Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 250551
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1151 PM CST WED DEC 24 2014

.UPDATE...
ISSUED AT 1145 PM CST WED DEC 24 2014

EVENING/OVERNIGHT UPDATES WERE MADE TO TWEAK CLOUDS AND
TEMPERATURES. THE BULK OF THE LOW CLOUDS HAVE SHIFTED EAST OF THE
AREA WITH INCREASING HIGH CLOUDS. STRONGER MIXING ACROSS EAST
CENTRAL AND SOUTHEAST NEBRASKA WITH AN INCREASING LOW LEVEL JET
SHOULD HELP TEMPERATURES FROM BOTTOMING OUT.

&&

.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 320 PM CST WED DEC 24 2014

PRIMARY FORECAST CONCERNS ARE CLOUD COVER TONIGHT INTO THURSDAY...
THEN SNOW CHANCES MAINLY FROM FRIDAY AFTERNOON INTO FRIDAY NIGHT.

THE SYSTEM THAT BROUGHT PCPN TO THE AREA YESTERDAY AND LAST NIGHT
CONTINUED TO MOVE OFF TO THE EAST. A WEAK RIDGE OF HIGH PRESSURE AT
THE SURFACE WAS BUILDING INTO THE AREA FROM THE WEST. EDGE OF LOW
CLOUDS CONTINUED TO WORK ITS WAY EASTWARD AS SHOWN BY RECENT METAR
OBSERVATIONS AND SATELLITE IMAGERY LOOPS. HIGH RESOLUTION SHORT
RANGE MODELS AND PATTERN RECOGNITION AGREE THAT LOW CLOUDS SHOULD
DECREASE FROM WEST TO EAST TONIGHT. HOWEVER...FAIRLY THICK HIGH
LEVEL CLOUDS ARE STREAMING TOWARD THE AREA FROM THE NORTHWEST.
RELATIVE HUMIDITY VALUES LOOK TO STAY FAIRLY HIGH WITH BROKEN TO
OVERCAST CIRRUS/CIRROSTRATUS CLOUDS AT LEAST PART OF THE NIGHT.
WEST/NORTHWEST WINDS THIS AFTERNOON WILL BECOME SOUTHERLY TONIGHT.
LOOK FOR LOWS TONIGHT IN THE LOWER AND MID 20S.

THE SHORTWAVE TROUGH WHICH WAS PUSHING INTO THE WESTERN UNITED
STATES TODAY (12 HOUR HEIGHT FALLS AT 12Z AT 500 MB WERE AS HIGH
AS 160 METERS IN THE PACIFIC NORTHWEST) WILL MOVE INTO THE CENTRAL
ROCKY MOUNTAIN REGION THURSDAY. MOST MODEL DATA SUGGESTS A CLOSED
LOW WILL DEVELOP OVER UTAH WITHIN THE TROUGH. LOCALLY...NO PCPN
IS EXPECTED FOR OUR AREA THURSDAY AND WE SHOULD SEE AT LEAST
PARTLY SUNNY SKIES.

SOME PARAMETERS ARE FAVORABLE FOR LIGHT SNOW ACROSS NORTHEAST
NEBRASKA THURSDAY NIGHT/FRIDAY MORNING BEHIND A COLD FRONT THAT
WILL BE PUSHING THROUGH THE REGION. LARGE SCALE FORCING HOWEVER
IS BETTER/STRONGER FROM FRIDAY AFTERNOON INTO FRIDAY EVENING (AS
SHOWN BY MID/UPPER LEVEL LAYER AVERAGE Q VECTORS...700 MB RELATIVE
HUMIDITIES AND MID LEVEL OMEGA VALUES. POTENTIAL SNOW AMOUNTS
RIGHT NOW LOOK LIKE THEY COULD REACH THE 0.5 TO 1.5 INCH RANGE.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 PM CST WED DEC 24 2014

FAIRLY SIGNIFICANT PATTERN CHANGE STARTS TO TAKE PLACE ON SUNDAY.
PATTERN TURNS STRONGLY MERIDIONAL AS A RIDGE DEVELOPS FROM THE
EASTERN PACIFIC ALONG 130-140 DEGREES WEST LONGITUDE UP INTO THE
YUKON TERRITORY. THIS FORCES TROUGH TO DEVELOP EAST OF THE RIDGE.
MUCH COLDER AIR WILL BE FORCED SOUTHWARD FROM CANADA INTO MID
AMERICA FOR THE EARLY AND MID PART OF NEXT WEEK. SOME SNOW WILL
BE POSSIBLE DURING THIS TRANSITION...MAINLY MONDAY INTO MONDAY
NIGHT. BEST POTENTIAL FOR ACCUMULATIONS IN THOSE PERIODS SEEMS TO
AGAIN BE ACROSS NORTHEAST NEBRASKA. GAVE THE 12Z ECMWF MODEL THE
MOST WEIGHT IN REGARDS TO PCPN POTENTIAL AND AMOUNTS (POSSIBLY 1
TO 2 INCHES FOR THE AREA). NOT COMPLETELY SOLD ON POTENTIAL FOR
ANOTHER LIGHT SNOW EVENT FOR TUESDAY/TUESDAY NIGHT ACROSS
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA (AS SHOWN BY 12Z ECMWF).
SIGNALS ARE HIGH ENOUGH HOWEVER TO INCLUDE A SLIGHT CHANCE IN
THOSE AREAS. WE WILL WATCH MODEL TRENDS AND CAN ADJUST LATER IF
NEEDED.

HIGHS MONDAY WILL BE IN THE TEENS NORTH/20S SOUTH...THEN HIGHS IN
THE TEENS ARE LIKELY ALL AREAS TUESDAY AND WEDNESDAY. LOWS WILL
BE COLD AS WELL...WITH MOSTLY SINGLE DIGITS...BUT SOME BELOW ZERO
READINGS MAY OCCUR WEDNESDAY MORNING IN THE NORTHERN PARTS OF THE
FORECAST AREA.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1138 PM CST WED DEC 24 2014

VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD WITH VARIABLE
AMOUNTS OF MID AND HIGH CLOUDS. SURFACE WINDS SHOULD BE FROM THE
SOUTHWEST THROUGH SOUTHEAST AT 6-12KTS.  LOW LEVEL WIND SHEAR WAS
CONTINUED THROUGH 17 OR 18Z AT KOMA AND KLNK. THURSDAY
NIGHT...SURFACE LOW PRESSURE WILL TRACK INTO EASTERN NEBRASKA AND
THIS WILL ALLOW THE COLD FRONT TO SLIP SOUTH AND THE SURFACE WINDS
TO TURN TO THE NORTH...FIRST AT KOFK...BUT LIGHT SOUTHEAST THEN
NORTHEAST AT KOMA AND KLNK.


&&

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

$$

UPDATE...ZAPOTOCNY
SHORT TERM...MILLER
LONG TERM...MILLER
AVIATION...ZAPOTOCNY


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