOVING DOWN ON THE BACK SIDE OF THE ERN CONUS LONGWAVE TROUGH THAT
WILL CROSS MO/IL ON MONDAY NIGHT. NAM HAS GONE FROM BEING SHALLOWER
THAN THE GFS ON ITS 12Z RUN TO BEING THE ONLY MODEL WITH A CLOSED
LOW BY 06Z TUESDAY ON THE MOST RECENT 18Z RUN.
HAVE UPPED POPS TO LIKELY FOR TONIGHT OVER S CNTRL IL. SNOW HAS
BEEN ON THE INCREASE OVER ERN IA THE PAST FEW HOURS AND GFS IS
SHOWING SOME LARGE SCALE ASCENT ALONG WITH SOME SOME WEAK MID
LEVEL FRONTOGENESIS DEPICTED BY THE RUC. THINK THERE COULD BE SOME
MINOR ACCUMULATIONS UP TO 1/2 INCH OVER THE ERN CWA BEFORE THIS
FORCING MOVES QUICKLY OUT OF THE CWA BETWEEN 06-12Z. HAVE JUST
SLIGHT CHANCES OF SNOW OR FLURRIES TOMORROW AS THERE WILL BE A
DECENT AMOUNT OF LOW LEVEL MOISTURE IN LOW LEVEL CYCLONIC FLOW.
UPPED CHANCE POPS TOMORROW NIGHT AND PUT IN A FEW TENTHS OF
SNOWFALL ON MONDAY NIGHT AS GFS TIME CROSS SECTIONS ARE SHOWING
LARGE SCALE ASCENT COINCIDENT WITH DEEP MOISTURE AOB 500MB.
SHORTWAVE QUICKLY MOVES OUT OF THE CWA LATE ON MONDAY NIGHT AND
HAVE GONE DRY TUESDAY AND WEDNESDAY AS SUBSIDENCE SETS IN A DEEPLY
DRY ATMOSPHERE.
TEMPERATURES ARE A BLEND OF GFS MOS AND SREF MEAN 2M TEMPS WHICH IS
A GOOD A COMPROMISE OF THE OTHER MOS GUIDANCE.
FLOW BECOMES LESS AMPLIFIED MIDWEEK AND THEN IS FAIRLY ZONAL
THROUGH NEXT WEEKEND. GFES IS SHOWING A SIGNIFICANT SPREAD IN
SOLUTIONS WITH THE TIMING OF SHORTWAVES MOVING IN THE THIS
PROGRESSIVE FLOW. HAVE GONE CLOSER TO THE ECWMF`S SOLUTION BECAUSE
IT IS SHOWING BETTER 24 HOUR CONTINUITY...AND IT`S DEPICTION OF
THE MAIN TROUGH AXIS MOVING THROUGH THE GREAT LAKES ON FRIDAY IS
SUPPORTED BY THE UKMET/CANADIAN VS. THE SLOWER OPERATIONAL GFS.
THIS TROUGH WILL A DRAG ACCOMPANYING COLD FRONT THROUGH MO/IL
THURSDAY NIGHT INTO FRIDAY. HAVE LEFT THIS A DRY FRONTAL PASSAGE
FOR NOW BECAUSE OF LIMITED MOISTURE SEEN ON MEDIUM RANGE MODELS.
HAVE ALSO LEFT THE REST OF FORECAST DRY BECAUSE OF THE AFOREMENTIONED
UNCERTAINTY AND THE NEW 12Z RUNS OF THE GFES MEAN/ECWMF KEEP SRN
STREAM QPF SOUTH OF THE CWA. ADJUSTED GFS MOS TEMPS UPWARD IN
THE WARM AIR ADVOCATION AHEAD OF FRIDAY`S FRONT...AND LEANED TOWARD
THE COOLER ECMWF TEMPS OVER THE WEEKEND BASED ON MODEL PREFERENCE.
BRITT
&&
.AVIATION...
/1126 PM CST SUN JAN 18 2009/
FOR THE 06Z TAFS...
MVFR CIGS CONTINUE TO BE THE PRIMARY CONCERN FOR AVIATORS ACROSS
THE BI-STATE REGION. ALSO...SOME VERY LIGHT SNOW...REDUCING THE
VISIBILITY TO MVFR IN SOME SPOTS WILL AFFECT AREAS ALONG AND EAST
OF THE MISSISSIPPI FOR THE NEXT FEW HOURS. ANY ACCUMULATIONS
SHOULD BE MINIMAL...BUT RUNWAYS AND RAMPS COULD GET SLICK IF LEFT
UNTREATED. THINK PATCHY MVFR CIGS WILL PLAGUE THE REGION THROUGH
SUNRISE...AND LIFT INTO A VFR DECK WITH DAYTIME HEATING. NEXT
UPPER LEVEL WAVE STILL LOOKS TO MOVE OVERHEAD MONDAY EVENING AND
THIS COULD SPREAD SOME MORE WIDESPREAD LIGHT SNOW WITH CIGS BLO
2000FT...AND VSBYS PROBABLY IN THE MVFR RANGE.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 190005
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
605 PM CST SUN JAN 18 2009
.DISCUSSION...
