Severe Thunderstorm Warning 195, NWS Grand Forks, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
820 PM CDT FRI OCT 22 2004

.DISCUSSION...CURRENT TRENDS SHOW INCREASING SHOWERS IN DEVELOPING
DEFORMATION ZONE EXTENDING WESTWARD FROM VALLEY CITY AND INTO
WESTERN SD. THUNDERSTORMS ARE QUICKLY DEVELOPING AND BEGINNING
TO TURN SEVERE IN NORTHEAST SD ON THE NOSE OF A DRY SLOT EVIDENT
ON WATER VAPOR LOOP. BUT THE DRY SLOT IS LOSING ITS NORTHWARD
MOMENTUM. STORMS FIRING IN THIS AREA ARE BARELY ELEVATED VS.
THOSE EXPECTED CLOSER TO FFM/WAH.

CONDITIONS ACROSS EASTERN ND/WESTCENTRAL AND NORTHWEST MN HAVE
BEEN RATHER TRANQUIL IF DREARY WITH A LITTLE RAIN AND FOG. BUT
THE NEW TRENDS ARE TOWARD THE CURRENT FORECAST WHICH IS FORECAST
OF THUNDERSTORMS IN THE SOUTH AND MUCH MORE RAIN EVERYWHERE ELSE.
HOWEVER...THE MAIN SHORTWAVE IS MOVING EAST-NORTHEAST ON SD/NE
BORDER AND THE ASSOCIATED UPPER JET TRENDING EASTWARD TOWARD IA.
SO NO UPDATE IS EXPECTED IN THE NEXT HOUR OR TWO AND WILL SEE HOW
THIS SYSTEM GOES.
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PREVIOUS DISCUSSION

.SHORT TERM...
REGION CONTINUES TO BE COVERED BY LIFR FOG/CLOUDS...WITH MAIN
WARMFRONT SURGING NORTH INTO SOUTHERN MN THIS AFTERNOON...WITH 60
DEWPOINTS MOVING NEAR SFC BOUNDARY CURRENTLY. LOW DEVELOPING NOW IN
CENTRAL NB...WITH BEST PRESSURE FALLS IN NORTHEAST SD NEAR ATY.
MODELS ARE SIMILAR IN TRACKING LOW PRESSURE FROM NORTHEAST SD THIS
EVENING INTO THE ARROWHEAD OF MN BY SATURDAY AFTERNOON...WHICH
APPEARS ON TRACK WITH CURRENT SFC MAP AND PRESSURE FALL PATTERN.

FOR TONIGHT...INITIAL CONCERN WILL BE EXTENT OF THUNDERSTORMS MAINLY
IN SOUTHERN 1/3 OF REGION. STRONG MOISTURE SURGE ON NOSE OF 50KT
850MB JET ALONG WITH SHOWALTERS DROPPING BELOW ZERO SHOULD AID
CONVECTION HERE. IN ADDITION...STRONG ISENTROPIC LIFT ALONG WITH
UPPER LEVEL DIVERGENCE IN LEFT EXIT REGION OF 120KT SPEED MAX WILL
ALSO AID SYNOPTIC SCALE LIFT. COULD BE A FEW SEVERE STORMS BETWEEN
00Z AND 06Z...MAINLY IN FAR SOUTHEASTERN AREAS WHERE STRONGEST 925MB
MOISTURE ADVECTION AND LIFT WILL BE. EXPECT MAIN THREAT TO BE HAIL
AND WIND...WITH FREEZING LEVELS AROUND 11000FT. WILL ADD SEVERE
WORDING TO FAR SOUTHERN ZONES FROM 00Z-09Z...WITH STRENGTH OF LOW
LEVEL JET...SHOWALTERS TO AROUND -3C AND STRONG DYNAMICS OF SYSTEM.
FURTHER NORTH...EXPECT A WIDESPREAD DEFORMATION RAIN BAND OVERNIGHT
ALONG WITH SOME EMBEDDED THUNDER JUST SOUTH OF GFK. MODELS SHOWING
SOME BANDED PRECIPITATION WITH STRONG 700MB FRONTOGENESIS ALSO
POSSIBLE FROM NEAR JMS TO GFK TO AROUND ROX...WHICH WILL SHIFT EAST
LATER TONIGHT. SOME RAIN AMOUNTS OF OVER AN INCH LIKELY NEAR
CONVECTION...WITH WIDESPREAD AMOUNTS FROM 0.50 TO 0.75 INCHES IN ALL
BUT FAR NORTHWEST. WITH ALL THIS SAID...WILL GO CATEGORICAL WITH
PRECIPITATION CHANCES TONIGHT IN ALL AREAS AND SLOWLY MOVE ACTIVITY
EAST LATER TONIGHT.

ON SATURDAY...EXPECT LOW TO SLOWLY PULL AWAY FROM THE REGION.
DEFORMATION RAINS WILL LINGER IN THE MORNING EAST OF THE VALLEY WITH
SLOW IMPROVEMENT AND SUBSIDENCE BY AFTERNOON. EXPECT TEMPS TO
RECOVER TO NEAR NORMAL FOR MOST AREAS. A WEAK RIDGE WILL MOVE OVER
THE REGION SATURDAY NIGHT BEFORE THE NEXT FAST MOVING SYSTEM AFFECTS
THE REGION BY SUNDAY.

