Hail and Damaging Wind in Nebraska, September 6, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
244 PM CDT THU SEP 6 2007

...FORECAST CHALLENGES ARE PRECIPITATION CHANCES MIDWEEK AND
TEMPERATURES...

.SYNOPSIS...WV IMAGERY INDICATING NUMEROUS UPPER LVL WAVES ACROSS
THE NRN PLAINS AND NRN ROCKIES THIS AFTERNOON. EASTERN MOST WAVE IS
LIFTING ACROSS CENTRAL AND EASTERN SO DAK ATTM. ANOTHER WAVE IS
LIFTING INTO NERN WYOMING AND THE THIRD ACROSS CENTRAL MT.
CONVECTION ASSOCIATED WITH THE EASTERN MOST TWO...LIFTING IN TO ERN
SO DAK...AS WELL AS NERN WY...NWRN NEBR AND WRN SO DAK. SURFACE
ANALYSIS AT 19Z INDICATING A SFC TROF EXTENDING FROM ERN SO
DAK...SSWD INTO CENTRAL AND SWRN NEBRASKA. TEMPERATURES RANGED FROM
AROUND 70 IN THE NORTH TO THE LWR 80S SOUTH.

.DISCUSSION...

NEAR TERM (TONIGHT THROUGH SUNDAY)...MAIN CHALLENGES BEYOND TONIGHT
ARE TEMPERATURES AND PRECIPITATION CHANCES FOR SUNDAY. FOR
TONIGHT...AM EXPECTING CONVECTION TO FIRE ACROSS THE CWA OVR THE
NEXT COUPLE OF HRS...AS THE EASTERN WYOMING WAVE ENTERS THE
PANHANDLE...AND INTERACTS WITH THE SFC TROF AND RICHER LOW LEVEL
MOISTURE. BEST CHANCES FOR ORGANIZED CONVECTION WILL BE EAST OF THE
SFC TROF...OR EAST OF A VALENTINE TO LBF LINE...WHERE CAPES WILL BE
WELL OVER 3000 J/KG. SVR THREAT STILL A POSSIBILITY EAST OF THIS
LINE...WHERE DEEP LAYER SHEAR WILL INCREASE TO AOA 50 KTS BY 00Z.
ONGOING FCST...HAS A DECENT HANDLE ON POPS WITH SCATTERED TO LIKELY
NORTH AND NORTHEAST...WITH ISOLATED POPS SOUTH AND WEST. ONLY MAJOR
CHANGES WERE TO SPEED UP ENDING OF PRECIPITATION AS WAVE SPEED AND
MODEL TRENDS ARE FASTER.

FRIDAY AND SATURDAY WILL BE PLEASANT...WITH HIGH PRESSURE BUILDING
OVHD TOMORROW. THIS FEATURE WILL SHIFT EWD FRIDAY NIGHT ALLOWING
SRLY FLOW TO RETURN ON SATURDAY. STRONG FRONTAL BOUNDARY WILL
APPROACH WESTERN AND NORTH CENTRAL NEBRASKA LATE SATURDAY AS AN UPPR
LVL DISTURBANCE LIFTS ACROSS THE DAKOTAS. ONGOING FCST HAS THIS
HANDLED WELL AND CONTINUED POPS LOOK GOOD. SUNDAY WILL BE CLOUDY AND
COOL AS THE COLD FRONT BECOMES ANCHORED ACROSS NRN KS. DECENT ERLY
FLOW AND H85 TEMPS IN THE SINGLE DIGITS WILL LIMIT HIGHS TO THE 60S
SUNDAY...SO DECREASED MAX TS ACCORDINGLY. PRECIPITATION CHANCES
SHOULD BE LIMITED...AS UPPR SUPPORT REMAINS WEST OF THE AREA UNTIL
SUNDAY NIGHT.