/311 PM CST SUN JAN 18 2009/
ONLY CONCERN IS CHANCES OF LIGHT SNOW THE NEXT TWO NIGHTS. PREFER
THE GFS OVER THAN NAM AS IT HAS BETTER CONTINUITY WITH SHORTWAVE
MOVING DOWN ON THE BACK SIDE OF THE ERN CONUS LONGWAVE TROUGH THAT
WILL CROSS MO/IL ON MONDAY NIGHT. NAM HAS GONE FROM BEING SHALLOWER
THAN THE GFS ON ITS 12Z RUN TO BEING THE ONLY MODEL WITH A CLOSED
LOW BY 06Z TUESDAY ON THE MOST RECENT 18Z RUN.
HAVE UPPED POPS TO LIKELY FOR TONIGHT OVER S CNTRL IL. SNOW HAS
BEEN ON THE INCREASE OVER ERN IA THE PAST FEW HOURS AND GFS IS
SHOWING SOME LARGE SCALE ASCENT ALONG WITH SOME SOME WEAK MID
LEVEL FRONTOGENESIS DEPICTED BY THE RUC. THINK THERE COULD BE SOME
MINOR ACCUMULATIONS UP TO 1/2 INCH OVER THE ERN CWA BEFORE THIS
FORCING MOVES QUICKLY OUT OF THE CWA BETWEEN 06-12Z. HAVE JUST
SLIGHT CHANCES OF SNOW OR FLURRIES TOMORROW AS THERE WILL BE A
DECENT AMOUNT OF LOW LEVEL MOISTURE IN LOW LEVEL CYCLONIC FLOW.
UPPED CHANCE POPS TOMORROW NIGHT AND PUT IN A FEW TENTHS OF
SNOWFALL ON MONDAY NIGHT AS GFS TIME CROSS SECTIONS ARE SHOWING
LARGE SCALE ASCENT COINCIDENT WITH DEEP MOISTURE AOB 500MB.
SHORTWAVE QUICKLY MOVES OUT OF THE CWA LATE ON MONDAY NIGHT AND
HAVE GONE DRY TUESDAY AND WEDNESDAY AS SUBSIDENCE SETS IN A DEEPLY
DRY ATMOSPHERE.
TEMPERATURES ARE A BLEND OF GFS MOS AND SREF MEAN 2M TEMPS WHICH IS
A GOOD A COMPROMISE OF THE OTHER MOS GUIDANCE.
FLOW BECOMES LESS AMPLIFIED MIDWEEK AND THEN IS FAIRLY ZONAL
THROUGH NEXT WEEKEND. GFES IS SHOWING A SIGNIFICANT SPREAD IN
SOLUTIONS WITH THE TIMING OF SHORTWAVES MOVING IN THE THIS
PROGRESSIVE FLOW. HAVE GONE CLOSER TO THE ECWMF`S SOLUTION BECAUSE
IT IS SHOWING BETTER 24 HOUR CONTINUITY...AND IT`S DEPICTION OF
THE MAIN TROUGH AXIS MOVING THROUGH THE GREAT LAKES ON FRIDAY IS
SUPPORTED BY THE UKMET/CANADIAN VS. THE SLOWER OPERATIONAL GFS.
THIS TROUGH WILL A DRAG ACCOMPANYING COLD FRONT THROUGH MO/IL
THURSDAY NIGHT INTO FRIDAY. HAVE LEFT THIS A DRY FRONTAL PASSAGE
FOR NOW BECAUSE OF LIMITED MOISTURE SEEN ON MEDIUM RANGE MODELS.
HAVE ALSO LEFT THE REST OF FORECAST DRY BECAUSE OF THE AFOREMENTIONED
UNCERTAINTY AND THE NEW 12Z RUNS OF THE GFES MEAN/ECWMF KEEP SRN
STREAM QPF SOUTH OF THE CWA. ADJUSTED GFS MOS TEMPS UPWARD IN
THE WARM AIR ADVOCATION AHEAD OF FRIDAY`S FRONT...AND LEANED TOWARD
THE COOLER ECMWF TEMPS OVER THE WEEKEND BASED ON MODEL PREFERENCE.
BRITT
&&
.AVIATION...
/539 PM CST SUN JAN 18 2009/
FOR THE 00Z TAFS...
PRIMARY CONCERN CONTINUES TO BE CIGS ACROSS THE BI-STATE REGION.
