Hail in South Dakota, August 17, 2006

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
131 PM MDT THU AUG 17 2006

.DISCUSSION...A FRONTAL BOUNDARY EXTENDS ACROSS SOUTHWESTERN SD AND
INTO NORTHEASTERN WYOMING. LARGE DEWPOINT GRADIENT WITH 50 DEWPOINT
IN GILLETTE...55 IN RAPID CITY...34 IN CUSTER...46 IN PINE RIDGE AND
60 IN VALENTINE. 18Z SOUNDING SHOWED IMPRESSIVE SHEAR WITH A WEAK
CAP STILL OVER THE AREA. CONVECTIVE TEMP WAS 95 AND CURRENTLY
94...SO THINGS SHOULD BE GETTING GOING SOON. SUPERCELLS WITH LARGE
HAIL WILL BE THE PRIMARY THREAT. BUT WOULD ALSO EXPECT DAMAGING
WINDS...LOCALLY HEAVY RAIN AND POSSIBLY A BRIEF...SHORT LIVED
TORNADO.

UPPER LEVEL LOW AND TROF CURRENTLY OVER IDAHO WILL PASS THROUGH LATE
TONIGHT AND TOMORROW BRINGING DECENT FORCING TO THE AREA. AVAILABLE
SURFACE MOISTURE COMBINED WITH LEFT OVER BOUNDARIES CREATED BY
STORMS TODAY WILL PRODUCE THUNDERSTORMS THOUGH TOMORROW NIGHT.

CURRENT FORECAST IS ON TRACK...SO ONLY MADE MINOR CHANGES. SURFACE
LOW DEVELOPING IN NORTHEAST WYOMING AND THE ASSOCIATED FRONTAL
BOUNDARY WILL MAKES ITS WAY ACROSS THE AREA THROUGH FRIDAY. PRESSURE
GRADIENT WILL STAY FAIRLY STRONG...SO INCREASED WINDS SLIGHTLY FROM
PREVIOUS FORECAST. LOWERED TEMPS SLIGHTLY ON SATURDAY WITH THE
NOTICEABLY COOLER AIR OVER THE AREA. NOT TOO SURE ABOUT POPS SUNDAY
AFTERNOON OVER THE BLACK HILLS...BUT LEFT IN BECAUSE COULD NOT FIND
A GOOD REASON TO REMOVE.

EXTENDED...AN UPPER LEVEL RIDGE WILL BUILD ACROSS THE ROCKIES NEXT
WEEK. GFS IS TRYING TO BRING THROUGH A FEW WAVES BUT HAVE LITTLE
CONFIDENCE IN MOISTURE AND PLACEMENT AT THIS TIME. DID ADD IN A
SLIGHT CHANCE FOR CENTRAL SOUTH DAKOTA AS THIS SYSTEM HAS BEEN IN A
FEW RUNS NOW AND TO COORDINATE WITH SURROUNDING OFFICES. OTHERWISE
LEFT THE REST OF THE EXTENDED WARM AND DRY.

&&

.AVIATION...MAINLY VFR CONDITIONS EXPECTED FOR THE REST OF
THURSDAY...EXCEPT NEAR TSRA LATER THIS AFTERNOON AND OVERNIGHT.
THERE IS A POSSIBILITY OF LOWER CEILINGS ACROSS THE AREA BY 12Z
FRIDAY.

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
1119 AM MDT THU AUG 17 2006

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-181300-
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-
1119 AM MDT (1219 PM CDT) THU AUG 17 2006

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

.DAY ONE...TODAY AND TONIGHT

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

SCATTERED TO NUMEROUS THUNDERSTORMS WILL BEGIN TO DEVELOP OVER
NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA BY MID AFTERNOON. SEVERE
WEATHER IS EXPECTED WITH LARGE HAIL AND DAMAGING WINDS BEING THE
MAIN THREATS. SOME THUNDERSTORMS MAY ALSO BE SLOW-MOVING...
WHICH WILL INCREASE THE CHANCE FOR LOCALLY HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

AN UPPER LEVEL DISTURBANCE WILL SWEEP A COLD FRONT ACROSS THE AREA
TOMORROW. SHOWERS AND THUNDERSTORMS ARE AGAIN EXPECTED TO DEVELOP
THROUGHOUT THE DAY. THERE IS A SLIGHT RISK THAT SOME STORMS MAY
BECOME SEVERE...PARTICULARLY ACROSS CENTRAL SOUTH DAKOTA. LARGE
HAIL AND DAMAGING WINDS WILL BE THE MAIN THREATS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TODAY.