Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 081805
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1205 PM CST MON FEB 8 2016

.UPDATE...
ISSUED AT 1205 PM CST MON FEB 8 2016

SENT OUT A MINOR UPDATE AS HEADLINE FOR WINTER WEATHER ADVISORY
IN EASTERN NEBRASKA EXPIRED...BUT CONTINUES IN IOWA. WIND ADVISORY
REMAINS IN EFFECT THIS AFTERNOON.

UPDATE ISSUED AT 940 AM CST MON FEB 8 2016

MADE SOME MINOR ADJUSTMENTS TO HEADLINES. EXTENDED WIND ADVISORY
AN HOUR TO AGREE WITH NEIGHBORING OFFICE AND EXTENDED WINTER
WEATHER ADVISORY FOR OUR IOWA COUNTIES UNTIL 6 PM.

SNOW SHOWERS CONTINUE TO MOVE QUICKLY SOUTH/SOUTHEAST ACROSS THE
AREA. COVERAGE OF PCPN AND VISIBILITIES FROM OBSERVATIONS AND WEB
CAMS ARE WORSE IN IOWA THAN NEBRASKA. THAT IS THE REASON FOR THE
DIFFERENCE IN EXPIRATION TIME.

TEMPERATURES MAY WARM SLIGHTLY YET TODAY BUT WILL SLIDE OFF MID TO
LATE AFTERNOON. READINGS UPSTREAM IN EASTERN SOUTH DAKOTA WERE IN
THE UPPER TEENS AND LOWER 20S.

FORECAST SOUNDINGS SHOW SOME LOW LEVEL MOISTURE AND POTENTIAL FOR
FLURRIES INTO THE EVENING BEFORE CLOUDS DECREASE LATER TONIGHT.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 345 AM CST MON FEB 8 2016

THE PRIMARY FORECAST CONCERN IS THE CONTINUATION OF STRONG
WINDS AND AREAS OF BLOWING SNOW TODAY.

08/00Z 500-MB ANALYSIS SHOWED THE PRIMARY AREA OF HEIGHT FALLS
LOCATED FROM THE MID-MO TO MID-MS VALLEYS IN ASSOCIATION WITH A
RAPIDLY AMPLIFYING MID-LEVEL TROUGH OVER THE CNTRL PART OF THE
NATION.  A 90-95 KT JET STREAK OBSERVED AT 500 MB FROM THE OZARK
PLATEAU INTO NRN HIGH PLAINS WILL PROGRESS INTO THE GULF COAST
STATES...CONTRIBUTING TO THE DEVELOPMENT OF A MAJOR TROUGH ACROSS
THE ERN HALF OF THE U.S. OVER THE NEXT 24-36 HOURS.  WEAK MID-LEVEL
PERTURBATIONS ON THE BACKSIDE OF THIS EVOLVING STORM SYSTEM IN
CONJUNCTION WITH STEEP LOW-LEVEL LAPSE IN THE LOWEST 1-1.5 KM AGL
HAVE CONTRIBUTED TO NW-SE-ORIENTED CONVECTIVE SNOW BANDS FROM
SERN SD/SWRN MN INTO NWRN MO EARLY THIS MORNING.

CONSENSUS OF LATEST CONVECTION-ALLOWING MODEL GUIDANCE IS SUGGESTIVE
THAT THE BULK OF THE SNOW SHOWERS SHOULD SHIFT TO THE SOUTH OF THE
AREA BY MID MORNING.  NONETHELESS...THE RECENT DUSTING OF SNOW
COUPLED WITH THE STRONG NW WINDS WILL CONTINUE REDUCE
VISIBILITIES...SO WE WILL TEMPORALLY EXTEND THE CURRENT WINTER
WEATHER ADVISORY UNTIL NOON.  OTHERWISE...09Z METAR DATA ACROSS THE
REGION INDICATE SUSTAINED WINDS OF 20 TO 25 MPH WITH GUSTS AS HIGH
AS 40-45 MPH. WHILE THE SURFACE PRESSURE GRADIENT WILL GRADUALLY
RELAX TODAY...THE ONSET OF DIURNAL MIXING OF THE BOUNDARY-LAYER WILL
PROMOTE THE DOWNWARD TRANSFER OF HIGHER-MOMENTUM FLOW ALOFT. THE NET
RESULT WILL BE ADVISORY-CRITERIA WIND SPEEDS CONTINUING TODAY
AREAWIDE. AS SUCH...WE WILL TEMPORALLY EXTEND THE WIND ADVISORY IN
EFFECT FOR NORTHEAST NEBRASKA FROM 18Z TO 23Z. SPEAKING OF
MIXING...THIS PROCESS HAS KEPT TEMPERATURES IN THE UPPER 20S TO
LOWER 30S EARLY THIS MORNING. AND WHILE WE MAY SOME DECREASE IN
CLOUDS FROM W-TO-E ACROSS THE AREA TODAY...WEAK COLD ADVECTION IN
THE LOW LEVELS WILL OFFSET ANY DIABATIC WARMING WITH ONLY A SMALL
UPTICK IN TEMPERATURES ANTICIPATED THIS AFTERNOON.

