Severe Thunderstorm Warning 59, NWS Aberdeen, SD

AREA FORECAST DISCUSSION FOR CENTRAL/NORTHCENTRAL AND
NORTHEAST SOUTH DAKOTA AND WEST CENTRAL MINNESOTA
NATIONAL WEATHER SERVICE ABERDEEN SD
300 PM CDT TUE JUN 8 1999

SOUNDING LIKE A BROKEN RECORD...FCST CONCERNS TAFTN DEAL WITH
IMPENDING CONVECTION. TSTORMS THIS MORN HAVE PUT OUT A BNDRY THAT
RUNS FROM NRN IOWA TO SERN SD...THEN NW INTO CENTRL SD. STORMS
FIRING ALONG BNDRY IN SRN MN ATTM...AND EXPECT STORMS TO BEGIN
FIRING ALONG CONVERGENCE ZONE IN WRN SD IN THE NEAR FUTURE. NSHARP
ETA FCST SNDG FOR ABR FOR 00Z TNT SHOWS A CAPE OF NR 4700 J/KG...-12
LI...NO CAP AND WBZ AROUND 8790. NGM FCSTD SNDG NOT AS SVR...BUT
AGAIN NGM UNDERFCSTING LOLVL MOIST RETURN. BY 00Z THTA-E RIDGE NOSES
INTO WCNTRL SD AND MOVES EAST DURING NIGHT. ALSO...7H VORT MAX
ROTATES INTO STATE AT 06Z AND EXITS BY 12Z...THEN REMAINDER OF CWA
REMAINS IN NVA AT 7H. MDL DIFFERENCE SHOWS UP AT 24 HRS. ETA CONTS
TO SLIDE LOW AND ASSOC TROF TO THE EAST...WHILE NGM HANGS UP
LOW...KEEPING MOST OF OUR CWA IN THE WARM SECTOR. WITH NO JET STREAK
DIGGING INTO WRN TROF...WOULD TEND TO BELIEVE THE MORE PROGRESSIVE
ETA/AVN SOLN OF MOVING SYSTEM THROUGH. WILL CONT TO HIT POPS HARD
TNT AND MENTION SVR AND HEAVY RAIN. FOR WED...WILL KEEP MENTION OF
TSRA...BUT WILL LOWER POPS IN NWRN CWA AS WK HIGH PRESSURE MOVES IN
BEHIND SYSTEM. HIGH CONTS TO BUILD INTO NRN PLAINS KEEPING NEXT LOW
PRESSURE SYSTEM SUPPRESSED TO THE SOUTH. WK CAA SHOULD ALSO HELP TO
STABILIZE THE ATMOS. WILL GO FOR A DRY FCST WED NIGHT AND THUR.
TEMPS WILL BE 5 TO 10 DEGREES COOLER ON THUR THAN WED WITH MUCH
NICER(DRIER) DWPTS.

.EXTENDED FORECAST...
MRF...ECMWF...AND CANADIAN MODELS IN BASIC AGREEMENT THIS EXTENDED
FORECAST PERIOD ON TRYING TO SLOWLY LIFT OUT PERSISTENT WESTERN U.S.
TROUGH UNDER INFLUENCE OF BUILDING RIDGE ALONG WEST COAST. REMNANTS
OF THIS TROUGH WILL REMAIN THROUGH SATURDAY AS IT LIFTS OUT...WITH A
SERIES OF WEAK-MODERATE SHORTWAVES PUSHIHG THROUGH NORTHERN PLAINS
AND WILL LIKELY CONTINUE TO FIRE LATE AFTERNOON-EVENING CONVECTION
THROUGH SATURDAY. UPPER RIDGE INFLUENCE NOT VERY STRONG BY
SUNDAY...BUT SURFACE HIGH TO THE WEST SHOULD CUT OFF MOIST LOW LEVEL
SOUTHERLY FLOW...SO WILL INDICATE DRY FOR SUNDAY. FMR TEMPS APPEAR
REASONABLE AND FOLLOWED.

.ABR...NONE.
HINTZ/LORENS