Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 211141 AAA
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
541 AM CST FRI NOV 21 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 338 AM CST FRI NOV 21 2014

ALL MODELS IN GOOD AGREEMENT IN THE NEAR TERM AND POINTING TOWARDS
A WARM UP TODAY. SOUTHERLY FLOW AND INCREASING MID CLOUDS WILL
HELP TO KEEP TEMPERATURES UP EARLY THIS MORNING WITH A WARM START
TO THE DAY. WARM FRONT WILL CONTINUE TO MOVE TO THE NORTHEAST
ACROSS THE NORTHERN PLAINS TODAY. STILL ABOUT AN INCH OF SNOW
ALONG AND NORTH OF HIGHWAY 20 TO THE SOUTH DAKOTA BORDER.
TEMPERATURE GRIDS WILL CONTINUE TO REFLECT THIS SNOW FIELD TODAY
AND TONIGHT. 850MB TEMPERATURES CLIMB TOWARDS 12C BY 22/18Z.
BELIEVE TEMPERATURE FORECAST MAY BE UNDER DONE AGAIN TODAY BUT
HAVE PUSHED THE ENVELOPE. HIGH TEMPERATURES YESTERDAY OUT DID
GUIDANCE BY A 1 CATEGORY AND BELIEVE THIS IS POSSIBLE AGAIN TODAY
WITH MODEL BIAS BASED ON SNOW COVER. PARTLY TO MOSTLY CLOUDY TODAY
WITH CLOUDS DECREASING THIS EVENING AND ANOTHER MILD EVENING WITH
GOOD WARM AIR ADVECTION. LOW TEMPERATURES IN THE 20S. DRY.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 338 AM CST FRI NOV 21 2014

12Z SATURDAY AND BEYOND.  A LEE SIDE SFC TROUGH WILL DEEPEN THROUGH
THE DAY ON SATURDAY...ALLOWING FOR A SOUTHWEST TRAJECTORY OF THE
LOWER TROPOSPHERIC WIND ACROSS THE ENTIRE CWA.  H85 TEMPERATURES BY
00Z SUNDAY WILL BE IN THE 9 TO 11 C RANGE...WHICH WOULD PROMOTE
HIGHS GENERALLY IN THE 50S AND 60S FOR MOST LOCATIONS.  GUIDANCE AS
OF LATE HAS SHOWN A COOL BIAS WITH THE NAM IMPACTED STILL BY
PERCEIVED SNOWPACK...THUS THE HIGH TEMPERATURE FORECAST WILL TRENDED
TOWARD THE WARMER MAV...AND THEN MANUALLY ADJUSTED A FEW DEGREES
WARMER FROM THERE.  THE FORECAST CALLS FOR LOWER 60S FOR ALL
LOCATIONS ALONG AND SOUTH OF INTERSTATE 80 NOW.  A COLD FRONT
HOWEVER WILL COOL TEMPERATURES FOR SUNDAY SOME 10-15 DEGREES.  LIGHT
PRECIPITATION...OR POSSIBLY FLURRIES/SPRINKLES WILL BE POSSIBLE
EARLY SUNDAY WITH THE PASSAGE OF THE UPPER TROUGH...HOWEVER BOTH THE
NAM AND THE GFS INDICATE A LESS THAN IDEAL MOISTURE PROFILE.  FOR
THIS WOULD LIKE TO SEE ANOTHER SET OF MODEL RUNS BEFORE ADDING A QPF
MENTION. NOTE HOWEVER A LIGHT SNOW MENTION WAS CONTINUED EARLY
SUNDAY ACROSS NORTHWEST NEBRASKA AS THE MODELS CONTINUE TO SHOW
BETTER MOISTURE IN PLACE.

