Severe Thunderstorm Warning 199, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
256 AM CDT FRI AUG 22 1997

TSRA TONIGHT AGAIN A CHALLENGE...THEN TEMPS INTO THE WEEKEND...

FOG PRODUCT AFTER ECLIPSE SHOWS LOW CLOUDS OVER THE SW WITH A
SLIGHTLY HIGHER DECK INTO PARTS OF NC. LOW DECK HAS MADE IT AS FAR W AS
KOGA. 6Z SFC ANALYSIS HAD 60+ DEW POINTS ACROSS SRN HALF OF THE STATE
WITH SOMEWHAT OF A DRYLINE/WIND SHIFT BETWEEN SNY AND OGA. WEAK WAVE
INDICATED ON WATER VAPOR TRIED TO GENERATE A FEW STORMS IN THE
PANHANDLE WHICH FELL APART QUICKLY AS IT ENTERED WRN CWA.

MODELS AGAIN SIMILAR WITH OVERALL PATTERN. NO GRIDS HERE TONIGHT...SO
HAVE TO RELY MAINLY ON AFOS GRAPHICS. NOT MUCH IN THE WAY OF LARGE
SCALE FORCING INDICATED THROUGH 48 HRS...HOWEVER THERE IS A WEAK WAVE
HINTED AT BY BOTH MODELS COMING ACROSS THE RIDGE BY 00Z SAT. UPPER
LEVEL SPEED MAX SHOWN BY 00Z UPPER AIR ANALYSIS MATCHES A WAVE SHOWN
MOVING ACROSS NRN CA ON GOES 9 IMAGERY. THIS WAVE LOOKS A LITTLE
STRONGER IN THE WATER VAPOR THAN MODELS MIGHT SUGGEST. THIS WAVE SHOULD
APPROACH THE WRN PART OF CWA LATE TONIGHT. THE QUESTION WILL BE WHETHER
CAP WILL BE STRONG ENOUGH. WILL EXPECT THAT IT WILL BE FURTHER W...BUT
WITHOUT GRIDDED DATA WILL STILL INCLUDE 20 PERCENT IN ERN PANHANLDE
COUNTIES. FURTHER E...ALTHO NO ISENTROPIC PROGS AVAILABLE...WOULD
EXPECTED LIFT TO BE GENERATED ALONG TROF WHICH SHOULD BE SOMEWHERE NEAR
A VTN-LBF LINE BY LATE AFTERNOON. WILL INCLUDE HIGHER POPS FROM THIS
LINE AND FURTHER E BASED ON SPC 94O.

AS TROF SHIFTS E BY SATURDAY AND RIDGE SHIFTS SLIGHTLY EWD INTO THE
AREA...TSRA CHANCES SHOULD LESSEN. 700 MB TEMPS SHOULD WARM ENOUGH TO
INHIBIT WIDESPREAD TSRA DEVELOPMENT ALSO...AND WILL ONLY INCLUDE ISOLD
POPS FOR NOW.

TEMPS WILL BE SLOW TO CLIMB INITIALLY WITH CLOUDS HANGING AROUND IN THE
MORNING...BUT SHOULD BE CLOSE TO WHAT THEY WERE THURS. LBF COOLER THAN
ELSEWHERE IN THE SW THURS...SO WILL UP LBF CCF TO MATCH THAT OF OGA
YDAY. 30M THICKNESS INCREASE BY SAT SHOULD ALLOW LOW 90S IN THE
SW...WHICH GUIDANCE SUGGESTS AS WELL. PROBABLY WILL NEED A MORNING
GROUP AT LEAST FOR SW TO INCLUDE LOW CLOUDS.

CCF
LBF BU 088/057 091/058 090 69-21
OGA BU 090/058 092/060 093 69-21
IML BU 090/057 092/058 093 69-11
VTN BU 085/056 091/057 092 69-21
ONL BB 085/060 090/062 091 69331

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NEZ004>010-022>029-035>038-056>059-069>071-231200-

SEVERE WEATHER OUTLOOK FOR WESTERN AND NORTH CENTRAL NEBRASKA
NATIONAL WEATHER SERVICE NORTH PLATTE NE
705 AM CDT (605 AM MDT) FRI AUG 22 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 IN PARTS OF NORTH CENTRAL AND
SOUTHWEST NEBRASKA BY LATE AFTERNOON INTO TONIGHT...

THERE IS A SLIGHT CHANCE FOR SEVERE THUNDERSTORMS LATE THIS AFTERNOON
INTO TONIGHT...EAST OF A LINE FROM MERRIMAN TO NORTH PLATTE. WIDELY
SCATTERED THUNDERSTORMS ARE POSSIBLE ACROSS THE REMAINDER OF THE AREA
BY THIS EVENING AS WELL...BUT ARE NOT EXPECTED TO REACH SEVERE LIMITS.

PLENTY OF LOW LEVEL MOISTURE WILL REMAIN ACROSS THE OUTLOOK AREA TODAY.
BY AFTERNOON...SUNSHINE WILL SERVE TO FURTHER DESTABILIZE THE
ATMOSPHERE ACROSS THE AREA. AN AREA OF LOW PRESSURE AT THE SURFACE WILL
MOVE SLOWLY EAST ACROSS THE PLAINS AS WELL AND IS EXPECTED TO EXTEND
FROM NEAR MERRIMAN TO NORTH PLATTE BY LATE AFTERNOON. AS AN UPPER LEVEL
DISTURBANCE ENTERS THE AREA...SCATTERED THUNDERSTORMS ARE EXPECTED TO
DEVELOP INITIALLY ACROSS NORTH CENTRAL NEBRASKA. FURTHER DEVELOPMENT
WILL THEN BE POSSIBLE ALONG THE AREA OF LOW PRESSURE BY NIGHTFALL. A
FEW STORMS WILL HAVE THE POTENTIAL TO PRODUCE LARGE HAIL AND DAMAGING
WINDS. COVERAGE OF THUNDERSTORMS IS EXPECTED TO BE SOMEWHAT LESS IN THE
WESTERN MOST PORTION OF THE OUTLOOK AREA AS UPPER LEVEL TEMPERATURES
WARM SERVING TO LIMIT STORM DEVELOPMENT IN THIS AREA.

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