Hail in Nebraska, October 12, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
254 PM CDT FRI OCT 12 2007

.DISCUSSION...
ALL MODELS ARE CONVERGING TOWARD THE TRACK OF THE GFS WITH THE
WEEKEND STORM SYSTEM. THE GFS AND OTHER MODELS ARE TRACKING THE
UPPER LEVEL LOW ACROSS NORTHERN KS PLACING WRN AND NCNTL NEB IN A
FAVORABLE AREA FOR WIDESPREAD RAIN. THE H7 LOW TRACKING VERY NEAR
THE KS-NEB BORDER CONTINUES TO SUGGEST HIGH POPS AND WIDESPREAD RAIN
NRN AND CNTL ZONES AND SLIGHTLY LOWER POPS WITH SCATTERED RAIN
ACROSS SRN ZONES.

WINDS SPEEDS...
THE SYSTEM WILL TRACK EAST SATURDAY AND SUNDAY AT 10 TO 15 MPH AND
PRODUCE A PROLONGED PERIOD WET AND WINDY WEATHER. THE LATEST SOLNS
SUGGEST NEAR WIND ADVISORY CONDITIONS DEVELOPING SUNDAY AFTN IN THE
NORTHWEST AND SPREADING EAST OVERNIGHT THROUGH MONDAY MORNING. LATER
FCSTS CAN ADJUST WIND SPEEDS UPWARD SLIGHTLY TOWARD THE GUIDANCE
WHICH PRODUCES THE MOST ACCURATE WIND SPEEDS. FCST SKILL WILL
INCREASE DURING THE NEXT 24 HRS.

SEVERE WEATHER...
THE SPC HAS OUTLOOKED PARTS OF CNTL AND SRN NEB FOR ELEVATED SEVERE
THUNDERSTORMS CAPABLE OF LARGE HAIL SATURDAY EVENING. STRONG WARM
AIR AND MOISTURE ADVECTIONS ARE EXPECTED TO AID IN THE
DESTABILIZATION OF THE ATMOSPHERE PRODUCING STORMS CAPABLE OF LARGE
HAIL. THIS PROCESS SHOULD BEGIN LATE EVENING...AFTER 9 PM AND
CONTINUE OVERNIGHT.

SUNDAY...THE NAM12 WHICH IS A SLOWER SOLN INDICATES THE SFC LOW
WILL BE ACROSS SRN NEBRASKA SUNDAY MORNING. ALTHOUGH THE FCST AREA IS
NOT OUTLOOKED FOR SVR WEATHER. UPPER LEVEL FORCING IN CONJUNCTION
WITH A SFC WARM FRONT COULD CAUSE THE ATM TO DESTABILIZE BETWEEN 11
AM AND 1 PM. THIS IS PROVISIONAL SINCE THE BEST AREA FOR SVR WEATHER
WILL BE ACROSS SOUTH CNTL NEB LATER IN THE AFTN.

CLOUD COVER AND FOG...
STRATUS IS EXPECTED TO CONTINUE TO EXPAND ACROSS THE FCST AREA
TONIGHT. LOW LEVEL MOISTURE ADVECTION...UPSLOPE WINDS...DRY AIR
ALOFT ALL SUGGEST HIGH PROBABILITY OF AREAS OF FOG DEVELOPING. THE
FCST INCLUDES AREAS OF FOG...SHRAS AND ISOLD TSTMS TONIGHT THROUGH
SATURDAY MORNING BUT THE FOG COULD LAST THROUGH SATURDAY NIGHT UNTIL
THE 850 MB COLD FRONT DROPS THROUGH SUNDAY.

RAINFALL...
HPC SUGGESTS TOTAL RAINFALL OF 1/2 TO NEARLY 2 INCHES WITH LEAST
AMOUNTS SOUTH AND HIGHEST RAINFALL IN THE NORTHEAST. THIS IS A BLEND
OF THE FASTER BUT WETTER GFS AND SLOWER BUT DRIER NAM12. THE
LATEST...12Z ECMWF IS SOMEWHAT WETTER. THIS SOLN IS THE SLOWEST AND
IS CLOSE TO THE UKMET. SO LATER FCSTS MAY HAVE TO EXTEND THE RAIN
INTO MONDAY EVENING IF THE ECMWF AND UKMET ARE VERIFYING.

TUESDAY...A BRIEF REPRIEVE.

