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000
FXUS63 KLBF 150215 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
915 PM CDT TUE MAY 14 2013

.SYNOPSIS...
ISSUED AT 307 PM CDT TUE MAY 14 2013

RIDGING ALOFT ACROSS THE WESTERN CONUS...HAS BEGUN TO
BREAK DOWN THIS MORNING AS A DECENT JET STREAK AND DISTURBANCE
TRAVERSES THE NORTHERN ROCKIES AND NRN HIGH PLAINS. DECENT H5 HT
FALLS WERE NOTED THIS MORNING...WITH 70 METER FALLS AT GREAT FALLS
MT AND 100 METER FALLS AT GLASGOW MT. FURTHER EAST...A TROUGH OF LOW
PRESSURE ALOFT EXTENDED FROM QUEBEC SWD INTO NEW ENGLAND...WHILE A
CLOSED LOW WAS PRESENT OVER NWRN MEXICO. AT THE SURFACE...A COLD
FRONT WAS ANCHORED ACROSS NORTHERN NEBRASKA...AND THE SRN
PROGRESSION OF THIS FEATURE HAS SLOWED OVER THE PAST COUPLE OF HOURS
AND AS OF 2 PM CDT...WAS PRESENT FROM KLBF TO KODX. AS OF 2 PM
CDT...TEMPERATURES RANGED FROM...85 AT VALENTINE...TO 96 AT IMPERIAL.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 307 PM CDT TUE MAY 14 2013

ABNORMALLY WARM AND DRY CONDITIONS TODAY HAVE ALLOWED FOR WIDESPREAD
RFW CRITERIA...THUS THE RED FLAG WARNING WILL REMAIN IN EFFECT
THROUGH 02Z THIS EVENING FOR NE FIRE ZONES 206...208 & 209.
OTHERWISE THE FOCUS OF THE SHORT TERM PERIODS SHIFTS TO STORM
CHANCES ACROSS OUR SOUTHERN AND SOUTHWESTERN ZONES THIS EVENING AND
TONIGHT.  A COLD FRONT HAS RAPIDLY DROPPED SOUTH ACROSS MUCH OF THE
FORECAST AREA...SAVE FOR THE FAR SOUTHEASTERN PORTIONS OF THE CWA.
THE COLD FRONT...AND ADDITIONALLY A PRE-FRONTAL TROUGH...ARE
CURRENTLY ACTING AS A FOCUSING MECHANISM...WITH AGITATED CU NOTED ON
THE REGIONAL VISIBLE SATELLITE STRETCHING FROM THE LEE OF THE PALMER
DIVIDE NORTHEAST THROUGH FAR NORTHWEST KANSAS INTO SOUTH CENTRAL
NEBRASKA.  THE INITIAL CELLS HAVE THUS FAR STRUGGLED ACROSS FAR
SOUTHWEST NEBRASKA EARLY THIS AFTERNOON...OWING MAINLY TO THE
ABNORMALLY DRY LOWER LEVELS.  HOWEVER MODEL GUIDANCE DOES INDICATE
THE POTENTIAL THAT A STORM OR TWO MAY BE ABLE TO MAINTAIN ITSELF.
PROXIMITY SOUNDINGS ACROSS SOUTHWEST NEBRASKA MAINTAIN AN INVERTED V
PROFILE WELL INTO THE OVERNIGHT...THUS VERY LITTLE RAIN WOULD BE
ANTICIPATED UNDER ANY STORM THAT CAN DEVELOP.  GUSTY ERRATIC WINDS
WOULD BE A CONCERN HOWEVER.  ALSO CANNOT ENTIRELY RULE OUT A NON
SUPERCELL SPIN UP THIS AFTERNOON/EARLY EVENING AS 0-1KM LAPSE RATES
ARE VERY STEEP AND CORRESPOND WELL WITH WEAK DEEP LAYER SHEAR AND
SUFFICIENT INSTABILITY.  SPC NON-SUPERCELL TORNADO PARAMETER HAS
CONSISTENTLY INCREASED THROUGHOUT THE AFTERNOON...WITH VALUES OF 5
NOW SHOWN ACROSS FRONTIER COUNTY NORTHEAST INTO FAR SOUTHEASTERN
CUSTER COUNTY.  INTO THE OVERNIGHT...NEAR TERM SOLUTIONS HINT AT
ACTIVITY BUILDING NORTHEAST FROM THE HIGHER TERRAIN OF EASTERN
COLORADO/WYOMING.  HAVE GENERALLY DOWNPLAYED THIS POTENTIAL WITH THE
WEAK STEERING CURRENTS AND DRY LOW LEVELS...BUT WILL LEAVE SLIGHT
CHANCES IN ACROSS OUR FAR WEST FOR NOW.