SNOW CHANCES REMAIN ACROSS NORTHERN NEBRASKA SUNDAY NIGHT INTO
MONDAY AS A CLOSED UPPER LEVEL LOW MOVES FROM THE EASTERN DAKOTAS
TOWARDS THE GREAT LAKES REGION.  AT THIS POINT MODEL AGREEMENT IS
LACKING...THUS WILL MAINTAIN ONLY A SLIGHT CHANCE MENTION.  NORTHWEST
FLOW ALOFT BEHIND THE PASSING UPPER LOW WILL KEEP CONDITIONS
SEASONAL FOR EARLY NEXT WEEK.  HIGHS WILL BE COOL ON MONDAY WITH
UPPER 20S ANTICIPATED ACROSS OUR NORTHERN ZONES...LOWER 40S FOR THE
SOUTH.  LOWS IN THE TEENS AND 20S SHOULD PREVAIL BOTH MONDAY AND
TUESDAY MORNING.  TEMPERATURES WARM SLIGHTLY FOR TUESDAY AS A LEE
TROUGH DEEPENS OFF THE HIGH PLAINS ALLOWING FOR A RETURN OF LOWER
TROPOSPHERIC SOUTHWEST FLOW.  MOST LOCATIONS SHOULD SEE HIGH IN THE
UPPER 30S TO LOW 40S...ACROSS SOUTHWEST NEBRASKA AND THE FAR EASTERN
PANHANDLE...MID 40S WILL BE POSSIBLE.

LATE TUESDAY AND BEYOND THE MODELS CONTINUE TO STRUGGLE WITH
CONSISTENCY AND GENERAL AGREEMENT.  BOTH THE GFS AND ECMWF DEPICT
ANOTHER SLUG OF ARCTIC AIR ARRIVING ATOP THE CENTRAL PLAINS SOMETIME
MID-WEEK.  IN ADDITION...BOTH MODELS GENERATE LIGHT QPF AT TIMES
ACROSS PORTIONS OF THE FORECAST AREA WITH FAVORABLE UPPER JET
DYNAMICS AND THE PASSAGE OF AN UPPER TROUGH/S/. BUT THE ECMWF HAS
FLOPPED FROM 24 HOURS AGO...NOW FAVORING A WARMER SOLUTION FOR
THURSDAY AND BEYOND...WHEREAS THE GFS IS DEPICTING SIGNIFICANTLY
COOLER TEMPERATURES /THIS IS A FLOP AS WELL/.  FOR COMPARISON BY 00Z
FRIDAY...THE GFS AND ECMWF ARE UPWARDS TO 20C DIFFERENT AT H85 OVER
WESTERN PORTIONS OF THE FORECAST AREA AS THE ECMWF IS QUICK TO FORCE
THE COLD AIR EAST /BIG REVERSAL FROM 24 HOURS AGO/.  THE GFS
SUGGESTS BELOW AVERAGE TEMPERATURES CONTINUING THROUGH THE REMAINDER
OF THE WEEK AND INTO THE WEEKEND...AGAIN AND CONTRADICTION TO 24
HOURS AGO BUT IS SLOWER WITH THE ARRIVAL OF THE ARCTIC INTRUSION.
GIVEN THE LONG RANGE MODELS ARE SHOWING LITTLE IF ANY
AGREEMENT...FELT THE BEST COURSE OF ACTION WAS TO EMPLOY THE BLENDED
FORECAST APPROACH /SUPERBLEND/.  THE SUPERBLEND /POSSIBLY
COMPROMISED FROM THE PREVIOUS COLDER ECMWF FORECAST/ SEEMS TO FAVOR
A SLIGHTLY COOLER SOLUTION.  THIS SUGGESTS HIGHS ON THURSDAY IN THE
20S FOR MUCH OF THE FORECAST AREA WITH THE POSSIBILITY OF LIGHT
SNOW.  OBVIOUSLY IMPACTS TO HOLIDAY TRAVEL COULD BE GREAT GIVEN THE
TIMING OF THE POTENTIAL SNOW/ARCTIC INTRUSION...IT MUST BE STATED
THAT FORECAST CONFIDENCE IS LOW BEYOND TUESDAY EVENING...ANTICIPATE
FORECAST CHANGES AS THE MODELS EVENTUAL CONVERGE ON A SOLUTION.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 541 AM CST FRI NOV 21 2014

A WARM FRONT WILL MOVE EAST ACROSS NEBRASKA TODAY WITH SOUTH TO
SOUTHWEST WINDS LESS THAN 10KTS AND CEILINGS AOA 10KFT.

&&

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

$$

SHORT TERM...POWER
LONG TERM...JACOBS
AVIATION...POWER





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