Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 292345
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
545 PM CST THU JAN 29 2015

.SYNOPSIS...
ISSUED AT 252 PM CST THU JAN 29 2015

AT 19Z WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH CENTERED OVER
THE UPPER MISSISSIPPI RIVER VALLEY...WITH A SWATH OF DRY AIR
EXTENDING FROM NORTHERN MISSOURI INTO WESTERN NEBRASKA. LOOKING
UPSTREAM...AN UPPER LEVEL LOW WAS OFF THE COAST OF BAJA CALIFORNIA
WITH A GOOD AMOUNT OF MOISTURE BEING PUSHED NORTH AHEAD OF IT INTO
THE SOUTHWESTERN CONUS. LOCALLY...CLEAR SKIES WERE SEEN ACROSS MUCH
OF NEBRASKA IN THE WAKE OF THE SHORTWAVE TROUGH. THE SUNSHINE AND
WARMING ALOFT HAS ALLOWED DECENT MIXING OF THE BOUNDARY LAYER
TODAY...WITH TEMPERATURES IN THE 40S BEING OBSERVED ACROSS THE
FORECAST AREA. THE PRESSURE GRADIENT WEAKENED THROUGH THE DAY AS
HIGH PRESSURE BUILT IN FROM THE WEST. THE GUSTY WINDS THAT REMAINED
ACROSS PORTIONS OF THE AREA THIS MORNING SUBSIDING IN MOST LOCATIONS
BY MID AFTERNOON.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 252 PM CST THU JAN 29 2015

THE SHORTWAVE TROUGH OVER THE MISSISSIPPI RIVER VALLEY REGION WILL
HEAD EASTWARD TONIGHT AND FRIDAY...WHILE THE UPPER LOW OFF THE WEST
COAST MOVES INTO THE SOUTHWEST CONUS. THIS WILL ALLOW RIDGING ALOFT
TO BUILD IN ACROSS THE CENTRAL PLAINS...WITH 850MB TEMPERATURES
INCREASING BY 4-7 DEGREES BY LATE IN THE DAY FRIDAY.
OVERNIGHT...HIGH PRESSURE AT THE SURFACE WILL MIGRATE EAST ACROSS
NEBRASKA...CAUSING WINDS TO DIMINISH AND EVENTUALLY TURN AROUND TO
THE SOUTH BY FRIDAY MORNING IN MOST AREAS. THE AIR OVER THE FORECAST
AREA WILL REMAIN QUITE DRY SO EXPECT GENERALLY CLEAR SKIES TONIGHT.
WITH THE CLEAR SKIES AND LIGHT WINDS SHOULD GET THE BOUNDARY LAYER
TO DECOUPLE EASILY AND THUS EXPECTING STRONG RADIATIONAL
COOLING...ESPECIALLY IN VALLEYS WHERE AIR SETTLES. SO DID GO A BIT
LOWER THAN THE PREVIOUS FORECAST FOR LOWS TONIGHT ALTHOUGH STAYED A
FEW DEGREES ABOVE MAV AND MET GUIDANCE WHICH SEEM TOO COLD WITH LOWS
NEARING 10F FOR SOME AREAS.

ON FRIDAY...WITH THE UPPER LEVEL LOW TO THE SOUTHWEST MIGRATING
ONSHORE...EXPECT SOME HIGH CLOUDS TO START PUSHING NORTHEAST INTO
THE REGION. THESE CLOUDS ARE CURRENTLY SEEN OVER SOUTHWEST COLORADO
AND INTO NEW MEXICO AND WESTERN TEXAS SO WITH THE EASTWARD MOVEMENT
OF THE SYSTEM EXPECTED...SHOULD START TO SEE AN INCREASE IN CLOUD
COVER BY MID DAY FRIDAY. THINKING THE CIRRUS WILL BE FAIRLY THIN
INITIALLY...THEN THICKEN LATER IN THE AFTERNOON SO NOT ANTICIPATING
THEM TO HAVE A LARGE IMPACT ON TEMPERATURES AT THIS TIME. WENT A BIT
WARMER FOR HIGHS AS HAS BEEN THE TREND LATELY WITH THE BOUNDARY
LAYER AGAIN EXPECTED TO INCUR DECENT MIXING...LIKELY ABOVE 850MB.
THIS WOULD PUT THE FORECAST AREA IN 50S FOR AFTERNOON HIGHS.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 252 PM CST THU JAN 29 2015

