Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 261705
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1105 AM CST WED NOV 26 2014

.SYNOPSIS...
ISSUED AT 403 AM CST WED NOV 26 2014

CLIPPER SYSTEM CURRENTLY MOVING SOUTHEAST THROUGH THE MID
MISSOURI VALLEY. COLDER AIR BEHIND THE COLD FRONT IS DROPPING INTO
NORTHERN NEBR. SOME SNOW SHOWERS LINGER IN ERN AND NERN SOUTH
DAKOTA AND ACROSS PARTS OF WYOMING INTO NERN COLORADO. ACROSS
WESTERN NEBRASKA...ISOLATED SNOW SHOWERS CONTINUE AS TEMPERATURES
MAINLY RANGE IN MID 30S.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 403 AM CST WED NOV 26 2014

A CLIPPER WILL MOVE QUICKLY SOUTHEAST TODAY...WITH ASSOCIATED
SURFACE LOW CENTER MOVING FROM SOUTHWEST IOWA EARLY THIS MORNING
INTO WESTERN KENTUCKY BY EARLY THIS EVENING. SCATTERED FLURRIES
EXPECTED FROM THE EASTERN PANHANDLE INTO WESTERN CHERRY COUNTY
TODAY...THEN EAST ACROSS NORTH CENTRAL NEBRASKA TONIGHT. TIME
SECTION IN NORTHERN SHERIDAN COUNTY REVEAL INCREASING DEEP MOISTURE
TODAY WITH FAVORABLE DENDRITIC TEMPERATURES. WHAT WILL BE LACKING
IS LIFT. ONLY POCKETS OF WEAK OMEGA WITHIN OVERALL WEAK SUBSIDENCE
TODAY INTO THIS EVENING. SIMILAR TIME SECTIONS EASTWARD ACROSS
NORTHERN NEBRASKA THROUGH TONIGHT. COLDER AIR WILL BE DRAWN INTO
WESTERN NEBRASKA TODAY WITH H85 TEMPS HOLDING NEAR -7C AT ONL...AND
MODERATING TO -2C TO -4C ACROSS SWRN NEBR. TEMPERATURES CURRENTLY IN
THE LOWER AND MID 30S IN NORTHERN NEBRASKA WILL FALL INTO THE LOWER
TO MID 20S THIS MORNING AND RECOVER MOSTLY INTO THE UPPER 20S FOR
DAYTIME HIGHS. HIGHS IN SWRN NEBR TO REACH THE UPPER 30S TO NEAR 40.
40S TO LOWER 50S ACROSS SWRN NEBR. TEMPERATURES A FEW DEGREES ABOVE
LATEST MET/MAV MOS GUIDANCE BLEND. BREEZY TO WINDY CONDITIONS THIS
MORNING WILL DIMINISH FROM WEST TO EAST TODAY. IN FACT BY THIS
AFTERNOON...WINDS ACROSS THE WESTERN HALF WILL RANGE FROM 5 TO 15
MPH.

MAINLY CLOUDY SKIES TONIGHT AS SCATTERED FLURRIES MOVE EASTWARD IN
NORTH CENTRAL OVERNIGHT. THERE WILL BE WARM AIR ADVECTION OCCURRING
TONIGHT AS WELL...AS H8 FRONT MOVES EAST TO NEAR A VTN AND BBW LINE BY
12Z WEDNESDAY. THIS REFLECTED SOMEWHAT IN TEMPERATURES RANGING FROM
THE LOWER 20S WESTERN SANDHILLS TO THE MID TEENS EAST.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 403 AM CST WED NOV 26 2014

FORECAST CONCERNS LARGELY DEAL WITH TEMPERATURES AS MODELS ARE
CONTINUING TO INDICATE ANOMALOUSLY WARM TEMPERATURES FOR THE END
OF THE WEEK...THEN WITH COLD TEMPERATURES RETURNING FOR THE START
OF NEXT WEEK.

