000
FXUS63 KABR 200153
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
853 PM CDT FRI SEP 19 2008

.UPDATE...
MINOR -SHRA HAVE DIMINISHED ACROSS THE FAR ERN CWA...WITH CLEAR
SKIES CURRENTLY OVER REGION. WEAK COOL FRONT CURRENTLY ALONG THE
ND/SD BORDER...AND WILL CONT TO SLOWLY TREK SOUTH OVERNIGHT. LIGHT
AND VARIABLE WINDS WILL TURN NORTHERLY OVERNIGHT. COND PRESSURE
DEFS SHOW THAT WITH EXCEPTION OF A FEW HIGH CLOUDS...CLEAR SKIES
SHOULD PREVAIL OVERNIGHT. UPDATED ZONES WILL BE SENT TO REMOVE
EVENING PCPN WORDING FOR THE KATY AREA.

UPDATED AVIATION DISCUSSION BELOW.


&&
.PREV DISCUSSION...
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
THE MAIN CHALLENGE IN THE SHORT TERM IS PRECIPITATION CHANCES THIS
EVENING AND AGAIN SUNDAY AND SUNDAY NIGHT. A WEAK UPPER LEVEL
TROUGH WILL BE OVER THE EASTERN PLAINS/MISSISSIPPI VALLEY TONIGHT.
A SURFACE TROUGH WILL EXTEND FROM NORTHEASTERN MINNESOTA TO NORTH
CENTRAL NEBRASKA THIS EVENING. CAPES IN THE 1000-1500 J/KG RANGE
AND LIS BETWEEN -2 AND -4 ALONG THE BOUNDARY WILL AID IN ALLOWING
WEAK THUNDERSTORMS TO CONTINUE INTO THE EARLY EVENING HOURS.
MOISTURE CONTINUES TO BE LIMITED AND NO LOW LEVEL JET IS EXPECTED
TONIGHT...SO DO NOT ANTICIPATE ANY SEVERE POSSIBILITY. A COLD
FRONT WILL DROP FROM SOUTHERN NORTH DAKOTA TO CENTRAL SOUTH DAKOTA
OVERNIGHT. THE UPPER TROUGH SLIDES EAST ON SATURDAY WITH A RIDGE
REACHING THE FAR WESTERN PLAINS. THE FRONTAL BOUNDARY WILL REMAIN
NEARLY STATIONARY THROUGH THE DAY AS HIGH PRESSURE SLIDES FROM
SOUTH CENTRAL CANADA TO NORTH OF THE GREAT LAKES...AND LOW
PRESSURE INTENSIFIES OVER MONTANA. SOME INSTABILITY REMAINS OVER
THE AREA...BUT DRIER AIR ASSOCIATED WITH THE HIGH LOOKS TO
COUNTERACT ENOUGH TO HINDER PRECIPITATION DEVELOPMENT. THE UPPER
RIDGE SLIDES EAST OF THE REGION SATURDAY NIGHT...WITH ENERGY
ASSOCIATED WITH A PACIFIC NORTHWEST TROUGH APPROACHING THE AREA.
THE SURFACE FRONT GETS PUSHED WEST OF THE REGION WITH A FAIRLY
TIGHT PRESSURE GRADIENT SETTING UP. THE ELONGATED TROUGH OF LOW
PRESSURE REMAINS WEST OF THE REGION SUNDAY...THEN BEGINS TO PUSH
BACK EASTWARD SUNDAY NIGHT. A FAIRLY POTENT SHORTWAVE WILL ROUND
THE BASE OF THE WESTERN TROUGH AND SLIDE ACROSS THE
DAKOTAS...AND IN ASSOCIATION WITH A 40-45 KNOT LOW LEVEL
JET...WILL ALLOW PRECIPITATION TO SPREAD EASTWARD ACROSS THE CWA
SUNDAY AFTERNOON AND SUNDAY NIGHT. NOT MUCH IN THE WAY OF
INSTABILITY AROUND...BUT WILL KEEP THE MENTION OF THUNDER GOING
DUE TO THE STRENGTH OF THE UPPER WAVE.

WILL SEE COOLER AIR MOVE IN TO THE EASTERN CWA WITH THE BACKDOOR
COLD FRONT TONIGHT AND SATURDAY. WILL THEN GO WITH TEMPERATURES
BACK AROUND NORMAL ON SUNDAY WITH STRONG SOUTHERLY FLOW BRINGING
SOMEWHAT WARMER AIR BACK OVER THE AREA.


.LONG TERM...MONDAY THROUGH FRIDAY
THE MAIN CHALLENGE IN THE EXTENDED CENTERS AROUND PRECIPITATION
CHANCES EARLY IN THE PERIOD.

THE GFS/ECMWF ARE IN A PRETTY GOOD AGREEMENT WITH THE HANDLING OF
THE MID/UPPER LEVEL FLOW PATTERN ACROSS THE REGION. THE PERIOD
BEGINS WITH A RIDGE OVER THE MIDWEST STATES AND A TROF THROUGH THE
ROCKIES. THIS LEAVES THE NORTHERN PLAINS UNDER SOUTHWEST FLOW
ALOFT. STRONG LLJ IS ALREADY ONGOING ACROSS THE CWA ON MONDAY WITH
A WARM FRONT LIFTING NORTHWARD. HARD TO DEFINED THE BREAK BETWEEN
CONVECTION ASSOCIATED WITH THE WARM FRONT AND CONVECTION WITH THE
SURFACE TROF SO HAVE MONDAY/MONDAY NIGHT AS 12 HOUR BLOCKS. UPPER
LEVEL RIDGE AMPLIFIES OVER THE GREAT LAKES REGIONS ON
TUESDAY...LEADING TO A SLOW PROGRESSION OF THE SURFACE TROF ACROSS
THE AREA. HOWEVER THE LATEST RUN OF THE GFS IS ABOUT 12 HOURS
FASTER WITH ENDING PCPN THEN THE PREVIOUS RUNS. HIGH PRESSURE
BUILDS IN BY WEDNESDAY MORNING WITH THE REGION UNDER NEARLY ZONAL
FLOW ALOFT. THIS ZONAL FLOW QUICKLY CHANGES AS A WEAK MID LEVEL
TROF MOVES THROUGH THE AREA LATE IN THE EXTENDED. NOT FULLY
CONVINCED THIS WILL OCCUR SO HAVE LEFT THURSDAY/FRIDAY DRY FOR NOW.


&&

.AVIATION...
VFR CONDS EXPECTED THROUGH 00Z SUNDAY. WEAK COOL FRONT IS PASSING
THROUGH AREA...AND IS EXPECTED TO BE ALONG THE SD/NEB BORDER BY
15Z. LITTLE IF ANY CLOUD COVER ASSOCIATED WITH FRONT. LIGHT AND
VARIABLE WINDS WILL TURN NORTHERLY AT 5 TO 10 MPH BEHIND FEATURE.



&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...HINTZ
SHORT TERM...PARKIN
LONG TERM...SD
AVIATION...HINTZ

WEATHER.GOV/ABERDEEN

000
FXUS63 KFSD 200146
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
840 PM CDT FRI SEP 19 2008

.DISCUSSION...
WEAK FNT LOCATED FM BKX-MHE-PKS THIS EVE AND WL LIKELY ONLY SAG A
LTL FURTHER SE TONIGHT PBLY STALLING ALONG THE I90 CORRIDOR BY 12Z.
NOT MUCH GOING ON ATTM...BUT AM CONCERNED THAT ISOLD TRW MAY FIRE UP
AGAIN AFT 08Z ALONG I90. NAM DOES SHOW SOME DECENT ELEVATED INSTABIL
ALONG WITH WEAK CINS AND DECENT ELEVATED H85 CAPE. CONVERGENCE IS
NOT ALL THAT IMPRESSIVE AND LLJ FAIRLY WEAK BUT STILL CUD BE ENUF
FOR AN ISOLD TRW LATE VCNTY OF I90. SO DID ADD ISOLD TO THAT AREA
AFTER 08Z. OTHERWISE REST OF FCST FOR TONIGHT LOOKS GOOD.

&&

.AVIATION...
VFR CONDITIONS EXPECTED TO PERSIST THRU 00Z SUN. ISOLATED TSRA
POSSIBLE ALONG I90 08Z-14Z SAT.

&&

.PREVIOUS DISCUSSION...
SMALL AREA OF ELEVATED TSRA FROM AROUND KATY INTO WCNTRL MN AT THIS
TIME IN AREA OF STRONGER MID LEVEL THETA-E CONVERGENCE AND 700-500MB
LAPSE RATES. THETA-E CONVERGENCE SLOWLY SAGS INTO SOUTHWEST MN THIS
EVENING. WILL CARRY SMALL POP FOR ISOLATED TSRA INTO KBKX/KMML/KDVP
AREAS FOR THIS EVENING...THOUGH WITH CLOUD BASES AT 10-12KFT...
PRECIP AMOUNTS AT THE SURFACE WILL BE MINIMAL. BETTER THETA-E
CONVERGENCE SLIDES INTO SOUTHERN CWA AHEAD OF WEAK BOUNDARY AND MID
LEVEL WAVE OVERNIGHT. HOWEVER MID LEVEL INSTABILITY NOT AS
SUPPORTIVE OF CONVECTION IN THIS AREA...AS STEEPER LAPSE RATES
REMAIN ACROSS NORTHWEST 1/2 OF THE CWA. HAVE PULLED MENTION OF
ISOLATED TSRA FROM NORTHWEST IOWA FOR LATER TONIGHT...BUT WILL BE
SOMETHING FOR NEXT SHIFT TO EVALUATE.

ON SATURDAY...WEAK BOUNDARY WILL MEANDER BACK TO THE NORTH AS IT
FALLS APART. WITH SLIGHTLY COOLER LOW LEVEL THERMAL FIELDS AND WINDS
TRANSITIONING TO A EAST/SOUTHEASTERLY FLOW...WILL SEE HIGH
TEMPERATURES A COUPLE OF DEGREES COOLER THAN TODAY. SATURDAY NIGHT
LOOKS DRY AND MILDER WITH WINDS STAYING UP. HIGH PRESSURE OVER THE
GREAT LAKES REGION WILL OOZE INTO THE MISSISSIPPI VALLEY ON
SUNDAY...INDUCING A STRONG SOUTHERLY FLOW OVER OUR REGION...AND WITH
A STRENGTHENING TROUGH OVER THE NORTHERN ROCKIES/WESTERN HIGH
PLAINS...STILL LOOKS TO BE A WINDY DAY. TEMPERATURES AGAIN WILL BE
JUST EITHER SIDE OF 80.

WITH THE STRONG SOUTHERLY FLOW...BETTER MOISTURE WILL BEGIN TO BE
ADVECTED NORTHWARD BY SUNDAY EVENING ON A STRENGTHENING LOW LEVEL
JET OVER CENTRAL SOUTH DAKOTA...AND THIS IN CONJUNCTION WITH A
SHORTWAVE MOVING OUT OF THE WESTERN PLAINS WILL BRING A CHANCE OF
PRECIPITATION TO THE AREA ON SUNDAY NIGHT INTO MONDAY. MONDAY LOOKS
LIKE ANOTHER WINDY DAY WITH A TIGHT PRESSURE GRADIENT REMAINING
ACROSS THE REGION. WITH CLOUDS/SHOWERS AND COOLER LOW LEVEL
TEMPERATURES...HIGHS ON MONDAY MAY BE AGAIN BE A SHADE
LOWER...GENERALLY IN THE MID AND UPPER 70S.

IN THE EXTENDED...TUESDAY THROUGH FRIDAY...STILL LOOKING TO BE A
RELATIVELY UNSETTLED PERIOD AS THE UPPER LEVEL TROUGH OVER THE
WESTERN U.S. AT THE START OF THE WEEK FINALLY PUSHES INTO THE
CENTRAL PORTIONS OF THE COUNTRY. MAIN WAVE MOVES THROUGH LATE
TUESDAY INTO WEDNESDAY...WITH SOME MODEL DISAGREEMENT ON TIMING OF
SYSTEM. BOTH THE GFS/CANADIAN ARE FASTER THEN THE ECMWF...SO SPED UP
TIMING JUST A BIT ON WEDNESDAY. MODELS HINTING AT SECONDARY WAVE
PUSHING THROUGH THE REGION IN THE THURSDAY TIME FRAME...BUT WITH
CONTINUED POOR MODEL AGREEMENT ON TRACK AND TIMING OF
SHORTWAVE...LEFT FORECAST DRY FOR NOW. STILL NO REAL COLD AIR IN
SITE...WITH TEMPERATURES FOR THE MIDDLE AND END OF NEXT WEEK
REMAINING MAINLY ABOVE NORMAL FOR THIS TIME OF YEAR.

&&


.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$

000
FXUS63 KUNR 200145
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
745 PM MDT FRI SEP 19 2008

.DISCUSSION...CURRENT FORECAST LOOKS GOOD. NO UPDATES PLANNED ATTM.

&&

.AVIATION...VFR CONDITIONS UNDER MOSTLY CLEAR SKIES ARE EXPECTED
THROUGH SATURDAY MORNING.

&&

.PREV DISCUSSION... /ISSUED 213 PM MDT FRI SEP 19 2008/

DISCUSSION...20Z SURFACE ANALYSIS HAD TROUGH FROM NORTHEAST MN
INTO NORTHEAST CO. WEAK HIGH OVER THE CWA WITH WEAK RETURN FLOW
BEGINNING OVER WY. SHOULD BE PLENTY OF STARS TONIGHT WITH A WIDE
RANGE OF LOWS DUE TO DEW POINTS IN THE 30S...ALTHOUGH MOISTENING
WILL OCCUR AS SOUTHERLY RETURN FLOW STRENGTHENS.