THERE`S ALSO SOME LIGHT SNOW/LIGHT FREEZING DRIZZLE OVER PARTS OF
SOUTHWEST ILLINOIS. THIS PRECIP SHOULD REMAIN CONFINED TO EASTERN
PORTIONS OF THE BI-STATE REGION...AND CIGS WILL LIKELY STAY VFR
ACROSS THE AREA THROUGH 04-06Z. I EXPECT TO SEE CIGS FALL
OVERNIGHT AS A WEAK UPPER LEVEL WAVE MOVES OVERHEAD. THE SURFACE
REFLECTION OF THIS SYSTEM WILL CAUSE WINDS TO VEER TO THE
NORTHWEST AS WELL. THINK CIGS SHOULD RISE AGAIN DURING THE
MORNING MONDAY...AND LOWER STRATO-CU LOOKS LIKE IT WILL SCATTER
OUT OVER MOST LOCATIONS DURING THE AFTERNOON. NEXT UPPER LEVEL
WAVE WILL RIPPLE OVER THE AREA MONDAY EVENING LOWERING CIGS BACK
INTO MVFR RANGE AND POSSIBLY PRODUCING SOME SNOW SHOWERS.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 182119
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
319 PM CST SUN JAN 18 2009
.DISCUSSION...
/311 PM CST SUN JAN 18 2009/
ONLY CONCERN IS CHANCES OF LIGHT SNOW THE NEXT TWO NIGHTS. PREFER
THE GFS OVER THAN NAM AS IT HAS BETTER CONTINUITY WITH SHORTWAVE
MOVING DOWN ON THE BACK SIDE OF THE ERN CONUS LONGWAVE TROUGH THAT
WILL CROSS MO/IL ON MONDAY NIGHT. NAM HAS GONE FROM BEING SHALLOWER
THAN THE GFS ON ITS 12Z RUN TO BEING THE ONLY MODEL WITH A CLOSED
LOW BY 06Z TUESDAY ON THE MOST RECENT 18Z RUN.
HAVE UPPED POPS TO LIKELY FOR TONIGHT OVER S CNTRL IL. SNOW HAS
BEEN ON THE INCREASE OVER ERN IA THE PAST FEW HOURS AND GFS IS
SHOWING SOME LARGE SCALE ASCENT ALONG WITH SOME SOME WEAK MID
LEVEL FRONTOGENESIS DEPICTED BY THE RUC. THINK THERE COULD BE SOME
MINOR ACCUMULATIONS UP TO 1/2 INCH OVER THE ERN CWA BEFORE THIS
FORCING MOVES QUICKLY OUT OF THE CWA BETWEEN 06-12Z. HAVE JUST
SLIGHT CHANCES OF SNOW OR FLURRIES TOMORROW AS THERE WILL BE A
DECENT AMOUNT OF LOW LEVEL MOISTURE IN LOW LEVEL CYCLONIC FLOW.
UPPED CHANCE POPS TOMORROW NIGHT AND PUT IN A FEW TENTHS OF
SNOWFALL ON MONDAY NIGHT AS GFS TIME CROSS SECTIONS ARE SHOWING
LARGE SCALE ASCENT COINCIDENT WITH DEEP MOISTURE AOB 500MB.
SHORTWAVE QUICKLY MOVES OUT OF THE CWA LATE ON MONDAY NIGHT AND
HAVE GONE DRY TUESDAY AND WEDNESDAY AS SUBSIDENCE SETS IN A DEEPLY
DRY ATMOSPHERE.
TEMPERATURES ARE A BLEND OF GFS MOS AND SREF MEAN 2M TEMPS WHICH IS
A GOOD A COMPROMISE OF THE OTHER MOS GUIDANCE.
FLOW BECOMES LESS AMPLIFIED MIDWEEK AND THEN IS FAIRLY ZONAL
THROUGH NEXT WEEKEND. GFES IS SHOWING A SIGNIFICANT SPREAD IN
SOLUTIONS WITH THE TIMING OF SHORTWAVES MOVING IN THE THIS
PROGRESSIVE FLOW. HAVE GONE CLOSER TO THE ECWMF`S SOLUTION BECAUSE
IT IS SHOWING BETTER 24 HOUR CONTINUITY...AND IT`S DEPICTION OF
THE MAIN TROUGH AXIS MOVING THROUGH THE GREAT LAKES ON FRIDAY IS
SUPPORTED BY THE UKMET/CANADIAN VS. THE SLOWER OPERATIONAL GFS.
THIS TROUGH WILL A DRAG ACCOMPANYING COLD FRONT THROUGH MO/IL
THURSDAY NIGHT INTO FRIDAY. HAVE LEFT THIS A DRY FRONTAL PASSAGE
FOR NOW BECAUSE OF LIMITED MOISTURE SEEN ON MEDIUM RANGE MODELS.
HAVE ALSO LEFT THE REST OF FORECAST DRY BECAUSE OF THE AFOREMENTIONED
UNCERTAINTY AND THE NEW 12Z RUNS OF THE GFES MEAN/ECWMF KEEP SRN
STREAM QPF SOUTH OF THE CWA. ADJUSTED GFS MOS TEMPS UPWARD IN
THE WARM AIR ADVOCATION AHEAD OF FRIDAY`S FRONT...AND LEANED TOWARD
THE COOLER ECMWF TEMPS OVER THE WEEKEND BASED ON MODEL PREFERENCE.
BRITT
&&
.AVIATION...