MODELS ARE IN FAIR AGREEMENT THROUGH LATER THIS WEEK BUT THERE
BEGINS TO BE ENOUGH CHANGES COMING INTO PLAY BY THE WEEKEND TO
LOWER CONFIDENCE GOING INTO THESE PERIODS. THE PRIMARY DIFFERENCE
HAS TO DO WITH THE EVOLVEMENT OF AN UPPER LEVEL SHORTWAVE TROUGH
AS IT MOVES FROM THE PACIFIC NORTHWEST INTO THE NORTHERN PLAINS.
THE GFS IS CURRENTLY THE FASTEST SOLUTION WHICH KEEPS THIS WAVE
LESS AMPLIFIED THAN THE ECMWF AND GEM SOLUTIONS. THE MODELS SEE
FURTHER DIVERGING THROUGH THE MIDDLE OF NEXT WEEK WHICH LED TO LOW
CONFIDENCE IN THE FORECAST PAST MONDAY WITH A BLEND OF THE MODEL
SOLUTIONS BEING USED FOR THE FORECAST.

QUIET WEATHER IS EXPECTED FOR THURSDAY AS RIDGING BEGINS TO BUILD
INTO THE CENTRAL PLAINS. THIS WILL LEAD TO WARMING TEMPERATURES
ALOFT...AND DO EXPECT THIS TO TRANSLATE TO THE
SURFACE...ESPECIALLY OVER WESTERN NEBRASKA. LOOKING INTO NORTH
CENTRAL NEBRASKA...A LARGE SURFACE HIGH WILL BE CENTERED OVER THE
MISSISSIPPI RIVER VALLEY WHICH WILL KEEP SOUTHEAST DRY AND COOL
FLOW INTO THESE AREAS. 850MB TEMPERATURES DO INCREASE BY AROUND
10C OVER THE FAR NORTHEAST PORTION OF THE FORECAST AREA...BUT
FORECAST SOUNDINGS SHOW THE BOUNDARY ONLY MIXING TO AROUND 900MB
IN THOSE LOCATIONS WHICH WOULD PUT HIGHS IN THE LOW TO MID 30S.
MEANWHILE OVER SOUTHWEST NEBRASKA...MIXING TO NEAR 850MB WITH
TEMPERATURES AT THAT LEVEL AROUND 13C WOULD BRING HIGHS TO AROUND
60.

A WARM FRONT MOVES ACROSS NEBRASKA THURSDAY NIGHT...FURTHER
INCREASING THE WARM AIR ADVECTION AND SWITCHING THE WINDS TO FAVORED
WARM DOWNSLOPE FLOW THROUGH FRIDAY. THE ECMWF WAS THE PREFERRED
SOLUTION WHICH HAS A STRONGER 850 AND 700MB LOW OVER SOUTHERN
SASKATCHEWAN BY 00Z FRIDAY. THIS IMPACTS THE STRENGTH OF THE WARM
AIR COMING INTO THE AREA...WITH THE ECMWF INCREASING 850MB
TEMPERATURES FOR THE ENTIRE FORECAST AREA ABOVE 12C. GETTING INTO
SOUTHERN NEBRASKA...THESE READINGS INCREASE TO NEAR 19C. FORECAST
SOUNDINGS OVER SOUTHWEST NEBRASKA SHOW BOUNDARY LAYER MIXING TO
NEAR 800 MB. THE WESTERLY WINDS WON/T BE REAL STRONG AS WINDS AT
THE TOP OF THE MIXED LAYER REMAIN UNDER 15KTS SO THEY WON/T HAVE A
LARGE IMPACT...BUT JUST MIXING THE WARM AIR TO THE SURFACE SHOULD
GIVE TEMPERATURES IN THE 50S AND 60S TO THE ENTIRE FORECAST AREA
WITH THE POTENTIAL FOR 70 DEGREE READINGS IN PLACES. OVERNIGHT
LOWS BOTH THURSDAY AND FRIDAY NIGHTS SHOULD STAY ABOVE NORMAL WITH
THE WARMER AIR IN PLACE...HOWEVER LIGHT WINDS AND CLEAR SKIES
SHOULD ENHANCE RADIATIONAL COOLING SO LOWS ARE NEAR OR SLIGHTLY
BELOW THE STATISTICAL GUIDANCE.

