Hail and Damaging Winds in Nebraska, July 19 to 20, 2010

AREA FORECAST DISCUSSION...CORRECTED AVIATION AND EXTENDED DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
315 PM CDT MON JUL 19 2010

.SYNOPSIS...
    AT 19Z...SURFACE ANALYSIS SHOWED SEVERAL LOW PRESSURE CENTERS IN
EAST CENTRAL WYOMING ...NORTH CENTRAL COLORADO AND WESTERN KANSAS. A
SURFACE FRONT WAS STRETCHED ACROSS NORTHERN AND EASTERN COLORADO
THROUGH KANSAS TO NORTHERN MISSOURI. THERE WERE HINTS OF ANOTHER
FRONT ACROSS THE WESTERN DAKOTAS AND NORTHERN WYOMING AND THROUGH
WESTERN MONTANA. DEWPOINTS AT OR ABOVE 70F WERE ADVANCING ACROSS
SOUTHERN NEBRASKA AND HAD REACHED LEXINGTON. IN THE VISIBLE
SATELLITE IMAGE...A BAND OF CLOUDS IN SOUTHWEST NEBRASKA BETRAYED
THE PRESENCE OF AN ARCHING BOUNDARY NORTH OF IMPERIAL AND MCCOOK AND
SOUTH OF NORTH PLATTE AND OGALLALA. THE SURFACE LAPS DATA CONVECTIVE
INHIBITION AT OR ABOVE 100J/KG IN SOUTHWEST NEBRASKA.
&&

.SHORT/MEDIUM RANGE...TONIGHT THROUGH THURSDAY NIGHT.
    THERE MAY BE TOO MUCH NEGATIVE ENERGY FOR CONVECTION TO DEVELOP
THIS EVENING BUT...WITH CONVECTIVE POTENTIAL ENERGY AT OR ABOVE
3000J/KG...WE CANNOT REALLY IGNORE THE POTENTIAL FOR CONVECTION. AS
A RESULT...WE HAVE AT LEAST SOME CHANCE OF THUNDERSTORMS IN FOR THIS
EVENING AND OVERNIGHT.
    THE SYNOPTIC SITUATION FOR TUESDAY IS SIMILAR TO THAT WE HAVE
TODAY...SO THERE IS AT LEAST A SLIGHT CHANCE TUESDAY AS WELL.
    THERE IS GENERAL AGREEMENT AMONG THE GEM...THE NAM AND THE GFS
THAT THE BOUNDARY WILL WORK NORTHWARD ACROSS NEBRASKA WEDNESDAY
NIGHT AND THURSDAY MORNING...OPENING A TRAJECTORY FROM THE TEXAS
GULF COAST THROUGH THE SOUTHERN PLAINS AND INTO THE CENTRAL AND
NORTHERN PLAINS. THIS WILL AGAIN HAVE ABUNDANT MOISTURE IN PLACE
WHEN A SURFACE TROUGH AND FRONT COME THROUGH THURSDAY EVENING. THE
RESULT WILL BE A CHANCE OF THUNDERSTORMS.

.EXTENDED...FRIDAY THROUGH MONDAY.
    FRIDAY THROUGH MONDAY...OPERATIONAL MODELS AND GFS ENSEMBLES
SHOW THE UPPER RIDGE BUILDING NORTH INTO THE CENTRAL PLAINS DURING
THE PERIOD...WITH A DECREASE IN WIND SPEEDS IN THE UPPER LEVELS.
THIS WILL LEAD TO LESS SHEAR FOR ANY ORGANIZED TSTM ACTIVITY...BUT
STILL EXPECTING PLENTY OF MID AND UPPER LEVEL MOISTURE AROUND...AND
WITH AFTERNOON HEATING OF A MOIST AND UNSTABLE BOUNDARY
LAYER...ISOLATED LATE AFTERNOON AND EVENING TSTMS WILL REMAIN
POSSIBLE. DESPITE THE UPPER RIDGE BUILDING INTO THE
AREA...STATIONARY FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY...SO
NO REAL HEAT ANTICIPATED. IT WILL CONTINUE TO BE WARM AND RATHER
HUMID HOWEVER...WITH HIGHS AROUND 90 TO 95 THROUGH THE
WEEKEND...WITH LOWS IN THE 60S TO NEAR 70.