SATURDAY...UPPER RIDGE OVER THE NORTHERN PLAINS BEGINS TO SHIFT
EAST IN RESPONSE TO UPPER LEVEL TROUGH BEING CARVED OUT OVER THE
ROCKIES. WEAK LOW DEVELOPS OVER MT WITH LEE TROUGH/PRESSURE FALLS
TIGHTENING PRESSURE GRADIENT. SOUTHERLY GEOSTROPHIC WINDS HIT
30KTS AND WOULD EXPECT A DECENT PORTION OF THAT TO REACH THE
SURFACE AS BOUNDARY LAYER COUPLES SATURDAY AFTERNOON LEADING TO
BREEZY SPOTS. NEAR LEE TROUGH AND UPSLOPE WINDS...COULD SEE AN
AFTERNOON -TSRA IN THE FAR WEST AND THEN OVER THE WESTERN HALF OF
THE CWA WITH LOW LEVEL JET SATURDAY NIGHT. SOUTHERLY WINDS SHOULD
PROMOTE A FEW 90F READINGS ON THE LEE SIDE OF THE HILLS FROM
SPEARFISH TO BELLE FOURCHE.

SUNDAY...SURFACE LOW SHIFTS INTO EASTERN MT AS SHARPENING UPPER
LEVEL TROUGH LIFTS INTO WY/MT. 12Z NAM/GFS DIFFER ON ULTIMATE
POSITION/SPEED OF THIS SYSTEM. GFS LIFTS IT FAST NORTH AND NAM
SLOWER/FURTHER SOUTH. WILL TAKE THE MEAN FOR NOW AND RAISE POPS A
BIT IN THE NORTH WHERE BEST FORCING/THETA-E ADVECTION CONSPIRE TO
PRODUCE FALLING LIQUID HYDROMETEORS. FORCING/AVAILABLE CAPE
SUFFICIENT FOR TSRA.

EXTENDED...AN UPPER LEVEL TROF WILL CROSS THE ROCKIES AND MOVE INTO
THE PLAINS FOR THE FIRST PART OF THE WORK WEEK...BRINGING A
CONTINUED CHANCE OF PRECIPITATION. TROF WILL PUSH TO THE EAST FOR
THE SECOND HALF OF THE WEEK AS AN UPPER LEVEL RIDGE SLOWLY BUILDS
OVER THE WESTERN UNITED STATES. THIS WILL BRING A RETURN TO DRY
WEATHER ALONG WITH A SLOW WARMING TREND.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

000
FXUS63 KUNR 192013
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
213 PM MDT FRI SEP 19 2008

.DISCUSSION...20Z SURFACE ANALYSIS HAD TROUGH FROM NORTHEAST MN
INTO NORTHEAST CO. WEAK HIGH OVER THE CWA WITH WEAK RETURN FLOW
BEGINNING OVER WY. SHOULD BE PLENTY OF STARS TONIGHT WITH A WIDE
RANGE OF LOWS DUE TO DEW POINTS IN THE 30S...ALTHOUGH MOISTENING
WILL OCCUR AS SOUTHERLY RETURN FLOW STRENGTHENS.

SATURDAY...UPPER RIDGE OVER THE NORTHERN PLAINS BEGINS TO SHIFT
EAST IN RESPONSE TO UPPER LEVEL TROUGH BEING CARVED OUT OVER THE
ROCKIES. WEAK LOW DEVELOPS OVER MT WITH LEE TROUGH/PRESSURE FALLS
TIGHTENING PRESSURE GRADIENT. SOUTHERLY GEOSTROPHIC WINDS HIT
30KTS AND WOULD EXPECT A DECENT PORTION OF THAT TO REACH THE
SURFACE AS BOUNDARY LAYER COUPLES SATURDAY AFTERNOON LEADING TO
BREEZY SPOTS. NEAR LEE TROUGH AND UPSLOPE WINDS...COULD SEE AN
AFTERNOON -TSRA IN THE FAR WEST AND THEN OVER THE WESTERN HALF OF
THE CWA WITH LOW LEVEL JET SATURDAY NIGHT. SOUTHERLY WINDS SHOULD
PROMOTE A FEW 90F READINGS ON THE LEE SIDE OF THE HILLS FROM
SPEARFISH TO BELLE FOURCHE.

SUNDAY...SURFACE LOW SHIFTS INTO EASTERN MT AS SHARPENING UPPER
LEVEL TROUGH LIFTS INTO WY/MT. 12Z NAM/GFS DIFFER ON ULTIMATE
POSITION/SPEED OF THIS SYSTEM. GFS LIFTS IT FAST NORTH AND NAM
SLOWER/FURTHER SOUTH. WILL TAKE THE MEAN FOR NOW AND RAISE POPS A
BIT IN THE NORTH WHERE BEST FORCING/THETA-E ADVECTION CONSPIRE TO
PRODUCE FALLING LIQUID HYDROMETEORS. FORCING/AVAILABLE CAPE
SUFFICIENT FOR TSRA.

EXTENDED...AN UPPER LEVEL TROF WILL CROSS THE ROCKIES AND MOVE INTO
THE PLAINS FOR THE FIRST PART OF THE WORK WEEK...BRINGING A
CONTINUED CHANCE OF PRECIPITATION. TROF WILL PUSH TO THE EAST FOR
THE SECOND HALF OF THE WEEK AS AN UPPER LEVEL RIDGE SLOWLY BUILDS
OVER THE WESTERN UNITED STATES. THIS WILL BRING A RETURN TO DRY
WEATHER ALONG WITH A SLOW WARMING TREND.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY MORNING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

HELGESON/SCHILD

000
FXUS63 KABR 192013
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
313 PM CDT FRI SEP 19 2008

.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
THE MAIN CHALLENGE IN THE SHORT TERM IS PRECIPITATION CHANCES THIS
EVENING AND AGAIN SUNDAY AND SUNDAY NIGHT. A WEAK UPPER LEVEL
TROUGH WILL BE OVER THE EASTERN PLAINS/MISSISSIPPI VALLEY TONIGHT.
A SURFACE TROUGH WILL EXTEND FROM NORTHEASTERN MINNESOTA TO NORTH
CENTRAL NEBRASKA THIS EVENING. CAPES IN THE 1000-1500 J/KG RANGE
AND LIS BETWEEN -2 AND -4 ALONG THE BOUNDARY WILL AID IN ALLOWING
WEAK THUNDERSTORMS TO CONTINUE INTO THE EARLY EVENING HOURS.
MOISTURE CONTINUES TO BE LIMITED AND NO LOW LEVEL JET IS EXPECTED
TONIGHT...SO DO NOT ANTICIPATE ANY SEVERE POSSIBILITY. A COLD
FRONT WILL DROP FROM SOUTHERN NORTH DAKOTA TO CENTRAL SOUTH DAKOTA
OVERNIGHT. THE UPPER TROUGH SLIDES EAST ON SATURDAY WITH A RIDGE
REACHING THE FAR WESTERN PLAINS. THE FRONTAL BOUNDARY WILL REMAIN
NEARLY STATIONARY THROUGH THE DAY AS HIGH PRESSURE SLIDES FROM
SOUTH CENTRAL CANADA TO NORTH OF THE GREAT LAKES...AND LOW
PRESSURE INTENSIFIES OVER MONTANA. SOME INSTABILITY REMAINS OVER
THE AREA...BUT DRIER AIR ASSOCIATED WITH THE HIGH LOOKS TO
COUNTERACT ENOUGH TO HINDER PRECIPITATION DEVELOPMENT. THE UPPER
RIDGE SLIDES EAST OF THE REGION SATURDAY NIGHT...WITH ENERGY
ASSOCIATED WITH A PACIFIC NORTHWEST TROUGH APPROACHING THE AREA.
THE SURFACE FRONT GETS PUSHED WEST OF THE REGION WITH A FAIRLY
TIGHT PRESSURE GRADIENT SETTING UP. THE ELONGATED TROUGH OF LOW
PRESSURE REMAINS WEST OF THE REGION SUNDAY...THEN BEGINS TO PUSH
BACK EASTWARD SUNDAY NIGHT. A FAIRLY POTENT SHORTWAVE WILL ROUND
THE BASE OF THE WESTERN TROUGH AND SLIDE ACROSS THE
DAKOTAS...AND IN ASSOCIATION WITH A 40-45 KNOT LOW LEVEL
JET...WILL ALLOW PRECIPITATION TO SPREAD EASTWARD ACROSS THE CWA
SUNDAY AFTERNOON AND SUNDAY NIGHT. NOT MUCH IN THE WAY OF
INSTABILITY AROUND...BUT WILL KEEP THE MENTION OF THUNDER GOING
DUE TO THE STRENGTH OF THE UPPER WAVE.

WILL SEE COOLER AIR MOVE IN TO THE EASTERN CWA WITH THE BACKDOOR
COLD FRONT TONIGHT AND SATURDAY. WILL THEN GO WITH TEMPERATURES
BACK AROUND NORMAL ON SUNDAY WITH STRONG SOUTHERLY FLOW BRINGING
SOMEWHAT WARMER AIR BACK OVER THE AREA.


.LONG TERM...MONDAY THROUGH FRIDAY
THE MAIN CHALLENGE IN THE EXTENDED CENTERS AROUND PRECIPITATION
CHANCES EARLY IN THE PERIOD.

THE GFS/ECMWF ARE IN A PRETTY GOOD AGREEMENT WITH THE HANDLING OF
THE MID/UPPER LEVEL FLOW PATTERN ACROSS THE REGION. THE PERIOD
BEGINS WITH A RIDGE OVER THE MIDWEST STATES AND A TROF THROUGH THE
ROCKIES. THIS LEAVES THE NORTHERN PLAINS UNDER SOUTHWEST FLOW
ALOFT. STRONG LLJ IS ALREADY ONGOING ACROSS THE CWA ON MONDAY WITH
A WARM FRONT LIFTING NORTHWARD. HARD TO DEFINE THE BREAK BETWEEN
CONVECTION ASSOCIATED WITH THE WARM FRONT AND CONVECTION WITH THE
SURFACE TROF SO HAVE MONDAY/MONDAY NIGHT AS 12 HOUR BLOCKS. UPPER
LEVEL RIDGE AMPLIFIES OVER THE GREAT LAKES REGION ON
TUESDAY...LEADING TO A SLOW PROGRESSION OF THE SURFACE TROF ACROSS
THE AREA. HOWEVER THE LATEST RUN OF THE GFS IS ABOUT 12 HOURS
FASTER ENDING PCPN THAN THE PREVIOUS RUNS. HIGH PRESSURE BUILDS IN
BY WEDNESDAY MORNING WITH THE REGION UNDER NEARLY ZONAL FLOW
ALOFT. THIS ZONAL FLOW QUICKLY CHANGES AS A WEAK MID LEVEL TROF
MOVES THROUGH THE AREA LATE IN THE EXTENDED. NOT FULLY CONVINCED
THIS WILL OCCUR SO HAVE LEFT THURSDAY/FRIDAY DRY FOR NOW.


&&

.AVIATION...
EXPECT VFR CONDITIONS THROUGH SATURDAY AFTERNOON WITH UNRESTRICTED
VISIBILITIES AND CIGS. AN ISOLATED SHOWER/THUNDERSTORM MAYBE POSSIBLE
AT KATY THROUGH 0Z TONIGHT.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
SHORT TERM...PARKIN
LONG TERM...SD
AVIATION...SD

WEATHER.GOV/ABERDEEN

000
FXUS63 KFSD 192008
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
300 PM CDT FRI SEP 19 2008

.DISCUSSION...

SMALL AREA OF ELEVATED TSRA FROM AROUND KATY INTO WCNTRL MN AT THIS
TIME IN AREA OF STRONGER MID LEVEL THETA-E CONVERGENCE AND 700-500MB
LAPSE RATES. THETA-E CONVERGENCE SLOWLY SAGS INTO SOUTHWEST MN THIS
EVENING. WILL CARRY SMALL POP FOR ISOLATED TSRA INTO KBKX/KMML/KDVP
AREAS FOR THIS EVENING...THOUGH WITH CLOUD BASES AT 10-12KFT...
PRECIP AMOUNTS AT THE SURFACE WILL BE MINIMAL. BETTER THETA-E
CONVERGENCE SLIDES INTO SOUTHERN CWA AHEAD OF WEAK BOUNDARY AND MID
LEVEL WAVE OVERNIGHT. HOWEVER MID LEVEL INSTABILITY NOT AS
SUPPORTIVE OF CONVECTION IN THIS AREA...AS STEEPER LAPSE RATES
REMAIN ACROSS NORTHWEST 1/2 OF THE CWA. HAVE PULLED MENTION OF
ISOLATED TSRA FROM NORTHWEST IOWA FOR LATER TONIGHT...BUT WILL BE
SOMETHING FOR NEXT SHIFT TO EVALUATE.

ON SATURDAY...WEAK BOUNDARY WILL MEANDER BACK TO THE NORTH AS IT
FALLS APART. WITH SLIGHTLY COOLER LOW LEVEL THERMAL FIELDS AND WINDS
TRANSITIONING TO A EAST/SOUTHEASTERLY FLOW...WILL SEE HIGH
TEMPERATURES A COUPLE OF DEGREES COOLER THAN TODAY. SATURDAY NIGHT
LOOKS DRY AND MILDER WITH WINDS STAYING UP. HIGH PRESSURE OVER THE
GREAT LAKES REGION WILL OOZE INTO THE MISSISSIPPI VALLEY ON
SUNDAY...INDUCING A STRONG SOUTHERLY FLOW OVER OUR REGION...AND WITH
A STRENGTHENING TROUGH OVER THE NORTHERN ROCKIES/WESTERN HIGH
PLAINS...STILL LOOKS TO BE A WINDY DAY. TEMPERATURES AGAIN WILL BE
JUST EITHER SIDE OF 80.

