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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KOAX 250544
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1144 PM CST SAT JAN 24 2015

.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 324 PM CST SAT JAN 24 2015

STRONG SHORTWAVE BRINGING COLDER TEMPERATURES AND A CHANCE FOR RAIN
AND SNOW THROUGH SUNDAY...THEN WARMER TEMPERATURES AGAIN TO START
THE WORK WEEK...REMAIN THE PRIMARY FORECAST CHALLENGES.

STRONG SHORTWAVE WAS NOTED ON WATER VAPOR IMAGERY DIVING THROUGH
EASTERN MONTANA THIS AFTERNOON. RAP ANALYSIS SHOWS 150KT 300MB JET
ACCOMPANYING SHORTWAVE. BOTH FEATURES WILL MOVE TOWARD OUR AREA
LATER THIS EVENING AND PROGRESS TO THE EAST ON SUNDAY. SCATTERED
SHOWERS WERE ALREADY OCCURRING IN WESTERN NEBRASKA CAUSED BY WEAK
VORTICITY LOBE AHEAD OF SHORTWAVE...WITH WING OF WARM ADVECTION
RAIN/SNOW EXTENDING FROM NORTH DAKOTA INTO EASTERN SOUTH DAKOTA
AHEAD OF MAIN SHORTWAVE. COULD SEE ISOLATED SHOWERS/SPRINKLES THIS
EVENING WITH WESTERN NEBRASKA ACTIVITY...BUT MAIN PRECIP CHANCE
WILL COME LATER THIS EVENING WITH NORTHERN PLAINS ACTIVITY. EXPECT
RAIN CHANCES TO INCREASE MARKEDLY BY MIDNIGHT ACROSS ALL OF
EASTERN NEBRASKA AND WESTERN IOWA...WITH LIKELY POPS IN OUR NORTH
WHERE LIFT ASSOCIATED BY MID LEVEL WARM ADVECTION IS MAXIMIZED.
FORECAST SOUNDINGS SUGGEST WARM SURFACE LAYER WILL KEEP PRECIP
LIQUID PAST MIDNIGHT BEFORE LOW LEVEL COLD ADVECTION KICKS
IN...CHANGING RAIN TO SNOW FROM NORTHWEST TO SOUTHEAST. BUT STILL
SURFACE AND BOUNDARY LAYER TEMPERATURES WILL BE SIGNIFICANTLY WARM
TO OFFER DOUBT WHETHER PRECIP WILL CHANGE TO ALL SNOW EXCEPT FOR
NORTHEAST NEBRASKA AND WEST CENTRAL IOWA. WHERE SNOW DOES
FALL...QPF LOOKS TO REMAIN UNDER A TENTH OF AN INCH WITH MELTING
OCCURRING AS WELL. THUS AMOUNTS OF A HALF INCH OR LESS ARE
FORECAST NORTH AND EAST OF THE OMAHA METRO AREA...WITH LITTLE
ACCUMULATION SOUTH AND WEST.

WINDS WILL ALSO KICK UP SIGNIFICANTLY OVERNIGHT...ESPECIALLY IN
NORTHEAST NEBRASKA. UNIDIRECTIONAL NORTHWESTERLY FLOW ACCOMPANIED
BY 50KT 850 JET...ALONG WITH LOW LEVEL INSTABILITY PROMOTING
MIXING OF BOUNDARY LAYER...SUGGEST WINDS OF 30 TO 45 MPH ARE
POSSIBLE BETWEEN MIDNIGHT AND MID SUNDAY MORNING. WILL ISSUE WIND
ADVISORY FOR PARTS OF OUR AREA TO COVER THIS.

PRECIPITATION SHOULD BE ENDING BY NOON SUNDAY...BUT STRONG COLD
ADVECTION WILL PERSIST DURING THE DAY. THUS TEMPERATURES WILL
PROBABLY REMAIN STEADY OF FALL MUCH OF THE DAY. HIGHS ONLY IN THE
30S ARE EXPECTED.

COOLDOWN BEHIND SYSTEM WILL BE BRIEF AS WINDS RETURN TO THE SOUTH OR
SOUTHWEST OVERNIGHT SUNDAY NIGHT AS ANOTHER SHORTWAVE MOVES ACROSS
THE NORTHERN PLAINS. TEMPS MAY RISE OVERNIGHT AFTER AN EVENING
LOW...THEN A WIND SHIFT BEHIND SURFACE TROUGH ASSOCIATED WITH
NORTHERN PLAINS SHORTWAVE WILL OCCUR EARLY MONDAY. GUSTY NORTHWEST
WINDS WILL PROMOTE DECENT MIXING MONDAY AFTERNOON WITH 850
TEMPERATURES IN THE 8-10C RANGE. HIGHS MONDAY AFTERNOON COULD REACH
60 IN OUR SOUTHWEST WITH PLENTY OF 50S ELSEWHERE.

