Severe Thunderstorm Warning 266, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
334 PM CDT SUN AUG 17 2003

...POPS MAIN FORECAST CHALLENGE THROUGH WEDNESDAY...

WV IMAGERY SHOWS A COUPLE OF WAVES TO LIFT NORTHEAST TONIGHT AS
SCATTERED CONVECTION ALREADY FIRING FROM THE BLACK HILLS SOUTHWEST
INTO THE EXTREME SW NEB PANHANDLE. SURFACE TROUGH AT 19Z EXTENDED
SOUTH JUST WEST OF THE ERN PANHANDLE COUNTIES WITH GREATEST
INSTABILITIES WEST OF A IEN TO LBF LINE.

NEAR-TERM MODELS SIMILAR WITH UPPER LOW TO MOVE SOUTHEAST ACROSS WRN
WYOMING TONIGHT...BEGIN TO ARC NORTHEAST MONDAY NIGHT THEN LIFTING
ACROSS THE NORTHWEST HIGH PLAINS TUESDAY AND EXITING NORTHEAST
WEDNESDAY.

THIS EVENING ELEVATED ISOLD CONVECTION WILL INCREASE OVER THE HIGH
PLAINS AS H85-H7 2D FRONTOGENESIS INCREASES. SOUTH WINDS
PREVAIL TO THE EAST WHILE COLDER AIR SPREADS SOUTH ACROSS THE
MOUNTAINS WITH H5 COLD POOL TO EXPAND EAST. INITIAL AREA OF LIFT
TO SHIFT EASTWARD ACROSS THE PANHANDLE AS H85 TROUGH AXIS MOVES
SOUTHEAST AND EXTENDS ACROSS SOUTHWEST NEB AFTER MIDNIGHT AND COLD
FRONT MOVES EAST OF PANHANDLE BY 18/06Z. KLBF ROAB AT 12Z
SHOWED FREEZING LVL HAD DROPPED NEAR 1 KFT OVER THE PAST 12 HOURS
WITH PRIMARY THREAT TONIGHT WITH STORMS TO BE LIGHTNING AND WINDS.
SOUNDING PROFILE SHOWS BEST MOISTURE AVAILABLE ABV 10 KFT ALTHOUGH
PWS IS FORECASTED JUST OVER AN INCH.

AN INCREASE IN CLOUD COVERAGE MONDAY WILL REDUCE SURFACE HEATING IN
THE WEST THROUGH WEDNESDAY AS THE SURFACE LOW AND ASSOCIATED COLD
FRONT MOVES EAST. THE FRONT APPEARS TO STALL OUT BY MONDAY AFTERNOON
AND WILL BRING THE CHANCE FOR RAINFALL THROUGH WEDNESDAY A.M.
AS H5 WAVE MOVES EAST NORTHEAST THROUGH THE PERIOD.

EXTENDED...MODELS SHOWING SOME DISCREPANCIES.  BOTH THE ECMWF AND
THE GFS EXTENDED SHOW UPPER LEVEL RIDGE BUILDING TO THE WEST
BUT DIFFER WITH WAVES RIDING UP AND OVER THE HIGH.  ECMWF SHOWING A
WAVE BY MID WEEK INTO ALBERTA AND THEN HAVING IT PROGRESS ACROSS
CANADA AND NORTHERN PLAINS QUICKLY BUT THE GFS EXTENDED SHOWS RIDGE
ALL THE WAY THROUGH SOUTHERN SASKATCHEWAN AND IS NOW SHOWING A
DEEPENING TROUGH OVER THE EASTERN COAST.  GFS ALSO SHOWING NORTHWEST
FLOW POSSIBLY RETURNING SO THIS COULD BRING THE CHANCE FOR SOME
ISOLATED SHOWERS BY THE END OF THE WEEK.  WILL KEEP AN EYE ON THIS TO
SEE IF THIS MATERIALIZES.

.LBF...NONE.

TLK/CAB

NEZ004>010-022>029-035>038-056>059-069>071-094-181045-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
315 PM CDT SUN AUG 17 2003

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

.DAY ONE...TONIGHT

THERE IS A SLIGHT CHANCE OF THUNDERSTORMS ACROSS WESTERN NEBRASKA
WEST OF A LINE FROM AINSWORTH TO HAYES CENTER. THUNDERSTORMS
DEVELOPING ALONG A SURFACE TROUGH ARE NOT EXPECTED TO REACH SEVERE
THUNDERSTORM CRITERIA OF DAMAGING WIND AND LARGE HAIL. HOWEVER...DRY
LOWER LEVELS WILL ENHANCE THE DOWNDRAFTS ALLOWING ISOLATED AND VERY
LOCALIZED DOWNBURSTS EXCEEDING 50 MPH AND APPROACHING SEVERE
CRITERIA.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

THERE IS A CHANCE OF THUNDERSTORMS AGAIN MONDAY THROUGH TUESDAY
NIGHT AS A STRONGER CANADIAN FRONT MOVES ONTO THE PLAINS. IN THE
VICINITY OF THE FRONT...THUNDERSTORM WINDS MAY APPROACH SEVERE
CRITERIA. HOWEVER...THE STRONG WIND AND HAIL WILL BE LOCALIZED.

.SPOTTER INFORMATION STATEMENT...

STORM SPOTTER ACTIVATION IS NOT EXPECTED TO BE NECESSARY THROUGH
SATURDAY.

POWER