Severe Thunderstorm Warning 162, NWS Grand Forks, ND

FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND
250 PM CDT TUE JUL 29 2003

MAIN FORECAST CHALLENGE IS PRECIPITATION. CURRENT SATELLITE IMAGERY
HAS MAJORITY OF AREA SUNNY...WITH MAINLY MID AND HIGH CLOUDS OVER E
ND AND PARTS OF NW MN. LATEST MSAS SURFACE ANALYSIS HAS ONE AREA OF
LOW PRESSURE BETWEEN HCO AND ROX...AND ANOTHER NEAR PIR...WITH A
COLD FRONT EXTENDING BETWEEN THE LOWS THROUGH E ND. WHEN COMPARING
INITIALIZATION CONDITIONS TO MODELS...ETA AND AVN BOTH CLOSE...SO
USED COMPROMISE SOLUTION FOR FORECAST. COLD FRONT CONTINUES MOVING E
TONIGHT. WITH GOOD UPPER LEVEL SHORTWAVE NOW STARTING TO CATCH UP TO
SURFACE BOUNDARY...PLENTY OF INSOLATION TODAY RESULTING IN LIS TO
-9...SURFACE DEWPOINTS POOLING AT 65+ ALONG AND AHEAD OF COLD
FRONT...STILL EXPECT SEVERE THUNDERSTORMS TO DEVELOP THIS EVENING.
AS A RESULT...PRETTY MUCH STAYED ON TRACK OF CURRENT FORECAST. COLD
FRONT EXITS AREA AFTER MIDNIGHT...BUT SECONDARY UPPER LEVEL
SHORTWAVE STARTS MOVING INTO AREA AS 500MB LOW DROPS THROUGH MB.
THEREFORE...KEPT CHANCE OF THUNDERSTORMS FOR MUCH OF THE AREA
THROUGH THE NIGHT.

FORECAST CHALLENGE FOR WED INTO THE WEEKEND REMAINS PRECIPITATION.
500MB LOW CUTS OFF OVER MN ARROWHEAD AND LINGERS OVER THE AREA. WITH
SHORTWAVES CONTINUING TO WRAP AROUND THE UPPER LEVEL LOW AND COLD
POOL ALOFT...EXPECT THUNDERSTORMS POTENTIAL TO REMAIN PRETTY MUCH
EACH DAY AS SURFACE HEATING WILL PROVIDE INSTABILITY FOR
THUNDERSTORM DEVELOPMENT.

EXTENDED...LONGWAVE RIDGE IN THE W AND TROUGH IN THE E FORECAST TO
REMAIN. HOWEVER...PATTERN IS FORECAST TO SHIFT SLIGHTLY E BETWEEN
DAY 4 AND DAY 7. GFS ENSEMBLE FORECAST A CUTOFF LOW OVER THE GREAT
LAKES. SHORT WAVE DROPS INTO THE TROUGH SAT. ENSEMBLE MEAN SHARPENS
ANOTHER TROUGH OVER THE W US ON SUN AND MON WITH DOWNSTREAM RIDGING
OVER THE N PLAINS. RIDGING SHOULD KICK GREAT LAKES TROUGH E ON SUN.
OLD 12Z GFS RUN IS CLOSER TO THE ENSEMBLE MEAN THAN THE 00Z RUN. NEW
12Z GFS RUN CONTINUES TO DIG W COAST TROUGH...BUT IS SLOWER LIFTING
OUT CUTOFF LOW WHICH WAS OLD 12Z SOLUTION. WILL KEEP CHANCE OF
PRECIPITATION FOR SAT. WILL TAKE OUT CHANCE OF PRECIPITATION FOR
LATE SUN INTO MON WITH BUILDING RIDGE.

.FGF...NONE.

NG/HOPPES

MNZ001>009-013>017-022>024-027>032-040-NDZ006>008-014>016-024-
026>030-038-039-049-052>054-291430-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS
853 AM CDT TUE JUL 29 2003

...SEVERE THUNDERSTORMS ARE EXPECTED ACROSS EASTERN NORTH DAKOTA AND
NORTHWEST MINNESOTA TODAY...

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

.DAY ONE...TODAY AND TONIGHT

A SLIGHT RISK OF SEVERE THUNDERSTORMS IS EXPECTED ACROSS ALL OF
EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA. SOME THUNDERSTORMS
WILL PRODUCE LARGE HAIL AND DAMAGING WINDS. THE STORMS WILL DEVELOP
AHEAD OF A STRONG COLD FRONT APPROACHING FROM THE WEST. THE
THUNDERSTORMS WILL MOVE INTO EASTERN NORTH DAKOTA AFTER 10 AM AND
CONTINUE INTO NORTHWEST AND WEST CENTRAL MINNESOTA LATE THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

THERE IS AGAIN A CHANCE OF THUNDERSTORMS ON WEDNESDAY THROUGHOUT THE
AREA...LINGERING IN NORTHWEST MINNESOTA ON THURSDAY AND FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS EXPECTED TODAY.

HOPPES