Severe Thunderstorm Warning 256, NWS Grand Forks, ND

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
250 PM CDT MON AUG 26 2002

...NEW SVR WATCH JUST ISSUED FOR ERN ND PER SPC CONF CALL...

MAIN CHALLENGE IS SVR WX POTENTIAL TONIGHT.

SFC MAP SHOWS CONTINUED WEAK FLOW OVER THE AREA MAKING BOUNDARY
IDENTIFICATION DIFFICULT.  SFC LOW IN SE WYOMING WITH A TROUGH NORTH
INTO FAR WRN ND.  OTHERWISE ERN/CNTRL ND AND WRN MN IN SOUTHEASTLY
FLOW.  DEW PTS HAVE MADE GOOD RECOVERY WITH MOST SITES IN THE 65 TO
70 RANGE...ONCE AGAIN A GOOD 4-8 DEGREES HIGHER THAN PROGGED BY ANY
MODEL.  MSAS SHOWS SFC LI DOWN TO -9 OVER NE ND AND ERN SD.  VSBL
SATELLITE HAS SHOWN TENDENCY FOR CU TO FORM IN AREA FROM BISMARCK TO
JUST WEST OF GRAND FORKS...BUT NOT MUCH GROWTH SINCE 18Z.  RADARS
SHOW TSRA IN NRN SD BACKBUILDING WESTWARD INTO NW SD IN AREA OF
THICKNESS DIFFLUENCE.

.SHORT TERM...
MODIFIED MESO ETA SOUNDINGS FOR TEMPS IN THE MID 80S AND DEW PTS IN
THE UPR 60S SHOWS CAPES AT 00Z AROUND 3600 J/KG AND LI TO -10 AT
KGFK.  WATER VAPOR SHOWS SOME WEAK EMBEDDED SHORT WAVES MOVING SOUTH
OF UPR LOW THRU SD/ND....BUT REALLLY HARD TO DISCERN WHICH ONE WILL
SET OFF ACTIVITY.  85H JET/THETA-E VALUES INCREASE A BIT OVERNIGHT
MAXING AROUND 06Z.  BASED ON PAST DAYS WEATHER AND CURRENT
INSTABILITY VALUES WOULD EXPECT SCT TSRA TO FIRE LATE THIS AFTN
NORTHEAST OF BISMARCK WITH POTENTIAL FOR GROWTH INTO A LARGER AREA
DURING THE EVENING.  WILL CONTINUE MENTION OF SVR THIS EVENING FOR
NW MN AND ERN ND.  FZG LEVELS AROUND 11.5 KFT.  THICKNESS FIELDS AND
UPR FLOW ALOFT WOULD SUGGEST SLOW MOVES WITH POTENTIAL FOR
BACKBUILDING OF ANY COMPLEX WHICH MAY FORM.  THIS COULD GIVE LOCALLY
HEAVY RAIN POTENTIAL.

.LONGER TERM...
50H UPR LOW IN SRN SASK WILL DRIFT ENE VERY SLOWLY INTO SRN MANITOBA
TUE-WED TIME FRAME AND WEAKEN FURTHER.  50H TEMPS WARM A BIT BUT LOW
LEVEL MOISTURE REMAINS HIGH WITH DEW PTS HOLDING IN THE 60S.  WITH
CONTINUED SHORT WAVES MOVING THRU AREA IN BROAD SW FLOW WILL
CONTINUE MENTION OF TSRA THRU WED.  ETA BRINGS A TROUGH INTO ERN ND
LATE WED AVN BRINGS IT THROUGH LATE TUESDAY.  WILL LEAN TOWARD
SLOWER ETA SOLN. WILL KEEP THURSDAY DRY AWAITING NEXT IMPULSE.
WILL KEEP TEMPS NEARLY SAME THRU PD.

.EXTENDED...
LONG RANGE MODELS IN PRETTY GOOD AGREEMENT. 500MB TROF
DEEPENS ALONG W US COAST...AS ANOTHER UPPER LEVEL TROF MOVES THROUGH
THE REGION BY THE WEEKEND. THEN...UPPER LEVEL RIDGE STARTS BUILDING
INTO THE AREA. WITH GOOD CONTINUITY TO PRIOR FORECAST...ONLY MINIMAL
NEEDED TO BOTH PRECIPITATION AND TEMPERATURES.

.FGF...NONE.

RIDDLE/NG

.FGF...NONE
RIDDLE

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-261800-

SPECIAL WEATHER STATEMENT...UDPATED
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
1050 AM CDT MON AUG 26 2002

...SCATTERED SEVERE THUNDERSTORMS ARE EXPECTED OVER EASTERN NORTH
DAKOTA AND EXTREME NORTHWEST MINNESOTA THIS AFTERNOON AND EVENING...

SYNOPSIS...MOIST UNSTABLE AIR WILL BE ACROSS THE AREA. A SLOW UPPER
LEVEL SYSTEM OVER SOUTHERN SASKATCHEWAN WILL DRIFT SLOWLY EAST.
AFTERNOON HEATING WITH COLD AIR ALOFT WILL DESTABILIZE THE
ATMOSPHERE AND CAUSE SCATTERED THUNDERSTORMS TO DEVELOP.

AREA OF CONCERN...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS
OVER ALL OF EASTERN NORTH DAKOTA AND OVER A SMALL PART OF NORTHWEST
MINNESOTA...GENERALLY WEST OF A ROSEAU TO ADA TO WAHPETON LINE.

TIME...START AFTER 2PM AND DIMINISH AFTER 1 AM TUESDAY MORNING.

TYPE OF HAZARD...MAINLY LARGE HAIL. ISOLATED HIGH WINDS.

HOPPES/RIDDLE

NNNN

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
347 PM CDT MON AUG 26 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0345 PM    EUCLID                    MN   1.00 INCH HAIL
08/26/02   POLK                           REPORTED BY PUBLIC.

DPORTER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
400 PM CDT MON AUG 26 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0345 PM    7 E EUCLID                MN   .88 INCH HAIL
08/26/02   POLK                           HAIL ONE INCH DEEP ON
                                          GROUND. REPORTED BY PUBLIC.

DPORTER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
411 PM CDT MON AUG 26 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0407 PM    6 SE EUCLID               MN   TORNADO
08/26/02   POLK                           REPORTED BY TRAINED
                                          SPOTTER.

DPORTER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
418 PM CDT MON AUG 26 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0400 PM    3 NE DOROTHY              MN   1.00 INCH HAIL
08/26/02   RED LAKE                       REPORTED BY PUBLIC.

DPORTER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND FORKS, ND
433 PM CDT MON AUG 26 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0415 PM    4 W ST. HILAIRE           MN   .88 INCH HAIL
08/26/02   PENNINGTON                     REPORTED BY PUBLIC.

0430 PM    RED LAKE FALLS            MN   .75 INCH HAIL
08/26/02   RED LAKE                       REPORTED BY CO-OP OBSERVER.

DPORTER