Hail in South Dakota, September 6, 2007

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
200 PM MDT THU SEP 6 2007

.DISCUSSION...CURRENT SURFACE MAP SHOWS COLD FRONT INTO EASTERN
SOUTH DAKOTA...WITH SECONDARY TROF MOVING ACROSS WESTERN NORTH
DAKOTA INTO EASTERN WYOMING. UPPER LOW MOVING ACROSS WESTERN SOUTH
DAKOTA AS UPPER TROF MOVES ACROSS MONTANA. SCATTERED
SHOWERS/THUNDERSTORMS ACROSS THE AREA.

FOR TONIGHT...SHOWERS/THUNDERSTORMS WILL END THIS EVENING AS UPPER
LOW SHOOTS OFF TO THE EAST. SKIES WILL BECOME PARTLY CLOUDY AS WEAK
HIGH PRESSURE BUILDS IN LATE TONIGHT. RETURN FLOW ON FRIDAY AS NEXT
SURFACE LOW DEVELOP ACROSS SOUTHEAST MONTANA/NORTHEAST WYOMING LATE
IN THE DAY. STRONG THETA-E ADVECTION ACROSS NORTHWEST SOUTH DAKOTA
FRIDAY NIGHT WITH 40-50KT LOW LEVEL JET WILL RESULT IN MORE SHOWER
ACTIVITY. WITH FORECAST SOUNDINGS SHOWING SOME ELEVATED CAPE...WITH
ADD MENTION OF THUNDER. SURFACE LOW MOVES ACROSS WESTERN SOUTH
DAKOTA SATURDAY MORNING...PULLING COLD FRONT THROUGH. TIMING OF COLD
FRONT WILL HAVE BIG IMPACT ON HIGH TEMPERATURES. WITH TIGHT PRESSURE
GRADIENT AND MODERATE COLD ADVECTION...WITH BE WINDY ACROSS THE
PLAINS OF WESTERN SOUTH DAKOTA.

EXTENDED...VIGOROUS UPPER LEVEL TROUGH WILL CROSS THE NORTHERN
PLAINS FROM SATURDAY NIGHT INTO EARLY NEXT WEEK. STRONG CYCLOGENESIS
AT THE SURFACE WILL OCCUR JUST AHEAD OF THE TROUGH ACROSS MUCH OF
THE FORECAST AREA. THIS WILL BRING WIDESPREAD RAIN TO THE FORECAST
AREA LATE SATURDAY NIGHT INTO MONDAY MORNING. MODEL 700MB TEMPS FALL
TO -6C WHILE 850 TEMPS FALL TO AROUND 3C BETWEEN MIDNIGHT SUNDAY AND
EARLY MONDAY MORNING. IF THE CURRENT GUIDANCE PLAYS OUT WITH DECENT
PRECIP RATES DURING THIS TIME PERIOD...COULD SEE SOME SNOW IN THE
HIGHER ELEVATIONS OF THE BLACK HILLS. MAIN SYSTEM PULLS OUT OF THE
FORECAST AREA ON MONDAY...WITH ANOTHER WEAK WAVE ON ITS HEELS FOR
MONDAY NIGHT. TEMPERATURES ON SUNDAY AND MONDAY WILL BE QUITE
CHILLY...WITH HIGHS STRUGGLING INTO THE 50S TO LOWER 60S. SHORTWAVE
RIDGE CROSSES THE NORTHERN PLAINS ON TUESDAY AND
WEDNESDAY...BRINGING MAINLY DRY CONDITIONS AND WARMER TEMPS.

&&

.AVIATION...SCATTERED -SHRA ALONG WITH SOME -TSRA WILL CROSS OVER
THE AREA THIS AFTERNOON AND EVENING AS A STRONG WEATHER SYSTEM MOVES
THROUGH THE NORTHERN PLAINS. THIS WILL RESULT IN AREAS OF MVFR
CIGS...PARTICULARLY OVER THE HIGHER TERRAIN OF NORTHEAST WYOMING AND
THE BLACK HILLS. MVFR VIS WILL ALSO BE POSSIBLE IN THE HEAVIER
RAINFALL. AREAS OF MVFR CIGS WILL PERSIST ACROSS THE HIGHER TERRAIN
OF NORTHEAST WYOMING AND THE BLACK HILLS THROUGH THE NIGHT AS THE
SYSTEM PULLS OUT OF THE AREA.

&&

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

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RAPID CITY SD
506 AM MDT THU SEP 6 2007

SDZ001-002-012>014-024>032-041>044-046-047-049-072>074-WYZ054>058-
071-070905-
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-
506 AM MDT (606 AM CDT) THU SEP 6 2007

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

.DAY ONE...TODAY AND TONIGHT

AN UPPER LEVEL DISTURBANCE WILL BRING NUMEROUS SHOWERS AND A FEW
THUNDERSTORMS TO MOST OF THE REGION TODAY AND THIS EVENING. SEVERE
THUNDERSTORMRS ARE NOT EXPECTED.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS ON SATURDAY...AS A COLD
FRONT CROSSES THE AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY.