Damaging Wind in Nebraska, July 6, 2009

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
258 PM CDT MON JUL 6 2009

.DISCUSSION...
ISOLATED THUNDERSTORMS ARE DEVELOPING A LITTLE LATER AND FARTHER
WEST ACROSS EASTERN WY THIS AFTN AS THE CAP IS A BIT STRONGER AND
THE UPPER LEVEL DISTURBANCE IS FARTHER WEST...SLOWLY EMERGING FROM
THE CNTL ROCKIES. THIS NAM IS BRINGING THIS DISTURBANCE ACROSS THE
WRN HALF OF THE FCST AREA TONIGHT AND THROUGH THE ERN ZONES TUESDAY
MORNING. IT SEEMS CONCEIVABLE FOR THE DISTURBANCE TO REMAIN INTACT
AS IT CROSSES THE FCST AREA SO ISOLATED SHOWERS AND THUNDERSTORMS
ARE FCST TONIGHT THROUGH TUESDAY MORNING.

SPC HAS SUGGESTED ISOLATED TO PERHAPS SCATTERED SEVERE STORMS LATE
TUESDAY AFTN AND EVENING. THE AREA OF CONCERN IS ALONG AND EAST OF
HIGHWAY 83 WITH THE GREATEST INSTABILITY ACROSS NERN ZONES. LOW
PRESSURE WILL FORM ACROSS WRN NEB TUESDAY AFTN FOCUSING INSTABILITY
AT THE TRIPLE PT OF THE SFC LOW NEAR KANW. LARGE HAIL AND WIND DAMAGE
ARE THE MAIN CONCERN. CAPE WILL APPROACH 4000 J/KG AND WINDS ALOFT
COULD BE SUFFICIENT FOR SUPER CELL DEVELOPMENT.

A WEAK PACIFIC COLD FRONT WILL APPROACH THE FCST AREA LATE WEDNESDAY.
A DRYLINE BULGE AHEAD OF THE FRONT ACROSS NORTH CNTL NEBRASKA WILL
ACT AS A FOCUS FOR ISOLATED SEVERE STORMS LATE IN THE AFTN AND
EVENING. A STRONG CAP WILL BE IN PLACE INHIBITING STORM DEVELOPMENT
BUT CAPE IS EXPECTED TO REACH CLOSE TO 5000 J/KG WITH 40 TO 50 KTS OF
BULK SHEAR. ISOLATED SUPER CELL STORMS COULD FIRE ALONG THE DRYLINE
WHICH WILL BE NEAR HIGHWAY 83.

MORE ISOLATED STORMS COULD DEVELOP LATE THURSDAY AS THE COLD FRONT
DROPS THROUGH WRN NEB AND INTO CNTL NEB. THE AREA OF CONCERN CLIPS
THE ERN EDGES OF THE FCST AREA AND IS FOCUSED MOSTLY EAST OF THE
FCST AREA.

EXTENDED FCST...OVERALL THE GFS AND ECMWF HAVE COME INTO BETTER
AGREEMENT SUGGESTING HIGHS MOSTLY IN THE 80S TO NEAR 90. MOST OF THE
RAINFALL IN THIS PATTERN IS EXPECTED TO FALL ACROSS THE NRN PLAINS
AND THE UPPER MIDWEST. THE MODELS SUGGEST A SIGNIFICANT CAP WILL BE
IN PLACE ACROSS THE CNTL PLAINS LIMITING RAINFALL. DEW PTS WILL BE IN
THE MID 60S PRODUCING VERY UNSTABLE ATMOSPHERIC CONDITIONS BUT THE
BEST FORCING IS EXPECTED TO BE NORTH OF THE FCST AREA.