WITH THE STRONG SOUTHERLY FLOW...BETTER MOISTURE WILL BEGIN TO BE
ADVECTED NORTHWARD BY SUNDAY EVENING ON A STRENGTHENING LOW LEVEL
JET OVER CENTRAL SOUTH DAKOTA...AND THIS IN CONJUNCTION WITH A
SHORTWAVE MOVING OUT OF THE WESTERN PLAINS WILL BRING A CHANCE OF
PRECIPITATION TO THE AREA ON SUNDAY NIGHT INTO MONDAY. MONDAY LOOKS
LIKE ANOTHER WINDY DAY WITH A TIGHT PRESSURE GRADIENT REMAINING
ACROSS THE REGION. WITH CLOUDS/SHOWERS AND COOLER LOW LEVEL
TEMPERATURES...HIGHS ON MONDAY MAY BE AGAIN BE A SHADE
LOWER...GENERALLY IN THE MID AND UPPER 70S.

IN THE EXTENDED...TUESDAY THROUGH FRIDAY...STILL LOOKING TO BE A
RELATIVELY UNSETTLED PERIOD AS THE UPPER LEVEL TROUGH OVER THE
WESTERN U.S. AT THE START OF THE WEEK FINALLY PUSHES INTO THE
CENTRAL PORTIONS OF THE COUNTRY. MAIN WAVE MOVES THROUGH LATE
TUESDAY INTO WEDNESDAY...WITH SOME MODEL DISAGREEMENT ON TIMING OF
SYSTEM. BOTH THE GFS/CANADIAN ARE FASTER THEN THE ECMWF...SO SPED UP
TIMING JUST A BIT ON WEDNESDAY. MODELS HINTING AT SECONDARY WAVE
PUSHING THROUGH THE REGION IN THE THURSDAY TIME FRAME...BUT WITH
CONTINUED POOR MODEL AGREEMENT ON TRACK AND TIMING OF
SHORTWAVE...LEFT FORECAST DRY FOR NOW. STILL NO REAL COLD AIR IN
SITE...WITH TEMPERATURES FOR THE MIDDLE AND END OF NEXT WEEK
REMAINING MAINLY ABOVE NORMAL FOR THIS TIME OF YEAR.

&&

.AVIATION...

VFR CONDITIONS EXPECTED TO PERSIST THRU 00Z SUN. ISOLATED TSRA
POSSIBLE FROM EAST CENTRAL SD INTO WEST CENTRAL AND SOUTHWEST MN
DURING THE LATE AFTERNOON AND EVENING...BUT NOT EXPECTED TO AFFECT
TAF LOCATIONS AT THIS TIME.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$

JM

000
FXUS63 KABR 191623 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1123 AM CDT FRI SEP 19 2008

.UPDATE...
ONLY UPDATE TO THE FORECAST WAS TO REMOVE POPS FOR THIS AFTERNOON
AS DRIER AIR IS MOVING INTO THE REGION BEHIND THE SURFACE TROUGH
CURRENTLY TRACKING ACROSS THE EASTERN CWA. NO CHANGES MADE TO
TEMPERATURES OR WINDS. NEW AVIATION DISCUSSION BELOW.


&&
.PREV DISCUSSION...
.SHORT TERM...TODAY THROUGH SUNDAY
MODELS AND GFS ENSEMBLES WERE SHOWING VERY GOOD AGREEMENT THROUGH
THE SHORT TERM. FOR TODAY...WEAK FRONTAL BOUNDARY/TROUGH WILL PUSH
SLOWLY ACROSS NORTHEAST SOUTH DAKOTA TODAY AND THEN TO THE SOUTH
OF THE CWA TONIGHT. A FEW HIGH BASED ACCAS SHRAS/TSRAS WERE
OCCURRING THIS MORNING ALONG THIS FRONT WITH THE HELP OF AN UPPER
LEVEL SHORT WAVE TROUGH ALONG WITH A LLJ AND STEEP MID LEVEL LAPSE
RATES. DONT EXPECT MUCH RAIN WITH THESE DUE TO THE HIGH BASES AND
DRIER LOW LEVEL AIR UNDERNEATH. ADDED IN 20 POPS ACROSS FAR
NORTHEAST SD AND WEST CENTRAL MN FOR THIS MORNING AS THIS ACTIVITY
MOVES SOUTH AND EAST. ALSO...ADDED IN POPS ACROSS THE SOUTHEAST
CWA FOR LATER THIS AFTERNOON WITH REDEVELOPMENT POSSIBLE ALONG THE
BOUNDARY WITH SURFACE HEATING AND INSTABILITY INCREASING.
OTHERWISE...THE MODELS SHOW A STRONG AREA OF SURFACE HIGH PRESSURE
IN CANADA TODAY SLIDING SOUTHEAST ACROSS THE GREAT LAKES REGION
THROUGH THE SHORT TERM. THIS WILL USHER IN COOLER
AIR...ESPECIALLY ACROSS THE EASTERN CWA FOR TONIGHT AND SATURDAY.
AFTER THE MID AND HIGH LEVEL CLOUDS MOVE OUT THIS MORNING...SKIES
ACROSS THE CWA SHOULD BE MOSTLY SUNNY WITH ANOTHER WARM DAY WITH
HIGHS IN THE 80S. SATURDAY WILL BE A COOLER DAY ACROSS THE CWA
WITH THE CANADIAN AIR PUSHING IN. LOWERED HIGHS FOR SATURDAY
ACROSS THE BOARD...ESPECIALLY IN NORTHEAST SD AND WEST CENTRAL MN.
QUITE A DIFFERENCE BETWEEN THE MAV AND MET FOR HIGHS OVER THE NEXT
FEW DAYS. THE COOLER AIR WILL RETREAT SATURDAY NIGHT AND SUNDAY
AS WINDS COME AROUND TO THE SOUTHEAST AND SOUTH AROUND THE
BACKSIDE OF THE HIGH PRESSURE AREA TO THE EAST. THE MODELS AND
GFS ENSEMBLES AGREE THAT AN NEGATIVELY TILTED UPPER LEVEL TROUGH
WILL BEGIN AFFECTING THE REGION FROM THE WEST COME SUNDAY.
THUS...EXPECT AN INCREASE IN CLOUDS ALONG WITH AN INCREASE IN
SOUTH WINDS AS THE SURFACE PRESSURE GRADIENT RESPONDS TO THIS
FEATURE. SUNDAY COULD ALSO BE A BREEZY/WINDY ONE ACROSS THE CWA.
KEPT IN THE 20 POPS FOR TSRAS IN THE WESTERN CWA FOR SUNDAY.

.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
FORECAST CHALLENGES CONTINUE TO CENTER AROUND THE TIMING OF A
HANDFUL OF SHORTWAVES SUNDAY NIGHT THROUGH TUESDAY NIGHT.

CURRENTLY IT LOOKS AS THOUGH EACH S/W TROF WILL BE SEPARATED IN
TIME AND SPACE BY APPX 12 TO 18 HOURS. AS SUCH...BETWEEN EACH
S/W...A BRIEF PERIOD OF NVA/SUBSIDENCE SHOULD PROVE TO HOLD
PRECIPITATION POTENTIAL AT BAY /EVEN THOUGH UPPER LEVEL FLOW
PATTERN WILL BE SW TO NE/...UNTIL THE PVA/LIFT ASSOCIATED WITH THE
NEXT S/W ENCROACHES FROM THE WEST AND SOUTHWEST. SO...TRIED TO
BREAK UP POPS ON DAYS 4 AN 5 INTO 6-HOURLY BLOCKS TO BETTER
HIGHLIGHT TIMEFRAMES WITH THE BEST CHANCES THOSE TWO DAYS. BEST
SHOT AT ORGANIZED CONVECTION CURRENTLY APPEARS TO BE ANCHORED ON
TUESDAY AFTERNOON/EVENING AS THE SYNOPTIC SCALE COLD FRONT THAT
SIGNALS AIRMASS CHANGE AND THE END OF PRECIPITATION CHANCES FOR
AWHILE WORKS ACROSS THE CWA. 0-6KM SHEAR IS PROGGED IN THE 00Z GFS
BETWEEN 40 AND 50 KNOTS AND SURFACE-BASED CAPE IS PROGGED TO BE
1000-1500J/KG WITH MINIMAL /IF ANY/ CINH.

TEMPERATURES WILL REMAIN AT OR ABOVE CLIMO NORMS MONDAY AND
TUESDAY AS SOUTHERLY LOW LEVEL WINDS WORK TO DRAW WARM AIR AND
MOISTURE NORTHWARD INTO THE CWA.


&&

.AVIATION...
P6SM VSBYS AND SKC BLO 10K FT AGL EXPECTED FOR ALL TERMINALS THROUGH
06Z SATURDAY. LIGHT AND VARIABLE WINDS WILL ALSO PREVAIL AT ALL
FOUR TERMINALS TODAY.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...PARKIN
SHORT TERM...MOHR
LONG TERM...DORN
AVIATION...SD

WEATHER.GOV/ABERDEEN

000
FXUS63 KFSD 191618
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1115 AM CDT FRI SEP 19 2008

.DISCUSSION...
MINIMAL ELEVATED TSRA CHANCE IS ONLY REAL CONCERN TODAY...AS GOING
FORECAST ALREADY HAS A GOOD HANDLE ON GUSTY SOUTHERLY WINDS AND
TEMPS STILL LOOKING GOOD THUS FAR. MID LEVEL LAPSE RATES FAVORABLE
ACROSS THE NORTHWEST 1/2 OF THE CWA DURING THE LATE AFTERNOON AND
OVERNIGHT...BUT BOTH NAM AND RUC SHOW LIMITED MOISTURE AVAILABLE TO
SUPPORT EVEN ISOLATED TSRA IN THIS AREA. BAND OF SOMEWHAT BETTER
MOISTURE SLIDES SOUTHEAST ACCOMPANYING WEAK BOUNDARY...BUT MOVING
INTO LESS FAVORABLE AREA OF MID LEVEL INSTABILITY AS THE NIGHT
PROGRESSES. HAVE REMOVED MENTION OF ISOLATED TSRA FROM THE FAR
NORTHWEST CWA FOR THE LATE AFTERNOON...AND WILL SEND UPDATED ZFP
FOR THAT SHORTLY. WILL HANG ONTO OVERNIGHT MENTION FOR NOW...BUT
WILL REEVALUATE BEFORE REGULAR ZFP ISSUANCE THIS AFTERNOON.

&&

.AVIATION...
VFR CONDITIONS EXPECTED TO PERSIST THRU 12Z SAT. ISOLATED TSRA
POSSIBLE NEAR BOUNDARY AS IT SAGS SOUTHEAST THROUGH THE AREA LATE
THIS AFTERNOON AND TONIGHT. HOWEVER...MOISTURE LIMITED AND BOUNDARY
WORKING INTO AREA OF LESS FAVORABLE MID LEVEL LAPSE RATES AS THE
NIGHT PROGRESSES. WL KEEP MENTION OF TSRA OUT OF TAFS DUE TO VERY
LOW LIKELIHOOD.

&&

.PREV DISCUSSION...
BRISK SLY FLOW BRINGING UP A MODICUM OF MOISTURE WITH IT TDA...
COMPARED TO YESTERDAYS RELATIVELY DRY DEWPOINTS TO THE SOUTH. FNTL
BOUNDARY FM NE TO SW SD HAS ALREADY PRODUCED A FEW TSTMS...WHICH MAY
GRAZE THE FAR NRN CWA THIS MRNG. HOWEVER...AS BOUNDARY MOVES SE AND
AIR MASS HEATS OUT THIS AFTN...AT LEAST ISOLD TSTMS SHOULD REDVLP FM
WRN TO NRN PTNS OF THE CWA...MOVG SEWD OVR CWA TNGT BEFORE FALLING
APART LATE. DEEP VEERING WIND PROFILE AND STEEP LAPSE RATES ARE A
CONCERN FOR EVEN AN ISOLD SVR STORM THIS AFTN INTO EARLY EVE. ONLY
DRAWBACK IS WEAK DYNAMICS AND MOISTURE SUPPLY. FNT WILL SAG SEWD OVR
CWA TNGT BEFORE RETURNING SLOWLY NWD AS A WMFNT THIS WEEKEND...WITH
SOME BACKDOOR COOLING EXPCD NERN HLF CWA. SSELY FLOW SHOULD REALLY
KICK IN BY SUN AFTN...BRINGING BACK BTR MOISTURE SUN NGT THRU EARLY
NEXT WEEK AHEAD OF DVLPG BROAD UPR TROF PUNCHING EWD FM RCKYS. UPPD
POPS SOME WITH FIRST GOOD WAVE SHOWN ON ALL MODELS MOVG EWD OVR CWA
FM SUN NGT THRU MON. GETS A LITTLE FUZZY AFT THAT WITH STILL SOME
SIGN OF REDVLPMT MON NGT AND TUE WITH INCRG MOISTURE AND DYNAMICS.
HOWEVER...TUE NGT STILL LOOKS LIKE THE MAIN CHC TSTMS MOVG EWD WITH
CDFNT...AND MASSAGED UP THE POPS SOME. THIS SYSTEM HAS THE POTENTIAL
TO FINALLY PROVIDE SOME NEEDED SIGNIFICANT PRECIP IN THE AREA. GFS
MOVES EVERYTHING THRU BY WED...BUT ECMWF STILL HAS A HANGBACK CHC
TSTMS AS PER PREV FCST INTO WED.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$
 JH

000
FXUS63 KUNR 191533
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 AM MDT FRI SEP 19 2008

.DISCUSSION...15Z SURFACE ANALYSIS HAD SURFACE BOUNDARY FROM
NORTHERN MN INTO WESTERN NE. DRIER AIR FILTERING INTO THE CWA
BEHIND BOUNDARY WITH DEW POINTS IN THE 30S. THIS SHOULD PRECLUDE
ANY CONVECTIVE DEVELOPMENT OVER THE CWA WITH SBCAPE NEAR ZERO.
ONLY EXCEPTION WOULD BE SOUTH CENTRAL SD...BUT POPS UNMENTIONABLE
AT THIS POINT. WILL UPDATE FORECAST TO DROP CLOUD COVER A
BIT...OTHERWISE NO REAL CHANGES.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 335 AM MDT FRI SEP 19 2008/

DISCUSSION...BROAD UPPER LEVEL RIDGE IS IN PLACE OVER MUCH OF THE
UNITED STATES WITH A SURFACE TROUGH STRETCHING FROM NORTHEASTERN
NORTH DAKOTA TO SOUTHWESTERN SOUTH DAKOTA. AN AREA OF CLOUDS AND A
FEW LINGERING SHOWERS AND THUNDERSTORMS ARE ASSOCIATED WITH THE
TROUGH. SHOWER ACTIVITY HAS DECREASED QUITE A BIT IN THE LAST FEW
HOURS AND EXPECT THE REMAINING SHOWERS TO HAVE DISSIPATED IN AN HOUR
OR TWO. DRY WEATHER AND WARM TEMPERATURES ARE EXPECTED TODAY AS THE
UPPER LEVEL RIDGE BRIEFLY REBUILDS OVER THE AREA.

