000
FXUS63 KUNR 232140
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
241 PM MST MON NOV 23 2009

.DISCUSSION...21Z SFC ANALYSIS SHOWS LOW PRESSURE CENTERED OVER 
CENTRAL KANSAS WITH A TROUGH EXTENDING INTO WESTERN MINNESOTA...AND 
HIGH PRESSURE OVER THE NORTHERN ROCKIES. UPPER ANALYSIS SHOWS A 
TROUGH OVER THE WESTERN DAKOTAS/NEBRASKA WITH THE UPPER HIGH OVER 
EASTERN COLORADO. 

REGIONAL RADAR MOSAIC SHOWS A BAND OF MOISTURE HAS ROTATED AROUND 
THE SURFACE LOW AND INTO SOUTH CENTRAL SOUTH DAKOTA. THE BAND 
CONTINUES TO SINK SOUTH AND EAST AND WILL BE OUT OF OUR CWA BY MID 
EVENING. SKIES WILL BECOME PARTLY CLOUDY AS THE UPPER TROUGH AXIS 
SHIFTS EAST TONIGHT.

TUESDAY WILL BE PARTLY CLOUDY AND WARMER AS A SHORTWAVE RIDGE 
CROSSES THE NORTHERN PLAINS...BUT THE NEXT FAST MOVING UPPER LEVEL 
LOW WILL ALREADY BE IMPACTING ND/MT BY EVENING. THE UPPER LOW WILL 
DIVE QUICKLY INTO THE UPPER MIDWEST ON TUESDAY NIGHT. MOISTURE AND 
FORCING AROUND THE UPPER TROUGH WILL BE SUFFICIENT FOR A CHANCE OF 
-SHSN OVER NORTHEASTERN WYOMING...THE BLACK HILLS...AND FAR 
SOUTHWESTERN SOUTH DAKOTA ON TUESDAY NIGHT. TUESDAY NIGHT WILL ALSO 
BE BREEZY/WINDY AS A COLD FRONT CROSSES THE FORECAST AREA.

ON WEDNESDAY...THE UPPER LOW WILL DROP INTO IOWA AS AN UPPER RIDGE 
BUILDS OVER THE NORTHERN ROCKIES. TEMPERATURES WILL BE NEAR GUIDANCE.

EXTENDED...AN UPPER LEVEL RIDGE WILL KEEP CONDITIONS WARM AND DRY 
FOR THANKSGIVING DAY AND FRIDAY. HIGH TEMPERATURES ARE EXPECTED TO 
BE IN THE 40S AND 50S. NEXT UPPER TROF MOVES ACROSS THE NORTHERN 
PLAINS ON SATURDAY AND SUNDAY. THIS WILL BRING COOLER TEMPERATURES 
AND A SLIGHT CHANCE OF PRECIPITATION TO MUCH OF THE AREA. 
 
&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY AFTERNOON. 
BRISK NORTHWEST WINDS THIS AFTERNOON WILL DIMINISH OVERNIGHT.

&&

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

$$
GR/SR