Severe Thunderstorm Warning 54, NWS Grand Forks, ND

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
255 PM CDT MON JUN 12 2000

FORECAST PROBLEM FOR TONIGHT IS PCPN. LATEST VIS SATELLITE IMAGERY
SHOWS CU DEVELOPMENT EXPANDING OVER ND SIDE OF CWFA WITH CONTINUED THINNING
OF HIGH LEVEL DECK ON MN SIDE OF CWFA. KMVX HAS S END OF TSRA LINE
MOVING ALONG FAR NW FRINGE OF CWFA. CURRENT MSAS SFC PRESSURE
ANALYSIS HAS SFC LOW OVER NE WY WITH WARM FRONT EXTENDING THROUGH
CWFA BETWEEN JMS AND DVL AND N OF GFK. WHEN COMPARING CURRENT MSAS
SFC PRESSURE PLOT TO MODELS...ETA AND AVN CLOSER THAN NGM...BUT ALL
MODELS DIFFER IN LOCATION AND STRENGTH OF SFC LOW. WITH ETA MATCHING
LOCATION OF WARM FRONT THE BEST...LEANED TOWARDS ITS SOLUTION...BUT
SLOWED TIMING CLOSER TO AVN...SINCE UPPER LEVEL TROF CONTINUES TO
DEEPEN AS IT MOVES INTO CWFA AND AS A RESULT...EXPECT SFC LOW TO
LINGER. MODEL SOUNDINGS SHOW ATMOSPHERE OVER CWFA CONTINUING TO
DESTABILIZE THROUGH MIDNIGHT WITH SWEAT INDICES ABOVE 400 FOR MUCH
OF CWFA AND OVER 500 FOR WC MN. WITH CURRENT MSAS LIS TO -8 OVER E
ND AND SFC TEMPS PUSHING INTO THE MIDDLE 80S...GOOD POTENTIAL FOR
TSRA AND SVR THIS EVENING AND TONIGHT. THANKS TO ABR FOR COORD.

FORECAST PROBLEM FOR SECOND AND THIRD PERIOD IS ALSO PCPN. SFC LOW
MOVES OUT OF SD INTO ND FOR TUE AND INTO NW MN BY 12Z WED. WITH LIS
AS LOW AS -8 AHEAD OF LOW...WIDESPREAD -TSRA STILL EXPECTED. THETA-E
RIDGE ALSO FOLLOWS ALONG AND AHEAD OF SFC LOW...PROVIDING POTENTIAL
FOR HEAVY RAIN TO N CWFA AS WELL.

FORECAST PROBLEM FOR FOURTH PERIOD IS PCPN. LOW PULLS E OF CWFA BY
18Z WED...PUTTING CWFA IN NW FLOW AND WRAP-AROUND STRATIFORM RAINS
EXPECTED UNDER CYCLONIC FLOW AND CAA.

EXTENDED...MAIN FEATURE IS SHRTWV TROF REDIGGING INTO THE NRN
PLAINS...WITH CONTINUED UNSETTLED BUT SEASONABLY COOLER WEATHER FOR
THE FGF CWFA. LONG RANGE MODELS STILL SHOWING SOME TIMING
DIFFERENCES...WITH ECMWF STILL GALLOPING AHEAD OF THE SLOWER MRF/AVN
SET. CANADIAN RUNNING FAST AND DEEP...WITH H5 CLOSED LOW CENTERED IN
NWRN ONT BY THURS AM. FOR NOW...WILL CONTINUE WITH AVN/MRF
SCENARIO...WITH A DUMBELLING H5 TROF SWEEPING BACK THROUGH THE
PRAIRIE PROVINCES THU. THIS GIVES SOME BREAK TO RAIN ACTIVITY OVR
THE CWFA LATE WED INTO THURS...WITH TSTM THREAT THURSDAY NIGHT INTO
FRIDAY...AS PER PREVIOUS PACKAGE. LATE WEEK TEMPS DROP INTO THE 60S
AS WE REMAIN UNDER A BROAD H5 TROF AND THICKNESSES COLLAPSE SUB
5580M. SOME CLDS POSSIBLE BUT GENERALLY DRY CONDITIONS EXPECTED.
WILL INDICATE WARMER TEMPS FOR EARLY NEXT WEEK AS MID CONTINENTAL H5
SHRTWV RIDGE DEVELOPS.

.FGF...NONE

NG/GUST