DRY WEATHER CONTINUES DURING THE DAY SATURDAY BEFORE THE NEXT SYSTEM
APPROACHES THE AREA SATURDAY NIGHT. WINDS WILL HAVE SWITCHED AROUND
TO THE SOUTHEAST BY SATURDAY AND BREEZY CONDITIONS ARE POSSIBLE AS
THE PRESSURE GRADIENT TIGHTENS AHEAD OF THIS NEXT SYSTEM. WITH THE
WARM TEMPERATURES AND STRONGER WINDS...FIRE WEATHER CONCERNS WILL
NEED TO BE MONITORED. CURRENTLY RELATIVE HUMIDITIES ON SATURDAY ARE
EXPECTED TO BE IN THE 20 TO 30 PERCENT RANGE WHICH DOES NOT MEET RED
FLAG CRITERIA SO THERE DOES NOT APPEAR TO BE A NEED FOR ANY FIRE
WEATHER HEADLINES. BREEZY CONDITIONS WILL AGAIN BE POSSIBLE SUNDAY
ALONG WITH SCATTERED SHOWERS AND THUNDERSTORMS AS AN UPPER LEVEL
TROUGH CROSSES THE NORTHERN PLAINS.

EXTENDED...BROAD UPPER LEVEL TROF WILL CROSS THE NORTHERN ROCKIES
AND SETTLE OVER THE NORTHERN PLAINS FOR THE FIRST PART ON NEXT WEEK.
A SERIES OF SHORTWAVES MOVING THROUGH THE CYCLONIC FLOW WILL BRING A
DAILY CHANCE OF PRECIPITATION THROUGH WEDNESDAY ALONG WITH COOLER
TEMPERATURES. MODELS MOVE TROF TO THE EAST FOR THE END OF THE
WEEK...BRINGING DRIER CONDITIONS TO THE AREA.

AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

HELGESON

000
FXUS63 KUNR 190934
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
335 AM MDT FRI SEP 19 2008

.DISCUSSION...BROAD UPPER LEVEL RIDGE IS IN PLACE OVER MUCH OF THE
UNITED STATES WITH A SURFACE TROUGH STRETCHING FROM NORTHEASTERN
NORTH DAKOTA TO SOUTHWESTERN SOUTH DAKOTA. AN AREA OF CLOUDS AND A
FEW LINGERING SHOWERS AND THUNDERSTORMS ARE ASSOCIATED WITH THE
TROUGH. SHOWER ACTIVITY HAS DECREASED QUITE A BIT IN THE LAST FEW
HOURS AND EXPECT THE REMAINING SHOWERS TO HAVE DISSIPATED IN AN HOUR
OR TWO. DRY WEATHER AND WARM TEMPERATURES ARE EXPECTED TODAY AS THE
UPPER LEVEL RIDGE BRIEFLY REBUILDS OVER THE AREA.

DRY WEATHER CONTINUES DURING THE DAY SATURDAY BEFORE THE NEXT SYSTEM
APPROACHES THE AREA SATURDAY NIGHT. WINDS WILL HAVE SWITCHED AROUND
TO THE SOUTHEAST BY SATURDAY AND BREEZY CONDITIONS ARE POSSIBLE AS
THE PRESSURE GRADIENT TIGHTENS AHEAD OF THIS NEXT SYSTEM. WITH THE
WARM TEMPERATURES AND STRONGER WINDS...FIRE WEATHER CONCERNS WILL
NEED TO BE MONITORED. CURRENTLY RELATIVE HUMIDITIES ON SATURDAY ARE
EXPECTED TO BE IN THE 20 TO 30 PERCENT RANGE WHICH DOES NOT MEET RED
FLAG CRITERIA SO THERE DOES NOT APPEAR TO BE A NEED FOR ANY FIRE
WEATHER HEADLINES. BREEZY CONDITIONS WILL AGAIN BE POSSIBLE SUNDAY
ALONG WITH SCATTERED SHOWERS AND THUNDERSTORMS AS AN UPPER LEVEL
TROUGH CROSSES THE NORTHERN PLAINS.

EXTENDED...BROAD UPPER LEVEL TROF WILL CROSS THE NORTHERN ROCKIES
AND SETTLE OVER THE NORTHERN PLAINS FOR THE FIRST PART ON NEXT WEEK.
A SERIES OF SHORTWAVES MOVING THROUGH THE CYCLONIC FLOW WILL BRING A
DAILY CHANCE OF PRECIPITATION THROUGH WEDNESDAY ALONG WITH COOLER
TEMPERATURES. MODELS MOVE TROF TO THE EAST FOR THE END OF THE
WEEK...BRINGING DRIER CONDITIONS TO THE AREA.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

000
FXUS63 KABR 190852
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
352 AM CDT FRI SEP 19 2008

.SHORT TERM...TODAY THROUGH SUNDAY
MODELS AND GFS ENSEMBLES WERE SHOWING VERY GOOD AGREEMENT THROUGH
THE SHORT TERM. FOR TODAY...WEAK FRONTAL BOUNDARY/TROUGH WILL PUSH
SLOWLY ACROSS NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MN TODAY AND
THEN TO THE SOUTH OF THE CWA TONIGHT. A FEW HIGH BASED ACCAS
SHRAS/TSRAS WERE OCCURRING THIS MORNING ALONG THIS FRONT WITH THE
HELP OF AN UPPER LEVEL SHORT WAVE TROUGH ALONG WITH A LLJ AND
STEEP MID LEVEL LAPSE RATES. DONT EXPECT MUCH RAIN WITH THESE DUE
TO THE HIGH BASES AND DRIER LOW LEVEL AIR UNDERNEATH. ADDED IN 20
POPS ACROSS FAR NORTHEAST SD AND WEST CENTRAL MN FOR THIS MORNING
AS THIS ACTIVITY MOVES SOUTH AND EAST. ALSO...ADDED IN POPS ACROSS
THE SOUTHEAST CWA FOR LATER THIS AFTERNOON WITH REDEVELOPMENT
POSSIBLE ALONG THE BOUNDARY WITH SURFACE HEATING AND INSTABILITY
INCREASING. OTHERWISE...THE MODELS SHOW A STRONG AREA OF SURFACE
HIGH PRESSURE IN CANADA TODAY SLIDING SOUTHEAST ACROSS THE GREAT
LAKES REGION THROUGH THE SHORT TERM. THIS WILL USHER IN COOLER
AIR...ESPECIALLY ACROSS THE EASTERN CWA FOR TONIGHT AND SATURDAY.
AFTER THE MID AND HIGH LEVEL CLOUDS MOVE OUT THIS MORNING...SKIES
ACROSS THE CWA SHOULD BE MOSTLY SUNNY WITH ANOTHER WARM DAY WITH
HIGHS IN THE 80S. SATURDAY WILL BE A COOLER DAY ACROSS THE CWA
WITH THE CANADIAN AIR PUSHING IN. LOWERED HIGHS FOR SATURDAY
ACROSS THE BOARD...ESPECIALLY IN NORTHEAST SD AND WEST CENTRAL MN.
QUITE A DIFFERENCE BETWEEN THE MAV AND MET FOR HIGHS OVER THE NEXT
FEW DAYS. THE COOLER AIR WILL RETREAT SATURDAY NIGHT AND SUNDAY AS
WINDS COME AROUND TO THE SOUTHEAST AND SOUTH AROUND THE BACKSIDE
OF THE HIGH PRESSURE AREA TO THE EAST. THE MODELS AND GFS
ENSEMBLES AGREE THAT A NEGATIVELY TILTED UPPER LEVEL TROUGH WILL
BEGIN AFFECTING THE REGION FROM THE WEST COME SUNDAY.
THUS...EXPECT AN INCREASE IN CLOUDS ALONG WITH AN INCREASE IN
SOUTH WINDS AS THE SURFACE PRESSURE GRADIENT RESPONDS TO THIS
FEATURE. SUNDAY COULD ALSO BE A BREEZY/WINDY ONE ACROSS THE CWA.
KEPT IN THE 20 POPS FOR TSRAS IN THE WESTERN CWA FOR SUNDAY.


.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
FORECAST CHALLENGES CONTINUE TO CENTER AROUND THE TIMING OF A
HANDFUL OF SHORTWAVES SUNDAY NIGHT THROUGH TUESDAY NIGHT.

CURRENTLY IT LOOKS AS THOUGH EACH S/W TROF WILL BE SEPARATED IN
TIME AND SPACE BY APPX 12 TO 18 HOURS. AS SUCH...BETWEEN EACH
S/W...A BRIEF PERIOD OF NVA/SUBSIDENCE SHOULD PROVE TO HOLD
PRECIPITATION POTENTIAL AT BAY /EVEN THOUGH UPPER LEVEL FLOW
PATTERN WILL BE SW TO NE/...UNTIL THE PVA/LIFT ASSOCIATED WITH THE
NEXT S/W ENCROACHES FROM THE WEST AND SOUTHWEST. SO...TRIED TO
BREAK UP POPS ON DAYS 4 AN 5 INTO 6-HOURLY BLOCKS TO BETTER
HIGHLIGHT TIMEFRAMES WITH THE BEST CHANCES THOSE TWO DAYS. BEST
SHOT AT ORGANIZED CONVECTION CURRENTLY APPEARS TO BE ANCHORED ON
TUESDAY AFTERNOON/EVENING AS THE SYNOPTIC SCALE COLD FRONT THAT
SIGNALS AIRMASS CHANGE AND THE END OF PRECIPITATION CHANCES FOR
AWHILE WORKS ACROSS THE CWA. 0-6KM SHEAR IS PROGGED IN THE 00Z GFS
BETWEEN 40 AND 50 KNOTS AND SURFACE-BASED CAPE IS PROGGED TO BE
1000-1500J/KG WITH MINIMAL /IF ANY/ CINH.

TEMPERATURES WILL REMAIN AT OR ABOVE CLIMO NORMS MONDAY AND
TUESDAY AS SOUTHERLY LOW LEVEL WINDS WORK TO DRAW WARM AIR AND
MOISTURE NORTHWARD INTO THE CWA.



&&

.AVIATION...
06Z TAFS FOR KABR...KATY...KPIR AND KMBG TERMINALS

P6SM VSBYS AND SKC BLO 8000 FT AGL EXPECTED FOR ALL TERMINALS
THROUGH 06Z SATURDAY. SCT/BKN100-150 CLOUDS EXPECTED TO CONTINUE
THEIR DRIFT EAST OVER THE KABR/KATY TERMINALS THROUGH 15Z THIS
MORNING. AN ISOLD -SHRA/TSRA REMAINS PSBL MAINLY BETWEEN 12Z AND
18Z ACROSS THE KATY TERMINAL THIS MORNING. LIGHT AND VARIABLE
WINDS WILL ALSO PREVAIL AT ALL FOUR TERMINALS TODAY.



&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
SHORT TERM...MOHR
LONG TERM...DORN
AVIATION...DORN

WEATHER.GOV/ABERDEEN

000
FXUS63 KFSD 190839
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
340 AM CDT FRI SEP 19 2008

.DISCUSSION...

BRISK SLY FLOW BRINGING UP A MODICUM OF MOISTURE WITH IT TDA...
COMPARED TO YESTERDAYS RELATIVELY DRY DEWPOINTS TO THE SOUTH. FNTL
BOUNDARY FM NE TO SW SD HAS ALREADY PRODUCED A FEW TSTMS...WHICH MAY
GRAZE THE FAR NRN CWA THIS MRNG. HOWEVER...AS BOUNDARY MOVES SE AND
AIR MASS HEATS OUT THIS AFTN...AT LEAST ISOLD TSTMS SHOULD REDVLP FM
WRN TO NRN PTNS OF THE CWA...MOVG SEWD OVR CWA TNGT BEFORE FALLING
APART LATE. DEEP VEERING WIND PROFILE AND STEEP LAPSE RATES ARE A
CONCERN FOR EVEN AN ISOLD SVR STORM THIS AFTN INTO EARLY EVE. ONLY
DRAWBACK IS WEAK DYNAMICS AND MOISTURE SUPPLY. FNT WILL SAG SEWD OVR
CWA TNGT BEFORE RETURNING SLOWLY NWD AS A WMFNT THIS WEEKEND...WITH
SOME BACKDOOR COOLING EXPCD NERN HLF CWA. SSELY FLOW SHOULD REALLY
KICK IN BY SUN AFTN...BRINGING BACK BTR MOISTURE SUN NGT THRU EARLY
NEXT WEEK AHEAD OF DVLPG BROAD UPR TROF PUNCHING EWD FM RCKYS. UPPD
POPS SOME WITH FIRST GOOD WAVE SHOWN ON ALL MODELS MOVG EWD OVR CWA
FM SUN NGT THRU MON. GETS A LITTLE FUZZY AFT THAT WITH STILL SOME
SIGN OF REDVLPMT MON NGT AND TUE WITH INCRG MOISTURE AND DYNAMICS.
HOWEVER...TUE NGT STILL LOOKS LIKE THE MAIN CHC TSTMS MOVG EWD WITH
CDFNT...AND MASSAGED UP THE POPS SOME. THIS SYSTEM HAS THE POTENTIAL
TO FINALLY PROVIDE SOME NEEDED SIGNIFICANT PRECIP IN THE AREA. GFS
MOVES EVERYTHING THRU BY WED...BUT ECMWF STILL HAS A HANGBACK CHC
TSTMS AS PER PREV FCST INTO WED.

