Severe Thunderstorm Warning 246, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
313 PM CDT SUN SEP 14 1997

FORECAST PROBLEM...CHANCES FOR THUNDERSTORMS AND TEMPERATURES

18Z SURFACE ANALYSIS SHOWING LOW PRESSURE OVER WESTERN SOUTH DAKOTA
WITH TROUGH EXTENDING SOUTH INTO THE NEBRASKA PANHANDLE. 60 DEGREE
DEWPOINTS EXTENDED WEST TO THE EASTERN PANHANDLE. KLNX RADAR INDICATED
MAIN PART OF SCATTERED PRECIP OVER ONL GROUP WITH WIDELY SCATTERED
LIGHT SHOWERS AND ISOLATED THUNDERSTORMS FROM IML NORTHEASTWARD.
WATER VAPOR IMAGERY INDICATES A SHORWAVE OVER WYOMING AND COLORADO
WHICH SHOULD MOVE INTO FA TONIGHT.

THE UPPER RIDGE IS PROGGED TO SHIFT EAST FROM THE PLAINS INTO THE MS
VALLEY BY END OF THE PERIOD WITH UPPER TROUGH MOVING INTO THE GREAT
BASIN. AT THE SURFACE...LOW PRESSURE WILL MOVE INTO THE PLAINS DURING
THE PERIOD.

TONIGHT...ETA GRIDDED DATA SHOWS ISENTROPIC LIFT TONIGHT ACROSS FA AS
NEXT WAVE MOVES IN. THETA-E RIDGE IS PROGGED OVER THE CENTRAL AND
NORTHCENTRAL PART OF NEBRASKA. BOUNDARY LAYER WINDS INDICATE SOUTH
10-20 AHEAD OF LOW IN NORTHERN PLAINS. SKY SHOULD REMAIN MOSTLY CLOUDY
AS NEXT WAVE APPROACHES. TEMPERATURES TONIGHT SHOULD BE A LITTLE WARMER
THAN GUIDANCE WITH CLOUDS AROUND.

MONDAY...SUBSIDENCE BEHIND WAVE WILL BRING MOSTLY SUNNY SKY IN THE
MORNING WITH PARTLY CLOUDY SKY IN AFTERNOON WITH HEATING. BOUNDARY
LAYER WINDS INDICATE SOUTHWEST 10-20 AHEAD OF TROUGH. SOME MORNING
SHOWERS AND CLOUDS WILL LINGER IN ANW-ONL GROUP. ALSO...SOME PATCHY
AREAS OF MORNING FOG IN LBF AREA FROM OVERNIGHT SHOWERS AND COOLING
BEHIND WAVE.

MONDAY NIGHT...ANOTHER WAVE BRINGS CHANCE OF THUNDERSTORMS TO PANHANDLE
WITH ISENTROPIC FORCING INDICATED. THESE SHOULD BE CONFINED TO THE
PANHANDLE AND NORTH CENTRAL NEBRASKA AS FLOW MOVES STORMS NORTHEAST INTO
SOUTH DAKOTA. BOUNDARY LAYER WINDS INDICATE SOUTH 10-20 AHEAD OF LOW IN
MONTANA.

TUESDAY...TROUGH POSITIONED FROM VTN-LBF AT 12Z. ONLY WEAK WAVES
INDICATED IN FLOW SO WILL DOWNPLAY POPS. WINDS NORTHWEST 10-15 BEHIND
TROUGH AND SOUTH 10-20 AHEAD.

LBF BB 059/091 059/084 050 2-1
OGA BB 059/090 058/083 050 2-1
IML BB 060/092 059/085 051 2-1
VTN BB 061/092 059/081 049 2-2
ONL BB 062/092 060/081 049 112

FS

NEZ004>010-022>029-035>038-056>059-069>071-151200-

SEVERE WEATHER OUTLOOK FOR WESTERN AND NORTH CENTRAL NEBRASKA
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1113 AM CDT (1013 AM MDT) SUN SEP 14 1997

THIS OUTLOOK PERTAINS TO THE FOLLOWING NEBRASKA COUNTIES...

ARTHUR     BLAINE     BOYD       BROWN      CHASE      CHERRY
CUSTER     DEUEL      FRONTIER   GARDEN     GARFIELD   GRANT
HAYES      HOLT       HOOKER     KEITH      KEYA PAHA  LINCOLN
LOGAN      LOUP       MCPHERSON  PERKINS    ROCK       SHERIDAN
THOMAS     WHEELER

...STORM SPOTTER ACTIVATION MAY BE NEEDED OVER PARTS OF NORTH CENTRAL
THIS AFTERNOON AND THIS EVENING...

THERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PORTIONS OF NORTH CENTRAL NEBRASKA. THE GREATEST RISK
OF SEVERE WEATHER IS NORTHEAST OF A LINE EXTENDING FROM RUSHVILLE TO
HYANNIS TO BURWELL. OTHER THUNDERSTORMS WHICH ARE NOT EXPECTED TO
REACH SEVERE LEVELS ARE POSSIBLE OVER THE REST OF THE OUTLOOK AREA.

SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS THE OUTLOOK AREA THE
REST OF THIS MORNING AND INTO THE AFTERNOON. SOME OF THESE STORMS MAY
PRODUCE HEAVY RAIN AND SMALL HAIL. LIMITED INSTABILITY SHOULD KEEP
THE STORMS BELOW SEVERE LIMITS.

BY LATE AFTERNOON...A DISTURBANCE ALOFT WILL APPROACH THE WESTERN PART
OF THE OUTLOOK AREA. SOUTHERLY WINDS WILL TRANSPORT ADDITIONAL MOISTURE
NORTHWARD ALONG A TROUGH OF LOW PRESSURE OVER WESTERN NEBRASKA. IF
AFTERNOON HEATING IS STRONG ENOUGH OVER WESTERN NEBRASKA THE ATMOSPHERE
WILL DESTABILIZE SUFFICIENTLY FOR THUNDERSTORMS TO DEVELOP NEAR THE
THE TROUGH OF LOW PRESSURE. THESE STORMS WOULD DRIFT EAST OUT OF THE
EASTERN PANHANDLE INTO THE REST OF THE OUTLOOK AREA INTO THE EVENING.
A FEW OF THE STORMS COULD REACH SEVERE LIMITS WITH LARGE HAIL AND
DAMAGING WINDS.

FS

NEZ004>010-022>029-035>038-056>059-069>071-151200-

SEVERE WEATHER OUTLOOK FOR WESTERN AND NORTH CENTRAL NEBRASKA
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1113 AM CDT (1013 AM MDT) SUN SEP 14 1997

THIS OUTLOOK PERTAINS TO THE FOLLOWING NEBRASKA COUNTIES...

ARTHUR     BLAINE     BOYD       BROWN      CHASE      CHERRY
CUSTER     DEUEL      FRONTIER   GARDEN     GARFIELD   GRANT
HAYES      HOLT       HOOKER     KEITH      KEYA PAHA  LINCOLN
LOGAN      LOUP       MCPHERSON  PERKINS    ROCK       SHERIDAN
THOMAS     WHEELER

...STORM SPOTTER ACTIVATION MAY BE NEEDED OVER PARTS OF NORTH CENTRAL
NEBRASKA THIS AFTERNOON AND THIS EVENING...

THERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING ACROSS PORTIONS OF NORTH CENTRAL NEBRASKA. THE GREATEST RISK
OF SEVERE WEATHER IS NORTHEAST OF A LINE EXTENDING FROM RUSHVILLE TO
HYANNIS TO BURWELL. OTHER THUNDERSTORMS WHICH ARE NOT EXPECTED TO
REACH SEVERE LEVELS ARE POSSIBLE OVER THE REST OF THE OUTLOOK AREA.

SCATTERED THUNDERSTORMS WILL CONTINUE ACROSS THE OUTLOOK AREA THE
REST OF THIS MORNING AND INTO THE AFTERNOON. SOME OF THESE STORMS MAY
PRODUCE HEAVY RAIN AND SMALL HAIL. LIMITED INSTABILITY SHOULD KEEP
THE STORMS BELOW SEVERE LIMITS.

BY LATE AFTERNOON...A DISTURBANCE ALOFT WILL APPROACH THE WESTERN PART
OF THE OUTLOOK AREA. SOUTHERLY WINDS WILL TRANSPORT ADDITIONAL MOISTURE
NORTHWARD ALONG A TROUGH OF LOW PRESSURE OVER WESTERN NEBRASKA. IF
AFTERNOON HEATING IS STRONG ENOUGH OVER WESTERN NEBRASKA THE ATMOSPHERE
WILL DESTABILIZE SUFFICIENTLY FOR THUNDERSTORMS TO DEVELOP NEAR THE
THE TROUGH OF LOW PRESSURE. THESE STORMS WOULD DRIFT EAST OUT OF THE
EASTERN PANHANDLE INTO THE REST OF THE OUTLOOK AREA INTO THE EVENING.
A FEW OF THE STORMS COULD REACH SEVERE LIMITS WITH LARGE HAIL AND
DAMAGING WINDS.

FS