/1137 AM CST SUN JAN 18 2009/
FOR THE 18Z TAFS...MVFR CIGS SHOULD CONTINUE ACROSS MUCH OF THE
REGION THIS AFTERNOON. CIGS SHOULD LIFT TO VFR THIS EVENING BEFORE
DROPPING AGAIN AROUND MIDNIGHT. AREA OF PRECIP ACROSS UIN SHOULD
MOVE S THIS AFTERNOON. SPOTTERS IN THE AREA REPORTED P-TYPE AS
SNOW GRAINS...AND HAVE THEREFORE KEPT P-TYPE AS SN IN TAFS.
UIN...STL AND SUS WILL BE ON EDGE OF LOWER CLOUDS TONIGHT AND HAVE
TRENDED TOWARD A MORE OPTIMISTIC APPROACH. WINDS SHOULD BECOME
LIGHTER TOMORROW MORNING AND CIGS SHOULD LIFT TO VFR AS WELL.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 181745
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1145 AM CST SUN JAN 18 2009
.DISCUSSION...
/223 AM CST SUN JAN 18 2009/
THE DEEP LONG WAVE TROF OVER THE ERN CONUS IS FORECAST TO PERSIST
THROUGH TUESDAY BEFORE FINALLY BREAKING DOWN WITH HEIGHTS ON THE
RISE BY MIDWEEK. IN THE MEAN TIME...A SERIES OF POTENT SHRTWV
TROFS DIGG ACROSS THE REGION WITHIN THE NNW FLOW REGIME WILL BRING
SEVERAL BOUTS OF COLDER AIR ALONG WITH A THREAT OF SOME LIGHT
SNOW. THE FIRST OF SEVERAL SHRTWVS TO IMPACT THE AREA TODAY AND
TONIGHT WAS PRODUCING SOME LIGHT SNOW FROM SRN IA INTO NW MO EARLY
THIS MORNING. THE SECOND AND STRONGER WAVE WILL IMPACT THE AREA
THIS AFTERNOON AND EVENING WILL BE ACCOMPANIED BY SOME FORMIDABLE
FORCING. WHILE I AM SURE WE WILL SEE SOME LIGHT SNOW...SPCLY FROM
EXTREME ERN MO INTO WRN IL...I AM NOT SURE HOW MUCH MEASURABLE
SNOWFALL THERE WILL BE. ATTM HAVE BOOSTED THE POPS INTO THE HIGHER
CHANCE RANGE. ANOTHER STRONG SHRTWV IS PROGGED TO DIGG SEWD ACROSS
REGION ON MONDAY AFTERNOON AND MON NIGHT. ONCE AGAIN IT APPEARS
THE GREATEST IMPACT FROM THIS WAVE WILL BE ACROSS ERN MO INTO WRN
IL. MID LEVEL CONVERGENCE...QVECTOR CONVERGENCE...AND OMEGA IS
EVEN STRONGER WITH THIS LATER SHRTWV. THEREFORE I INTRODUCED LOW
CHANCE POPS FOR MEASURABLE SNOWFALL ACROSS MOST OF THE CWA IN
LIEU OF THE PREVIOUS MENTION OF FLURRIES. ANY SNOWFALL AMOUNTS
WITH EITHER OF THESE SYSTEMS IS EXPECTED TO BE LIGHT...GENERALLY A
HALF INCH OR LESS. MONDAY AND TUESDAY SHOULD BOTH BE SEASONABLY
COLD DAYS WITH H85 TEMPS FCST TO BE AOB -10 DEGC. WAA DEVELOPS ON
TUESDAY NIGHT AND THIS COMBINED WITH THE AFOREMENTIONED HEIGHT
RISES ALOFT...SHOULD RESULT IN A GOOD WARM-UP ON WEDNESDAY WITH
MOST LOCATIONS CLIMBING INTO THE 40S.
GLASS
&&
.AVIATION...
/1137 AM CST SUN JAN 18 2009/
FOR THE 18Z TAFS...MVFR CIGS SHOULD CONTINUE ACROSS MUCH OF THE
REGION THIS AFTERNOON. CIGS SHOULD LIFT TO VFR THIS EVENING BEFORE
DROPPING AGAIN AROUND MIDNIGHT. AREA OF PRECIP ACROSS UIN SHOULD
MOVE S THIS AFTERNOON. SPOTTERS IN THE AREA REPORTED P-TYPE AS
SNOW GRAINS...AND HAVE THEREFORE KEPT P-TYPE AS SN IN TAFS.
UIN...STL AND SUS WILL BE ON EDGE OF LOWER CLOUDS TONIGHT AND HAVE
TRENDED TOWARD A MORE OPTIMISTIC APPROACH. WINDS SHOULD BECOME
LIGHTER TOMORROW MORNING AND CIGS SHOULD LIFT TO VFR AS WELL.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 181147
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
547 AM CST SUN JAN 18 2009
.DISCUSSION...
