Severe Thunderstorm Warning 33, NWS Rapid City, SD

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY
300 PM MDT SAT JUN 22 2002

WATER VAPOR IMAGERY SHOWS NEXT SHORTWAVE ROTATING INTO SE WY ATTM
WITH CONVECTION FIRING AS UPPER DIVERGENCE INCREASES ACROSS THE
AREA. N-S SURFACE TROUGH HAS MOVED E INTO SWRN SD WITH WARM FRONT
EXTENDING FROM NEAR BLKHLS TO NE SD. DEWPOINTS RANGE FROM 55F TO 65F
AHEAD OF THE TROUGH IN SC SD BUT CAP REMAINS IN PLACE. CAP MAY BE
BROKEN THIS EVENING AS LEADING SHORTWAVE CROSSES CENTRAL SD. TO THE
WEST OF THE TROUGH OVER NE WYOMING...DEWPOINTS HAVE FALLEN INTO THE
MID 40S AS WRLY DOWNSLOPE WINDS INDUCE LL DRYING. INVERTED V TYPE
SOUNDINGS POINT TO POSSIBLILITY OF DRY MICROBURST OR LARGE HAIL.
FOCUS FOR POSSIBLE SEVERE WILL SHIFT NORTHEASTWARD TOWARD NW SD THIS
EVENING.

ON SUNDAY...UPPER LOW MOVES FROM NE MT ACROSS ND. ETA BUFKIT
SOUNDINGS INDICATE GREATEST LIFT AND INSTABILITY WILL BE ACROSS OUR
NRN ZONES...CLOSER TO THE UPPER LOW. HAVE TRIMMED BACK PRECIP
COVERAGE AND REMOVED FROM OUR SRN ZONES ON SUNDAY. A WEAK SHORTWAVE
CROSSES THE REGION ON MONDAY BUT WITH LL MOISTURE LACKING AND A WEAK
CAPPING INVERSION WILL LEAVE THE FORECAST DRY. UPPER RIDGE BUILDS
OVER THE NRN PLAINS FOR TUESDAY THROUGH THURSDAY. AVN INDICATING A
FEW WEAK DISTURBANCES ACROSS THE REGION ON THOSE DAYS...BUT ANY
CONVECTION IS EXPECTED TO BE ISOLATED...LEAVING THE MAJORITY OF WRN
SD AND NE WY DRY. A TROUGH PASSING TO THE NORTH WILL FLATTEN THE
RIDGE ON FRIDAY...WITH A SFC COLD FRONT PASSING THROUGH AS WELL.
THIS WILL BRING THE BEST CHANCE OF RAIN FOR THE WEEK WITH A RETURN
TO DRY WEATHER AND ONLY SLIGHTLY COOLER TEMPERATURES ON SATURDAY.

.UNR...NONE.
GR