WEDNESDAY THROUGH FRIDAY...THE ECMWF IS RACING ANOTHER STORM SYSTEM
THROUGH THE CENTRAL PLAINS WEDNESDAY WITH A SECOND SYSTEM CLOSELY
FOLLOWING ON FRIDAY. THE OFFICIAL FCST FOLLOWS THE HPC FCST WHICH
CALLS FOR RAIN WEDNESDAY NIGHT AND THURSDAY. THE GFS IS FARTHER
NORTH CARVING A SINGLE SYSTEM THROUGH THE NRN PLAINS THURSDAY. THUS
THE MODELS ARE IN POOR AGREEMENT WITH THESE SYSTEMS AND FCST
CONFIDENCE IS LOW.

FCST TEMPERATURES ARE THE USUAL BLEND OF THE NAM12 AND GUIDANCE DAYS
1 THROUGH 4. HPC GRIDS WERE THE BASIS OF THE DAY 5 THROUGH 7 FCST.

&&

.AVIATION...
CEILING LOWERING TO MVFR WILL BE THE COMMON FOCUS THIS EVENING AS
MOISTURE SPREADS NORTH. BY MIDNIGHT IFR CONDITIONS WILL INCREASE
ACROSS THE SOUTHWEST WITH VISIBILITIES LOWERING WITH PATCHY FOG
EARLY. BEFORE DAYBREAK THE SOUTHWEST CAN EXPECTED VISIBILITIES FROM
1/2 TO 1 MILE NORTH TO INTERSTATE 80 THAT COULD AS FAR NORTH AS
HIGHWAY 2 THROUGH 15Z SATURDAY. THE LOW CEILING AND VISIBILITIES
WILL IMPROVE TO MVFR THROUGH NOONTIME WITH LITTLE CHANCE EXPECTED
UNTIL LATE AFTERNOON WHEN THE CHANCE FOR CONVECTION WILL INCREASE.
&&

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

&&

CDC

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
300 PM CDT FRI OCT 12 2007

NEZ004>010-022>029-035>038-056>059-069>071-094-130615-
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-
300 PM CDT FRI OCT 12 2007 /200 PM MDT FRI OCT 12 2007/

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

.DAY ONE...TONIGHT.

SOUTHEAST WINDS WILL CHANNEL MOISTURE NORTHWEST ACROSS THE
FORECAST AREA TONIGHT. THE DEEPING BOUNDARY LAYER MOISTURE WILL
HELP ADVANCE LOW CLOUD CEILINGS NORTH WITH AREAS OF FOG DEVELOPING
OVERNIGHT. A FRONTAL BOUNDARY TO THE SOUTH WILL ALSO FOCUS THE
POTENTIAL FOR ISOLATED THUNDERSTORMS ACROSS THE WEST CENTRAL AND
SOUTH WEST THAT WILL SHIFT NORTHWARD OVERNIGHT. THUNDERSTORMS THAT
FORM TONIGHT WILL BE ELEVATED WITH THE POTENTIAL FOR STRONG WINDS
AND SMALL HAIL...ISOLATED SEVERE THUNDERSTORMS CANNOT BE RULED OUT.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SATURDAY THROUGH
SATURDAY NIGHT. THE PRIMARY RISK IS LARGE HAIL...DAMAGING WIND AN
VERY HEAVY RAIN. A STRONG STORM SYSTEM IS EXPECTED TO COME ACROSS
THE ROCKIES AND LINK UP WITH A NEARLY STATIONARY FRONT.
INSTABILITY AND LOW LEVEL WIND PROFILES WILL BE FAVORABLE FOR
ISOLATED SUPER CELL DEVELOPMENT SATURDAY EVENING. THEN...WIDESPREAD
RAIN AND THUNDERSTORMS ARE EXPECTED TO CONTINUE THROUGH SUNDAY.
HEAVY RAIN IS THE PRIMARY CONCERN THROUGH SUNDAY EVENING AND EARLY
MONDAY WITH WIDESPREAD 72 HOUR TOTALS EXCEEDING AND INCH AND
ISOLATED AMOUNTS GREATER THAT TWO INCHES. AT THIS TIME...IT
APPEARS THAT THE HEAVIEST RAINFALL TOTALS WILL BE IN NORTH CENTRAL
AND NORTHWEST NEBRASKA ALONG AND NORTH OF STATE HIGHWAY 2.

.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

JRS/KECK