/223 AM CST SUN JAN 18 2009/
THE DEEP LONG WAVE TROF OVER THE ERN CONUS IS FORECAST TO PERSIST
THROUGH TUESDAY BEFORE FINALLY BREAKING DOWN WITH HEIGHTS ON THE
RISE BY MIDWEEK. IN THE MEAN TIME...A SERIES OF POTENT SHRTWV
TROFS DIGG ACROSS THE REGION WITHIN THE NNW FLOW REGIME WILL BRING
SEVERAL BOUTS OF COLDER AIR ALONG WITH A THREAT OF SOME LIGHT
SNOW. THE FIRST OF SEVERAL SHRTWVS TO IMPACT THE AREA TODAY AND
TONIGHT WAS PRODUCING SOME LIGHT SNOW FROM SRN IA INTO NW MO EARLY
THIS MORNING. THE SECOND AND STRONGER WAVE WILL IMPACT THE AREA
THIS AFTERNOON AND EVENING WILL BE ACCOMPANIED BY SOME FORMIDABLE
FORCING. WHILE I AM SURE WE WILL SEE SOME LIGHT SNOW...SPCLY FROM
EXTREME ERN MO INTO WRN IL...I AM NOT SURE HOW MUCH MEASURABLE
SNOWFALL THERE WILL BE. ATTM HAVE BOOSTED THE POPS INTO THE HIGHER
CHANCE RANGE. ANOTHER STRONG SHRTWV IS PROGGED TO DIGG SEWD ACROSS
REGION ON MONDAY AFTERNOON AND MON NIGHT. ONCE AGAIN IT APPEARS
THE GREATEST IMPACT FROM THIS WAVE WILL BE ACROSS ERN MO INTO WRN
IL. MID LEVEL CONVERGENCE...QVECTOR CONVERGENCE...AND OMEGA IS
EVEN STRONGER WITH THIS LATER SHRTWV. THEREFORE I INTRODUCED LOW
CHANCE POPS FOR MEASURABLE SNOWFALL ACROSS MOST OF THE CWA IN
LIEU OF THE PREVIOUS MENTION OF FLURRIES. ANY SNOWFALL AMOUNTS
WITH EITHER OF THESE SYSTEMS IS EXPECTED TO BE LIGHT...GENERALLY A
HALF INCH OR LESS. MONDAY AND TUESDAY SHOULD BOTH BE SEASONABLY
COLD DAYS WITH H85 TEMPS FCST TO BE AOB -10 DEGC. WAA DEVELOPS ON
TUESDAY NIGHT AND THIS COMBINED WITH THE AFOREMENTIONED HEIGHT
RISES ALOFT...SHOULD RESULT IN A GOOD WARM-UP ON WEDNESDAY WITH
MOST LOCATIONS CLIMBING INTO THE 40S.
GLASS
&&
.AVIATION...
/502 AM CST SUN JAN 18 2009/
FOR THE 12Z TAFS...SHRTWVS WILL CONT TO ROTATE SEWD THRU THE AREA
TDA ARND THE GRT LKS MID-UPR LVL LOW. THESE SHRTWVS AND ASSOCIATED
WK SFC TROFS ALONG WITH COLD MID LVL TEMPS ON THE SWRN PERIPHERY
OF THE MID LVL TROF SHOULD BRING INTERMITTENT FLURRIES ALONG WITH
SCT SNOW SHOWERS TO ERN MO AND WRN IL FM UIN S THRU THE STL METRO
AREA LTR THIS MRNG AND THIS AFTN. CEILINGS WILL LIKELY LWR LTR
THIS MRNG AS THE STRATUS CLOUD CVR ACRS IA ADVCTS SEWD THRU THE
TAF SITES. UIN WILL LIKELY HAVE THE LOWEST CIG HGTS JUST BLW 2000
FT WHILE COU SHOULD HAVE THE HIGHEST CIG HGTS ARND 2500 FT.
W-NWLY SFC WNDS SHOULD BCM MORE N-NWLY TGT BHND THE WK SFC TROF
MOVG S-SE OF THE TAF SITES BY TGT.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 180838
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
238 AM CST SUN JAN 18 2009
.DISCUSSION...