ON SUNDAY...EXPECT SHOWERS TO MOVE FROM WEST TO EAST AS WEAK LOW
PRESSURE MOVES THROUGH THE AREA. BEST CHANCE OF RAIN WILL BE IN THE
NORTH...WHERE BEST UPPER SUPPORT WILL BE. WILL ONLY MENTION ISOLATED
SHOWERS IN SOUTH WITH DRY LAYER BENEATH 700MB. TEMPS WILL BE COOLER
THAN SATURDAY WITH INCREASING CLOUDS AND PRECIPITATION CHANCES.

BY MONDAY...ANOTHER RIDGE BUILDS IN FOR A DRY DAY WITH TEMPS A FEW
DEGREES BELOW NORMAL.

.LONG TERM...
LONGWAVE TROUGH REMAINS OVER THE WEST COAST THROUGH THE PERIOD WITH
SOUTHWEST FLOW ALOFT OVER THE NORTHERN PLAINS. OPERATIONAL GFS IN
REASONABLE AGREEMENT WITH THE ENSEMBLE MEAN TUESDAY BUT BECOMES ONE
OF THE HIGHER AMPLITUDE SOLUTIONS BY FRIDAY. 120 HR 12Z GFS IS QUITE
SIMILAR TO THE 00Z GFS. THE ECMWF WAS SLOWER THAN THE 12Z GFS. WILL
USE THE GFS BUT WILL SLOW IT DOWN. SEVERAL SHORT WAVES IN THE FLOW
WILL PRODUCE A CHANCE OF RAIN THROUGH MUCH OF THE PERIOD WITH THE
BEST CHANCE NEXT FRIDAY.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...

ND...NONE.
MN...NONE.

&&

GV/KELLENBENZ/HOPPES

HAZARDOUS WEATHER OUTLOOK ...CORRECTION
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
718 AM CDT FRI OCT 22 2004

CORRECTION TO ADD WADENA COUNTY IN UCG CODING.  NO CHANGE TO TEXT.

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-221436-
BARNES ND-BENSON ND-CASS ND-CAVALIER ND-CLAY MN-EAST BECKER MN-
EAST MARSHALL MN-EAST OTTER TAIL MN-EAST POLK MN-
EASTERN WALSH COUNTY ND-EDDY ND-GRAND FORKS ND-GRANT MN-GRIGGS ND-
HUBBARD MN-KITTSON MN-LAKE OF THE WOODS MN-MAHNOMEN MN-NELSON ND-
NORMAN MN-NORTH BELTRAMI MN-NORTH CLEARWATER MN-PEMBINA ND-
PENNINGTON MN-RAMSEY ND-RANSOM ND-RED LAKE MN-RICHLAND ND-ROSEAU MN-
SARGENT ND-SOUTH BELTRAMI MN-SOUTH CLEARWATER MN-STEELE ND-TOWNER ND-
TRAILL ND-WADENA MN-WEST BECKER MN-WEST MARSHALL MN-WEST OTTER TAIL
MN-WEST POLK MN-WESTERN WALSH COUNTY ND-WILKIN MN-
INCLUDING THE CITIES OF...BEMIDJI...DETROIT LAKES...DEVILS LAKE...
FARGO...FERGUS FALLS...GRAFTON...GRAND FORKS...LANGDON...ROSEAU...
THIEF RIVER FALLS...VALLEY CITY AND WAHPETON
718 AM CDT FRI OCT 22 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN NORTH DAKOTA...WEST
CENTRAL AND NORTHWEST MINNESOTA.

.DAY ONE...TODAY AND TONIGHT

SCATTERED THUNDERSTORMS ARE EXPECTED VERY LATE THIS AFTERNOON AND
EVENING OVER THE SOUTHEAST CORNER OF NORTH DAKOTA AND WEST CENTRAL
MINNESOTA...MAINLY SOUTH OF A BEMIDJI TO FARGO TO LISBON LINE.  A
FEW STORMS MAY APPROACH SEVERE LIMITS IN THIS AREA WITH THE MAIN
THREAT BEING LARGE HAIL.  THE BEST CHANCE FOR SEVERE WEATHER LATE
TODAY AND THIS EVENING WILL BE FURTHER SOUTH ACROSS SOUTHWEST
MINNESOTA.  LOW PRESSURE DEVELOPING NEAR DENVER WILL MOVE NORTHEAST
AND BE NEAR FERGUS FALLS BY MIDNIGHT AND THEN TO NEAR INTERNATIONAL
FALLS SATURDAY MORNING.  WIDESPREAD RAIN WILL OCCUR OVER THE ENTIRE
REGION ALONG WITH A FEW THUNDERSTORMS LATER TODAY INTO EARLY
SATURDAY AS THE SYSTEM APPROACHES.

RAINFALL AMOUNTS OVER AN INCH WILL BE POSSIBLE WITH THIS SYSTEM.
WHILE THIS AMOUNT OF RAIN WILL CAUSE SOME PONDING ON ROADS AND
FIELDS...NO WIDESPREAD FLOODING IS ANTICIPATED.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MIGHT BE NEEDED LATE THIS AFTERNOON OR EVENING
OVER WEST CENTRAL MINNESOTA AND OVER THE SOUTHEASTERN CORNER OF
NORTH DAKOTA.

DTR