Severe Thunderstorm Warning 365, NWS Grand Forks, ND

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
321 PM CDT SUN AUG 26 2001

...FORECAST PROBLEM TONIGHT IS SVR AND HEAVY RAIN POTENTIAL...

.CURRENT CONDITIONS...18Z SFC ANALYSIS SHOWED LOW CENTER OVER ABR
WITH WARM FRONT EXTENDING TO VICINITY OF AXN. INVERTED TROF HAS
JUST PUSHED EAST OF DVL AND JMS AND APPEARS TO HAVE SLOWED DOWN.
BEST 3 HOUR PRESSURE FALLS WOULD HAVE LOW CENTER TRACK INTO FFM
VICINITY BY 00Z. SATELLITE AND RADAR IMAGERY SHOWING TCU LINE
FORMING ALONG INVERTED TROF ATTM.

.SHORT TERM...TSTMS EXPECTED TO FIRE ALONG INVERTED TROF WITH A
SPLIT SVR REGIME. LARGE HAIL IS LIKELY ALONG THE INTERNATIONAL
BORDER WHERE FREEZING LEVELS HAVE COME DOWN SLIGHTLY. A TORNADIC
THREAT STILL REMAINS IN THE VICINITY OF THE WARM FRONT ALONG THE
SOUTHERN TIER OF THE FA WHERE GOOD SPEED AND DIRECTIONAL SHEAR HAVE
PRODUCED HELICITY VALUES IN THE 300-500 M2/S2 RANGE. AS THE TROF
MOVES EASTWARD TONIGHT...THE SVR THREAT SHOULD END DURING THE
03Z-05Z TIME FRAME. HEAVY RAINFALL OVER SATURATED GROUND REMAINS A
THREAT FOR THE SOUTHERN ZONES. DUE TO THE TROF MOVEMENT...WILL TRIM
FAR WESTERN ZONES FROM THE WATCH AND END THE WATCH AT 04Z. RAPIDLY
FALLING SFC DEW POINTS ARE AGAIN ENTERING CENTRAL ND AND SHOULD
SPREAD EASTWARD OVERNIGHT.

.MID TERM...QUIET PERIOD EXPECTED THROUGH TUESDAY AS HIGH PRESSURE
DOMINATES THE ENTIRE NORTHERN PLAINS. 850 MB COLD ADVECTION IS NOT
REAL STRONG OVER THE FA...THUS TEMPERATURES THROUGH THE PERIOD SHOULD
REMAIN NEAR NORMAL. RETURN FLOW BEGINS TO INCREASE ON TUESDAY AHEAD
OF STRONGER COLD FRONT PUSHING DOWN TUESDAY NIGHT. SIGNIFICANT TSTM
EVENT EXPECTED WITH FROPA AS IT MOVES THROUGH.

.EXTENDED...
MODELS AGAIN HAVE GOOD CONTINUITY AND ARE CONSISTENT WITH OVERALL
DETAILS. FRONTAL PASSAGE STILL LOOKS ON TARGET FOR TUE
NIGHT/WED...ALONG WITH ANOTHER ROUND OF CONVECTION.
THEREAFTER...HIGH PRESSURE SHOULD BUILD IN AS TEMPS COOL TO NEAR OR
SLIGHTLY BELOW NORMAL. BY NEXT WEEKEND...HIGH SHIFTS EAST UNDER REX
TYPE BLOCK CONFIGURATION...AS TEMPS WARM TO NEAR OR SLIGHTLY ABOVE
NORMAL WITH DRY WEATHER PERSISTING.

COORD WITH SPC...THANKS.

.FGF...FLASH FLOOD WATCH THIS EVENING FOR NDZ030-039-053 AND
       MNZ002-003-027>032-040

BRAMER/KELLENBENZ

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-261805-

SPECIAL WEATHER STATEMENT
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
1141 AM CDT SUN AUG 26 2001

...SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF EASTERN NORTH
DAKOTA...NORTHWEST AND WEST CENTRAL MINNESOTA THIS AFTERNOON AND
EVENING...

SYNOPSIS...AN AREA OF LOW PRESSURE CURRENTLY LOCATED SOUTH OF
JAMESTOWN WILL TRACK NORTHEAST ACROSS THE REGION THIS AFTERNOON AND
EVENING. A TROUGH OF LOW PRESSURE AND A WARM FRONT ASSOCIATED WITH
THE LOW PRESSURE CENTER WILL BE THE FOCUSING MECHANISMS FOR
THUNDERSTORM DEVELOPMENT...SOME OF WHICH MAY BE SEVERE.

AREA OF CONCERN...SEVERE THUNDERSTORMS ARE POSSIBLE EAST OF A LINE
FROM ROSEAU MINNESOTA TO COOPERSTOWN NORTH DAKOTA TO VALLEY CITY TO
FORMAN.

TIME...BETWEEN 1 PM AND 10 PM.

TYPE OF HAZARD...MAIN THREATS WILL BE LARGE HAIL AND DAMAGING WINDS.
ISOLATED TORNADOES ARE ALSO POSSIBLE. LOCALLY VERY HEAVY RAINFALL
MAY CAUSE FLASH FLOODING SOUTH OF A NEW ROCKFORD TO MAYVILLE TO PARK
RAPIDS MINNESOTA LINE. SPOTTER ACTIVATION MAY BE NEEDED BY EARLY
AFTERNOON.

BRAMER