/223 AM CST SUN JAN 18 2009/
THE DEEP LONG WAVE TROF OVER THE ERN CONUS IS FORECAST TO PERSIST
THROUGH TUESDAY BEFORE FINALLY BREAKING DOWN WITH HEIGHTS ON THE
RISE BY MIDWEEK. IN THE MEAN TIME...A SERIES OF POTENT SHRTWV
TROFS DIGG ACROSS THE REGION WITHIN THE NNW FLOW REGIME WILL BRING
SEVERAL BOUTS OF COLDER AIR ALONG WITH A THREAT OF SOME LIGHT
SNOW. THE FIRST OF SEVERAL SHRTWVS TO IMPACT THE AREA TODAY AND
TONIGHT WAS PRODUCING SOME LIGHT SNOW FROM SRN IA INTO NW MO EARLY
THIS MORNING. THE SECOND AND STRONGER WAVE WILL IMPACT THE AREA
THIS AFTERNOON AND EVENING WILL BE ACCOMPANIED BY SOME FORMIDABLE
FORCING. WHILE I AM SURE WE WILL SEE SOME LIGHT SNOW...SPCLY FROM
EXTREME ERN MO INTO WRN IL...I AM NOT SURE HOW MUCH MEASURABLE
SNOWFALL THERE WILL BE. ATTM HAVE BOOSTED THE POPS INTO THE HIGHER
CHANCE RANGE. ANOTHER STRONG SHRTWV IS PROGGED TO DIGG SEWD ACROSS
REGION ON MONDAY AFTERNOON AND MON NIGHT. ONCE AGAIN IT APPEARS
THE GREATEST IMPACT FROM THIS WAVE WILL BE ACROSS ERN MO INTO WRN
IL. MID LEVEL CONVERGENCE...QVECTOR CONVERGENCE...AND OMEGA IS
EVEN STRONGER WITH THIS LATER SHRTWV. THEREFORE I INTRODUCED LOW
CHANCE POPS FOR MEASURABLE SNOWFALL ACROSS MOST OF THE CWA IN
LIEU OF THE PREVIOUS MENTION OF FLURRIES. ANY SNOWFALL AMOUNTS
WITH EITHER OF THESE SYSTEMS IS EXPECTED TO BE LIGHT...GENERALLY A
HALF INCH OR LESS. MONDAY AND TUESDAY SHOULD BOTH BE SEASONABLY
COLD DAYS WITH H85 TEMPS FCST TO BE AOB -10 DEGC. WAA DEVELOPS ON
TUESDAY NIGHT AND THIS COMBINED WITH THE AFOREMENTIONED HEIGHT
RISES ALOFT...SHOULD RESULT IN A GOOD WARM-UP ON WEDNESDAY WITH
MOST LOCATIONS CLIMBING INTO THE 40S.
GLASS
&&
.AVIATION...
/1124 PM CST SAT JAN 17 2009/
FOR THE 06Z TAFS...
PRIMARY PROBLEM CONTINUES TO BE CIGS. MODELS ARE GENERALLY TOO
AGGRESSIVE IN BRINGING THE MVFR CIGS INTO THE REGION...BUT IT
APPEARS THAT THE RUC MIGHT HAVE THE BEST HANDLE ON THINGS. IT`S
ALSO PICKING UP THE BLOB OF SNOW OVER WESTERN IOWA MOVING
SOUTHEAST INTO MISSOURI. SINCE THE RUC SEEMS TO BE VERIFYING THE
BEST RIGHT NOW...HAVE BASED MY 06Z TERMINALS ON IT. THE CIGS WILL
STILL MAKE IT DOWN INTO THE REGION...BUT IT WILL LIKELY NOT BE
UNTIL BETWEEN 09Z AND 12Z. LIGHT SNOW SHOWERS LOOK TO RIPPLE
ACROSS NORTHWEST INTO CENTRAL MISSOURI...LIKELY SPREADING EAST
TOWARD THE MISSISSIPPI RIVER. I THINK CIGS WILL STILL STAY BETWEEN
1000-2000FT EXCEPT IN THE OCCASIONAL SNOW SHOWER. ONCE THE CIGS
GET GO DOWN...THEY LOOK LIKELY TO STAY DOWN THROUGH MOST OF THE
DAY.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 180533
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
1133 PM CST SAT JAN 17 2009
.DISCUSSION...
/350 PM CST SAT JAN 17 2009/
MODELS ARE IN GOOD MASS FIELD AGREEMENT AT H500...WITH HIGHLY
AMPLIFIED LONGWAVE RIDGE OVER THE WRN CONUS AND A DEEP LONGWAVE TROF
OVER THE ERN CONUS ATTM CONTINUING THRU TUESDAY. AT THAT TIME...WE
ARE LOOKING AT THE LONGWAVE BLOCKING PATTERN IN THE W BREAKING DOWN
SOME BUT THE SAME GENERAL NWLY FLOW ALOFT CONTINUING. THE BIGGEST
CHANGES BY NEXT WEEKEND WILL OCCUR OVER THE WRN CONUS WHERE SPLIT
FLOW REGIME DEVELOPS...WITH PERHAPS ANOTHER ARCTIC AIR INTRUSION
INTO THE CNTRL CONUS.
NWLY FLOW WILL MAKE PCPN FORECASTS A CHALLENGE...WITH A SERIES OF
DISTURBANCES COMING SEWD THRU THE AREA OVER THE NEXT FEW DAYS...BUT
STRUGGLING HAVING ENOUGH MOISTURE AT THE LOW AND MID LEVELS TO WORK
WITH IN GENERATING A WIDESPREAD AREA OF PCPN. INSTEAD...SHOULD
PREDOMINANTLY SEE A SERIES OF CHANCES FOR FLURRIES...WITH THE
EXCEPTION BEING ON SUNDAY AND SUNDAY NIGHT WHERE THE MOST MOISTURE
WILL BE PRESENT TO WORK OFF OF. WITH GOOD MODEL AGREEMENT ON LIGHT
QPF OUTPUT AND GENERAL TRACK...WILL EDGE POPS UP A BIT MORE TO MID
RANGE...WITH THE POTENTIAL FOR A NARROW AREA TO RECEIVE AN INCH OR
SO OF SNOW...PROBABLY E OF THE MS RIVER. ALL THE OTHER SHORTWAVES...