&&

.AVIATION...

VFR CONDITIONS EXPECTED TO PERSIST THRU 12Z SAT. HOWEVER...SOME LOW
LVL WIND SHEAR BASED FROM 300 TO 800 FT AGL IS LKLY TO CONTINUE
THROUGH SHORTLY AFTER DAYBREAK... WITH LOW LEVEL JET IN PLACE ACROSS
THE REGION. ISOLD TSRA SHUD REMAIN NORTH OF KHON AREA EARLY
MORNING...WITH ISOLATED STORMS NEARBY AFT 20Z AS FRONTAL BOUNDARY
WORKS SEWRD INTO AREA. THIS BNDRY WL CONTINUE TO PRESS SOUTHEAST
OVERNIGHT WITH THE LOW END RISK TOWARD KFSD AREA AFT 00Z..AND AFT
06Z AT KSUX. WL LKLY NOT MENTION IN 12Z TAFS DUE TO VERY LOW
LIKELIHOOD.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$
RYRHOLM/CHAPMAN

000
FXUS63 KABR 190250
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
950 PM CDT THU SEP 18 2008

.UPDATE...
LOW PRESSURE AND ASSOCIATED SFC TROF CURRENTLY ALONG THE MO
RIVER...WITH SCT -TSRA DEVELOPING EAST OF KBIS IN ND. LATEST RUC
ADVERTISES 85H WINDS TO INCREASE TO 30 TO 40 KTS OVERNIGHT ACROSS
THE EAST. WITH MINOR 7H OMEGA OCCURRING...CANT ARGUE AGAINST THE
ISOLD/SLGT CHC POPS CURRENTLY IN FCST. FOR NOW...CURRENT GRIDS ARE
IN FINE SHAPE WITH ONLY HOURLY TWEAKS REQUIRED. NO ZONE FORECAST
PACKAGE UPDATE PLANNED ATTM.

UPDATED AVIATION DISCUSSION BELOW.


&&
.PREV DISCUSSION...
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
THE MAIN CHALLENGE IN THE NEAR TERM IS PRECIPITATION CHANCES
TONIGHT. A WEAK UPPER LEVEL TROUGH WILL TRACK ACROSS THE PLAINS
TONIGHT AND FRIDAY AHEAD OF A RIDGE SETTING UP OVER THE ROCKIES.
WEAK PVA WILL BE OVER THE NORTHERN CWA TONIGHT. A SURFACE TROUGH
CURRENTLY LOCATED FROM LAKE WINNIPEG TO EASTERN COLORADO WILL ALSO
SLOWLY APPROACH THE REGION. AHEAD OF THIS TROUGH...A 20 TO 35 KNOT
LLJ WILL DEVELOP TONIGHT IN ASSOCIATION WITH 1000-1500 J/KG OF
CAPE AND LIS IN THE -2 TO -5 RANGE. TWO LIMITING FACTORS WILL BE
700 MB TEMPS AROUND +8 TO +9 AND LIMITED MOISTURE.
THEREFORE...WILL JUST KEEP A SMALL POP GOING ACROSS THE NORTHERN
CWA CLOSER TO THE UPPER LEVEL ENERGY. IF ANY STORMS DO GET
GOING...THEY MAY HAVE THE POTENTIAL TO PRODUCE SOME SMALL HAIL. A
COLD FRONT WILL DROP OUT OF CANADA TO NORTHERN NORTH DAKOTA
TONIGHT. THIS FRONT REACHES SOUTHERN NORTH DAKOTA BY FRIDAY
AFTERNOON...THEN PUSHES TO SOUTHERN SOUTH DAKOTA FRIDAY NIGHT
BEFORE STALLING OUT THROUGH THE DAY SATURDAY...THEN PUSHING BACK
NORTH AS A WARM FRONT SATURDAY NIGHT AS LOW PRESSURE STRENGTHENS
OVER THE NORTHERN ROCKIES. EVEN THOUGH WEAK INSTABILITY REMAINS
OVER THE AREA IN ASSOCIATION WITH THE FRONT...MOISTURE WILL
CONTINUE TO BE VERY LIMITED THROUGH THE REST OF THE PERIOD...AND
HAVE DECIDED TO KEEP THE MENTION OF PRECIPITATION OUT AT THIS
TIME.

EXPECT ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH THE PERIOD AS
H85 TEMPS REMAIN IN THE MID TEENS TO LOWER 20S. WILL STICK WILL
HIGHS MAINLY IN THE 80S AND LOWS IN THE 50S.

.LONG TERM...SUNDAY THROUGH THURSDAY
THE MAIN CHALLENGE IN THE EXTENDED DEALS WITH PRECIPITATION AS
MODELS SHOW A COUPLE OF WAVES PASSING THROUGH THE REGION.

THE PERIOD BEGINS WITH AREA OF LOW PRESSURE OVER THE NORTHERN HIGH
PLAINS WITH STRONG SOUTHERLY FLOW/WAA UP THE PLAIN STATES. THE
SURFACE LOW TAKES ON A BIT OF A NEGATIVE TILT...LEADING TO A
SLOWER PROGRESSION. HAVE BACKED PCPN OFF BY SIX HOURS...AND WOULD
NOT BE SURPRISED IF PCPN IS REMOVED ALL TOGETHER ON SUNDAY. SUNDAY
NIGHT HOWEVER...WITH A STRONG LLJ OF 40KTS AND 25KTS OF 0-1KM BULK
SHEAR...HAVE INCREASED POPS SOME ACROSS THE AREA. SURFACE LOW
MOVES NNE INTO CENTRAL SASKATCHEWAN ON TUESDAY...WITH THE
MID/UPPER LEVEL FLOW PATTERN DE-AMPLIFYING OVER THE REGION. THE
MID/UPPER LEVEL TROF AXIS SLOWLY PUSHES EASTWARD ON
WEDNESDAY...ENDING PCPN CHANCES. HIGH PRESSURE BUILDS IN THERE
AFTER...WITH THE GFS SHOWING WARMER AIR WORKING BACK INTO THE AREA
FOR THE NEXT WEEKEND.


&&

.AVIATION...
P6SM VSBYS EXPECTED FOR ALL TERMINALS THROUGH 00Z SATURDAY.
SCT/BKN130 CLOUDS EXPECTED TO DRIFT EAST ACROSS KMBG/KPIR
TERMINALS THROUGH 10Z...AND ACROSS KABR/KATY TERMINALS THROUGH
13Z. ISOLD -TSRA IS PSBL AFT 06Z FOR THE KABR/KATY TERMINALS...BUT
CONFIDENCE OF ACTUAL DEVELOPMENT IS LOW...SO LEFT OUT OF TERMINAL
FCSTS ATTM.



&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...HINTZ
SHORT TERM...TMT
LONG TERM...PARKIN
AVIATION...HINTZ

WEATHER.GOV/ABERDEEN

000
FXUS63 KUNR 190249
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
849 PM MDT THU SEP 18 2008

.DISCUSSION...A FEW SHOWERS AND THUNDERSTORMS ARE ONGOING ACROSS
PORTIONS OF SOUTHWESTERN AND SOUTH CENTRAL SOUTH DAKOTA THIS
EVENING ALONG THE SFC TROUGH/FRONT. COVERAGE AND INTENSITY HAVE
DECREASED DURING THE PAST HOUR WITH THE END OF DIURNAL HEATING AND
EXPECT THAT TREND TO CONTINUE OVER THE NEXT COUPLE OF HOURS. HAVE
UPDATED THE FORECAST TO ADJUST LOCATION OF POPS/WX AND CLOUDS.

&&

.AVIATION...ISOLD THUNDERSTORMS WILL BE POSSIBLE THROUGH EARLY
THIS EVENING OVER PTNS OF SOUTHWESTERN AND SOUTH CENTRAL SOUTH DAKOTA
...THOUGH ANY PRECIPITATION IS EXPECTED TO BE LIGHT. OTHERWISE...VFR
CONDITIONS ARE EXPECTED THROUGH FRIDAY.


&&

.PREV DISCUSSION... /ISSUED 216 PM MDT THU SEP 18 2008/

DISCUSSION...20Z SURFACE ANALYSIS HAD WEAK LOW NEAR K2WX AND
TROUGH INTO SOUTHEAST WY. SURFACE BOUNDARY FOCUS FOR ISOLATED
-TSRA ACTIVITY THIS AFTERNOON...HELPED BY WEAK WAVE MOVING ACROSS
WY AT THE MOMENT PER WATER VAPOUR. EXPECT ACTIVITY WILL BE
DIURNALLY DRIVEN WITH BOUNDARY LAYER QUICKLY BECOMING STABLE AFTER
SUNSET. WILL END ISOLATED -TSRA BY 03Z. OVERNIGHT LOWS WILL VARY A
LOT WITH DEW POINTS IN THE 30S AND 40S FILTERING SOUTH.

FRIDAY/SATURDAY...SURFACE BOUNDARY WASHES OUT AS UPPER RIDGE
BUILDS BACK OVER THE NORTHERN PLAINS. HIGHS IN THE 80S WILL AGAIN
BE WIDESPREAD ON THE PLAINS. BREEZY CONDITIONS WILL DEVELOP
SATURDAY AS GRADIENT TIGHTENS AHEAD OF APPROACHING UPPER LEVEL WAVE.

SATURDAY NIGHT...UPPER RIDGE BREAKS DOWN AS SHORTWAVE ZIPS THROUGH
NORTHERN ROCKIES. LOW LEVEL JET EXPECTED TO BRING SLIGHT CHANCE
OF -TSRA OVER PORTIONS OF THE CWA...ESPECIALLY IN THE WEST THERE
850-700MB THETA-E ADVECTION MAXIMIZED.

EXTENDED...SOUTHWESTERLY FLOW AHEAD OF WESTERN CONUS TROF. A
SERIES OF DISTURBANCES MOVING THROUGH THE FLOW WILL BRING A DAILY
CHANCE OF PRECIPITATION THROUGH WEDNESDAY ALONG WITH COOLER
TEMPERATURES. MODELS MOVE TROF TO THE EAST FOR THE END OF THE
WEEK...BRINGING DRY CONDITIONS.



&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

000
FXUS63 KFSD 190139
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
840 PM CDT THU SEP 18 2008

.DISCUSSION...

FORECAST IN GOOD SHAPE TONIGHT WITH ONLY MINOR UPDATE IN THE NEAR
TERM.  TEMPERATURES FALLING OFF RAPIDLY ACROSS EASTERN CWA WHERE
ATMOSPHERE HAS DECOUPLED AND WINDS HAVE DROPPED TO 5-10 KNOTS.
HOWEVER...EXPECT WINDS TO INCREASE OVER THE NEXT FEW HOURS AS LOW
LEVEL JET BEGINS TO INCREASE.  VAD WIND PROFILER HAS 30-40 KNOTS IN
THE LOWEST FEW THOUSAND FEET. AS THE CORE OF WINDS SPREADS
EAST...EXPECT TEMPERATURES TO LEVEL OFF TONIGHT. HAVE MADE SOME
MINOR ADJUSTMENTS TO TEMPERATURES IN THE NEAR TERM...BUT LOWS STILL
APPEAR TO BE REASONABLE. NEW PFM SENT...NO NEED TO UPDATE THE ZFP.
/BT

&&
.AVIATION...
MAINLY VFR CONDITIONS EXPECTED THROUGH 00Z SATURDAY...THOUGH
VISIBILITIES COULD DROP BRIEFLY TO AROUND 5SM SUNRISE FRIDAY
MORNING. VISIBILITIES SHOULD IMPROVE SHORTLY AFTER SUNRISE.

&&
.PREV DISCUSSION...
A PRETTY STOUT PRESSURE GRADIENT WILL REMAIN ACROSS THE AREA THIS
EVENING AS A SURFACE TROUGH APPROACHES FROM WESTERN SOUTH
DAKOTA...AND THIS WILL KEEP WINDS UP THROUGH THE EARLY NIGHTTIME
HOURS. WILL SEE WINDS DIMINISH SOME LATER TONIGHT AS GRADIENT
LESSENS...THOUGH REMAINING IN THE 10 KT RANGE OVER MOST OF THE
CWA...WITH STRONGER WINDS PERSISTING OVER THE HIGHER ELEVATIONS OF
THE BUFFALO RIDGE. TEMPERATURES WILL BE EVEN WARMER TONIGHT WITH THE
RELATIVELY BREEZY CONDITIONS IN A SOUTHERLY LOW LEVEL FLOW...AND
OVERNIGHT LOWS WILL DROP INTO THE UPPER 50S TO LOWER 60S.

AS EXPECTED...FRIDAY SHOULD PROVE TO BE A PRETTY BREEZY OVER
ESPECIALLY THE EAST...BUT SHOULD ABATE SOME BY AFTERNOON.
OTHERWISE...LOW LEVEL THERMAL FIELD SIMILAR TO TODAY SO LOOKING FOR
HIGHS MAINLY IN THE 80S.

