Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 200556
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1156 PM CST WED NOV 19 2014

.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 310 PM CST WED NOV 19 2014

PCPN CHANCES FROM THURSDAY NIGHT INTO SATURDAY WILL PROVIDE THE
MAIN FORECAST CHALLENGES IN THIS PERIOD...BUT TEMPERATURES ARE
ALSO A CONCERN.

COLD CANADIAN HIGH PRESSURE AT THE SURFACE WILL BE THE MAIN FACTOR
FOR OUR WEATHER INTO THURSDAY...WITH MAINLY DRY CONDITIONS OTHER
THAN MAYBE A FEW FLURRIES.

TONIGHT...CLOUD COVER AMOUNT IS PROBLEMATIC AND THE LATEST SHORT
RANGE HIGH RESOLUTION MODELS ARE NOT IN VERY GOOD AGREEMENT. WILL
KEEP A BIT MORE CLOUD COVER GOING...FAIRLY CLOSE TO WHAT THE RAP
NAM 925 MB AND 850 MB RELATIVE HUMIDITY FORECASTS SUGGEST. LOWS
WILL BE IN THE SINGLE DIGITS AND TEENS.

THURSDAY...SURFACE RIDGE WILL BUILD OVER THE AREA WITH FAIRLY
LIGHT WINDS. WITH POOR MIXING...IT APPEARS HIGHS WILL ONLY
REACH THE MID 20S NORTH AND RANGE TO LOWER OR MID 30S SOUTH.

THE UPPER AIR CHARTS FROM THIS MORNING SHOWED A BLOCKING RIDGE AT
500 MB EXTENDING FROM THE WESTERN UNITED STATES UP ACROSS WESTERN
CANADA AND THEN INTO THE BEAUFORT SEA. SPLIT FLOW WAS IN PLACE
OVER THE EASTERN PACIFIC. SHORTWAVE ENERGY MOVING EAST FROM THE
EASTERN PACIFIC WILL BREAK DOWN THE RIDGE. THAT ENERGY WILL MOVE
INTO THE ROCKY MOUNTAIN REGION AND THEN EVENTUALLY OUT INTO MID
AMERICA.

AS THE PREVIOUSLY MENTIONED SURFACE RIDGE DRIFTS EAST BY THURSDAY
NIGHT...SOUTHERLY WINDS WILL CAUSE SOME WEAK LOW LEVEL WARM AIR
ADVECTION AND BRING AN INCREASE IN LOW LEVEL MOISTURE. WE HAVE
HAD SOME MENTION OF FREEZING DRIZZLE IN FOR THURSDAY NIGHT AND
EARLY FRIDAY. MOST RECENT FORECAST SOUNDINGS ARE NOT OVERLY
SUPPORTIVE OF THAT IN OUR AREA...BUT WILL LEAVE IN FOR CONTINUITY
FOR NOW IN THE WESTERN PARTS OF THE FORECAST AREA. THAT MIGHT GET
REMOVED IN FUTURE FORECASTS. FORCING FOR MEASURABLE PCPN REMAINS
VERY WEAK THROUGH FRIDAY.

LOW LEVEL MOISTURE DEEPENS FRIDAY NIGHT INTO SATURDAY...AND THERE
WILL BE SOME SLIGHTY BETTER FORCING FOR UPWARD VERTICAL MOTION.
PREVIOUS FORECASTS HAD SOME LOW PCPN PROBABILITIES GOING FROM
FRIDAY NIGHT INTO SATURDAY. KEPT THOSE IN PLACE...SINCE EVERYTHING
WAS STILL PRETTY MUCH ON TRACK. FORECAST SOUNDINGS AND SURFACE
TEMPERATURES WILL BE CRITICAL FOR PCPN TYPE. KEPT A MENTION OF
RAIN OR LIGHT FREEZING RAIN. FOR NOW...THIS DOES NOT LOOK LIKE
MUCH OF AN EVENT FOR OMAHA/COUNCIL BLUFFS OR LINCOLN BUT IT COULD
BE FARTHER TO THE SOUTHEAST. WE WILL KEEP A CLOSE EYE ON IT...AND
FINE TUNE THINGS AS THE EVENT GETS CLOSER.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 310 PM CST WED NOV 19 2014

INITIALLY A SHORTWAVE TROUGH WILL EXTEND FROM WESTERN OKLAHOMA DOWN
INTO TEXAS...WITH ANOTHER FROM ALBERTA AND SASKATCHEWAN INTO
MONTANA. SOUTHERN WAVE WILL LIFT NORTHEAST TOWARD MISSOURI...WHICH
COULD HELP BRING SOME LIGHT PCPN TO PARTS OF OUR AREA. PCPN TYPE
WILL STILL BE AN ISSUE WITH TEMPERATURES NEAR FREEZING. CHANCES
WILL REMAIN HIGHEST TO OUR SOUTH AND EAST. THE NORTHERN STREAM
WAVE WILL PUSH EAST ACROSS MAINLY THE NORTHERN PLAINS BUT MAY
BRING SOME LIGHT SNOW TO OUR AREA FROM LATE SUNDAY AFTERNOON INTO
SUNDAY NIGHT AND MONDAY. THE 00Z ECMWF WAS THE MOST AGGRESSIVE
WITH SNOW FOR OUR LOCAL AREA ON MONDAY...BUT THE 12Z ECMWF HAD
BACKED OFF CONSIDERABLY AND WAS IN BETTER AGREEMENT WITH THE 12Z
GFS.

THE GFS AND ECMWF LARGE SCALE FEATURES REMAIN SIMILAR FROM SUNDAY
INTO TUESDAY...BUT THEN BEGIN TO DIVERGE. CONFIDENCE DROPS TO
AROUND AVERAGE OR SLIGHTLY BELOW BY WEDNESDAY. IT DOES LOOKS DRY
FOR TUESDAY AND WEDNESDAY AT THIS POINT. HIGHS IN THIS PERIOD WILL
BE MOSTLY 30S AND 40S BUT LOWS WILL BE QUITE VARIABLE.

&&

.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1143 PM CST WED NOV 19 2014

BAND OF MVFR CIGS STRETCH FROM CANADA SOUTHEAST INTO NORTHEAST
NEBRASKA...HOWEVER THERE ARE BREAKS IN THE CLOUDS. SHORTRANGE
MODELS DO RE-DEVELOP THESE OVERNIGHT MAINLY FOR KOFK AND KOMA.
RESULT WILL BE VARIABLE CONDITIONS BETWEEN VFR AND PERIODS OF
MVFR CIGS OVERNIGHT AND THURSDAY. WINDS WILL BE LIGHT AND
VARIABLE.

&&

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

$$

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



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