Severe Thunderstorm Warning 229, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
312 PM CDT SAT JUL 10 2010

.DISCUSSION...

DEWPOINTS IN THE MID AND UPPER 60S AHEAD OF A GOOD UPR LEVEL WAVE
PUSHING INTO THE PANHANDLE WILL SET THE STAGE FOR SCATTERED
THUNDERSTORMS TONIGHT. BEST MLCAPES...AROUND 1500 J/KG...POOL TO
THE EAST OF A LINE FROM MERRIMAN TO IMPERIAL THIS AFTERNOON AND
TRANSITIONING EAST AHEAD OF THE SFC TROF TONIGHT. BULK SHEAR OF
AROUND 35KTS WILL AID IN BRINGING SOME OF THESE STORMS INTO SEVERE
RANGE. BEFORE SUNSET...EXPECT THE STORMS TO MAINLY BE A LARGE HAIL
AND WIND THREAT. HOWEVER AFTER SUNSET...LOW LEVEL JET SHOULD FEED
THE STORMS WHICH MAY DEVELOP INTO AN MCS. ONE MODEL DEVELOPS THIS
MCS ACROSS THE SOUTHERN HALF OF THE CWA WHILE ANOTHER DEVELOPS AN
MCS LATE ACROSS SOUTH CENTRAL SOUTH DAKOTA AND MOVES IT SOUTHEASTWARD.

SUNDAY...NORTHERLY WINDS WILL USHER IN SLIGHTLY COOLER
TEMPERATURES...ESPECIALLY ACROSS NORTHERN NEBRASKA WHERE HIGHS
WILL ONLY MAKE IT INTO THE LOWER 80S. THE TEMPERATURES WILL NOT
KEEP SHOWERS AND THUNDERSTORMS FROM DEVELOPING THOUGH. THROUGH THE
AFTERNOON A FRONTAL BOUNDARY SLIDES FROM NORTHWEST TO SOUTHEAST.
CAPES ARE ONLY MINIMAL SO REALLY DOUBT STORMS WILL BECOME SEVERE.

MONDAY...HIGH PRESSURE MOVES OFF TO THE EAST WITH MOISTURE
RETURNING TO THE AREA. THE BEST INSTABILITY WILL POOL OVER THE
PANHANDLE BY AFTERNOON SUPPORTING SHOWERS AND THUNDERSTORMS ONCE AGAIN.

.EXTENDED....
DURING THE MIDDLE OF THE UPCOMING WEEK THE NEXT SYSTEM WILL DROP OUT
OF THE HIGH LATTITUDES INTO THE CENTRAL CANADIAN PRAIRIES. SFC LOW
AHEAD OF THIS SYSTEM SHOULD TRAVERSE THE PLAINS JUST NORTH OF NEB
AND FORCE A FRONT THROUGH THE CWA WEDNESDAY AFTERNOON/EVENING. AS
EXPECTED SOME DIFFERENCES IN TIMING WITH UPPER MASS FIELDS AND
ARRIVAL TIME OF FRONT INTO CWA. AS SUCH DID LEAN TOWARD HPC GUIDANCE
AND SMALL CHANCE POPS BUT BELIEVE A SLOWER SOLN RATHER THAN FASTER
IS THE WAY TO GO ATTM. WITH LARGE RIDGE IN PLACE OVER THE SOUTHERN
PLAINS...FRONT MAY NOT MAKE MUCH PROGRESS PAST SOUTHERN NEB
BORDER...BUT THIS WILL ALSO DEPEND ON STRENGTH OF CONVECTION. WILL
LEAVE A SMALL THREAT OF CONVECTION IN FORECAST ACROSS SOUTHERN CWA
INTO THURSDAY EVENING WITH MOISTURE MOST LIKELY TO POOL NEAR THIS
BOUNDARY. WESTERN RIDGE SHOULD THEN BEGIN TO BUILD INTO CENTRAL
PLAINS BY LATE WEEK AND THE FRONT SHOULD QUICKLY LIFT NORTHWARD INTO
DAKOTAS AND INCREASING MID LEVEL TEMPS SHOULD BEGIN TO CREATE A MORE
EFFECTIVE CAP TO CONVECTION ACROSS THE HIGH PLAINS. TEMPS LOOK NEAR
SEASONAL THOUGH MUCH OF EXTENDED WITH A SHARPER WARMING TREND
EXPECTED TO DEVELOP BY LATE WEEK INTO THE WEEKEND AS THE UPPER RIDGE
EXPANDS OUT OF THE SOUTHWEST CONUS AND BUILDS OVERHEAD.