TONIGHT AND MONDAY AND MONDAY NIGHT...WILL HANDLE WITH
NON-ACCUMULATING FLURRIES FOR NOW.
TEMP TRENDS WILL BE BACK ON THE WAY DOWN AFTER OUR BRIEF MILD DAY...
RELATIVELY...TODAY. BUT THERE WILL BE A LACK OF ARCTIC AIRMASSES FOR
A WHILE...SO COLD AIR WILL NOT QUITE HAVE AS MUCH BITE AS THE PAST
FEW DAYS. NEXT WEEKEND MAY BREAK THAT STREAK THOUGH.
TES
&&
.AVIATION...
/1124 PM CST SAT JAN 17 2009/
FOR THE 06Z TAFS...
PRIMARY PROBLEM CONTINUES TO BE CIGS. MODELS ARE GENERALLY TOO
AGGRESSIVE IN BRINGING THE MVFR CIGS INTO THE REGION...BUT IT
APPEARS THAT THE RUC MIGHT HAVE THE BEST HANDLE ON THINGS. IT`S
ALSO PICKING UP THE BLOB OF SNOW OVER WESTERN IOWA MOVING
SOUTHEAST INTO MISSOURI. SINCE THE RUC SEEMS TO BE VERIFYING THE
BEST RIGHT NOW...HAVE BASED MY 06Z TERMINALS ON IT. THE CIGS WILL
STILL MAKE IT DOWN INTO THE REGION...BUT IT WILL LIKELY NOT BE
UNTIL BETWEEN 09Z AND 12Z. LIGHT SNOW SHOWERS LOOK TO RIPPLE
ACROSS NORTHWEST INTO CENTRAL MISSOURI...LIKELY SPREADING EAST
TOWARD THE MISSISSIPPI RIVER. I THINK CIGS WILL STILL STAY BETWEEN
1000-2000FT EXCEPT IN THE OCCASIONAL SNOW SHOWER. ONCE THE CIGS
GET GO DOWN...THEY LOOK LIKELY TO STAY DOWN THROUGH MOST OF THE
DAY.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 172347
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE ST LOUIS MO
547 PM CST SAT JAN 17 2009
.DISCUSSION...
/350 PM CST SAT JAN 17 2009/
MODELS ARE IN GOOD MASS FIELD AGREEMENT AT H500...WITH HIGHLY
AMPLIFIED LONGWAVE RIDGE OVER THE WRN CONUS AND A DEEP LONGWAVE TROF
OVER THE ERN CONUS ATTM CONTINUING THRU TUESDAY. AT THAT TIME...WE
ARE LOOKING AT THE LONGWAVE BLOCKING PATTERN IN THE W BREAKING DOWN
SOME BUT THE SAME GENERAL NWLY FLOW ALOFT CONTINUING. THE BIGGEST
CHANGES BY NEXT WEEKEND WILL OCCUR OVER THE WRN CONUS WHERE SPLIT
FLOW REGIME DEVELOPS...WITH PERHAPS ANOTHER ARCTIC AIR INTRUSION
INTO THE CNTRL CONUS.
NWLY FLOW WILL MAKE PCPN FORECASTS A CHALLENGE...WITH A SERIES OF
DISTURBANCES COMING SEWD THRU THE AREA OVER THE NEXT FEW DAYS...BUT
STRUGGLING HAVING ENOUGH MOISTURE AT THE LOW AND MID LEVELS TO WORK
WITH IN GENERATING A WIDESPREAD AREA OF PCPN. INSTEAD...SHOULD
PREDOMINANTLY SEE A SERIES OF CHANCES FOR FLURRIES...WITH THE
EXCEPTION BEING ON SUNDAY AND SUNDAY NIGHT WHERE THE MOST MOISTURE
WILL BE PRESENT TO WORK OFF OF. WITH GOOD MODEL AGREEMENT ON LIGHT
QPF OUTPUT AND GENERAL TRACK...WILL EDGE POPS UP A BIT MORE TO MID
RANGE...WITH THE POTENTIAL FOR A NARROW AREA TO RECEIVE AN INCH OR
SO OF SNOW...PROBABLY E OF THE MS RIVER. ALL THE OTHER SHORTWAVES...
TONIGHT AND MONDAY AND MONDAY NIGHT...WILL HANDLE WITH
NON-ACCUMULATING FLURRIES FOR NOW.
TEMP TRENDS WILL BE BACK ON THE WAY DOWN AFTER OUR BRIEF MILD DAY...
RELATIVELY...TODAY. BUT THERE WILL BE A LACK OF ARCTIC AIRMASSES FOR
A WHILE...SO COLD AIR WILL NOT QUITE HAVE AS MUCH BITE AS THE PAST
FEW DAYS. NEXT WEEKEND MAY BREAK THAT STREAK THOUGH.
