Area Forecast Discussion
Issued by NWS North Platte, NE

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KLBF 211125
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
525 AM CST WED JAN 21 2015

.SYNOPSIS...
ISSUED AT 348 AM CST WED JAN 21 2015

THE 0745Z WATER VAPOR IMAGERY SHOWED A POTENTIAL VORTICITY ANOMALY
OVER SOUTHERN IDAHO...NORTHERN UTAH AND SOUTHWEST WYOMING JUST
SOUTHWEST OF AN OPEN CYCLONIC CIRCULATION FROM NORTH DAKOTA TO
NORTHEAST IDAHO. THERE WAS ALSO AN ANOMALY IN SOUTHERN CALIFORNIA
AND NORTHERN BAJA WHERE AN UPPER TROUGH WAS DIGGING. THERE WAS
STRONG POTENTIAL VORTICITY ANOMALY OVER THE SOUTHWEST YUKON TO THE
GULF OF ALASKA. THE 08Z MSL ANALYSIS SHOWED A FRONT DRAPED FROM
SOUTHERN MINNESOTA...THROUGH THE DAKOTAS AND PRAIRIE PROVINCES...TO
A LOW IN THE GULF OF ALASKA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 348 AM CST WED JAN 21 2015

AS THE UPPER TROUGH PIVOTS THROUGH NEBRASKA THIS AFTERNOON AND
EVENING...SOME FRONTOGENETIC LIFT DEVELOPS IN THE 275-290K MOIST
LAYER BUT THE UPWARD MOTION IS NOT REAL STRONG. STILL...WITH
MOISTURE AND UPWARD MOTION...ISOLATED LIGHT SNOW SHOWERS ARE
POSSIBLE THIS AFTERNOON AND EARLY EVENING IN NORTHERN NEBRASKA.  THE
ASSOCIATED FRONT...NOW ACROSS THE DAKOTAS...WILL BRING SIGNIFICANTLY
LOWER TEMPERATURES TODAY AND TONIGHT WHEN COMPARED TO THIS MORNING
AND YESTERDAY.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 348 AM CST WED JAN 21 2015

PRIMARY FORECAST CHALLENGES THROUGH THIS PERIOD DEAL WITH
TEMPERATURES AND WINDS.

MODEL SOLUTIONS ARE IN GOOD AGREEMENT THROUGHOUT THE NEXT 7 DAYS
IN TERMS OF THE LARGE SCALE PATTERN ALTHOUGH THERE IS SOME
DIFFERENCES IN TIMING OF THE WEAK SHORTWAVE TROUGHS MOVING ACROSS
THE REGION. SENSIBLE WEATHER IMPACTS FROM THESE DIFFERENCES WILL
BE MINIMAL AS DRY AIR WILL BE DOMINANT LEADING TO LITTLE OR NO
CHANCES FOR PRECIPITATION LOCALLY EVEN AS THESE SYSTEMS MOVE
ACROSS THE AREA.

BEGINNING ON THURSDAY...AN ELONGATED AREA OF LOW PRESSURE ALOFT
FROM THE FOUR CORNERS INTO THE OHIO RIVER VALLEY WILL HAVE PASSED
THROUGH NEBRASKA BRINGING SUBSIDENT AIR TO THE REGION...ALONG WITH
WARMER AIR. THE MODELS ARE SHOWING THE WARMER AIR /850MB
TEMPERATURES GREATER THAN 0C/ WILL MOVE INTO THE FORECAST AREA
MAINLY IN THE MID TO LATE AFTERNOON HOURS SO ALTHOUGH TEMPERATURES
WILL BE WARMER THURSDAY THAN TODAY...THINKING HIGHS WILL BE
LIMITED TO THE LOW TO MID 40S EVEN WITH GOOD AFTERNOON MIXING
OF THE BOUNDARY LAYER WHICH IS ASSUMED WILL OCCUR. LOWS THURSDAY
NIGHT ARE A BIT PROBLEMATIC. A WARM FRONT MOVES INTO WESTERN
NEBRASKA OVERNIGHT WITH WINDS INCREASING BEHIND IT. BUT AHEAD OF
THE SYSTEM WINDS SHOULD DROP OFF AND WITH MOSTLY CLEAR SKIES
DECOUPLING SHOULD OCCUR WITH GOOD RADIATIONAL COOLING. SO THE
QUESTION IS HOW MUCH TIME THE AREA WILL HAVE TO GET TEMPERATURES
TO DROP BEFORE THE FRONT MOVES IN TO START WARMING THINGS UP. MANY
OF THE FORECAST MODEL SOLUTIONS PROVIDED DATA WITH LOWS QUITE
COLD BUT WITH THE APPROACHING FRONT AND INCREASING WINDS...FELT
THESE SOLUTIONS WOULD BE TOO COLD SO KEPT TEMPERATURES SIMILAR TO
THE PRIOR FORECAST.

TEMPERATURES WARM A BIT ON FRIDAY...BUT NOT SIGNIFICANTLY AS 850MB
TEMPERATURES ARE LOOKING TO RISE TO ABOUT 2C-3C ACROSS THE LOCAL
AREA. WHAT WILL HELP WITH THE WARMING IS THAT AGAIN GOOD MIXING IS
EXPECTED WITH BREEZY WEST TO NORTHWEST WINDS SO SHOULD SEE HIGHS
RISE ABOVE NORMAL...INTO THE UPPER 40S AND LOW 50S ACROSS THE
AREA. DID ADJUST WINDS UP A BIT FOR FRIDAY AFTERNOON. THINKING
MANY AREAS /ESPECIALLY OVER THE SOUTHEAST HALF OF THE FORECAST
AREA WHERE NO SNOWPACK REMAINS/ WILL AT LEAST SEE MIXING TO
850MB. AT THIS LEVEL WINDS ARE PROJECTED TO BE AT 30-40KTS.

