FXUS63 KFSD 020916
AFDFSD

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA 
NATIONAL WEATHER SERVICE SIOUX FALLS SD
315 AM CST WED DEC 2 2009

.DISCUSSION...
BRISK NWLY FLOW OF GRADUALLY COLDER AIR AT THE SFC AND ALOFT TDA
THRU THURS...WITH GENLY 15 TO 30 MPH DAYTIME WINDS. DID RAISE HIGHS 
A LIT TDA ESP SERN CWA WHERE THERE SHOULD BE SOME FILTERED SUNSHINE 
AND AIR MASS STILL NOT QUITE AS COLD. VERY COLD UPR LOW WITH 500 MB 
TEMPS NEAR MINUS 38C ROTATING SEWD INTO NWRN ND ATTM...AS CAN BE 
SEEN ON SATELLITE. SCT -SHSN ASSCD WITH THIS FEATURE...EXTDG FM NERN 
MONT AND WRN ND TO SCNTRL CANADA...AND WHICH SHOULD GRADUALLY SPREAD 
SEWD INTO CWA TNGT...AND THEN THRU THE ERN CWA THURS. PUT IN SOME 
POPS AND SEVERAL TENTHS OF SNOWFALL WITH THIS SYSTEM MOVG INTO THE 
NRN CWA TNGT AND THRU THE ERN CWA THURS...BUT OVERALL SCT FLURRIES 
WILL BE THE RULE TNGT THRU THU NGT IN THE CWA...AND IN THE ERN CWA 
FRI AS COLD AND MOIST UNSTABLE NWLY FLOW LINGERS. OVERALL PREV FCST 
TEMPS IN THE BALLPARK AND DID NOT CHANGE. NEXT BIG QUESTION IS THE 
EXTD...AS MODELS FLIP/FLOPPING WITH VARIOUS SHORT WAVES ARE EJECTED 
OUT OF THE DVLPG UPR TROF IN THE INTERMOUNTAIN WEST. COMPOSITE OF 
MODELS WOULD GIVE CHC SNOW SKIRTING THE SRN CWA SUN NGT...AND THE 
NEXT BTR WAVE AFFECTING MOST OF THE CWA MON NGT AND TUES...SO STAY 
TUNED FOR LATER FCSTS./ RYRHOLM

&&

.AVIATION...
MVFR CIGS WL BE PREVALENT THROUGH THE MORNING MAINLY EAST OF A KBKX 
TO KSPW AREAS. COOLING TMPS ALFT ARE LKLY TO RESULT IN DEVELOPMENT 
OF A MVFR/LOWER VFR SC FIELD IN AREAS WHERE PARTIAL SUNSHINE 
PREVAILS LEADING INTO THE 16Z-19Z TIMEFRAME. MORE WIDESPREAD MVFR 
CIGS WL ACCOMPANY A DISTURBANCE SOUTHWARD TONIGHT INTO THU MORNING. 
WL ALSO LKLY FIND DEVELOPMENT OF SCATTERED FLURRIES AND AREAS OF 
LIGHT SNOWFALL...WHICH COULD DRAG VSBYS DOWN BRIEFLY INTO 1-2SM 
RANGE...BUT CARRYING A PREVAILING 4-6SM PROBABLY MORE LKLY 
OVERALL...STARTING TOWARD 04Z KHON...08Z KFSD. WITH BEST DYNAMIC 
SUPPORT FOR LIFT THRU NERN CWA...WL KEEP PCPN OUT OF KSUX. MOST WIND 
GUSTS THRU THE DAY SHUD TOP OUT IN THE 25 TO 30 KT RANGE...WITH FLOW 
ALFT BETWEEN SYSTEMS JUST A TOUCH WEAKER THAN YDA. /CHAPMAN

&& 

.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.

$$