Severe Thunderstorm Warning 102, NWS Grand Forks, ND

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
840 PM CDT SUN JUL 11 2004

.DISCUSSION...
FORECAST CHALLENGE OVERNIGHT WILL BE POTENTIAL FOR SEVERE MCS ALONG
WITH FLOODING. MAIN SFC BOUNDARY STILL OVER EASTERN MT/WESTERN ND AS
STRONG SHORTWAVE EJECTS INTO WESTERN MT. SHORTWAVE AND SFC BOUNDARY
WILL SHIFT QUICKLY EAST TONIGHT AS 50KT AT 500MB OVERSPREADS CENTRAL
ND AFTER 06Z. STRONG INSTABILITY WITH SHOWALTERS AROUND -9C ALONG
WITH CAPES AROUND 3000 J/KG WILL ALSO SPREADS INTO MOST OF EASTERN
ND AFTER MIDNIGHT. EXPECT LOW LEVEL JET TO ALSO INTENSIFY IN WARM
ADVECTION ZONE AHEAD OF SHORTWAVE WITH EXTREME UPPER LEVEL
DIVERGENCE ALSO DEVELOPING OVER CENTRAL ND AROUND 06Z THEN MOVING
INTO EASTERN ND TOWARDS 10Z. SUPERCELLS DEVELOPING THIS EVENING IN
EASTERN MT AND WESTERN ND ARE EXPECTED TO EVOLVE INTO A LINEAR MCS
OVERNIGHT. WITH STRENGTH OF DEEP LAYERED
SHEAR...SHORTWAVE...INSTABILITY AND DEEP MOISTURE...EXPECT
INCREASING LIKELIHOOD FOR A SEVERE MCS TO MOVE ACROSS EASTERN ND
INTO WESTERN MN BETWEEN 06-12Z TIMEFRAME. MCS SHOULD PROPAGATE
EASTWARD QUICKLY AROUND 40-50KT...BUT PRECIPITABLE WATERS WILL
INCREASE TO AROUND 2 INCHES ACROSS EASTERN ND LATE TONIGHT.
THEREFORE...FLOODING POTENTIAL IS POSSIBLE WITH 2 INCH/HR RAIN
AMOUNTS POSSIBLE. FLOOD WATCH CURRENTLY IN EFFECT FOR WHOLE AREA
STILL LOOKS GOOD AND WILL NOT ADJUST WITH TORRENTIAL RAIN POSSIBLE
ANYWHERE LATER TONIGHT.

ALSO LOOKED AT JOHNS/HIRT DERECHO CHECKLIST AND MOST PARAMETERS LINE
UP FOR POSSIBLE PROGRESSIVE DERECHO DEVELOPMENT TONIGHT. BEST CHANCE
APPEARS TO BE ACROSS SOUTH WHERE 70 DEWPOINTS WILL RESIDE...BUT
STRONGER FORCING TO NORTH COULD ALSO EFFECT EVOLUTION OF MCS. ETA
MODEL CONTINUES TO PORTRAY MESO-HIGH DEVELOPING ALONG WITH COLD POOL
WHICH WOULD PROMOTE MOMENTUM TRANSPORT OF STRONGER WINDS ALOFT. WILL
HAVE TO CLOSELY MONITOR MCS AS IT DEVELOPS TONIGHT ACROSS WESTERN
DAKOTAS AND TRACKS INTO OUR REGION AFTER MIDNIGHT.

OVERALL GRIDS ARE IN EXCELLENT SHAPE. MAY TWEAK TIMING OF THUNDER
SOME AND INCREASE QPF OVERNIGHT AS WELL.

.FGF WATCHES/WARNINGS/ADVISORIES...

ND...FLOOD WATCH LATE TONIGHT AND MONDAY MORNING.
MN...FLOOD WATCH LATE TONIGHT AND MONDAY MORNING.

&&

KELLENBENZ

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
930 AM CDT SUN JUL 11 2004

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-111500-
BARNES-BENSON-CASS-CAVALIER-CLAY-EAST BECKER-EAST MARSHALL-
EAST OTTER TAIL-EAST POLK-EASTERN WALSH COUNTY-EDDY-GRAND FORKS-
GRANT-GRIGGS-HUBBARD-KITTSON-LAKE OF THE WOODS-MAHNOMEN-NELSON-
NORMAN-NORTH BELTRAMI-NORTH CLEARWATER-PEMBINA-PENNINGTON-RAMSEY-
RANSOM-RED LAKE-RICHLAND-ROSEAU-SARGENT-SOUTH BELTRAMI-
SOUTH CLEARWATER-STEELE-TOWNER-TRAILL-WADENA-WEST BECKER-
WEST MARSHALL-WEST OTTER TAIL-WEST POLK-WESTERN WALSH COUNTY-WILKIN-
930 AM CDT SUN JUL 11 2004

...FLOOD WATCH IN EFFECT FOR LATE TONIGHT AND MONDAY MORNING...

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

.DAY ONE...TODAY AND TONIGHT.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE AREA LATE
TONIGHT. THE MAIN THREAT FROM THESE STORMS WILL BE LARGE HAIL AND
DAMAGING WINDS. MANY AREAS HAVE RECEIVED HEAVY RAINFALL THE PAST
SEVERAL DAYS AND ARE SATURATED...SO RUNOFF AND FLOODING COULD BECOME
A PROBLEM. THUS A FLOOD WATCH HAS BEEN POSTED FOR THE ENTIRE REGION
FOR LATE TONIGHT INTO MONDAY MORNING. THE POTENTIAL EXISTS FOR
ADDITIONAL RAINFALL AMOUNTS OF 2 TO 4 INCHES FROM THESE STORMS.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.
THE SLIGHT RISK FOR SEVERE THUNDERSTORMS SHOULD LINGER INTO THE
FIRST PART OF MONDAY ESPECIALLY EAST OF THE VALLEY. ADDITIONAL
THUNDERSTORM ACTIVITY IS POSSIBLE FRIDAY NIGHT AND SATURDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION PROBABLY MAY BE NEEDED LATE TONIGHT INTO
MONDAY MORNING.

GODON