FRIDAY NIGHT WILL BE ANOTHER QUIET NIGHT WITH A WEAK BOUNDARY
LEAKING INTO THE AREA FROM THE NORTH. NOT EXPECTING ANY
PRECIPITATION FROM THIS FRONT BUT IT SHOULD ALLOW FOR WINDS TO DROP
OFF AND BECOME A LITTLE MORE EASTERLY WITH LOWS IN THE 50S.

SATURDAY MAY END UP BEING A NICE DAY AS WINDS RECOVER FROM A THE
WEAK FRONT AND TURN FROM THE EAST TO THE SOUTHEAST. LOW LEVEL
THERMAL FIELDS AGAIN SIMILAR TO TODAY AND FRIDAY SO HIGHS FROM THE
UPPER 70S IN SW MN TO THE MID 80S IN CENTRAL SD EXPECTED.

SUNDAY LOOKS WINDY AND WARM WITH HIGHS ABOUT 10 DEGREES ABOVE
NORMAL. THERE WILL BE A WEAK WAVE SCRAPING THE NORTHWEST AND WILL
CONTINUE SOME LOW POPS OVER CENTRAL SD ON SUNDAY AFTERNOON AND
NIGHT.

IN THE LATTER PERIODS(MON-THU)...MUCH MORE UNSETTLED WITH A DECENT
AMOUNT OF DISAGREEMENT...SO NOT PLANNING ON ANY MAJOR CHANGES TO THE
PACKAGE. WILL STILL LEAN TOWARDS THE SLOWER SOLUTIONS IN THIS CASE
AND HAVE THE HIGHEST POPS CENTERED AROUND WEDNESDAY. OVERALL...VERY
MILD THROUGH THE PERIOD WITH ABOVE NORMAL TEMPERATURES. THIS WILL BE
OFFSET BY A NEAR DAILY 15 TO 30 MPH WIND...BUT BY THURSDAY THE WIND
SHOULD BEGIN TO SUBSIDE. MAIN DIFFERENCES WITH THIS SET OF MODELS IS
THAT THE GFS AND ECMWF ARE QUITE A BIT FASTER WITH THE WAVE AND
SUBSEQUENT SFC FRONT. SO AGAIN...LEANING ON THE SLOWER SIDE. AT THIS
TIME...THE AIR DOES NOT APPEAR TO BE VERY COLD BEHIND THIS MID WEEK
FRONT BUT IF THE LAST COUPLE OF GFS RUNS AND TO SOME EXTENT THE
ECMWF RUNS ARE CORRECT SOMETHING COLDER WILL BE POSSIBLE BY LATE IN
THE WEEKEND.

&&

.AVIATION...
VFR CONDITIONS THROUGH THE NIGHT...THOUGH WITH LOW LEVEL JET IN
PLACE ACROSS THE REGION...WILL EXPERIENCE A DECENT WIND SPEED SHEAR
ZONE BETWEEN 500 TO 1000 FT AGL AT TAF SITES.

&&


.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$

08

000
FXUS63 KFSD 182026
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
326 PM CDT THU SEP 18 2008

.DISCUSSION...
A PRETTY STOUT PRESSURE GRADIENT WILL REMAIN ACROSS THE AREA THIS
EVENING AS A SURFACE TROUGH APPROACHES FROM WESTERN SOUTH
DAKOTA...AND THIS WILL KEEP WINDS UP THROUGH THE EARLY NIGHTTIME
HOURS. WILL SEE WINDS DIMINISH SOME LATER TONIGHT AS GRADIENT
LESSENS...THOUGH REMAINING IN THE 10 KT RANGE OVER MOST OF THE
CWA...WITH STRONGER WINDS PERSISTING OVER THE HIGHER ELEVATIONS OF
THE BUFFALO RIDGE. TEMPERATURES WILL BE EVEN WARMER TONIGHT WITH THE
RELATIVELY BREEZY CONDITIONS IN A SOUTHERLY LOW LEVEL FLOW...AND
OVERNIGHT LOWS WILL DROP INTO THE UPPER 50S TO LOWER 60S.

AS EXPECTED...FRIDAY SHOULD PROVE TO BE A PRETTY BREEZY OVER
ESPECIALLY THE EAST...BUT SHOULD ABATE SOME BY AFTERNOON.
OTHERWISE...LOW LEVEL THERMAL FIELD SIMILAR TO TODAY SO LOOKING FOR
HIGHS MAINLY IN THE 80S.

FRIDAY NIGHT WILL BE ANOTHER QUIET NIGHT WITH A WEAK BOUNDARY
LEAKING INTO THE AREA FROM THE NORTH. NOT EXPECTING ANY
PRECIPITATION FROM THIS FRONT BUT IT SHOULD ALLOW FOR WINDS TO DROP
OFF AND BECOME A LITTLE MORE EASTERLY WITH LOWS IN THE 50S.

SATURDAY MAY END UP BEING A NICE DAY AS WINDS RECOVER FROM A THE
WEAK FRONT AND TURN FROM THE EAST TO THE SOUTHEAST. LOW LEVEL
THERMAL FIELDS AGAIN SIMILAR TO TODAY AND FRIDAY SO HIGHS FROM THE
UPPER 70S IN SW MN TO THE MID 80S IN CENTRAL SD EXPECTED.

SUNDAY LOOKS WINDY AND WARM WITH HIGHS ABOUT 10 DEGREES ABOVE
NORMAL. THERE WILL BE A WEAK WAVE SCRAPING THE NORTHWEST AND WILL
CONTINUE SOME LOW POPS OVER CENTRAL SD ON SUNDAY AFTERNOON AND
NIGHT.

IN THE LATTER PERIODS(MON-THU)...MUCH MORE UNSETTLED WITH A DECENT
AMOUNT OF DISAGREEMENT...SO NOT PLANNING ON ANY MAJOR CHANGES TO THE
PACKAGE. WILL STILL LEAN TOWARDS THE SLOWER SOLUTIONS IN THIS CASE
AND HAVE THE HIGHEST POPS CENTERED AROUND WEDNESDAY. OVERALL...VERY
MILD THROUGH THE PERIOD WITH ABOVE NORMAL TEMPERATURES. THIS WILL BE
OFFSET BY A NEAR DAILY 15 TO 30 MPH WIND...BUT BY THURSDAY THE WIND
SHOULD BEGIN TO SUBSIDE. MAIN DIFFERENCES WITH THIS SET OF MODELS IS
THAT THE GFS AND ECMWF ARE QUITE A BIT FASTER WITH THE WAVE AND
SUBSEQUENT SFC FRONT. SO AGAIN...LEANING ON THE SLOWER SIDE. AT THIS
TIME...THE AIR DOES NOT APPEAR TO BE VERY COLD BEHIND THIS MID WEEK
FRONT BUT IF THE LAST COUPLE OF GFS RUNS AND TO SOME EXTENT THE
ECMWF RUNS ARE CORRECT SOMETHING COLDER WILL BE POSSIBLE BY LATE IN
THE WEEKEND.

&&

.AVIATION...
VFR CONDITIONS THROUGH THE NIGHT...THOUGH WITH LOW LEVEL JET IN
PLACE ACROSS THE REGION...WILL EXPERIENCE A DECENT WIND SPEED SHEAR
ZONE BETWEEN 500 TO 1000 FT AGL AT TAF SITES.

&&


.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$

08

000
FXUS63 KABR 182016
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
316 PM CDT THU SEP 18 2008

.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
THE MAIN CHALLENGE IN THE NEAR TERM IS PRECIPITATION CHANCES
TONIGHT. A WEAK UPPER LEVEL TROUGH WILL TRACK ACROSS THE PLAINS
TONIGHT AND FRIDAY AHEAD OF A RIDGE SETTING UP OVER THE ROCKIES.
WEAK PVA WILL BE OVER THE NORTHERN CWA TONIGHT. A SURFACE TROUGH
CURRENTLY LOCATED FROM LAKE WINNIPEG TO EASTERN COLORADO WILL ALSO
SLOWLY APPROACH THE REGION. AHEAD OF THIS TROUGH...A 20 TO 35 KNOT
LLJ WILL DEVELOP TONIGHT IN ASSOCIATION WITH 1000-1500 J/KG OF
CAPE AND LIS IN THE -2 TO -5 RANGE. TWO LIMITING FACTORS WILL BE
700 MB TEMPS AROUND +8 TO +9 AND LIMITED MOISTURE.
THEREFORE...WILL JUST KEEP A SMALL POP GOING ACROSS THE NORTHERN
CWA CLOSER TO THE UPPER LEVEL ENERGY. IF ANY STORMS DO GET
GOING...THEY MAY HAVE THE POTENTIAL TO PRODUCE SOME SMALL HAIL. A
COLD FRONT WILL DROP OUT OF CANADA TO NORTHERN NORTH DAKOTA
TONIGHT. THIS FRONT REACHES SOUTHERN NORTH DAKOTA BY FRIDAY
AFTERNOON...THEN PUSHES TO SOUTHERN SOUTH DAKOTA FRIDAY NIGHT
BEFORE STALLING OUT THROUGH THE DAY SATURDAY...THEN PUSHING BACK
NORTH AS A WARM FRONT SATURDAY NIGHT AS LOW PRESSURE STRENGTHENS
OVER THE NORTHERN ROCKIES. EVEN THOUGH WEAK INSTABILITY REMAINS
OVER THE AREA IN ASSOCIATION WITH THE FRONT...MOISTURE WILL
CONTINUE TO BE VERY LIMITED THROUGH THE REST OF THE PERIOD...AND
HAVE DECIDED TO KEEP THE MENTION OF PRECIPITATION OUT AT THIS
TIME.

EXPECT ABOVE NORMAL TEMPERATURES TO CONTINUE THROUGH THE PERIOD AS
H85 TEMPS REMAIN IN THE MID TEENS TO LOWER 20S. WILL STICK WILL
HIGHS MAINLY IN THE 80S AND LOWS IN THE 50S.

.LONG TERM...SUNDAY THROUGH THURSDAY
THE MAIN CHALLENGE IN THE EXTENDED DEALS WITH PRECIPITATION AS
MODELS SHOW A COUPLE OF WAVES PASSING THROUGH THE REGION.

THE PERIOD BEGINS WITH AREA OF LOW PRESSURE OVER THE NORTHERN HIGH
PLAINS WITH STRONG SOUTHERLY FLOW/WAA UP THE PLAIN STATES. THE
SURFACE LOW TAKES ON A BIT OF A NEGATIVE TILT...LEADING TO A
SLOWER PROGRESSION. HAVE BACKED PCPN OFF BY SIX HOURS...AND WOULD
NOT BE SURPRISED IF PCPN IS REMOVED ALL TOGETHER ON SUNDAY. SUNDAY
NIGHT HOWEVER...WITH A STRONG LLJ OF 40KTS AND 25KTS OF 0-1KM BULK
SHEAR...HAVE INCREASED POPS SOME ACROSS THE AREA. SURFACE LOW
MOVES NNE INTO CENTRAL SASKATCHEWAN ON TUESDAY...WITH THE
MID/UPPER LEVEL FLOW PATTERN DE-AMPLIFYING OVER THE REGION. THE
MID/UPPER LEVEL TROF AXIS SLOWLY PUSHES EASTWARD ON
WEDNESDAY...ENDING PCPN CHANCES. HIGH PRESSURE BUILDS IN THERE
AFTER...WITH THE GFS SHOWING WARMER AIR WORKING BACK INTO THE AREA
FOR THE NEXT WEEKEND.


&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH FRIDAY EVENING.
SOME MID/HIGH CLOUDS ARE EXPECTED AT ALL TERMINALS LATER THIS
EVENING...WITH CIGS AOA 8K FEET. AN ISOLATED SHOWER/THUNDERSTORM
MAYBE POSSIBLE LATER THIS THIS EVENING AT KMBG AND KABR.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
SHORT TERM...PARKIN
LONG TERM...SD
AVIATION...SD

WEATHER.GOV/ABERDEEN

000
FXUS63 KUNR 182016
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
216 PM MDT THU SEP 18 2008

.DISCUSSION...20Z SURFACE ANALYSIS HAD WEAK LOW NEAR K2WX AND
TROUGH INTO SOUTHEAST WY. SURFACE BOUNDARY FOCUS FOR ISOLATED
-TSRA ACTIVITY THIS AFTERNOON...HELPED BY WEAK WAVE MOVING ACROSS
WY AT THE MOMENT PER WATER VAPOUR. EXPECT ACTIVITY WILL BE
DIURNALLY DRIVEN WITH BOUNDARY LAYER QUICKLY BECOMING STABLE AFTER
SUNSET. WILL END ISOLATED -TSRA BY 03Z. OVERNIGHT LOWS WILL VARY A
LOT WITH DEW POINTS IN THE 30S AND 40S FILTERING SOUTH.

FRIDAY/SATURDAY...SURFACE BOUNDARY WASHES OUT AS UPPER RIDGE
BUILDS BACK OVER THE NORTHERN PLAINS. HIGHS IN THE 80S WILL AGAIN
BE WIDESPREAD ON THE PLAINS. BREEZY CONDITIONS WILL DEVELOP
SATURDAY AS GRADIENT TIGHTENS AHEAD OF APPROACHING UPPER LEVEL WAVE.

SATURDAY NIGHT...UPPER RIDGE BREAKS DOWN AS SHORTWAVE ZIPS THROUGH
NORTHERN ROCKIES. LOW LEVEL JET EXPECTED TO BRING SLIGHT CHANCE
OF -TSRA OVER PORTIONS OF THE CWA...ESPECIALLY IN THE WEST THERE
850-700MB THETA-E ADVECTION MAXIMIZED.

