Severe Thunderstorm Warning 241, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
315 AM CDT TUE JUL 29 2003

FOCUS OF FORECAST PRECIPITATION TODAY AND WEDNESDAY.

H5 HIGH PRESSURE CENTERED OVER GREAT BASIN WITH TROUGH OVER THE
EASTERN CONUS. WATER VAPOR HAS NEXT SYSTEM OVER THE WESTERN
PROVINCES OF CANADA POISED TO DROP INTO THE NORTHERN PLAINS TONIGHT.

AT THE SURFACE WEAK HIGH PRESSURE CENTERED OVER NEBRASKA.

IN WATER VAPOR WAVE SEEN OVER NORTHEAST WYOMING WILL BE MOVING EAST
OVER NIGHT AND PHASE WITH UPPER LEVEL SYSTEM TODAY.

AGAIN TONIGHT MODELS SEEM TO BE IN FAIR AGREEMENT WITH UPPER AIR
PATTERN THROUGH 84HRS WITH ETA HAVING SLIGHTLY HIGHER HEIGHTS OVER
FORECAST AREA AND GFS BRINGING DEEPER...STRONGER...LOW INTO GREAT
LAKES REGION.

SURFACE FEATURES ALL OVER THE PLACE. THE ETA IS FASTER WITH BRINGING
SYSTEM THROUGH TODAY. WILL USE A BLEND OF BOTH MODELS.

TODAY WITH TROUGH SLIDING ACROSS NORTHERN TIER AND WAVE OVER
NORTHEAST WYOMING WILL KEEP SLIGHT CHANCE SOUTH AND CHANCE NORTHEAST
FOR THIS AFTERNOON. BEST DIVERGENCE ALOFT OVER NORTHEAST
ZONES...ALONG WITH 250MB JET STREAK DIVING INTO AREA. MOST ENERGY
CONFINED TO NORTHEAST ZONES. FAIRLY FAST MOVING SYSTEM SHOULD CLEAR
MOST OF FORECAST AREA BY 6Z. PWS HAVE DRIED OUT CONSIDERABLY BUT
BEST LOW LEVEL MOISTURE ALSO OVER NORTHEAST ZONES.

WEDNESDAY GOOD SUBSIDENCE BEHIND SYSTEM WITH FRONT STALLING OUT OVER
KANSAS AND TRAILING OFF TO THE NORTHWEST INTO THE EASTERN PLAINS OF
COLORADO AND WYOMING. WILL TAKE MENTION OF PRECIPITATION OUT OF THE
FORECAST.

WEDNESDAY NIGHT AS NEXT BIT OF ENERGY CARTWHEELS AROUND UPPER LOW
OVER MINNESOTA  ANOTHER SLIGHT CHANCE WITH BETTER DYNAMICS NORTHEAST
ZONES AGAIN AS VORT MAX...JET STREAK AND LOW LEVEL MOISTURE
CONCENTRATED IN THIS AREA.

REMAINDER OF EXTENDED ON TRACK.

.LBF...NONE.

POWER

NEZ004>010-022>029-035>038-056>059-069>071-094-301030-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1108 AM CDT TUE JUL 29 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND NORTH CENTRAL
NEBRASKA.

.DAY ONE...THUNDERSTORM DEVELOPMENT IS EXPECTED THIS AFTERNOON INTO
TONIGHT ACROSS THE OUTLOOK AREA. ISOLATED THUNDERSTORMS MAY
INITIALLY FORM ACROSS THE NORTHWEST AFTER 4 PM CDT (3 PM MDT) ALONG
EXISTING BOUNDARIES LAID OUT BY MORNING CONVECTION IN THE PANHANDLE.
A COLD FRONT THEN ENTERS THE NORTHWEST WITH A SLIGHT CHANCE FOR
SEVERE THUNDERSTORMS TO FORM GENERALLY NORTHEAST OF A LINE FROM
VALENTINE...TO BROWNLEE IN CHERRY COUNTY...TO BREWSTER IN BLAINE
COUNTY...AND SARGENT IN CUSTER COUNTY.

THIS AFTERNOON THE COLD FRONT WILL DRIVE SOUTHEAST WITH THE GREATEST
INSTABILITY TO EXIST ACROSS THE NORTH CENTRAL FOR SCATTERED
THUNDERSTORM DEVELOPMENT. AS THE UPPER LEVEL DISTURBANCES MOVE
SOUTHEAST...LOW LEVEL INSTABILITY...ADEQUATE LOW LEVEL MOISTURE AND
DECENT MID LEVEL SHEAR WILL RESULT WITH THUNDERSTORMS...SOME ON THE
SEVERE SIDE TO PRODUCE LARGE HAIL AND DAMAGING WINDS THIS EVENING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

NO SEVERE THUNDERSTORM DEVELOPMENT IS EXPECTED AT THIS TIME THROUGH
MONDAY. AN UPPER LEVEL LOW OVER THE GREAT LAKES REGION WILL ROTATE
SLOWLY EAST THROUGH MONDAY AS THE UPPER RIDGE REMAINS ANCHORED OVER
THE DESERT SOUTHWEST. A WEAK FRONTAL BOUNDARY WILL SLIDE SOUTH
THROUGH THE PLAINS LATE THURSDAY INTO FRIDAY...THEN THE BOUNDARY
BACKING WEST TO OVER THE HIGH PLAINS FOR THE WEEKEND. UPPER LEVEL
DISTURBANCES MOVING SOUTHEAST INTO THE PLAINS DURING THIS PERIOD
WILL RESULT IN A SLIGHT CHANCE FOR THUNDERSTORM DEVELOPMENT ALONG
AND NEAR THE BOUNDARIES THURSDAY NIGHT THROUGH MONDAY. MOISTURE WILL
BE LIMITED IN THE NORTHWEST FLOW WITH CONVECTION THAT DOES FORM TO
BE HIGH BASED...PRODUCING MORE WIND THAN RAINFALL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED ACROSS THE NORTH CENTRAL THIS
AFTERNOON AND EVENING.

TLK