WHILE THIS IS OCCURRING...THE SYSTEM NOW OVER SOUTHERN CALIFORNIA
WILL TRACK EAST ACROSS THE SOUTHERN PLAINS. THIS WILL ALLOW
RIDGING TO BUILD EASTWARD FROM THE WESTERN CONUS INTO THE PLAINS.
BY SATURDAY AFTERNOON THE UPPER LEVEL PATTERN WILL BE WEST COAST
RIDGE/EAST COAST TROUGH KEEPING THE LOCAL AREA IN NORTHWEST FLOW
DESPITE THE WARM AIR MOVING EAST FROM UNDER THE RIDGE. BY LATE IN
THE DAY SATURDAY 850MB TEMPERATURES ARE LOOKING TO INCREASE TO
AROUND 5-8C...THEN TO 8-10C BY SUNDAY AFTERNOON.

A SHORTWAVE TROUGH WILL TOP THE RIDGE AND MOVE THROUGH THE FLOW
ACROSS THE NORTHERN PLAINS SATURDAY NIGHT THEN INTO THE MID
MISSISSIPPI RIVER VALLEY REGION ON SUNDAY. THE MODELS SHOW THIS
BEING A FAIRLY POTENT SYSTEM WITH A STRONG ASSOCIATED PV ANOMALY.
AS THIS PASSES...IT WILL BRING THE ONLY CHANCE FOR SOME
PRECIPITATION TO THE FORECAST AREA DURING THE NEXT WEEK...AND IT
IS A SMALL CHANCE WITH THE MAJORITY OF THE MOISTURE AND UPWARD
MOTION SEEN NORTH OF THE FORECAST AREA. TIMING FOR THE BEST CHANCE
FOR PRECIPITATION WILL BE SATURDAY AFTERNOON AND EVENING...WITH
CHANCES DIMINISHING BEYOND 06Z SUNDAY. WHAT IS LOOKING LIKELY WILL
BE STRONGER WINDS FOR BOTH SATURDAY AND SUNDAY. MORE CLOUD COVER
IS EXPECTED FOR SATURDAY WITH A WEAKER PRESSURE GRADIENT AT THE
SURFACE SO MIXING MAY NOT BE AS SUBSTANTIAL AS IS EXPECTED FOR
SUNDAY AS THE AREA WILL BE ON THE BACKSIDE OF THE SYSTEM AS WELL
AS IN THE RIGHT EXIT REGION OF THE UPPER LEVEL JET...LEADING TO
STRONG SUBSIDENCE. THAT BEING SAID...THE PRESSURE GRADIENT ON
SUNDAY ISN/T TERRIBLY TIGHT EITHER...BUT WITH MIXING LOOKING
LIKELY TO 800MB OR HIGHER STRONG WINDS OF 40-50KTS SHOULD BE
REALIZED AT THE SURFACE.

THEN FOR MONDAY AND TUESDAY...THE MAIN STORY WILL BE TEMPERATURES
AS THE UPPER LEVEL RIDGE SHIFTS EAST. BY TUESDAY IT SHOULD BE
ORIENTED FROM THE PACIFIC NORTHWEST INTO NORTHERN MEXICO.
TEMPERATURES ALOFT WILL CONTINUE TO RISE WITH THE MODELS SHOWING
850MB TEMPERATURES UP TO 12-14C ACROSS SOUTHERN NEBRASKA TUESDAY
AFTERNOON. TEMPERATURES HAVE BEEN INCREASED BY SEVERAL DEGREES
ACROSS THE ENTIRE FORECAST AREA WITH 60 DEGREE READINGS LOOKING
VERY POSSIBLE...ESPECIALLY OVER SOUTHWEST NEBRASKA. FORECAST
TEMPERATURES FROM THE MODELS CONTINUE TO SHOW AN IMPACT FROM
SNOWCOVER OVER THE PANHANDLE AND NORTHERN NEBRASKA BUT UNSURE OF
HOW MUCH OF AN IMPACT THIS WILL HONESTLY HAVE INTO TUESDAY AS THE
SNOW SHOULD BE CONTINUING TO DIMINISH THROUGH THE NEXT 5 DAYS. IF
NEEDED THESE AREAS CAN BE TRENDED UPWARD IN UPCOMING FORECASTS. AT
THIS TIME...STANDARDIZED ANOMALIES ARE WARM FOR THE REGION FOR
MONDAY AND TUESDAY...BUT NOT AS STRONG AS WAS EXPECTED. DATA IS
SHOWING 1-2 STANDARD DEVIATIONS ABOVE NORMAL SO ALTHOUGH IT WILL
BE WARM...MAY BE A WAYS FROM NEARING RECORD VALUES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 522 AM CST WED JAN 21 2015

CEILINGS ARE EXPECTED TO BE ABOVE 3000 FEET AGL THROUGH MID
MORNING. SOME MARGINAL CEILINGS ARE POSSIBLE IN NORTHERN NEBRASKA
AFTER 14Z AND CONTINUING THROUGH EARLY THIS EVENING ABOUT 03Z.
WIND 300-340 WILL INCREASE TO 13-15G20-25KT BY 18Z.

&&

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

$$

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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.