EXTENDED...SOUTHWESTERLY FLOW AHEAD OF WESTERN CONUS TROF. A
SERIES OF DISTURBANCES MOVING THROUGH THE FLOW WILL BRING A DAILY
CHANCE OF PRECIPITATION THROUGH WEDNESDAY ALONG WITH COOLER
TEMPERATURES. MODELS MOVE TROF TO THE EAST FOR THE END OF THE
WEEK...BRINGING DRY CONDITIONS.

&&

.AVIATION...ISOLD THUNDERSTORMS WILL BE POSSIBLE THROUGH EARLY THIS
EVENING OVER NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA...THOUGH ANY
PRECIPITATION IS EXPECTED TO BE LIGHT. OTHERWISE...VFR CONDITIONS
ARE EXPECTED THROUGH FRIDAY.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

HELGESON/SCHILD

000
FXUS63 KABR 181619 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1119 AM CDT THU SEP 18 2008

.UPDATE...
NO MAJOR CHANGES MADE TO THE FORECAST THIS MORNING. DID INCREASE
POPS SLIGHTLY ACROSS THE NORTHWESTERN CWA TO ACCOUNT FOR POSSIBLE
LATE AFTERNOON DEVELOPMENT WITH THE APPROACHING SURFACE TROUGH. NO
CHANGES MADE TO TEMPERATURES OR WINDS.


&&
.PREV DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
FORECAST CHALLENGES INCLUDE FROPA TIMING AND TEMPERATURES...ALONG
WITH SMALL CHANCES FOR PRECIPITATION.

CURRENTLY...RETURN FLOW PATTERN IS ESTABLISHING ACROSS THE
CWA...WITH A LOW PRESSURE TROF AT THE SURFACE TAKING SHAPE ACROSS
THE NORTHERN HIGH PLAINS/FRONT RANGE.

TODAY...THIS RETURN FLOW WILL INCLUDE SOME BREEZY CONDITIONS FROM
THE SOUTH AS A 20 TO 30 KNOT LOW LEVEL JET MIXES OUT. IT WILL BE
WARMER TODAY THAN YESTERDAY AS THE SOUTHERLY WINDS WILL ALSO
INCLUDE WEAK LOW LEVEL WAA.

TONIGHT...A LOW PRESSURE TROF BEGINS TO MOVE INTO THE CWA FROM THE
NORTHWEST...WHILE A LOW LEVEL JET RESIDES ALONG AND AHEAD OF THE
BOUNDARY. THERE IS STILL SOME MID-LEVEL ENERGY BEING PROGGED TO
OVERSPREAD THE CWA TONIGHT...SO AM CONTINUING THE SLT CHANCE POPS
FOR TONIGHT.

ONCE THE MID-LEVEL ENERGY PUSHES SE OF THE CWA ON
FRIDAY...AND LOW LEVEL JET SUPPORT DISAPPEARS...AND MOST ALL OF
THE BEST /ALBEIT MEAGER/ LOW LEVEL MOISTURE GETS SHUNTED TO JUST
SOUTH OF THE CWA...PRECIPITATION CHANCES DIMINISH ENOUGH TO LEAVE
PRECIP MENTION OUT OF THE GRIDS FRO FRIDAY THROUGH SATURDAY.

NEW TRENDS/WRINKLES...BOTH THE 00Z NAM AND GFS SOLUTIONS ARE
BEGINNING TO HIT INSTABILITY/SHEAR A LITTLE BIT HARDER ON
SATURDAY...DESPITE THE LACK OF DESIRED MID-LEVEL LIFT/LOW LEVEL
MOISTURE CONVERGENCE...AS A BACKDOOR COLD FRONT THAT WORKS INTO
THE CWA FROM THE NORTH FRIDAY NIGHT...EITHER STALLS OUT ACROSS THE
SOUTHERN CWA ON SATURDAY...OR GRADUALLY BEGINS TO WORK BACK TO THE
NORTH BY SATURDAY AFTERNOON. MODEL PRECIP OUTPUT IS SPOTTY AT
BEST...AND STILL THINKING THAT THURSDAY NIGHT STANDS THE BEST SHOT
AT SEEING SOME ISOLATED CONVECTION DEVELOP.

WARMEST TEMPERATURES ARE EXPECTED TODAY AND FRIDAY...WITH COOLER
READINGS ENSUING ON SATURDAY IN COOLER AIR FILTERING IN BEHIND THE
BACKDOOR COLD FROPA FRIDAY NIGHT.

.LONG TERM...SUNDAY MORNING THROUGH MONDAY NIGHT

THE EXTENDED PERIOD IS SOME WHAT ACTIVE TONIGHT. THE PERIOD OPENS
WITH THE REMNANTS OF THE LAST PACIFIC LOW NOW WEAKENED TO A
NEGATIVE TILT TROUGH IN WESTERN MONTANA. THE SURFACE REFLECTION OF
THIS IS AN ELONGATED SURFACE TROUGH IN EASTERN MONTANA WITH A COLD
FRONT TRAILING THROUGH WYOMING. THERE IS ALSO AN OLD BAROCLINIC
ZONE ACROSS THE EASTERN DAKOTAS THAT WILL BE MOVING NORTH AS A
WARM FRONT SUNDAY. SUNDAY AFTERNOON GOOD WARM ADVECTION IS TAKING
PLACE AHEAD OF THE COLD FRONT WITH MOISTURE POOLING IN THE
DAKOTAS. THIS FRONT WILL WASH OUT SUNDAY NIGHT AS IT MOVES INTO
THE DAKOTAS AS A NEW WAVE ALOFT DIGS ALONG THE WEST COAST. THE
ORIGINAL TROUGH WEAKENS AND IS ABSORBED INTO THE UPPER FLOW
HOWEVER A SIGNIFICANT WAVE MOVES EAST AND APPEARS TO HELP FOCUS
THIS CONVECTION FARTHER SOUTH. EXPECT PROBABILITIES ARE STILL
WARRANTED IN THIS AREA WITH THIS FEATURE. AS THIS SYSTEM MOVES
THROUGH ON MONDAY THE NEXT WAVE ALOFT IS APPROACHING AND PUSHING A
SURFACE LOW INTO THE AREA MONDAY NIGHT. TEMPERATURES IN THE GRIDS
LOOK GOOD AS H5 RIDGE MOVES ACROSS AND THE SUBSEQUENT FLOW IS FROM
THE PACIFIC SO FAIRLY MILD.


&&

.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH TONIGHT. CEILINGS WILL BE
UNLIMITED AND VISIBILITIES UNRESTRICTED. A TIGHTENING SURFACE
PRESSURE GRADIENT WILL BRING GUSTY SOUTH WINDS TODAY. GUSTS AS
HIGH AS 30 KTS CAN BE EXPECTED THIS AFTERNOON...DIMINISHING
TONIGHT.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
UPDATE...PARKIN
SHORT TERM...DORN
LONG TERM...KEEFE
AVIATION...KEEFE

WEATHER.GOV/ABERDEEN

000
FXUS63 KFSD 181538
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
1030 AM CDT THU SEP 18 2008

.DISCUSSION...

ANOTHER RELATIVELY QUIET MORNING ACROSS THE REGION. ARE BEGINNING TO
SEE WINDS PICKING UP IN OUR WEST AS ANTICIPATED WITH SURFACE TROUGH
PUSHING INTO THE WESTERN HIGH PLAINS. TEMPERATURES LOOKING TO ALSO
BE ON TRACK AT THIS POINT...SO ONLY MINOR MODIFICATIONS MADE TO
FORECAST TO ACCOUNT FOR REAL TIME TRENDS. MINOR UPDATES ALREADY
OUT.  /JM

&&

.AVIATION...

VFR CONDITIONS EXPECTED THROUGH FRIDAY MORNING. WINDS WILL INCREASE
THROUGH THE LATE MORNING FOR THE KHON AND KFSD AREAS...WITH GUSTS TO
AROUND 25 KTS POSSIBLE THRU THE AFTN RESULTING IN SOME LOW LVL
TURBULENCE. WINDS SPEEDS WL NOT BE AS STRONG FOR THE KSUX AREA ON
THE EDGE OF THE LOW LVL GRADIENT. WHILE NOT EXPECTED TO REACH LLWS
CRITERIA...LIMITED LO LVL DECOUPLING AFTER SUNSET TONIGHT AND THE
LOCATION OF THE SWLY LLJ WL SET US A STRONG SHEAR ZONE BTWN 500-900
FT AGL 05Z THRU 13Z.  /CHAPMAN

&&


.PREV DISCUSSION...

BENIGN WEATHER PATTERN WILL CHANGE IN THIS FCST WITH MORE ISSUES TO
WORRY ABOUT. FIRST WILL BE STG SOUTH WINDS INCRG TO 15 TO 30 MPH IN
WRN TO NRN CWA THIS AFTN...DECOUPLING SOME TNGT...AND AFFECTING SERN
HLF CWA FOR FRI. AIR MASS HAS BEEN MIXING OUT TO MAX LATELY WITH DRY
GROUND AND ABUNDANT SUNSHINE...AND WILL GO SLIGHTLY WARMER THAN GUID
AND PREV FCST FOR HIGHS. OTHER ISSUE IS STEEPENING LAPSE RATES THRU
FRI AFTN AHEAD OF WEAK BOUNDARY MOVG TOWARDS NRN CWA. IF MOISTURE
AND CONVERGENCE WERE STRONGER...WOULD PUT IN A CHC TSTMS INTO NRN
CWA LATE FRI AFTN...MOVG SWD INTO CWA FRI EVE. LATER SHIFTS WILL
HAVE TO LOOK AT THIS FURTHER. BOUNDARY RETURNS NWD OVR CWA THIS
WEEKEND...FLWD BY INCRG SLY WINDS AGAIN THRU SUN...BUT THIS TIME
WITH MUCH BTR MOISTURE EXPCD. THIS SHOULD SET UP A DECENT CHC TSTMS
DVLPG IN SWRN HLF CWA LATE SUN NGT AND THRU CWA MON MRNG...AS ALL
MODELS INDICATING A GOOD SHORT WAVE PUNCHING ENE INTO UPR RIDGE.
THIS MAY ALSO BRING CONSIDERABLE LOW CLOUDS MAINLY ALG AND EAST OF
I29 ON MON...AND COOLED THE HIGHS SOME. STG SLY FLOW OF WARMER AND
HUMID AIR WILL CONTINUE FROM LATE MON THRU TUES...BUT NEXT CHC TSTMS
MAY HOLD OFF TIL TUES NGT WITH CDFNT AND STG UPR UPR TROF.

&&


.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$
RYRHOLM

000
FXUS63 KUNR 181508
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
908 AM MDT THU SEP 18 2008

.DISCUSSION...15Z SURFACE ANALYSIS HAD WEAK LOW OVER WESTERN ND
WITH WEAK SLOW MOVING TROUGH INTO CENTRAL WY. THIS TROUGH WILL
INCH INTO THE CWA THIS AFTERNOON. WEAK WAVE OVER NORTHWEST WY WILL
MOVE OVER THE TROUGH AND COMBINE WITH 500-1000J/KG CAPE. CAP
WEAKENS ENOUGH TO INTRODUCE 15 POPS TO REST OF THE NORTHWEST HALF
OF THE CWA. REST OF FORECAST IN GOOD SHAPE.

&&

.AVIATION...VFR CONDITIONS WILL CONTINUE ACROSS MUCH OF THE AREA
THROUGH TONIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE AROUND THE
BLACK HILLS AREA THIS AFTERNOON AND EVENING.

&&

.PREV DISCUSSION... /ISSUED 300 AM MDT THU SEP 18 2008/

DISCUSSION...AN UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE WEATHER
FOR THE WESTERN HALF OF THE UNITED STATES. MOSTLY DRY AND WARM
CONDITIONS ARE EXPECTED AGAIN TODAY. A WEAK UPPER LEVEL WAVE AND
SURFACE TROUGH ARE EXPECTED TO MOVE THROUGH THE RIDGE THIS AFTERNOON
WHICH WILL SHIFT WINDS AROUND TO THE NORTH AND MAY INITIATE A
THUNDERSTORM OR TWO OVER THE BLACK HILLS. ANY ACTIVITY THAT DEVELOPS
SHOULD DISSIPATE QUICKLY AFTER THE TROUGH PASSES AND THE SUN GOES
DOWN. MORE QUIET WEATHER IS EXPECTED FOR FRIDAY AND SATURDAY AS THE
RIDGE HOLDS STEADY. THE NEXT SYSTEM APPROACHES THE AREA LATE
SATURDAY WHEN A FEW SHOWERS OR THUNDERSTORMS WILL AGAIN BE POSSIBLE.

EXTENDED...UPPER LEVEL RIDGE WILL MOVE EAST OF THE AREA LATER THIS
WEEKEND...WITH SOUTHWESTERLY FLOW ALOFT DEVELOPING AHEAD OF WESTERN
CONUS TROF. A SERIES OF DISTURBANCES IN THE FLOW SHOULD BRING
OCCASIONAL CHANCES FOR SHOWERS AND A FEW STORMS FROM SUNDAY THROUGH
AT LEAST TUESDAY. TEMPERATURES WILL DROP BACK CLOSER TO AVERAGE
LEVELS DURING THE PERIOD...WITH HIGHS MOSTLY IN THE 70S AND LOWER
80S.

