Severe Thunderstorm Warning 138, NWS Rapid City, SD

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
230 PM MDT WED AUG 21 2002

MDLS IN FAIR AGREEMENT WITH SYNOPTIC FEATURES BUT DIFFER A BIT ON
PLACEMENT AND TIMING OF DISTURBANCES. A FEW STORMS DVLPG OVR THE BLK
HILLS AND NE WY ATTM AND EXPECT THAT MORE STORMS WL CONTINUE DVLPG
TO THE N AND E OF THIS AREA THROUGH THE REMAINDER OF THE AFTN AND
INTO THE EVE AS S/W LIFTS OUT OF ERN WY. LO CLDS HAVE REMAINED IN
PLACE ACRS NRN HALF OF CWA THIS AFTN...AND NO REASON THEY WL GO AWAY
TNGT. THINKING IS THAT AS WINDS BECOME MORE E-NE OVR AREA...THIS WL
HELP MORE LO CLDS TO DVLP OVR MUCH OF THE CWA. SINCE THIS MOISTURE
IS PRETTY SHALLOW...MOST OF THE HILLS SHLD STAY PTLY CLDY. LOWS SHLD
ONCE AGAIN BE ABV MOS GIVEN CURRENT DEW POINTS ACRS CWA AND WHAT WL
ADVECT IN FM THE E.

THU WINDS WL START TO SHIFT TO THE SE AS HI MOVES OVR GT LKS. GD
SETUP FOR STRONG SE WINDS BY AFTN ACRS WRN HALF OF CWA. BIGGEST
QUESTION IS HOW MUCH THE LO CLDS WL BREAK UP THROUGH THE DAY.  THINK
IT MAY BE TOUGH FOR FAR ERN COUNTIES TO GET OUT OF THE LO CLDS
BEFORE MID AFTN WHEN WINDS SHIFT AND HAVE KEPT TEMPS THERE ABOUT 5
DEG COOLER THAN THE W WHERE IT SHLD WARM INTO THE MID TO UPR 80S.
SOME WEAK RIDGING WL TAKE PLACE OVR AREA THROUGH THE DAY...BUT A
WEAK DISTURBANCE WL MOVE THRU THE S IN THE AFTN AND MAY TRIGGER A
FEW STORMS. ANOTHER S/W WL APPROACH NE WY LATE AND MAY SEE A FEW
STORMS THERE AS WELL. KEPT N DRY. THU NIGHT...S/W FM NE WY WL MOVE
ACRS WRN CWA AND HAVE KEPT 20 POPS GOING. OTHERWISE LOWS AGAIN IN
THE UPR 50S TO LWR 60S AS SE WINDS SHLD KEEP SOME LL MOISTURE AROUND.

FRI...A COUPLE OF DISTURBANCES WL MOVE ACRS CWA AND CONTINUE A CHC
FOR TSMS WITH DECENT MOISTURE AROUND. CAPES WL BE 1000-1500J/KG WITH
LTL OR NO CIN. INCLUDED 30 POPS EVERYWHERE. TEMPS SHLD REACH THE 80S
EVERYWHERE AS LO CLDS SHLD BE AT A MINIMUM. EXPECT MAINLY DRY CONDS
ACRS AREA FRI NIGHT AS GD NVA ACRS CWA. AVN SHOWING TROF ROTATING
THRU AREA SAT AND PUT IN A CHC FOR TSMS AGAIN ACRS CWA. TEMPS
SIMILAR TO FRI.

IN THE EXTENDED...SUN KEPT DRY WITH NO REAL DISTURBANCE MVG
THRU...BUT UPR TROF APPROACHES AREA BY MON WITH A CHC FOR TSMS THRU
WED ALONG WITH COOLER TEMPS...MAINLY IN THE MID TO UPR 70S BY TUE
AND WED.

.UNR...FLOOD WATCH UNTIL 930 PM MDT FOR LAWRENCE COUNTY-SDZ024.
JMG

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
815 PM MDT WED AUG 21 2002

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

0350 PM    6S WOOD                   SD   1 INCH HAIL
08/21/02   MELLETTE                       REPORTED BY PUBLIC.

0515 PM    18NW WITTEN               SD   .88 INCH HAIL
08/21/02   TRIPP                          REPORTED BY PUBLIC.

0525 PM    1S WINNER                 SD   1 INCH HAIL
08/21/02   TRIPP                          REPORTED BY SPOTTER.

0650 PM    10NE ZEONA                SD   1.75 INCH HAIL
08/21/02   PERKINS                        REPORTED BY PUBLIC.
                                          FELL FOR 15 MINUTES

WFO UNR STAFF