Damaging Wind in South Dakota, August 10, 2005

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
750 PM MDT WED AUG 10 2005

.DISCUSSION...THE MAIN FORECAST CONCERN TONIGHT IS THE EVOLUTION OF
CONVECTION. THE PRIMARY MESOSCALE CONVECTIVE SYSTEM (MCS) WILL TRACK
ALONG AND TO THE SOUTH OF SRN SD WHERE A LOW-LEVEL JET (LLJ) FOCUSES
MOISTURE AND ASCENT. A SECONDARY MCS SHOULD MOVE ALONG NRN SD DUE TO
A SECONDARY AND WEAKER LLJ...ALONG WITH A POTENT WAVE TRACKING EAST-
WARD ACROSS SRN MT AND NRN WY. THERE STILL APPEARS TO BE SOME THREAT
FOR SEVERE WEATHER...BUT FOR THE MOST PART THE CAPE PROFILES ARE
RATHER THIN WHICH IS MORE CONDUCIVE TO LOCALLY HEAVY RAINS INSTEAD
OF LARGE HAIL. INDEED...REGIONAL PRECIPITABLE WATER VALUES FROM THE
00Z RAOBS WERE 120-174 PERCENT OF AVERAGE. AS A RESULT OF THESE TWO
MCSS...THERE MAY BE A HOLE IN THE RAINFALL PATTERN RIGHT OVER
RAPID CITY. IN GENERAL THE FORECAST HAS THINGS HANDLED WELL...BUT
MAY FINE TUNE THE POPS BASED ON LATEST RADAR/SATELLITE TRENDS.

EXTENDED...RAISED POPS FOR FRIDAY NIGHT TO 40-50 PERCENT AS THE
MODEL SIGNAL HAS BEEN CONSISTENT THE PAST SEVERAL RUNS WITH A POTENT
WAVE ROTATING THROUGH THE BLACK HILLS REGION. LOW-LEVEL MOISTURE AND
FRONTOGENESIS ALSO APPEAR QUITE FAVORABLE.

&&

.AVIATION...SCATTERED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED
ACROSS THE TWEB ROUTES THRU MUCH OF THE EVENING. BEST CHANCES FOR
THUNDERSTORMS AT RAP AND GCC SHOULD BE UNTIL 06Z. OTHERWISE...VFR
CONDITIONS CAN GENERALLY BE EXPECTED THRU THURSDAY MORNING.

&&

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

&&

BUNKERS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
630 AM MDT WED AUG 10 2005

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-111300-
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-
630 AM MDT (730 AM CDT) WED AUG 10 2005

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

.DAY ONE...TODAY AND TONIGHT

THERE IS A SLIGHT RISK OF SEVERE WEATHER OVER WESTERN AND SOUTH
CENTRAL SOUTH DAKOTA...AND OVER NORTHEASTERN WYOMING FOR TODAY.

ISOLATED THUNDERSTORMS WILL CONTINUE TO MOVE THROUGH NORTHEAST
WYOMING AND WESTERN SOUTH DAKOTA THIS MORNING. LATER THIS MORNING
AND EARLY THIS AFTERNOON ANOTHER DISTURBANCE WILL MOVE INTO
THE AREA. SCATTERED THUNDERSTORMS WILL DEVELOP OVER NORTHEAST
WYOMING AND FAR WESTERN SOUTH DAKOTA...AND INCREASE IN COVERAGE AND
INTENSITY THROUGHOUT THE DAY...MOVING INTO CENTRAL SOUTH DAKOTA BY
LATE THIS AFTERNOON INTO THIS EVENING. SOME OF THESE THUNDERSTORMS
WILL HAVE THE POTENTIAL TO BECOME SEVERE. THE MAIN THREATS FROM
THESE STORMS WILL BE LARGE HAIL AND DAMAGING WIND GUSTS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

THERE IS A SLIGHT RISK OF SEVERE WEATHER OVER WESTERN AND SOUTH
CENTRAL SOUTH DAKOTA...AND OVER FAR NORTHEASTERN WYOMING ON THURSDAY
AS ANOTHER DISTURBANCE MOVES THROUGH THE AREA. LARGE HAIL AND
DAMAGING WIND GUSTS WILL BE THE MAIN THREATS. THE CHANCE FOR
THUNDERSTORMS WILL REMAIN IN THE FORECAST THROUGH MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
705 PM MDT WED AUG 10 2005

SDZ013-024>032-041>044-072>074-110200-
BENNETT-CENTRAL BLACK HILLS-CUSTER CO PLAINS-FALL RIVER-HAAKON-
HERMOSA FOOT HILLS-JACKSON-NORTHERN BLACK HILLS-NORTHERN FOOT HILLS-
NORTHERN MEADE CO PLAINS-PENNINGTON CO PLAINS-RAPID CITY-SHANNON-
SOUTHERN BLACK HILLS-SOUTHERN FOOT HILLS-SOUTHERN MEADE CO PLAINS-
STURGIS/PIEDMONT FOOT HILLS-
705 PM MDT WED AUG 10 2005

...SEVERE THUNDERSTORM WATCH NUMBER 712 HAS BEEN CANCELLED FOR
SOUTH DAKOTA...

THE THREAT OF SEVERE WEATHER HAS DIMINISHED OVER SOUTHWESTERN SOUTH
DAKOTA...SO THE SEVERE THUNDERSTORM WATCH IS NO LONGER IN EFFECT FOR
THIS AREA. HOWEVER...SCATTERED SHOWERS AND THUNDERSTORMS ARE STILL
EXPECTED FOR THE REMAINDER OF THE EVENING.

MJB

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE RAPID CITY SD
900 PM MDT WED AUG 10 2005

WYZ054>058-071-110400-
NORTHEASTERN CROOK-NORTHERN CAMPBELL-SOUTHERN CAMPBELL-WESTERN CROOK-
WESTON-WYOMING BLACK HILLS-
900 PM MDT WED AUG 10 2005

...SEVERE THUNDERSTORM WATCH NUMBER 712 HAS EXPIRED...

THE THREAT OF SEVERE WEATHER HAS DIMINISHED OVER NORTHEASTERN
WYOMING...SO THE SEVERE THUNDERSTORM WATCH IS NO LONGER IN EFFECT FOR
THIS AREA. HOWEVER...SCATTERED SHOWERS AND THUNDERSTORMS ARE STILL
EXPECTED FOR THE REST OF THE EVENING.

MJB