Severe Thunderstorm Warning 162, NWS Rapid City, SD

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
315 AM MDT MON AUG 26 2002

WATER VAPOR IMAGERY SHOWS UPPER LOW OVER NE MONTANA THIS MORNING
WITH TROUGH DEVELOPING TO OUR WEST TODAY AS NEXT SHORTWAVE MOVES
ASHORE AND SYNCS UP WITH THE UPPER LOW. THIS COMBINATION SWINGS A
VORT MAX ACROSS OUR CWA THIS AFTERNOON. AS THE SURFACE...ANALYSIS
PLACES SFC LOW CENTER OVER SE WYOMING WITH INVERTED TROUGH EXTENDING
NORTHEASTWARD INTO SE ND. THIS WILL BECOME THE FOCUS FOR
THUNDERSTORM DEVELOPMENT THIS AFTERNOON AS LOW LEVEL MOISTURE
INCREASES SE OF THE TROUGH AND CAPE RISES TO 2000 TO 3000 J/KG. HIGH
TEMPERATURES ARE FORECAST TO BE AROUND 5F WARMER THAN THE CONVECTIVE
TEMPS...BREAKING THE WEAK CAP BY LATE AFTERNOON. WEAK LL JET WILL
CONTINUE TO FEED MOISTURE INTO THE STORMS OVERNIGHT...WITH BOTH AVN
AND ETA POINTING TO MCS DEVELOPING THEN HEADING SLOWLY SE TONIGHT.
ETA INDICATES STORMS DEVELOPING OVER SW AND CENT WYOMING WILL MOVE
INTO NE WYOMING AFTER MIDNIGHT.

AN UPPER LEVEL TROUGH TO OUR WEST WILL REMAIN THE DOMINANT WEATHER
FEATURE THROUGH MOST OF THE WEEK. SHORTWAVES WILL CONTINUE TO ROTATE
ACROSS OUR CWA IN UNSTABEL SOUTHWEST FLOW...WITH LARGE DIFFERENCES
ON THE TIMING BETWEEN THE MODELS. THIS WARRANTS KEEPING LOW POPS IN
THE FORECAST...WITH TEMPS REMAINING NEAR NORMAL...DEPENDING MAINLY
ON CLOUD COVER. EXTENDED CONTINUES THIS TREND SO HAVE MADE NO
CHANGES THERE.

.UNR...NONE
GR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
130 AM MDT MON AUG 26 2002

TIME(MDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0125 AM    WHITE RIVER               SD   1.25 INCH HAIL
08/26/02   MELLETTE