FRIDAY THROUGH SUNDAY...NO REAL CHANGE TO THE FCST THINKING. THE COLD
FRONT WILL DROP SOUTH INTO KS OR CLOSE TO THE NEB-KS BORDER AND ACT
AS A FOCUS FOR ISOLATED STRONG TO SEVERE THUNDERSTORMS. THE GFS AND
ECMWF INDICATE CAPE VALUES OF 2000 TO 4000 J/KG EACH AFTN AND WINDS
ALOFT WILL REMAIN STRONG THE NRN PERIPHERY OF THE UPPER LEVEL RIDGE
REMAINS ACROSS NEB. THIS SUGGESTS THE POTENTIAL FOR ISOLATED SUPER
CELL STORMS LATE IN THE DAY OR AT NIGHT.

MONDAY...AN UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE NRN
ROCKIES. THIS SHOULD LIFT THE COLD FRONT NORTH WITH TEMPERATURES
WARMING SOMEWHAT. PCPN CHANCES ARE UNCERTAIN.

&&

.AVIATION...
EXPECTING MOSTLY VFR CONDITIONS FOR THE NEXT 24 HOURS. THE ONLY
EXCEPTION WOULD BE INVOF ANY ISOLATED THUNDERSTORM ACTIVITY THAT MAY
DEVELOP LATE THIS AFTERNOON AND INTO THIS EVENING. ANY SUCH ACTIVITY
SHOULD BE QUITE ISOLATED...AND DID NOT INCLUDE ANY MENTION IN THE
TAF/S. OTHERWISE...FOR BOTH KLBF AND KVTN...LOOK FOR SOME INCREASE
IN MID AND HIGH LEVEL CLOUDINESS THIS EVENING...ALONG WITH SOUTH
WINDS 10 TO 15 KTS. THESE CONDITIONS SHOULD PREVAIL THROUGH 18Z
TUESDAY.
&&

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

CDC/BT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
328 PM CDT MON JUL 6 2009

NEZ004>010-022>029-035>038-056>059-069>071-094-072030-
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-
328 PM CDT MON JUL 6 2009 /228 PM MDT MON JUL 6 2009/

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

.DAY ONE...TONIGHT.

SCATTERED THUNDERSTORMS DEVELOPING ACROSS EASTERN WYOMING LATE
THIS AFTERNOON...ARE EXPECTED TO DRIFT SOUTHEAST INTO PARTS OF
WESTERN NEBRASKA THIS EVENING. AN ISOLATED SEVERE STORM IS
POSSIBLE ALONG AND WEST OF A RUSHVILLE TO IMPERIAL LINE. LARGE
HAIL AND DAMAGING WINDS WOULD BE THE MAIN THREATS WITH ANY STORM
THAT BECOMES SEVERE.

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

LOW PRESSURE...AND AN ASSOCIATED SURFACE TROUGH...WILL MOVE INTO
CENTRAL NEBRASKA BY TUESDAY AFTERNOON. THIS SURFACE TROUGH WILL
BECOME THE FOCUS FOR WIDELY SCATTERED THUNDERSTORM DEVELOPMENT BY
LATE TUESDAY AFTERNOON. WIND SHEAR AND INSTABILITY WILL BE
SUCH...THAT IF STORMS DEVELOP...THEY WILL QUICKLY BECOME SEVERE.
LARGE HAIL AND DAMAGING WINDS APPEAR TO BE THE MAIN THREATS...BUT
AN ISOLATED TORNADO CANNOT BE RULED OUT. THE BEST CHANCE FOR
SEVERE THUNDERSTORMS WILL BE ALONG AND EAST OF A VALENTINE...TO
NORTH PLATTE...TO BENKELMAN LINE.

A STATIONARY FRONT WILL MEANDER BACK AND FORTH ACROSS THE AREA
WEDNESDAY THROUGH SUNDAY...ALONG WITH PERIODIC CHANCES FOR
THUNDERSTORMS. WIND SHEAR AND INSTABILITY WILL SUPPORT AT LEAST A
SLIGHT CHANCE FOR SEVERE THUNDERSTORMS. LATER OUTLOOKS WILL
DETERMINE THE BEST AREA FOR SEVERE THUNDERSTORM DEVELOPMENT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL MOST LIKELY NOT BE NEEDED TONIGHT.

&&

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

TAYLOR