FXUS63 KUNR 130934
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
234 AM MST SAT MAR 13 2010

.DISCUSSION...CURRENT SURFACE MAP SHOWS HIGH PRESSURE ACROSS THE
DAKOTAS WITH TROF ACROSS CENTRAL MONTANA/WYOMING. LOW STRATUS/FOG
ACROSS CENTRAL SOUTH DAKOTA IS SLOWLY SPREADING WEST...AND IS
ALONG/EAST OF A LINE FROM DUPREE- ROSEBUD. AS HIGH SLIDES
EAST...RETURN FLOW WILL INCREASE ALLOWING LOW STRATUS TO SPREAD
FURTHER WEST. THIS WILL RESULT IN TIGHT GRADIENT IN
TEMPERATURES...WITH CLOUDS KEEPING HIGHS IN THE 30S WHILE SUNSHINE
WILL PUSH TEMPS TO AROUND 50. STRATUS/FOG WILL SPREAD ACROSS THE
REMAINDER OF WESTERN SOUTH DAKOTA TONIGHT. COULD BE SOME LOCALLY
DENSE FOG IN WESTERN SOUTH DAKOTA.

UPPER LEVEL TROF ACROSS WESTERN U.S. CROSSES ROCKIES
TONIGHT/SUNDAY. ENERGY SPLITS WITH LOW DROPPING INTO SOUTHERN
ROCKIES WITH WEAKER TROF SLIDING EAST ALONG CANADIAN BORDER. WITH
MINIMAL Q-VECT CONVERGENCE AND MID LEVEL LAPSE RATES OF
5-6C/KM...LOOKS LIKE A DRY FORECAST. HOWEVER...WILL KEEP A FEW
RAIN/SNOW SHOWERS ACROSS NORTHEAST WYOMING. COLD FRONT WILL SLIDE
ACROSS THE AREA EARLY SUNDAY. HIGH PRESSURE ACROSS THE AREA SUNDAY
NIGHT WITH FORECAST SOUNDINGS SUPPORTING SOME PATCHY FOG. DRY AND
WARMER ON MONDAY.

EXTENDED...RIDGE WILL MOVE INTO THE CWA ON TUESDAY BRINGING WARM AND
DRY CONDITIONS TO THE CWA THROUGH WEDNESDAY. RIDGE WILL FLATTEN ON THURSDAY
AS FLOW ALOFT TRANSITIONS INTO ZONAL. A SHORTWAVE WILL CROSS THE CWA
THURSDAY INTO FRIDAY BRINGING A COLD FRONT...COOLER
TEMPERATURES...AND A SLIGHT CHANCE OF RAIN OR SNOW FOR THE END OF
THE WEEK.

&&

.AVIATION...MVFR/IFR CONDITIONS DUE TO CIGS/FOG WILL CONTINUE ACROSS
SOUTH CENTRAL SOUTH DAKOTA THROUGH THIS MORNING. THE LOW STRATUS AND
FOG WILL SLOWLY PUSH WEST TONIGHT BRINGING MVFR/IFR CIGS AND
VISIBILITIES INTO WESTERN SOUTH DAKOTA AND PORTIONS OF NORTHEAST
WYOMING. OTHERWISE...VFR CONDITIONS CAN BE EXPECTED.


&&

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

$$




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