Flash Flood and Hail in South Dakota, August 10, 2006

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
338 AM CDT THU AUG 10 2006

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
CONVECTION ONGOING THIS MORNING ALONG THE ND/SD BORDER IN
ASSOCIATION WITH WARM FRONTAL BOUNDARY. THIS ACTIVITY IS SLOWLY
SAGGING SOUTH AND WILL AFFECT MCPHERSON AND NORTHERN BROWN COUNTIES
DURING THE NEXT HOUR. DO NOT EXPECT CONVECTION TO LAST DEEP INTO THE
MORNING HOURS AS OUTFLOW BOUNDARIES FROM PREVIOUS CONVECTION HAS
STABILIZED ATMOSPHERE. WILL SEE THUNDERSTORMS DEVELOPING ONCE AGAIN
THIS AFTERNOON AS SHORT WAVE CURRENTLY LOCATED OVER MT MOVES SE INTO
THE DAKOTAS. SVR PARAMETERS LOOK GOOD ACROSS CENTRAL SD THIS
AFTERNOON AND HAVE INCLUDED POSSIBLE SEVERE IN GRIDS/ZONE WORDING.
HI RES NAM HAS DONE FAIRLY WELL NAILING DOWN CONVECTION PAST COUPLE
NIGHTS AND FOR THIS AFTERNOON...IT SHOWS CONVECTION BEGINNING
SOMEWHERE ACROSS NW SD/SW ND AND MOVES ACTIVITY SE TOWARDS CENTRAL
SD. PATTERN ACTUALLY LOOKS FAIRLY ACTIVE THROUGH THE SHORT TERM WITH
SEVERAL WAVES MOVING ACROSS THE AREA. NEXT WAVE OF SIGNIFICANCE
MOVES THROUGH LATE FRIDAY NIGHT INTO EARLY SATURDAY MORNING. HAVE
INCREASED POPS ACROSS THE WESTERN COUNTIES FOR FRIDAY NIGHT.
TEMPERATURES WERE COOLED JUST A COUPLE DEGREES...MAINLY ACROSS THE
SW COUNTIES. THINKING THAT SLIGHTLY INCREASED CLOUD COVER ASSOCIATED
WITH SHORTWAVES WILL KEEP TEMPS DOWN A TAD.

.LONG TERM...SUNDAY THROUGH WEDNESDAY
MAIN FCST CHALLENGE IN THE EXTENDED DEALS WITH PCPN CHANCES
EARLY...THEN LATE IN THE EXTENDED.

MODELS ARE BEGINNING TO SHOW A RATHER UNSETTLED PATTERN TAKING
SHAPE...WITH TROUGHING IN THE WEST WITH SW FLOW ALOFT SETTING UP
OVER THE CWA. GULF BEGINS TO OPEN UP ALLOWING AMPLE MOISTURE TO
FINALLY FLOW NORTHWARD. THE 00Z GFS SFC SOLN AT 12Z SUNDAY SHOWS
FRONTAL BOUNDARY PARALLEL TO 5H FLOW...WHICH MATCHES THE 00Z
CANADIAN SOLN AS WELL. THE 00Z NAM SOLN HAS A MORE PERPENDICULAR
FLOW. GIVEN DIGGING NW SYSTEM...AM MORE INCLINED TO BUY INTO THE GFS
SOLN. RESULT IS BETTER TSRA CHANCES DURING THE DAY SUNDAY AND SUNDAY
NIGHT AS FROPA PASSES THRU. ALSO UPPED DWPTS A BIT MORE DURING THE
DAY SUNDAY.

DRY AND COOL WEATHER PREVAILS THEN FOR MONDAY AND TUESDAY AS HIGH
PRESSURE MOVES THROUGH. HEIGHTS BEGIN TO REBOUND A BIT MORE BY
WEDNESDAY WITH SW FLOW REGIME TAKING SHAPE AGAIN. IF THIS PATTERN
REMAINS...MAY HAVE TO ADD TSRA CHANCES TO WEDNESDAY AFTERNOON PERIOD
WITH NEXT WAVE EJECTING OUT OF BASE OF TROF AND INTO CWA.

TEMP WISE...CURRENT GRIDS HAVE DECENT HANDLE ON THINGS. DID NUDGE
TEMPS DOWN JUST A TAD FOR SUNDAY NIGHT AND MONDAY GIVEN CAA PATTERN
BEHIND EXITING FRONT.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

TT/DH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE ABERDEEN SD
526 AM CDT THU AUG 10 2006

MNZ039-046-SDZ003>011-015>023-033>037-045-048-051-111030-
TRAVERSE-BIG STONE-CORSON-CAMPBELL-MCPHERSON-BROWN-MARSHALL-
ROBERTS-WALWORTH-EDMUNDS-DAY-DEWEY-POTTER-FAULK-SPINK-CLARK-
CODINGTON-GRANT-HAMLIN-DEUEL-STANLEY-SULLY-HUGHES-HYDE-HAND-JONES-
LYMAN-BUFFALO-
526 AM CDT THU AUG 10 2006 /426 AM MDT THU AUG 10 2006/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WEST CENTRAL
MINNESOTA...CENTRAL SOUTH DAKOTA...NORTH CENTRAL SOUTH DAKOTA AND
NORTHEAST SOUTH DAKOTA.

.DAY ONE...TODAY AND TONIGHT

SHOWERS AND THUNDERSTORMS WILL OCCUR NORTH OF A BOWDLE-WARNER-
WEBSTER LINE DURING THE EARLY MORNING HOURS. THE MAIN THREAT WITH
THESE STORMS IS CLOUD TO GROUND LIGHTNING. MORE THUNDERSTORMS ARE
EXPECTED TO MOVE INTO PORTIONS OF CENTRAL SOUTH DAKOTA LATER THIS
AFTERNOON. SEVERE STORMS ARE POSSIBLE WITH HAIL AND STRONG WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORM CHANCES EXIST FROM FRIDAY NIGHT THROUGH SUNDAY NIGHT.
SEVERE WEATHER IS POSSIBLE WITH SOME OF THE STORMS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BECOME NECESSARY THIS AFTERNOON ACROSS
CENTRAL SOUTH DAKOTA.

TT