A QUICK SHOT OF HIGH PRESSURE OVERHEAD TUESDAY MORNING WILL MOVE OFF
TO THE EAST...BRINGING SOUTHEASTERLY LOW LEVEL FLOW TUESDAY
AFTERNOON. THIS IS NORMALLY NOT A WARM WIND FOR US...SO TEMPS WILL
BE A GOOD 5 OR 10 DEGREES COOLER TUESDAY AFTERNOON DESPITE A SIMILAR-
TO-MONDAY LOW LEVEL TEMPERATURE PROFILE. STILL SHOULD SEE HIGHS IN
THE 50S MOST AREAS.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 324 PM CST SAT JAN 24 2015

ANOTHER WARM DAY WEDNESDAY WILL BE FOLLOWED BY COOLER TEMPERATURES
THROUGH THE END OF THE WEEK...AND LIKELY SIGNIFICANTLY COLDER BY
NEXT WEEKEND.

UPPER PATTERN WILL BECOME BRIEFLY ZONAL IN THE PLAINS ON WEDNESDAY
AS A PACIFIC SHORTWAVE APPROACHES FROM THE WEST. ANOTHER MILD DAY
WEDNESDAY IS FORECAST AHEAD OF THIS SHORTWAVE WITH SOUTH TO
SOUTHWEST FLOW PUMPING TEMPS BACK INTO THE 50S. SIGNIFICANT COOLING
IS EXPECTED BEHIND THIS WAVE WITH 850 TEMPERATURES DROPPING SOME 20C
BETWEEN WEDNESDAY AND THURSDAY AFTERNOONS. SOME LIGHT PRECIPITATION
IS POSSIBLE...BUT TRACK OF SURFACE LOW WILL BE WELL TO OUR
NORTHEAST. HIGH PRESSURE OVERHEAD THURSDAY WILL KEEP TEMPERATURES
FROM CLIMBING TOO FAR...WITH HIGHS STRUGGLING TO TOP 40. A LITTLE
WARMER FRIDAY AS SOUTH WINDS RETURN BRIEFLY AHEAD OF A STRONG COLD
FRONT DROPPING OUT OF THE NORTHERN PLAINS.

ECMWF AND GFS DIFFER GREATLY FOR FRIDAY NIGHT AND SATURDAY FORECAST.
GFS BRINGS A CLASSIC OVERRUNNING PATTERN TO THE PLAINS WITH
SIGNIFICANT SNOWFALL POSSIBLE. ECMWF KEEPS PRECIPITATION WELL SOUTH
OF OUR AREA AND SLAMS THE PLAINS WITH MINUS 20C 850 AIR. FOR NOW OUR
FORECAST WILL BLEND THESE TWO SCENARIOS WITH COLDER TEMPERATURES AND
A SMALL CHANCE FOR SNOW FRIDAY NIGHT AND SATURDAY.

&&

.AVIATION...
-- Changed Discussion --
(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1140 PM CST SAT JAN 24 2015

LITTLE CHANGE FROM THE PREVIOUS FORECAST. EXPECT VERY WINDY
CONDITIONS THROUGH MID SUNDAY MORNING. CEILINGS ARE BEGINNING TO
FALL ACROSS THE AREA. FOR NOW HAVE MVFR CONDITIONS DOMINATING THIS
FORECAST BUT WOULDN/T BE SURPRISED TO SEE IFR CEILINGS FROM 10-14Z
AT OFK AND OMA. ALSO CAN/T RULE OUT A LIGHT RAIN/SNOW OVERNIGHT
BUT DON/T THINK THESE SHOULD LIMIT VISIBILITY MUCH. BUT THE MAIN
STORY SHOULD BE THE WIND AND LOW CEILING POTENTIAL.
-- End Changed Discussion --

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NE...WIND ADVISORY UNTIL 9 AM CST SUNDAY FOR NEZ011-012-015>018-
     030>033-042>044-050-051-065-066-078.

IA...NONE.
-- End Changed Discussion --
&&

$$

SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...PEARSON