WITHIN A POST FRONTAL REGIME...TEMPERATURES ON WEDNESDAY WILL BE
NOTICEABLY COOLER...HIGHS IN THE UPPER 70S TO LOWER 80S SHOULD
PREVAIL.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 307 PM CDT TUE MAY 14 2013

WEDNESDAY NIGHT THROUGH FRIDAY...THE MAIN FORECASTING CHALLENGES
IN THE MID RANGE ARE PRECIPITATION CHANCES THURSDAY AND FRIDAY. AS
WAS THE CASE YESTERDAY...BOTH THE NAM AND GFS INITIALIZED WELL
WITH A DECENT MID LEVEL SHORTWAVE NOTED OFF THE COAST OF CENTRAL
CALIFORNIA. BOTH MODELS TRACK THIS FEATURE EAST ACROSS THE CENTRAL
ROCKIES THROUGH 48 HOURS. AS WAS THE CASE YESTERDAY...THE NAM IS
FASTER WITH THIS FEATURE THROUGH WEDNESDAY...ABOUT 12 HOURS
FASTER...WHICH PLACES THIS FEATURE IN EASTERN COLORADO BY 00Z
THURSDAY (WEDNESDAY EVENING). THE GFS HAS THIS FEATURE IN EASTERN
COLORADO BY 12Z THURSDAY. SINCE THE GFS HAS REMAINED CONSISTENT
WITH THE TIMING OF THIS FEATURE...WILL LEAN TOWARD A DRY FCST WEDS
NIGHT AND START POPS IN THE WEST THURSDAY MORNING...AND CONTINUE
THEM EAST INTO THE REMAINDER OF THE FORECAST AREA THROUGH THURSDAY
EVENING. THE UPPER LEVEL PATTERN WILL AMPLIFY FURTHER THURSDAY
NIGHT INTO FRIDAY. THIS WILL STRENGTHEN A LEE SIDE TROUGH OFF TO
THE WEST OF THE FORECAST AREA...LEADING TO INCREASING SRLY WINDS
AND AN INFLUX OF LOW LEVEL MOISTURE. DECIDED TO INCREASE CLOUD
COVER IN THE WESTERN CWA FRIDAY MORNING AS THE INFLUX OF MOISTURE
MAY LEAD TO THE DEVELOPMENT OF LOW CLOUDINESS. THIS IS SUPPORTED
BY THE LATEST NAM AND MET AND MAV GUIDANCE. WITH SRLY WINDS
EXPECTED ACROSS THE CWA FRIDAY AND BACKED WINDS WELL NORTH OF THE
FORECAST AREA...LOW LEVEL CLOUDS WILL BURN OFF BY LATE MORNING.
THE FORECAST THEN SHIFTS TO THE THREAT FOR THUNDERSTORMS IN THE
WEST FRIDAY AFTERNOON AS A LEAD DISTURBANCE CROSSES THE CENTRAL
ROCKIES...LIFTING INTO THE WESTERN DAKOTAS. A WELL PRONOUNCED DRY
LINE WILL EXTEND FROM THE EASTERN PANHANDLE INTO EASTERN COLORADO
FRIDAY AFTERNOON. THE CAP WILL BE WEAKEST IN NEBRASKA AND SOUTH
DAKOTA...WITH IT REMAINING FAIRLY STRONG IN WESTERN KANSAS. WITH
THE H5 WINDS ORIENTED SSW TO NNE...THE BULK OF THE ACTIVITY IS
EXPECTED TO REMAIN WEST OF NORTH PLATTE THROUGH FRIDAY AFTERNOON.
DEEP LAYER SHEAR FRIDAY AFTERNOON WILL BE ON THE ORDER OF 25 TO 35
KTS ACROSS THE PANHANDLE AND WESTERN AREAS...SO MAINLY STRONG
STORMS ARE EXPECTED WITH THE THREAT FOR SEVERE STORMS RELATIVELY
LOW.