AVIATION...VFR CONDITIONS WILL CONTINUE ACROSS MUCH OF THE AREA
THROUGH TONIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE AROUND THE
BLACK HILLS AREA THIS AFTERNOON AND EVENING.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

HELGESON

000
FXUS63 KUNR 180902
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
300 AM MDT THU SEP 18 2008

.DISCUSSION...AN UPPER LEVEL RIDGE CONTINUES TO DOMINATE THE WEATHER
FOR THE WESTERN HALF OF THE UNITED STATES. MOSTLY DRY AND WARM
CONDITIONS ARE EXPECTED AGAIN TODAY. A WEAK UPPER LEVEL WAVE AND
SURFACE TROUGH ARE EXPECTED TO MOVE THROUGH THE RIDGE THIS AFTERNOON
WHICH WILL SHIFT WINDS AROUND TO THE NORTH AND MAY INITIATE A
THUNDERSTORM OR TWO OVER THE BLACK HILLS. ANY ACTIVITY THAT DEVELOPS
SHOULD DISSIPATE QUICKLY AFTER THE TROUGH PASSES AND THE SUN GOES
DOWN. MORE QUIET WEATHER IS EXPECTED FOR FRIDAY AND SATURDAY AS THE
RIDGE HOLDS STEADY. THE NEXT SYSTEM APPROACHES THE AREA LATE
SATURDAY WHEN A FEW SHOWERS OR THUNDERSTORMS WILL AGAIN BE POSSIBLE.

EXTENDED...UPPER LEVEL RIDGE WILL MOVE EAST OF THE AREA LATER THIS
WEEKEND...WITH SOUTHWESTERLY FLOW ALOFT DEVELOPING AHEAD OF WESTERN
CONUS TROF. A SERIES OF DISTURBANCES IN THE FLOW SHOULD BRING
OCCASIONAL CHANCES FOR SHOWERS AND A FEW STORMS FROM SUNDAY THROUGH
AT LEAST TUESDAY. TEMPERATURES WILL DROP BACK CLOSER TO AVERAGE
LEVELS DURING THE PERIOD...WITH HIGHS MOSTLY IN THE 70S AND LOWER
80S.

&&

.AVIATION...VFR CONDITIONS WILL CONTINUE ACROSS MUCH OF THE AREA
THROUGH TONIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE AROUND THE
BLACK HILLS AREA THIS AFTERNOON AND EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.

&&

$$

000
FXUS63 KFSD 180836
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
335 AM CDT THU SEP 18 2008

.DISCUSSION...

BENIGN WEATHER PATTERN WILL CHANGE IN THIS FCST WITH MORE ISSUES TO
WORRY ABOUT. FIRST WILL BE STG SOUTH WINDS INCRG TO 15 TO 30 MPH IN
WRN TO NRN CWA THIS AFTN...DECOUPLING SOME TNGT...AND AFFECTING SERN
HLF CWA FOR FRI. AIR MASS HAS BEEN MIXING OUT TO MAX LATELY WITH DRY
GROUND AND ABUNDANT SUNSHINE...AND WILL GO SLIGHTLY WARMER THAN GUID
AND PREV FCST FOR HIGHS. OTHER ISSUE IS STEEPENING LAPSE RATES THRU
FRI AFTN AHEAD OF WEAK BOUNDARY MOVG TOWARDS NRN CWA. IF MOISTURE
AND CONVERGENCE WERE STRONGER...WOULD PUT IN A CHC TSTMS INTO NRN
CWA LATE FRI AFTN...MOVG SWD INTO CWA FRI EVE. LATER SHIFTS WILL
HAVE TO LOOK AT THIS FURTHER. BOUNDARY RETURNS NWD OVR CWA THIS
WEEKEND...FLWD BY INCRG SLY WINDS AGAIN THRU SUN...BUT THIS TIME
WITH MUCH BTR MOISTURE EXPCD. THIS SHOULD SET UP A DECENT CHC TSTMS
DVLPG IN SWRN HLF CWA LATE SUN NGT AND THRU CWA MON MRNG...AS ALL
MODELS INDICATING A GOOD SHORT WAVE PUNCHING ENE INTO UPR RIDGE.
THIS MAY ALSO BRING CONSIDERABLE LOW CLOUDS MAINLY ALG AND EAST OF
I29 ON MON...AND COOLED THE HIGHS SOME. STG SLY FLOW OF WARMER AND
HUMID AIR WILL CONTINUE FROM LATE MON THRU TUES...BUT NEXT CHC TSTMS
MAY HOLD OFF TIL TUES NGT WITH CDFNT AND STG UPR UPR TROF.

&&

.AVIATION...

VFR CONDITIONS EXPECTED THROUGH FRIDAY MORNING. WINDS WILL INCREASE
BY MID TO LATE MORNING FOR THE KHON AND KFSD AREAS...WITH GUSTS TO
AROUND 25 KTS POSSIBLE THRU THE AFTN RESULTING IN SOME LOW LVL
TURBULENCE. WINDS SPEEDS WL NOT BE AS STRONG FOR THE KSUX AREA ON
THE EDGE OF THE LOW LVL GRADIENT. WHILE NOT EXPECTED TO REACH LLWS
CRITERIA...LIMITED LO LVL DECOUPLING AFTER SUNSET TONIGHT AND THE
LOCATION OF THE SWLY LLJ WL SET US A STRONG SHEAR ZONE BTWN 500-900
FT AGL 05Z THRU 13Z.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$
RYRHOLM/CHAPMAN

000
FXUS63 KFSD 180835
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
335 AM CDT THU SEP 18 2008

.DISCUSSION...

BENIGN WEATHER PATTERN WILL CHANGE IN THIS FCST WITH AN INCRG ISSUES
TO WORRY ABOUT. FIRST WILL BE STG SOUTH WINDS INCRG TO 15 TO 30 MPH
IN WRN TO NRN CWA THIS AFTN...DECOUPLING SOME TNGT...AND AFFECTING
SERN HLF CWA FOR FRI. AIR MASS HAS BEEN MIXING OUT TO MAX LATELY
WITH DRY GROUND AND ABUNDANT SUNSHINE...AND WILL GO SLIGHTLY WARMER
THAN GUID AND PREV FCST FOR HIGHS. OTHER ISSUE IS STEEPENING LAPSE
RATES THRU FRI AFTN AHEAD OF WEAK BOUNDARY MOVG TOWARDS NRN CWA. IF
MOISTURE AND CONVERGENCE WERE STRONGER...WOULD PUT IN A CHC TSTMS
INTO NRN CWA LATE FRI AFTN...MOVG SWD INTO CWA FRI EVE. LATER SHIFTS
WILL HAVE TO LOOK AT THIS FURTHER. BOUNDARY RETURNS NWD OVR CWA THIS
WEEKEND...FLWD BY INCRG SLY WINDS AGAIN THRU SUN...BUT THIS TIME
WITH MUCH BTR MOISTURE EXPCD. THIS SHOULD SET UP A DECENT CHC TSTMS
DVLPG IN SWRN HLF CWA LATE SUN NGT AND THRU CWA MON MRNG...AS ALL
MODELS INDICATING A GOOD SHORT WAVE PUNCHING ENE INTO UPR RIDGE.
THIS MAY ALSO BRING CONSIDERABLE LOW CLOUDS MAINLY ALG AND EAST OF
I29 ON MON...AND COOLED THE HIGHS SOME. STG SLY FLOW OF WARMER AND
HUMID AIR WILL CONTINUE FROM LATE MON THRU TUES...BUT NEXT CHC
TSTMS MAY HOLD OFF TIL TUES NGT WITH CDFNT AND STG UPR UPR TROF.

&&

.AVIATION...

VFR CONDITIONS EXPECTED THROUGH FRIDAY MORNING. WINDS WILL INCREASE
BY MID TO LATE MORNING FOR THE KHON AND KFSD AREAS...WITH GUSTS TO
AROUND 25 KTS POSSIBLE THRU THE AFTN RESULTING IN SOME LOW LVL
TURBULENCE. WINDS SPEEDS WL NOT BE AS STRONG FOR THE KSUX AREA ON
THE EDGE OF THE LOW LVL GRADIENT. WHILE NOT EXPECTED TO REACH LLWS
CRITERIA...LIMITED LO LVL DECOUPLING AFTER SUNSET TONIGHT AND THE
LOCATION OF THE SWLY LLJ WL SET US A STRONG SHEAR ZONE BTWN 500-900
FT AGL 05Z THRU 13Z.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

$$
RYRHOLM/CHAPMAN

000
FXUS63 KABR 180824
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
324 AM CDT THU SEP 18 2008

.SHORT TERM...TODAY THROUGH SATURDAY
FORECAST CHALLENGES INCLUDE FROPA TIMING AND TEMPERATURES...ALONG
WITH SMALL CHANCES FOR PRECIPITATION.

CURRENTLY...RETURN FLOW PATTERN IS ESTABLISHING ACROSS THE
CWA...WITH A LOW PRESSURE TROF AT THE SURFACE TAKING SHAPE ACROSS
THE NORTHERN HIGH PLAINS/FRONT RANGE.

TODAY...THIS RETURN FLOW WILL INCLUDE SOME BREEZY CONDITIONS FROM
THE SOUTH AS A 20 TO 30 KNOT LOW LEVEL JET MIXES OUT. IT WILL BE
WARMER TODAY THAN YESTERDAY AS THE SOUTHERLY WINDS WILL ALSO
INCLUDE WEAK LOW LEVEL WAA.

TONIGHT...A LOW PRESSURE TROF BEGINS TO MOVE INTO THE CWA FROM THE
NORTHWEST...WHILE A LOW LEVEL JET RESIDES ALONG AND AHEAD OF THE
BOUNDARY. THERE IS STILL SOME MID-LEVEL ENERGY BEING PROGGED TO
OVERSPREAD THE CWA TONIGHT...SO AM CONTINUING THE SLT CHANCE POPS
FOR TONIGHT.

ONCE THE MID-LEVEL ENERGY PUSHES SE OF THE CWA ON
FRIDAY...AND LOW LEVEL JET SUPPORT DISAPPEARS...AND MOST ALL OF
THE BEST /ALBEIT MEAGER/ LOW LEVEL MOISTURE GETS SHUNTED TO JUST
SOUTH OF THE CWA...PRECIPITATION CHANCES DIMINISH ENOUGH TO LEAVE
PRECIP MENTION OUT OF THE GRIDS FRO FRIDAY THROUGH SATURDAY.

NEW TRENDS/WRINKLES...BOTH THE 00Z NAM AND GFS SOLUTIONS ARE
BEGINNING TO HIT INSTABILITY/SHEAR A LITTLE BIT HARDER ON
SATURDAY...DESPITE THE LACK OF DESIRED MID-LEVEL LIFT/LOW LEVEL
MOISTURE CONVERGENCE...AS A BACKDOOR COLD FRONT THAT WORKS INTO
THE CWA FROM THE NORTH FRIDAY NIGHT...EITHER STALLS OUT ACROSS THE
SOUTHERN CWA ON SATURDAY...OR GRADUALLY BEGINS TO WORK BACK TO THE
NORTH BY SATURDAY AFTERNOON. MODEL PRECIP OUTPUT IS SPOTTY AT
BEST...AND STILL THINKING THAT THURSDAY NIGHT STANDS THE BEST SHOT
AT SEEING SOME ISOLATED CONVECTION DEVELOP.

WARMEST TEMPERATURES ARE EXPECTED TODAY AND FRIDAY...WITH COOLER
READINGS ENSUING ON SATURDAY IN COOLER AIR FILTERING IN BEHIND THE
BACKDOOR COLD FROPA FRIDAY NIGHT.


.LONG TERM...SUNDAY MORNING THROUGH MONDAY NIGHT

THE EXTENDED PERIOD IS SOME WHAT ACTIVE TONIGHT. THE PERIOD OPENS
WITH THE REMNANTS OF THE LAST PACIFIC LOW NOW WEAKENED TO A
NEGATIVE TILT TROUGH IN WESTERN MONTANA. THE SURFACE REFLECTION OF
THIS IS AN ELONGATED SURFACE TROUGH IN EASTERN MONTANA WITH A COLD
FRONT TRAILING THROUGH WYOMING. THERE IS ALSO AN OLD BAROCLINIC
ZONE ACROSS THE EASTERN DAKOTAS THAT WILL BE MOVING NORTH AS A
WARM FRONT SUNDAY. SUNDAY AFTERNOON GOOD WARM ADVECTION IS TAKING
PLACE AHEAD OF THE COLD FRONT WITH MOISTURE POOLING IN THE
DAKOTAS. THIS FRONT WILL WASH OUT SUNDAY NIGHT AS IT MOVES INTO
THE DAKOTAS AS A NEW WAVE ALOFT DIGS ALONG THE WEST COAST. THE
ORIGINAL TROUGH WEAKENS AND IS ABSORBED INTO THE UPPER FLOW
HOWEVER A SIGNIFICANT WAVE MOVES EAST AND APPEARS TO HELP FOCUS
THIS CONVECTION FARTHER SOUTH. EXPECT PROBABILITIES ARE STILL
WARRANTED IN THIS AREA WITH THIS FEATURE. AS THIS SYSTEM MOVES
THROUGH ON MONDAY THE NEXT WAVE ALOFT IS APPROACHING AND PUSHING A
SURFACE LOW INTO THE AREA MONDAY NIGHT. TEMPERATURES IN THE GRIDS
LOOK GOOD AS H5 RIDGE MOVES ACROSS AND THE SUBSEQUENT FLOW IS FROM
THE PACIFIC SO FAIRLY MILD.


&&

.AVIATION...
GOOD VFR CONDITIONS WILL CONTINUE THROUGH TONIGHT. CEILINGS ARE
UNLIMITED AND VISIBILITY IS UNRESTRICTED. A TIGHTENING SURFACE
PRESSURE GRADIENT WILL BRING GUSTY SOUTH WINDS TODAY. GUST AS HIGH
AS 25 TO 35 KTS CAN BE EXPECTED THIS AFTERNOON DIMINISHING TONIGHT.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$
SHORT TERM...DORN
LONG TERM...KEEFE
AVIATION...KEEFE

WEATHER.GOV/ABERDEEN