TES
&&
.AVIATION...
/538 PM CST SAT JAN 17 2009/
FOR THE 00Z TAFS...
PRIMARY CONCERN FOR AVIATORS TONIGHT WILL BE LOWERING CIGS ACROSS
THE AREA...SECONDARY CONCERN WILL BE POSSIBLE SNOW SHOWERS.
COMPARING MODEL GUIDANCE TO OBS IT SEEMS THAT THE MODELS ARE TOO
LOW WITH THE CIGS THEY`RE FORECASTING. CIGS SHOULD EVENTUALLY GO
BELOW 2000FT...BUT IT`S GOING TO BE AFTER 06Z FOR MOST OF THE AREA
AS ALL THESE LOWER CIGS ARE WAY BACK IN IOWA AT THIS TIME. DON`T
THINK THERE`S GOING TO BE MUCH IFR...EXCEPT WHERE THE SPOT SNOW
SHOWER BRIEFLY LOWERS CIGS AND VSBYS. I LEFT MENTION OF THIS OUT
OF THE TERMINALS BECAUSE I THINK COVERAGE WILL BE PRETTY SPARSE.
CIGS WILL GRADUALLY RISE BACK ABOVE 2000FT TOMORROW AFTERNOON.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
000
FXUS63 KLSX 172150
AFDLSX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
350 PM CST SAT JAN 17 2009
.DISCUSSION...
/350 PM CST SAT JAN 17 2009/
MODELS ARE IN GOOD MASS FIELD AGREEMENT AT H500...WITH HIGHLY
AMPLIFIED LONGWAVE RIDGE OVER THE WRN CONUS AND A DEEP LONGWAVE TROF
OVER THE ERN CONUS ATTM CONTINUING THRU TUESDAY. AT THAT TIME...WE
ARE LOOKING AT THE LONGWAVE BLOCKING PATTERN IN THE W BREAKING DOWN
SOME BUT THE SAME GENERAL NWLY FLOW ALOFT CONTINUING. THE BIGGEST
CHANGES BY NEXT WEEKEND WILL OCCUR OVER THE WRN CONUS WHERE SPLIT
FLOW REGIME DEVELOPS...WITH PERHAPS ANOTHER ARCTIC AIR INTRUSION
INTO THE CNTRL CONUS.
NWLY FLOW WILL MAKE PCPN FORECASTS A CHALLENGE...WITH A SERIES OF
DISTURBANCES COMING SEWD THRU THE AREA OVER THE NEXT FEW DAYS...BUT
STRUGGLING HAVING ENOUGH MOISTURE AT THE LOW AND MID LEVELS TO WORK
WITH IN GENERATING A WIDESPREAD AREA OF PCPN. INSTEAD...SHOULD
PREDOMINANTLY SEE A SERIES OF CHANCES FOR FLURRIES...WITH THE
EXCEPTION BEING ON SUNDAY AND SUNDAY NIGHT WHERE THE MOST MOISTURE
WILL BE PRESENT TO WORK OFF OF. WITH GOOD MODEL AGREEMENT ON LIGHT
QPF OUTPUT AND GENERAL TRACK...WILL EDGE POPS UP A BIT MORE TO MID
RANGE...WITH THE POTENTIAL FOR A NARROW AREA TO RECEIVE AN INCH OR
SO OF SNOW...PROBABLY E OF THE MS RIVER. ALL THE OTHER SHORTWAVES...
TONIGHT AND MONDAY AND MONDAY NIGHT...WILL HANDLE WITH
NON-ACCUMULATING FLURRIES FOR NOW.
TEMP TRENDS WILL BE BACK ON THE WAY DOWN AFTER OUR BRIEF MILD DAY...
RELATIVELY...TODAY. BUT THERE WILL BE A LACK OF ARCTIC AIRMASSES FOR
A WHILE...SO COLD AIR WILL NOT QUITE HAVE AS MUCH BITE AS THE PAST
FEW DAYS. NEXT WEEKEND MAY BREAK THAT STREAK THOUGH.
TES
&&
.AVIATION...
/1126 AM CST SAT JAN 17 2009/
FOR THE 18Z TAFS...MVFR CIGS ACROSS IA WILL CONTINUE TO QUICKLY
SINK SOUTH OVER THE REGION. CIGS BELOW 2 KFT WILL LAG BEHIND THE
FRONT BY A COUPLE OF HOURS. SHSN WILL BE POSSIBLE TONIGHT. DUE TO
UNCERTAINTY IN TIMING...HAVE NOT MENTIONED IN TAFS EXCEPT FOR
UIN. IFR CIGS WILL ALSO BE POSSIBLE TONIGHT. HOWEVER...MODELS MAY
HAVE LOWER CLOUDS OVERDONE SO HAVE ONLY HINTED AT LOWER CIGS. CIGS
SHOULD GRADUALLY IMPROVE TOMORROW BETWEEN THE LATE MORNING AND
EARLY AFTERNOON HOURS.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
| 
