Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 211144
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
544 AM CST SUN DEC 21 2014

.UPDATE...
ISSUED AT 509 AM CST SUN DEC 21 2014

UPDATED TO TRIM A FEW COUNTIES FROM THE DENSE FOG ADVISORY AS
VISIBILITIES CONTINUE TO IMPROVE.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 259 AM CST SUN DEC 21 2014

SHORT TERM FORECAST CONCERNS WILL BE THE EXTENT OF FOG/DENSE FOG/HEADLINES
...RAIN SUNDAY NIGHT THEN SNOW MONDAY NIGHT INTO TUESDAY
NIGHT...ACCUMULATING SNOW POTENTIAL THURSDAY AND THURSDAY NIGHT.

QUITE VARIABLE CONDITIONS THIS MORNING WITH FOG...SOME DENSE...AND
OTHER LOCATIONS THAT HAVE IMPROVED ABOVE 6SM. 900MB WINDS HAVE
INCREASED TO 25 TO 30KTS AND WITH A WARM FRONT LIFTING NORTH...HAS
ALLOWED VISIBILITIES TO IMPROVE. NORTH OF THE WARM FRONT...THE FOG
REMAINS DENSE...THUS WILL CONTINUE THE DENSE FOG ADVISORY FOR NINE
COUNTIES IN PARTS OF NORTHEAST NEBRASKA.

OF NOTE ON THE WATER VAPOR SATELLITE IMAGERY IS DARKENING OVER
WASHINGTON STATE. THIS IS ASSOCIATED WITH A 140+KT JET MOVING
INTO THE PACIFIC NORTHWEST. THE STRONG JET WILL CONTINUE TO DIVE
INTO THE WESTERN U.S. AND WILL CAUSE THE H5 TROF TO DEEPEN OVER
THE CENTRAL U.S. AND SURFACE LOW PRESSURE DEEPENING OVER NORTH
DAKOTA. PWAT VALUES ON THE OAX SOUNDING WERE 0.41 OF AN INCH AND
AGAIN WE WERE SATURATED IN THE LOWEST 1.5 KM. THE PWAT SHOULD
INCREASE TO AROUND .5-.6 THROUGH TONIGHT. AS LAPSE RATES
STEEPEN...OMEGA INCREASES AND THERE IS ADDITIONAL UPPER LEVEL
DIVERGENCE WITH THE APPROACHING JET.

ISENTROPIC LIFT ON THE 290K SURFACE/WARM AIR ADVECTION IS BEING
REFLECTED IN AN EXPANSION OF THE STRATUS ACROSS KANSAS. THERE IS
SOME DENSE FOG ALSO BEING REPORTED. THE RAP/HRRR BRING SOME OF
THESE LOW VISIBILITIES BACK INTO THE FORECAST AREA THIS
MORNING...BUT THEN IMPROVE VISIBILITIES BY 18Z. LOOK FOR THE LOW
CLOUDS TO CONTINUE TO ADVANCE NORTHEAST INTO SOUTHEAST NEBRASKA
AND SOUTHWEST IOWA AND THERE COULD BE SOME LIGHT RAIN WITH THIS BY
LATE AFTERNOON. HAVE FURTHER INCREASED POPS FOR TONIGHT...ESPECIALLY
ACROSS NORTHERN AND CENTRAL SECTIONS OF THE FORECAST AREA.
TEMPERATURES APPEAR MILD ENOUGH FOR MOST OF THIS TO FALL AS RAIN.

THE STORM SYSTEM REMAINS IN THE AREA MONDAY THROUGH TUESDAY NIGHT.
THERE IS A BREAK IN THE PRECIPITATION...THEN THE COLDER AIR WRAPS
INTO THE SYSTEM AND A RAIN SNOW MIX OR SNOW IS FORECAST FOR MONDAY
NIGHT AND TUESDAY WITH LIGHT SNOW ACCUMULATIONS. WINDY CONDITIONS
CAN BE EXPECTED FOR TUESDAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 259 AM CST SUN DEC 21 2014

THE MODELS HAVE NOT BEEN CONSISTENT ON THE STORM SYSTEM FOR
THURSDAY AND FRIDAY. LOOK FOR MID LEVEL RIDGING WEDNESDAY...THEN A
MID LEVEL TROF WILL MOVE OUT OF THE ROCKIES INTO THE PLAINS
THURSDAY AFTERNOON AND THURSDAY NIGHT. FRONTOGENESIS WITH THIS
BAND OF PRECIPITATION COULD RESULT IN LIGHT TO MODERATE AMOUNTS OF
SNOW.  FOR NOW WILL MENTION THE POTENTIAL FOR ACCUMULATING SNOW.

&&

.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 525 AM CST SUN DEC 21 2014

VARIABLE IFR TO MVFR CONDITIONS ARE ANTICIPATED THIS TAF CYCLE.
SOUTHERLY LOW LEVEL MOIST FLOW WILL CONTINUE THROUGHOUT THE DAY AS
LOW PRESSURE OVER THE NORTHERN PLAINS SINKS TO THE SOUTHEAST. THIS
LOW WILL BRING A GOOD CHANCE OF RAIN TO THE AREA FROM WEST TO
EAST LATER IN THE TAF PERIOD.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR NEZ011-012-
     016-017-030.

IA...NONE.
&&

$$

UPDATE...ZAPOTOCNY
SHORT TERM...ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...KERN


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