THE FORECAST HIGHS FOR SATURDAY HAVE BEEN INCREASED A BIT AS
MODELS HAVE TRENDED BACK TO A SLOWER PASSAGE OF THE NEXT COLD
FRONT WHICH IS NOW AGAIN MOVING ACROSS THE FORECAST AREA SATURDAY
NIGHT. AS THE MODELS HAVE BEEN HAVING A HARD TIME PICKING UP ON
THE TIMING OF THIS DIDN/T WANT TO GO TOO WARM...DESPITE THE ECMWF
KEEPING 850MB TEMPERATURES AT 13-18C OVER THE FORECAST AREA. IF
THIS TREND CONTINUES...MAY BE ANOTHER DAY OF 70 DEGREE POTENTIALS
OVER SOUTHERN NEBRASKA.

THE COLD FRONT MOVING IN FOR SUNDAY WILL BRING MUCH COLDER AIR
BACK TO THE REGION...HOWEVER AGAIN THERE ARE DISCREPANCIES BETWEEN
MODEL SOLUTIONS OF EXACTLY HOW COLD. AS MENTIONED
PREVIOUSLY...TRENDED TOWARDS THE ECMWF WHICH IS THE COLDER
SOLUTION AND DROPS 850MB TEMPERATURES DOWN TO A RANGE OF -11 TO
-18 BY 00Z MONDAY. THE CURRENT FORECAST HAS HIGHS FOR SUNDAY IN
THE 20S AND 30S...BUT IT IS POSSIBLE FOR THOSE TO BE TOO WARM IF
THE ECMWF ENDS UP BEING CORRECT. THINK ALSO THAT IT WILL BE LIKELY
THAT WINDS WILL NEED TO BE INCREASED BEHIND THE FRONT. A TIGHT
PRESSURE GRADIENT AND STRONG COLD AIR ADVECTION AND SUBSIDENCE
BEHIND THE FRONT SHOULD LEAD TO MIXING OF THE MIXED LAYER AND
BREEZY TO STRONG WINDS. WILL CONTINUE TO WATCH THIS IN COMING
FORECASTS. SUNDAY NIGHT/MONDAY MORNING SHOULD BE THE COLDEST
PERIOD OF THE NEXT WEEK AS THE COLD AIRMASS REMAINS IN PLACE AND
HIGH PRESSURE IS SET TO BE OVER THE AREA. CURRENTLY HAVE LOWS
IN THE LOW TEENS BUT MAY NEED TO GO COLDER ESPECIALLY IF THE HIGH
ENDS UP DIRECTLY OVERHEAD.

LOOKING FURTHER INTO THE WEEK...AS SAID PREVIOUSLY...LARGE MODEL
DIVERGENCE OCCURS WITH AT ONE POINT THE AREA BEING UNDER COMPLETE
OPPOSITE FLOW. IN GENERAL THOUGH...THE COLD AIRMASS FROM EARLY IN
THE WEEK SHOULD MOVE OFF TO THE EAST ALLOWING TEMPERATURES TO AT
LEAST WARM TO NEAR NORMAL...EVEN IF NORTHWEST FLOW WOULD PERSIST.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1105 AM CST WED NOV 26 2014

.AVIATION...MODEL GUIDANCE CONTINUES TO INDICATE MVFR OR LOWER
CEILINGS THAT WILL EVENTUALLY BREAK THIS AFTERNOON AT KLBF.  SKIES
ARE ANTICIPATED TO BE VFR BY 20Z.  AT KVTN...SKIES WILL REMAIN
OVERCAST THROUGH MUCH OF THE DAY...IN FACT MUCH OF THE NEAR TERM
GUIDANCE INDICATES KVTN REMAINING AT MVFR OR LOWER THROUGH THE
FORECAST CYCLE.  WILL BRIEFLY INCLUDE A SCT030 CEILING THIS
AFTERNOON AT KVTN...BUT THEN TREND SKIES BELOW MVFR THIS EVENING.
OTHERWISE -SN IS CURRENTLY FALLING ACROSS THE EASTERN
PANHANDLE...IMPACTS FROM THE SNOW THIS AFTERNOON WILL BE MINIMAL AS
VISBY REDUCTIONS WILL ONLY FALL BRIEFLY BLO 6SM...THIS SNOW IS NOT
ANTICIPATED TO IMPACT KLBF OR KVTN.

&&

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

$$

SHORT TERM...ROBERG
LONG TERM...BROOKS
AVIATION...KECK/JACOBS






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