&&

.AVIATION...
    RATHER LOW CONFIDENCE IN OVERALL FORECAST FOR THE NEXT 24 HRS.
DISTURBANCE ACROSS NORTHERN WY AND MT SHOULD HELP IGNITE TSTMS
ACROSS WESTERN SD AND EASTERN WY THIS AFTERNOON. THIS ACTIVITY WILL
THEN MOVE EAST INTO NORTH CENTRAL NEB LATE THIS EVENING AND
OVERNIGHT. HAVE INCLUDED A TEMPO GROUP FOR TSTMS FOR KVTN AFTER 06Z.
THIS WILL HAVE TO BE WATCHED THOUGH...AS STORMS MAY MOVE IN BEFORE
THAT TIME...BUT PROBABLY NOT UNTIL AT LEAST MID EVENING. FURTHER
SOUTH...THERE IS SOME CHANCE OF A TSTM MOVING INTO THE AREA AFTER
MID EVENING...BUT CONFIDENCE IS LOWER AND HAVE NOT INCLUDED ANY
POSSIBILITY IN THE TAF ATTM. WINDS EXPECTED TO BE VRB AT 10 KTS OR
LESS...BUT GUSTY INVOF ANY TSTM.
&&

.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&

SHORT/MEDIUM RANGE...SPRINGER
AVIATION/EXTENDED...TAYLOR

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
438 PM CDT MON JUL 19 2010

NEZ004>010-022>029-035>038-056>059-069>071-094-202145-
SHERIDAN-EASTERN CHERRY-KEYA PAHA-BOYD-BROWN-ROCK-HOLT-GARDEN-
GRANT-HOOKER-THOMAS-BLAINE-LOUP-GARFIELD-WHEELER-ARTHUR-MCPHERSON-
LOGAN-CUSTER-DEUEL-KEITH-PERKINS-LINCOLN-CHASE-HAYES-FRONTIER-
WESTERN CHERRY-
438 PM CDT MON JUL 19 2010 /338 PM MDT MON JUL 19 2010/

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

.DAY ONE...TONIGHT.

THUNDERSTORMS DEVELOPING ACROSS WESTERN SOUTH DAKOTA AND NORTHEAST
WYOMING...ARE EXPECTED TO DEVELOP INTO A THUNDERSTORM COMPLEX AS
THEY DROP SOUTH INTO NEBRASKA LATER THIS EVENING. SOME OF THE
THUNDERSTORMS MAY BE SEVERE...WITH DAMAGING WINDS AND LARGE HAIL.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER THE NEBRASKA
PANHANDLE...WEST OF A LINE FROM MERRIMAN TO OSHKOSH ON TUESDAY.
TEMPERATURES RISING INTO THE 90S...WILL COMBINE WITH ABUNDANT LOW
LEVEL MOISTURE...AND CONTRIBUTE TO THUNDERSTORM DEVELOPMENT. THE
MAIN THREAT WITH STORMS THAT DEVELOP WILL BE LARGE HAIL.

WEDNESDAY...A FRONTAL BOUNDARY WILL BE STALLED OUT OVER
NEBRASKA...AND BE THE FOCUS FOR SEVERE THUNDERSTORM DEVELOPMENT.
THE MAIN THREAT WITH STORMS THAT DEVELOP WILL BE LARGE HAIL AND
DAMAGING THUNDERSTORM WINDS...HOWEVER...CONDITIONS MAY BECOME
FAVORABLE FOR ISOLATED TORNADOES AS WELL.

WITH THE STATIONARY FRONT REMAINING IN THE AREA...AND A FAVORABLE
UPPER AIR PATTERN...THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE INTO
LATE WEEK. AT THIS TIME...A WIDESPREAD OUTBREAK OF SEVERE
THUNDERSTORMS IS NOT EXPECTED...BUT ISOLATED SEVERE THUNDERSTORMS
CANNOT BE RULED OUT..

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER THIS EVENING...AND INTO THE
OVERNIGHT HOURS.

&&

THIS PRODUCT IS NOW AVAILABLE...ALONG WITH OTHER WEATHER...
HYDROLOGICAL AND CLIMATOLOGICAL INFORMATION...AT
HTTP://WWW.WEATHER.GOV/NORTHPLATTE

TAYLOR