Severe Thunderstorm Warning 190, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
255 PM CDT SAT JUL 22 2000

...FORECAST CHALLENGE WILL BE CLOUDS EARLY ON SATURDAY THEN TEMPS...

MCS CONTINUES TO PUSH TO THE SOUTH SOUTHEAST INTO CENTRAL KANSAS.
ANOTHER AREA OF THUNDERSTORMS CONTINUES TO MOVE INTO NRN CWA. THIS
AREA SHOULD DISSIPATE QUICKLY AS IT MOVES INTO LESS FAVORABLE OMEGA
AND UPPER LEVEL DIVERGENCE. CEILINGS WILL HAVE TO BE MONITORED AS
WINDS SHOULD DIMINISH AND BL RH VALUES INCREASE TO NEAR 100 PERCENT
ACROSS MUCH OF CWA...TOWARD SUNRISE.

500 MB FEATURES AT MODEL INITIALIZATION REMAIN FAIRLY SIMILAR TO
LAST NIGHT. HIGH HEIGHTS ARE LOCATED FROM THE FOUR CORNERS TO
EASTERN TEXAS. LOW HEIGHTS ARE LOCATED OVER EASTERN ONTARIO. RIDGE
OVER WERN CONUS SEEMS SLIGHTLY STRONGER COMPARED TO YESTERDAY.
SURFACE FEATURES AT INITIALIZATION INDICATE HIGH PRESSURE OVER
DAKOTAS WITH THERMAL LOW OVER AZ. LATEST SURFACE ANALYSIS AGREES
FAIRLY WELL WITH 40 KM ETA POSITION OF SURFACE HIGH OVER SW MN.
ALSO...FAIRLY GOOD AGREEMENT WITH THE 40KM ETA AND POSITION OF MCS
OVER KANSAS. AVN SEEMS TO MISS THE MARK WITH VORT CENTER OVER NCENT
NEBRASKA. WILL HEDGE ON THE 40 KM ETA AND ETA SOLUTION.

TODAY...WILL NEED TO MONITOR SITUATION FOR FORMATION OF LOW CLOUDS
AND STRATUS AND MAY HAVE MENTION OF MOSTLY CLOUDY CONDITIONS EARLY
IN PERIOD THROUGHOUT CWA. SKIES SHOULD BEGIN TO CLEAR OUT BY MID
DAY. WILL PUT IN POPS IN NERN COUNTIES IN RESPONSE TO 700 MB VORT
MAX OVER SE SD. ADDITIONALLY THERE IS SOME POSITIVE OMEGA OVER THE
SAME AREA THIS AFTERNOON. AVN MOS AND NGM MOS ARE IN GOOD AGREEMENT
WITH AFTN TEMPS...WILL HEDGE ON UPPER 70S OVER ERN ZONES TO AROUND
85 FOR THE PANHANDLE COUNTIES.

TONIGHT...FAVORABLE INSTABILITY ACROSS MOST OF CWA WITH LI
APPROACHING -7 AND CAPE AROUND 2000 J/KG OVER SWRN CWA. ABSENCE OF
DIVERGENCE...SHORTWAVE...AND OMEGA INDICATES THUNDERSTORMS IF ANY
SHOULD DECAY AFTER SUNSET. WILL MENTION 20 POPS ACROSS PANHANDLE
AND SW COUNTIES IN RESPONSE TO SHORTWAVE OVER NE CO AND NEBRASKA
PANHANDLE...AND HIGHER LAPSE RATES PRESENT HERE. ADDITIONALLY...WILL
HAVE TO MENTION POPS IN NERN COUNTIES AS ANOTHER SHORTWAVE MOVES
IN FROM SD. GUIDANCE SEEMS REASONABLE WITH TEMPS. ETA FCST
DEWPOINTS INDICATE NO REAL DRYING OF AIRMASS...SO WILL GO WITH
GUIDANCE ON TEMPS.

SUNDAY...EXCELLENT CAPE AND LI BY AFTN OVER WERN CWA BUT BEST
FORCING DOES NOT MOVE IN TILL AFTER SUNDOWN. FAVORABLE LAPSE
RATES MAY FIRE OFF ISOLATED THUNDERSTORMS IN THE EARLY EVENING. WILL
MENTION SLIGHT CHANCE FOR THUNDERSTORMS FOR PANHANDLE AND SW
COUNTIES. WITH RIDGE MOVING IN FROM ROCKIES AND 850 MB TEMPS
INCREASING TO 24 C...TEMPS SHOULD BE 5 TO 10 DEGREES WARMER THAN
TODAY. WILL GO 85 TO 90 ACROSS MOST OF CWA WITH AROUND 90 IN
PANHANDLE AND SW COUNTIES DUE TO DRIER AIRMASS.

EXTENDED...WILL EXAMINE CLOSER WHEN NEW MRF COMES IN. LATE AVN
INDICATES SOME BREAKING DOWN IN THE RIDGE OVER ROCKIES AND A
SHORTWAVE RIDING SOUTH BY LATE MONDAY. MAY MENTION THREAT OF
SHOWERS AND THUNDERSTORMS ON MONDAY.

.LBF...NONE
CLB/DDB

NEZ004>010-022>029-035>038-056>059-069>071-222045-

SEVERE WEATHER OUTLOOK FOR WESTERN AND NORTH CENTRAL NEBRASKA
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1120 AM CDT SAT JUL 22 2000

...STORM SPOTTER ACTIVATION IS NOT EXPECTED TONIGHT...

THERE IS A CHANCE OF THUNDERSTORMS TONIGHT ACROSS PORTIONS
OF NORTH CENTRAL NEBRASKA...AND ACROSS THE EASTERN PANHANDLE AND
SOUTHWEST NEBRASKA.  THESE THUNDERSTORMS ARE NOT EXPECTED TO REACH
SEVERE LIMITS.

AN UPPER LEVEL DISTURBANCE WILL SWING SOUTHEAST INTO NORTH CENTRAL
NEBRASKA LATE THIS AFTERNOON AND EVENING BRINGING A CHANCE OF
THUNDERSTORMS TO THE AREA.  ALTHOUGH THERE WILL BE PLENTY OF LOW
LEVEL MOISTURE IN PLACE...THE ATMOSPHERE WILL ONLY BE MODERATELY
UNSTABLE.  THEREFORE MOST THUNDERSTORMS ARE EXPECTED TO REMAIN BELOW
SEVERE LEVELS.  A FEW ISOLATED STORMS MAY REACH SEVERE LEVELS.

WIDELY SCATTERED THUNDERSTORMS WILL DEVELOP LATE TONIGHT IN THE
EASTERN PANHANDLE AND SOUTHWEST NEBRASKA AS ANOTHER UPPER LEVEL
DISTURBANCE MOVES INTO THE AREA.  LIMITED INSTABILITY IS EXPECTED TO
KEEP MOST OF THESE STORMS BELOW SEVERE LEVELS.

SLM