Damaging Wind in South Dakota, June 21, 2009

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
200 PM MDT SUN JUN 21 2009

.DISCUSSION...CURRENT SURFACE ANALYSIS PLACES LOW PRESSURE NEAR THE
MONTANA/SASKATCHEWAN BORDER WITH TROF DIPPING SOUTH NEAR THE MON-DAK
BORDER. UPPER LEVEL ANALYSIS PLACES SOUTHWESTERLY FLOW ALOFT. A FEW
THUNDERSTORMS HAVE DEVELOPED OVER SOUTHWEST NORTH DAKOTA IN VICINITY
OF AFOREMENTIONED SURFACE TROF.

FOR TONIGHT...A FEW THUNDERSTORMS WILL CONTINUE TO DEVELOP ALONG AND
AHEAD OF AFOREMENTIONED TROF AXIS IN AREA OF MARGINAL INSTABILITY
AND SHEAR. DO NOT EXPECT MUCH IN THE WAY OF SEVERE WITH
THIS...THOUGH A STRONG STORM OR TWO WILL NOT BE OUT OF THE QUESTION.

ON MONDAY...SOUTHWEST FLOW REMAINS OVER THE AREA WITH SURFACE LOW
DEVELOPING NEAR CENTRAL SOUTH DAKOTA. EXPECT A FEW STORMS COULD
DEVELOP OVER THE EASTERN CWFA IN THE AFTERNOON...THOUGH ACTIVITY
SHOULD SLIDE EAST BY THE EVENING AS THE LOW PUSHES INTO EASTERN SD.

FOR TUESDAY...MODELS HAVE BEEN JUMPING AROUND ON THE AMOUNT OF
INSTABILITY EXPECTED THIS DAY...BUT EARLIER RUNS SIGNIFIED HIGHER
CAPE VALUES. EXPECTED 0-6 KM BULK SHEAR OF 45KTS+ ACROSS MUCH OF THE
CWFA WOULD BE PLENTY TO SUPPORT ROTATING UPDRAFTS. ALTHOUGH THE
SHORT WAVE PROGGED TO COME THROUGH THAT DAY APPEARS RATHER WEAK...IT
MAY BE ENOUGH TO TRIGGER OFF SOME STORMS. WILL HAVE TO KEEP AN EYE
ON THIS DAY FOR POSSIBLE SEVERE THREAT.

EXTENDED...MORE SUMMER-LIKE CONDS CAN BE EXPECTED FOR WED THRU
SATURDAY. PERIODIC S/WS WILL BRING OCCASIONAL CHCS OF SHWS/ TSTMS.
TEMPS WILL BE SLIGHTLY ABOVE NORMAL THRU THE EXTENDED PERIOD.

&&

.AVIATION...VFR CONDS WILL CONTINUE THROUGH THE FCST PERIOD. A FEW
SCT TSTMS ARE POSSIBLE THRU 03Z ACRS NERN WY AND FAR WRN SD.

&&

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

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
602 AM MDT SUN JUN 21 2009

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-221300-
BENNETT-BUTTE-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON-
HARDING-HERMOSA FOOT HILLS-JACKSON-MELLETTE-NORTHEASTERN CROOK-
NORTHERN BLACK HILLS-NORTHERN CAMPBELL-NORTHERN FOOT HILLS-
NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-PERKINS-RAPID CITY-
SHANNON-SOUTHERN BLACK HILLS-SOUTHERN CAMPBELL-SOUTHERN FOOT HILLS-
SOUTHERN MEADE CO PLAINS-STURGIS/PIEDMONT FOOT HILLS-TODD-TRIPP-
WESTERN CROOK-WESTON-WYOMING BLACK HILLS-ZIEBACH-
602 AM MDT (702 AM CDT) SUN JUN 21 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN SOUTH DAKOTA AND
NORTHEASTERN WYOMING.

.DAY ONE...TODAY AND TONIGHT

ISOLATED THUNDERSTORMS ARE EXPECTED ACROSS PORTIONS OF NORTHEASTERN
WYOMING AND NORTHWESTERN SOUTH DAKOTA TODAY AND TONIGHT. SEVERE
THUNDERSTORMS ARE NOT ANTICIPATED...BUT A STORM OR TWO COULD BE ON
THE STRONG SIDE WITH GUSTY WINDS AND SMALL HAIL.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

DAILY CHANCES FOR THUNDERSTORMS WILL CONTINUE ACROSS MUCH OF THE
AREA DURING THE WEEK. THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS
TUESDAY AFTERNOON AND EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.