A FRONT COMING INTO SOUTHERN NEBRASKA FRIDAY NIGHT AND SATURDAY WILL
BEGIN PICKING UP MOISTURE APPROXIMATELY ALONG AND SOUTH OF
INTERSTATE HIGHWAY 80. IN THAT AREA...THE SYSTEM RELATIVE ISENTROPIC
LIFT GAINS ENHANCEMENT FROM FRONTOGENESIS AND MARGINAL STABILITY TO
GENERATE SIGNIFICANT LIFT. ALTHOUGH SATURATED AIR IS LIFTED INTO THE
DENDRITIC GROWTH ZONE...TEMPERATURES IN THE LOWEST 3000 FEET ARE
EXPECTED TO BE AT OR ABOVE 0C. BY THE TIME THE LOW LEVEL
TEMPERATURES ARE BELOW 0C...THE STRONGEST LIFT WILL HAVE MOVED OFF
TO THE EAST. AS A RESULT...WE THINK THAT PRECIPITATION...IF ANY...
WILL BE A MIX OF RAIN AND SNOW SATURDAY CHANGING OVER TO SNOW
SATURDAY NIGHT. IF ANY SNOW ACCUMULATIONS DO OCCUR...IT WILL BE
QUITE LIGHT. THIS WOULD LEAVE MOST OF CENTRAL AND WESTERN NEBRASKA
WITH LITTLE POTENTIAL FOR SIGNIFICANT PRECIPITATION. THE POTENTIAL
FOR PRECIPITATION ALONG AND SOUTH OF INTERSTATE 80 WILL BE TEMPERED
BY THE UNCERTAINTY BECAUSE OF MODEL DIFFERENCES. ALSO...AS THE UPPER
TROUGH PIVOTS ACROSS NORTHERN NEBRASKA...SOME FRONTOGENETIC LIFT
BECOMES MANIFEST WITH ENHANCEMENT ALOFT IN THE RIGHT REAR QUADRANT
OF THE JET STREAK LATE SATURDAY NIGHT TO VERY EARLY SUNDAY.

AFTER A BRIEF PERIOD OF RETURN FLOW MONDAY...ANOTHER SYSTEM IS
EXPECTED TO DEVELOP OVER COLORADO MONDAY NIGHT AND TUESDAY. MOIST
AIR LIFTING UP OVER A QUASI-STATIONARY FRONT IN KANSAS WILL BRING
SOME POTENTIAL FOR SNOW TO NEBRASKA MONDAY AND TUESDAY. THE LIFT IN
THE 290-300K LAYER IS EXPECTED TO BE ENHANCED WITH FRONTOGENESIS AND
WEAK INSTABILITY. UNCERTAINTY IS HIGH REGARDING THE LOCATION OF THE
LIFT AND THE RESULTING PRECIPITATION.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 544 PM CST THU JAN 29 2015

VISUAL FLIGHT RULES CAN BE EXPECTED ACROSS WESTERN NEBRASKA THE
NEXT 24 HRS. THERE WILL BE AN INCREASE IN MID AND HIGH CLOUDINESS
BY FRIDAY AFTERNOON...ESPECIALLY ACROSS SOUTHWEST NEBRASKA. LIGHT
AND VARIABLE WINDS TONIGHT WILL BECOME SOUTH TO SOUTHWEST 12G18KT
AFTER 18Z.

&&

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

$$

SYNOPSIS...BROOKS
SHORT TERM...BROOKS
LONG TERM...SPRINGER
AVIATION...ROBERG







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