Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 061133
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
533 AM CST SAT FEB 6 2016

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 322 AM CST SAT FEB 6 2016

THE PRIMARY FORECAST CONCERN IS THE POTENTIAL FOR STRONG WINDS
SUNDAY INTO MONDAY.

A POSITIVELY TILTED SHORT-WAVE TROUGH STRETCHING FROM AN UPPER LOW
JUST SOUTH OF HUDSON BAY INTO THE SRN PLAINS WILL QUICKLY SHIFT EAST
IN ADVANCE OF A POTENT UPSTREAM SHORT-WAVE TROUGH WHICH WILL
TRANSLATE ALONG THE INTERNATIONAL BORDER FROM THE NRN ROCKIES TO
UPPER GREAT LAKES TODAY INTO TONIGHT. TEMPORARY SUBSIDENCE/RIDGING
ON THE BACKSIDE OF THE FORMER AND AHEAD OF THE LATTER WILL PROMOTE
DOWNSLOPE WARMING TODAY WITH TEMPERATURES REBOUNDING TO NEAR OR
SLIGHTLY ABOVE SEASONAL NORMALS. SOME PATCHY FOG WILL BE REMAIN
POSSIBLE INTO MID MORNING...PRIOR TO THE ONSET OF DEEP BOUNDARY-
LAYER MIXING.

A MID TO UPPER-LEVEL JET STREAK FOLLOWING ON THE HEELS OF THE
INTERNATIONAL-BORDER IMPULSE WILL PROGRESS FROM THE NRN HIGH PLAINS
INTO THE OZARK PLATEAU SATURDAY NIGHT INTO SUNDAY...CONTRIBUTING TO
THE FORMATION OF A CLOSED UPPER LOW OVER THE GREAT LAKES AND THE
RAPID AMPLIFICATION OF A BROADER-SCALE TROUGH CENTERED OVER THE MS
VALLEY. THIS UPPER-AIR PATTERN EVOLUTION WILL DRIVE A SURFACE COLD
FRONT SEWD THROUGH THE FORECAST AREA BY DAYBREAK SUNDAY. WHILE
SOME RAIN OR SNOW SHOWERS WILL BECOME POSSIBLE SUNDAY AFTERNOON
OVER PORTIONS OF NERN NEB INTO W-CNTRL IA...THE AIR MASS IN THE
WAKE OF THE FRONT WILL INITIALLY BE RELATIVELY DRY WITH ONLY SOME
INCREASE IN CLOUDS EXPECTED.

THE PRIMARY IMPACT OF THE EVOLVING GREAT LAKES SYSTEM WILL BE
NORTHWEST WINDS WHICH WILL STRENGTHEN THROUGH THE DAY /SUNDAY/
OWING TO STEEPENING LAPSE RATES IN THE LOWEST 1-2 KM AGL...AND
RESULTANT DOWNWARD TRANSFER OF HIGHER-MOMENTUM FLOW ALOFT. AT THIS
POINT...IT APPEARS THAT WINDS WILL REMAIN BELOW HIGH WIND WARNING
CRITERIA...THOUGH AN ADVISORY MAY BE NECESSARY AT SOME POINT
DURING THE SUNDAY INTO MONDAY TIME PERIOD.

SUNDAY NIGHT INTO MONDAY...CONTINUED MID-TROPOSPHERIC COLD ADVECTION
AND WEAK FORCING FOR ASCENT ON THE PERIPHERY OF THE GREAT LAKES
CYCLONE WILL YIELD A LOW-PROBABILITY CHANCE FOR SNOW
SHOWERS...MAINLY ALONG AND EAST OF THE MISSOURI RIVER. GRADIENT FLOW
ON THE BACKSIDE OF THE LARGE-SCALE TROUGH WILL REMAIN STRONG WITH
GUSTY NORTH OR NORTHWEST WINDS CONTINUING INTO MONDAY AFTERNOON.
THIS COULD LEAD TO AREAS OF BLOWING SNOW...PARTICULARLY SUNDAY
NIGHT THROUGH MONDAY MORNING.

.LONG TERM...(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 322 AM CST SAT FEB 6 2016

LATEST MEDIUM-RANGE GUIDANCE /E.G. GEFS AND DETERMINISTIC ECMWF AND
GFS/ IS IN REASONABLY GOOD AGREEMENT IN DEPICTING THE GRADUAL EWD
SHIFT OF THE UPPER TROUGH THIS UPCOMING WEEK WITH MID-LEVEL FLOW
BECOMING MORE NWLY FROM THE NRN ROCKIES INTO MID-MS VALLEY. THE
MEAN LOW-LEVEL BAROCLINIC ZONE WILL SUBSEQUENTLY ORIENT IN SIMILAR
FASHION...GENERALLY BISECTING THE MID-MO VALLEY FOR SEVERAL DAYS.
THE UPSHOT IS THAT ANY SMALL PERTURBATIONS MOVING THROUGH THIS
FLOW PATTERN WILL CAUSE LATITUDINAL OSCILLATIONS IN THE
BAROCLINIC ZONE...INTRODUCING CONSIDERABLE UNCERTAINTY IN
TEMPERATURE AND PRECIPITATION FORECASTS. WE WILL MAINTAIN THE
NOTION OF A GRADUAL WARM UP FROM EARLY THROUGH MID WEEK WITH A DRY
FORECAST...BUT THIS WILL BE SUBJECT TO CHANGE.

&&

.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 529 AM CST SAT FEB 6 2016

SHORT-LIVED VISIBILITY RESTRICTIONS BEHIND THE CLEARING LINE MAY
OCCUR AT KOMA AND WILL CONTINUE AT KLNK. HAVE BROUGHT KOMA DOWN TO
1/2SM...SIMILAR TO VISIBILITY UPSTREAM...BUT LEFT KLNK IN MVFR
RANGE. ONCE THE VISIBILITY CLEARS...VFR CONDITIONS WILL CONTINUE
AT KOMA/KLNK THROUGH THE TAF CYCLE. AT KOFK...VISIBILITY ALREADY
HAS IMPROVED...BUT GUIDANCE SUGGESTS ANOTHER RESTRICTION AGAIN
TONIGHT...AND HAVE INCLUDED A TEMPO GROUP TO SUGGEST THE
POTENTIAL. WINDS WILL REMAIN 10KT OR LESS THROUGH THE TAF
CYCLE...WITH VARIABLE DIRECTION THIS MORNING BECOMING MORE
WESTERLY THIS AFTERNOON AND TONIGHT.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...MEAD
LONG TERM...MEAD
AVIATION...MAYES


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