FXUS63 KFSD 010926
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
326 AM CST TUE DEC 1 2009

MAIN CHALLENGES FOR TODAY WILL BE TEMPERATURES AND WINDS WITH THE 
PASSAGE OF A STRONG COLD FRONT THROUGH THE AREA. EARLY THIS 
MORNING...THE COLD FRONT IS STILL BARELY NUDGING INTO EXTREME 
NORTHWESTERN SOUTH DAKOTA...THOUGH EXPECTING IT TO BE APPROACHING 
OUR FAR WESTERN CWA BY 12Z. MODELS IN PRETTY GOOD AGREEMENT ON 
TIMING OF THE FRONT...WHICH WOULD GET IT INTO OUR FAR SOUTHEAST 
AROUND 21Z. STRONG COLD AIR ADVECTION WILL ENSUE BEHIND THE 
FRONT...AND WITH STEEP LOW LEVEL LAPSE RATES AND 2 TO 4 MB PRESSURE 
RISES WITH THE PASSAGE OF THE BOUNDARY...ELECTED TO ISSUE A WIND 
ADVISORY FOR PARTS OF THE JAMES RIVER VALLEY FOR THIS AFTERNOON 
WHERE 925/850 MB WINDS ARE PROGGED TO BE AROUND 30/45KT 
RESPECTIVELY. DAY SHIFT WILL HAVE TO WATCH TO SEE IF AN ADVISORY IS 
NEEDED FARTHER TO THE EAST LATER IN THE DAY. TEMPERATURES ARE ALSO 
TRICKY...DEPENDENT ON SPEED OF THE SYSTEM AND ANY CLOUD COVER WITH 
THE FRONT. AT THIS POINT...PREFRONTAL MIXING/WARMING SHOULD ALLOW 
OUR SOUTHEASTERN AREAS TO GET INTO THE LOWER TO MID 50S BEFORE THE 
FRONTAL PASSAGE. MODELS PROGGING A BAND OF MID CLOUDS WITH THE 
FRONT...SO COULD SEE TEMPERATURES FALL TEMPORARILY WITH THE PASSAGE 
OF THE FRONT...THEN COULD SEE A SLIGHT REBOUND...MAINLY IN OUR 
WEST...WITH BETTER MIXING AND BREAKS IN THE CLOUDS. IN ANY 
EVENT...LOOKS LIKE A GENERAL NONDIURNAL TREND WITH RESPECT TO 
TEMPERATURES.

WINDS WILL STAY UP TONIGHT...PREVENTING TEMPERATURES FROM COMPLETELY 
BOTTOMING OUT...THIS ALONG WITH BROKEN CLOUDS...WILL KEEP LOWS IN THE 
20S ACROSS THE AREA.

ON WEDNESDAY...THE UPPER LEVEL TROUGH REALLY BEGINS TO SETTLE INTO 
THE NORTHERN PLAINS...WITH LOWER CLOUDS INCREASING FROM THE NORTH 
THROUGH THE DAY. WHILE HIGHS ARE EXPECTED TO BE IN THE LOWER TO MID 
30S...WITH STOUT NORTHWESTERLY WINDS CONTINUING OVER THE 
REGION...WIND CHILLS WILL BE IN THE TEENS TO LOWER 20S. WITH A 
LITTLE DEEPER MOISTURE/CONTINUING CAA/AND WEAK LIFT OVER THE 
AREA...STILL THINKING WE COULD SEE SOME FLURRY ACTIVITY ON WEDNESDAY 
NIGHT INTO THURSDAY AS THE TROUGH CONTINUES TO DEEPEN OVER THE 
CENTRAL PART OF THE NATION. THE BRUNT OF THE COLD AIR WILL BE FELT 
ON THURSDAY AND THURSDAY NIGHT...WHEN 925 MB TEMPS WILL BE IN THE 
RANGE OF -8 TO -11 C ACROSS OUR CWA...SO LOOKING FOR HIGHS IN THE 
LOWER TO MID 20S WITH LOWS EITHER SIDE OF 10 DEGREES.

AIRMASS BEGINS TO MODERATE SLIGHTLY BY FRIDAY AS THE TROUGH AXIS 
MOVES TO THE EAST...WITH HIGHS A COUPLE OF DEGREES WARMER THAN 
THURSDAY...ESPECIALLY IN OUR WEST. LOOKS LIKE WE WILL HAVE A HARD 
TIME GETTING RID OF THE STRATOCU ON FRIDAY...THOUGH MAY SEE A 
DECREASE IN CLOUDS IN OUR WEST BY LATER IN THE AFTERNOON.  /JM

&& 

.AVIATION...

VFR EXPCD THRU 06Z TNGT. HOWEVER...STG NWLY WINDS OF 25 TO 40 KTS 
WILL SWEEP SEWD BEHIND A CDFNT INTO THE JAMES VALLEY BY 18Z...AND 
SPREAD INTO MUCH OF THE REMAINDER OF THE AREA DURG THE AFTN BEFORE 
BEGINNING TO DECOUPLE IN THE EVENING HOURS. /RYRHOLM

&&

.FSD WATCHES/WARNINGS/ADVISORIES...

IA...NONE.
MN...NONE.
NE...NONE.
SD...WIND ADVISORY FROM NOON TODAY TO 6 PM CST THIS EVENING FOR 
     SDZ038-039-050-052>054-057>060-063-064.

&&

$$