Severe Thunderstorm Warning 1, NWS Grand Forks, ND

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
230 PM CDT WED MAY 9 2001

FORECAST CHALLENGE REMAINS TSRA THREAT WITH APPROACHING S/W AND SFC
BOUNDARY THIS EVENING.

.CURRENT...LATEST SURFACE ANALYSIS INDICATES LOW PRESSURE AND
SURFACE TROF/WIND SHIFT HAS MOVED TO NEAR A KJMS TO KDVL LINE. DEW
POINTS HAVE JUMPED UP THIS AFTERNOON INTO THE LOWER 50'S THIS
AFTERNOON WITH MOISTURE POOLING ALONG THE TROUGH COMBINED WITH
EVAPOTRANSPIRATION. LAPS AND MSAS ANALYSIS CONTINUES TO INDICATE LI'S
OF 0C TO -4C AND LAPS RATES AOA 8 C/KM ACROSS THE ENTIRE CWA WITH
CAPES APPROACHING 1000 J/KG IN THE VALLEY. HOWEVER CINH IS STILL
RUNNING AOB -180 J/KG...HOWEVER THERE IS AN AREA OF -20 J/KG BETWEEN
KJMS AND KBIS AND AREA OF CU IS POPPING UP IN THIS AREA ON THE
VISIBLE SATELLITE IMAGERY. SHORTWAVE JUST NOW CROSSING OVER INTO
NORTH DAKOTA FROM MONTANA. ETA MODEL INITIALIZED THE BEST AND HAS
BEEN HANDLING THE MOVEMENT OF THE TROF WELL TODAY. AVN IS A TAD TO
SLOW. SO WILL GO WITH EXTRAPOLATION OF FEATURES EARLY ON AND THEN GO
WITH THE ETA FOR THE REMAINDER OF THE PACKAGE.

.SHORT TERM...THING MAINLY FOR THIS EVENING IS WHEN/WHERE AND IF
CONVECTION WILL FIRE IN THE CWA. SHORT WAVE WILL CONTINUE
PROGRESSION TO THE EAST THIS EVENING AND WILL BEGIN TO MOVE SURFACE
TROF AND LOW PRESSURE CENTER TO THE EAST NORTHEAST THIS EVENING.
AIRMASS WILL CONTINUE TO DESTABILIZE THROUGH THE AFTERNOON WITH LI'S
APPROACHING -6C BY 00Z AND CAPES ANYWHERE BETWEEN 1500 AND 2000
J/KG. CINH ALSO DECREASE TO -10 TO -40 J/KG AREAWIDE BY 00Z.
LIMITING FACTOR STILL IN THE FACT THAT WE HAVE VERY DRY AIR AT 850
MB. OTHERWISE ALL OTHER PARAMETERS LOOKING GOOD FOR SVR
THUNDERSTORMS. STILL THINK THAT THE THUNDERSTORMS WILL BEGIN TO FIRE
UP JUST EAST OF THE RED RIVER BEFORE QUICKLY EXITING THIS EVENING.
THIS WOULD HAVE TO BE WATCHED CLOSELY FOR SVR POTENTIAL. WILL LET
LAST MINUTE SATELLITE AND RADAR TRENDS DETERMINE AREAL COVERAGE
WORDING IN THE ZONES...BUT ATTM THINKING WIDELY SCATTERED AT BEST.
OTHERWISE PARTLY CLOUDY LOOKS GOOD TONIGHT AS SOME MID CLOUD UP
STREAM WILL MOVE ACROSS THE CWA.

.LONG TERM...TOMORROW WILL PROBABLY START OUT AS MOSTLY SUNNY...BUT
WILL QUICKLY TURN TO BKN IN THE AFTERNOON AS CU RULES SUGGEST BKN IN
THE AFTERNOON WITH THE DAYTIME HEATING. WILL STILL WORD
OPTIMISTIC PARTLY CLOUDY IN THE ZONES AT THIS TIME DUE TO THE
UNCERTAINTY. THIS WILL HAVE AN EFFECT ON TEMPERATURES ACROSS THE
AREA...BUT MIDDLE 60S LOOK GOOD MOST AREAS WITH WEAK COOL ADVECTION.
OTHERWISE REMOVED THE MENTION OF SHOWERS ON FRIDAY AS FRONT REMAINS
STATIONARY ACROSS KANSAS AND IOWA LIMITING ANY MOISTURE RETURN. ALSO
WAVE THAT WAS PROGGED EARLY TO MOVE ACROSS IS STILL WELL TO THE WEST
OF THE CWA.

EXTENDED...MODELS START OUT SIMILAR AND THEN DIVERGE SIGNIFICANTLY
FOR LATTER EXTENDED WITH THE MRF THE MOST PROGRESSIVE. UPPER LEVEL
RIDGE MOVES INTO CWFA BY 00Z SUN...THEN UPPER LEVEL LOW PLOWS INTO
RIDGE. SO...KEPT DRY FORECAST THROUGH WEEKEND AND PCPN IN FOR MON
AND TUE...AS MRF AND ECMWF MOVE UPPER LEVEL LOW SE TOWARD N CWFA.
LOW PULLS E...SO WILL KEEP WED DRY AT THIS TIME. AS FAR AS TEMPS...
STUCK CLOSER TO AVN AND MEX NUMBERS...WITH TEMPS HOLDING NEAR NORMAL.

.FGF...NONE.

BRAZZELL/NG