FRIDAY NIGHT THROUGH TUESDAY...THE BEFOREMENTIONED TROUGH OF LOW
PRESSURE WILL APPROACH THE CENTRAL PLAINS SATURDAY AND SATURDAY
NIGHT. SHOWERS AND THUNDERSTORMS WILL DEVELOP SATURDAY AFTERNOON AND
EVENING...AND TRAVERSE EAST INTO CENTRAL AND EASTERN NEBRASKA
SATURDAY NIGHT. SUFFICIENT SHEAR EXISTS...ALONG WITH PLENTY OF
MOISTURE...FOR SEVERE THUNDERSTORMS SATURDAY AFTERNOON AND SATURDAY
NIGHT. ATTM...FAR EASTERN PORTIONS OF THE FORECAST AREA ARE
OUTLOOKED FOR SEVERE WEATHER SATURDAY. THINKING HERE IS THAT THE
SEVERE THREAT WILL BE FURTHER WEST...ENCOMPASSING AT LEAST THE
CENTRAL...AND PORTIONS OF THE WESTERN CWA SATURDAY AND SATURDAY
NIGHT. THIS IS DUE TO INCREASED AMPLIFICATION OF THE H5 TROUGH AND
LOW LEVEL MOISTURE BEING PRESENT ACROSS MOST OF THE FORECAST
AREA...THE EXCEPTION BEING THE EASTERN PANHANDLE. BEYOND
SATURDAY...NO MAJOR CHANGES PLANNED TO THE EXTENDED ATTM.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 608 PM CDT TUE MAY 14 2013

VFR/MVFR IS EXPECTED OVERNIGHT...VFR IS EXPECTED WEDNESDAY. THE
DEVELOPING CLUSTER OF SHOWERS AND THUNDERSTORMS WEST OF KAIA
THROUGH KDGW SHOULD MOVE EAST THIS EVENING AND DISSIPATE ACROSS
WRN NEB. THE HRRR MODEL SHOWS THE ACTIVITY BECOMING MORE NUMEROUS
WITH A DAMAGING WIND THREAT WHILE THE RAP13 MODEL SHOWS THE
ACTIVITY FALLING APART BEFORE REACHING WRN NEB. GIVEN THE ONGOING
MOISTURE ADVECTION...THE HRRR IS FAVORED. STORM ACTIVITY COULD
REMAIN STRONG THROUGH 05Z AND WEAKEN AND DISSIPATE BY AROUND 08Z-
10Z. VFR IS EXPECTED THEREAFTER.


&&

.FIRE WEATHER...
ISSUED AT 913 PM CDT TUE MAY 14 2013

RELATIVE HUMIDITY AND WIND CONDITIONS HAVE IMPROVED THIS EVENING
AS TEMPERATURES DROP AND WINDS CONTINUE TO DIMINISH. BECAUSE OF
THIS...THE RED FLAG WARNING WHICH WAS IN PLACE FOR FIRE ZONES
206...208...AND 209 HAS BEEN ALLOWED TO EXPIRE AT 9 PM.

&&

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

$$

SYNOPSIS...CLB
SHORT TERM...JACOBS
LONG TERM...CLB
AVIATION...CDC
FIRE WEATHER...BROOKS