&&

.AVIATION...
EXPECTING CONVECTION TO INCREASE ACROSS WESTERN NEBRASKA THROUGH THE
LATE AFTERNOON AND EVENING HOURS. VFR CONDITIONS WILL PRIMARILY BE
IN PLACE...HOWEVER MVFR/NEAR IFR CONDITIONS COULD BE FOUND NEAR THE
THUNDERSTORMS. THE LOWERED FLIGHT CONDITIONS WILL MAINLY BE FROM
RESTRICTIONS TO VSBY IN THE FORM OF HEAVY RAINFALL...GUSTY
WINDS...AND POSSIBLY HAIL. CHANCES ARE FAIR THAT BOTH THE KLBF AND
KVTN TERMINALS WILL BE IN THE VCNTY OF THESE STRONGER STORMS IN THE
23Z TO 04Z TIME FRAME. THESE STRONGER STORMS SHOULD BE AVOIDED BY
AIRCRAFT AS WELL AS THE LESS INTENSE STORMS ACROSS FAR WESTERN
NEBRSKA DUE TO THE THREAT OF DOWNBURST WINDS. QUIETER VFR CONDITIONS
SHOULD PREVAIL WITH THE PASSAGE OF THESE STORMS INTO MID DAY SUNDAY.
.AVIATION...

&&

.LBF WATCHES/WARNINGS/ADVISORIES...SEVERE THUNDERSTORM WATCH UNTIL 10 PM CDT /9 PM MDT/ THIS
EVENING FOR NEZ004>010-022>029-035>038-056>059-069>071-094.

&&

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
244 PM CDT SAT JUL 10 2010

NEZ004>010-022>029-035>038-056>059-069>071-094-111945-
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-
244 PM CDT SAT JUL 10 2010 /144 PM MDT SAT JUL 10 2010/

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

.DAY ONE...THIS EVENING AND TONIGHT.

THUNDERSTORM COVERAGE SHOULD INCREASE ACROSS WESTERN NEBRASKA
THROUGH THE EARLY EVENING HOURS...WITH THESE STORMS SPREADING
EASTWARD ACROSS NORTH CENTRAL NEBRASKA THROUGH MIDNIGHT. FAVORABLE WIND
SHEAR PROFILES AND MODERATE INSTABILITY WILL ALLOW FOR SEVERE
THUNDERSTORM THUNDERSTORM DEVELOPMENT AS WELL. LARGE HAIL AND
DAMAGING WIND GUSTS OVER 60 MPH WILL BE THE PRIMARY THREATS WITH
THESE STORMS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

INSTABILITY WILL BUILD INTO WESTERN AND NORTH CENTRAL NEBRASKA
AGAIN SUNDAY AFTERNOON. THEN...A FRONT PRESSING SOUTHWARD ACROSS
NEBRASKA WILL FOCUS THE LIFT FOR A CONVECTIVE SYSTEM TO DEVELOP
AND TRACK ACROSS NEBRASKA. THIS WILL BRING POTENTIAL FOR
THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS CENTRAL AND
SOUTHWEST NEBRASKA.

THE ACTIVE PATTERN WILL CONTINUE MONDAY AFTERNOON AND EVENING AS
THE FRONT CONTINUES OVER THE AREA...AND THUNDERSTORMS CAN BE
EXPECTED ONCE AGAIN. AT THIS TIME...IT APPEARS THAT THE GREATEST
THREAT OF SEVERE WEATHER WILL BE IN THE EASTERN PANHANDLE AND
SOUTHWEST NEBRASKA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THROUGH TONIGHT.

&&

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

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