LONG TERM (MONDAY THROUGH THURSDAY)...BETTER CONSISTENCY NOTED WITH
THE MID AND LONG RANGE MODEL SOLUTIONS THIS AM. GFS ENSEMBLES ARE IN
BETTER AGREEMENT AS WELL. IRONICALLY...THE 6Z OPERATIONAL GFS SOLN
THIS AM IS ACTUALLY THE COOLEST OUTLIER COMPARED TO ENSEMBLE
MEAN...SO DIDNT TREND TEMPS AS LOW AS THE GUIDANCE SUGGESTS. IN THE
EXTENDED...BEST CHANCES FOR PRECIPITATION REMAIN ON SUNDAY NIGHT AND
EARLY MONDAY...BEHIND THE EXITING COLD FRONT AND AHEAD OF AN APPG
CANADIAN TROF. BOTH THE 06Z AND 12Z GFS SOLUTIONS INDICATION A
PROLONGED PERIOD OF DEEP ISENTROPIC LIFT ACROSS THE HIGH PLAINS FOR
SUNDAY AFTERNOON THROUGH MONDAY. THE NEW 12Z GFS RUN HAS SHIFTED THE
CORE OF THIS LIFT 50 TO 100 MILES FURTHER NORTH...SO HIGHEST POPS IN
THE NRN CWA WILL CONTINUE.

&&

AVIATION...
MAINLY VFR CONDITIONS THE NEXT 24 HOURS...HOWEVER AS SEVERAL SURFACE
TROFS MOVE ACROSS THE REGION BRIEF MVFR AND EVEN IFR CONDITIONS WILL
BE POSSIBLE AS SCT TO NMRS TSRA ARE EXPECTED ALONG THE BOUNDARIES.
THUNDERSTORMS WILL LIKELY DROP THE CIGS TO MVFR CONDITIONS WITH
OVC015 POSSIBLE. VSBYS DROPPING TO LESS THAN 2 MILES WITH MODERATE
TO HEAVY RAINFALL WILL BE POSSIBLE. MAIN/FINAL COLD FRONT/TROF WILL
PUSH INTO EASTERN NEBRASKA BY EARLY MORNING WITH SKIES CLEARING
BEHIND THE FRONT.

&&

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

&&

CLB/MASEK

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NORTH PLATTE NE
317 PM CDT THU SEP 6 2007

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-
317 PM CDT THU SEP 6 2007 /217 PM MDT THU SEP 6 2007/

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

.DAY ONE...TONIGHT.

AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE REGION TONIGHT AND
INTERACT WITH A SURFACE COLD FRONT...PRODUCING SCATTERED SHOWERS
AND THUNDERSTORMS. THERE IS A SLIGHT RISK FOR THE THUNDERSTORMS TO
BECOME SEVERE...MAINLY EAST OF LINE FROM VALENTINE IN CHERRY
COUNTY THROUGH CHAPPELL IN DEUEL COUNTY. LARGE HAIL AND DAMAGING
WIND GUSTS ARE POSSIBLE.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A STRONG COLD FRONT IS FORECAST TO SWEEP ACROSS WESTERN AND NORTH
CENTRAL NEBRASKA SATURDAY NIGHT BRINGING A GOOD CHANCE FOR SHOWERS
AND THUNDERSTORMS SATURDAY NIGHT INTO SUNDAY NIGHT. NO SEVERE
THUNDERSTORMS ARE EXPECTED AT THIS TIME. IN ADDITION FALL LIKE
TEMPERATURES WILL OCCUR SUNDAY AND MONDAY WITH HIGHS ONLY IN THE
60S MOST AREAS. LOWS TUESDAY MORNING MAY RANGE AS LOW AS THE UPPER
30S TO MID 40S.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED FOR AREAS MAINLY EAST OF A LINE
FROM SPRINGVIEW IN KEYA PAHA COUNTY THROUGH STOCKVILLE IN FRONTIER
COUNTY.

&&

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

MASEK