ONLY A SLIGHT EWD SHIFT OF THE LARGE-SCALE TROUGH IS FORECAST FROM
TONIGHT THROUGH WEDNESDAY...AND AS MENTIONED ABOVE...THIS WILL
RESULT IN GRADUALLY DECREASING WIND SPEEDS BEGINNING TONIGHT. WE
WILL REMAIN ON THE WRN PERIPHERY OF A COLD CONTINENTAL AIR MASS
PRESENT OVER MUCH OF THE ERN U.S INTO MID WEEK...SO HIGHS WILL
REMAIN IN THE 20S AND 30S. THERE IS SOME INDICATION IN NAM AND
GFS GUIDANCE THAT AN INCREASE IN LOWER TO MID-LEVEL FRONTOGENESIS
COULD FOSTER A BAND OF LIGHT SNOW FROM CNTRL SD INTO N-CNTRL AND
PERHAPS NERN NEB TUESDAY NIGHT INTO WEDNESDAY. THE ECMWF AND
SHORT-RANGE ENSEMBLE GUIDANCE MAINTAIN A DRY FORECAST...WHICH IS
THE WAY WE WILL LEAN AT THIS TIME.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 345 AM CST MON FEB 8 2016

THE MEDIUM-RANGE MODELS ARE IN REASONABLY GOOD AGREEMENT THROUGH
ABOUT FRIDAY WITH RESPECT TO THE LARGE-SCALE PATTERN.  IN
GENERAL...THESE DATA INDICATE THE GRADUAL EWD SHIFT AND DE-
AMPLIFICATION OF THE ERN U.S. TROUGH THROUGH THURSDAY BEFORE THE
TROUGH RE-INTENSIFIES FRIDAY INTO THIS WEEKEND OVER THE ERN THIRD OF
THE NATION. WE WILL SEE A GRADUAL TRANSITION TO NWLY FLOW IN THE MID-
LEVELS WITH A NUMBER OF WEAK PERTURBATIONS TRANSLATING SEWD THROUGH
THIS FLOW REGIME.  WHILE THE CHANCE FOR PRECIPITATION WILL NOT BE
HIGH WITH THESE TRANSITORY SYSTEMS...THEY WILL AUGMENT THE LOCATION
OF THE MEAN LOW-LEVEL BAROCLINIC ZONE.  DETAILS IN THE TIMING OF
THESE FEATURES VARY FROM MODEL-TO-MODEL...AND AS SUCH...CONFIDENCE
IN OUR TEMPERATURE FORECASTS REMAINS RATHER LOW.

SATURDAY AND SUNDAY...THERE ARE INDICATIONS THAT A SHORT-WAVE TROUGH
WILL TEMPORARILY DAMPEN THE WRN U.S. RIDGE...PRIOR TO TRACKING INTO
THE N-CNTRL U.S. THE DETERMINISTIC GFS IS SIMILAR TO THE GEFS MEAN
IN SUGGESTING THAT THIS IMPULSE WILL BE RATHER LOW-AMPLITUDE IN
CHARACTER.  IN CONTRAST...THE ECMWF DEPICTS A MUCH MORE AMPLIFIED
SOLUTION WHICH WOULD BRING A CHANCE OF PRECIPITATION TO THE AREA
SUNDAY. CERTAINTY IN EITHER SOLUTION REMAINS LOW AT THIS TIME.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1205 PM CST MON FEB 8 2016

SOME MVFR CEILING SHOULD LINGER THIS AFTERNOON WITH OCCASIONAL
LIGHT SNOW SHOWERS...ESPECIALLY AT KOMA. THE MAJORITY OF THE
SHORT RANGE MODEL GUIDANCE TENDS TO DECREASE CLOUDS BELOW 5000
FEET LATE THIS AFTERNOON OR EARLY EVENING...WITH VARIABLE MID AND
HIGH CLOUDS AFTER THAT. THERE IS SOME GUIDANCE THAT DOES KEEP
MVFR CEILINGS WELL INTO THE EVENING...SO THAT IS POSSIBLE. EXPECT
A GRADUAL DECREASE IN WINDS LATE THIS AFTERNOON AND EVENING...
WITH GUSTS ENDING OVERNIGHT.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR NEZ011-012-015>018-
     030>034-042>045-050>053-065>068-078-088>093.

IA...WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043-
     055-056-069-079-080-090-091.

     WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR IAZ043-055-056-069-
     079-080-090-091.

&&

$$

UPDATE...MILLER
SHORT TERM...MEAD
LONG TERM...MEAD
AVIATION...MILLER


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