FXUS63 KOAX 092113
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
313 PM CST THU DEC 9 2010
.SHORT TERM...TONIGHT THROUGH SUNDAY. THE MAIN FORECAST CHALLENGES
CONTINUE TO BE THE WEEKEND WINTER WEATHER SYSTEM AND ITS EFFECT ON
TEMPS/POPS/PRECIP TYPE. MODELS CONTINUE TO REMAIN IN AGREEMENT
THAT THIS WILL BE MOSTLY A NON EVENT FOR THE LOCAL CWFA FOR
SNOWFALL ACCUMULATIONS...WITH HIGHER AMOUNTS TO THE NORTH AND EAST
ACROSS THE DAKOTA...UPPER MISSISSIPPI RIVER VALLEY AND IOWA.
IN THE NEAR TERM...WOW WHAT AN AMAZINGLY MILD AND PLEASANT DAY FOR
MID NOVEMBER. A WARM FRONT HAS PUSHED WELL EAST OF THE AREA...SKIES
HAVE CLEARED OUT...AND A WEST OR NORTHWEST DOWNSLOPING FLOW HAS
ALLOWED TEMPS TO WARM INTO THE 50S. THIS TREND WILL CONTINUE
OVERNIGHT WITH ANOTHER MILD NIGHT AS LIGHT WESTERLY FLOW PREVAILS.
OPTED TO GO MORE WITH 3 HOURLY MOS VALUES FOR LOWS VERSUS ABSOLUTE
VALUES WHICH SEEM TOO LOW.
ANOTHER VERY MILD DAY ON FRIDAY IN ADVANCE OF THE NEXT WEATHER
SYSTEM...WITH LEE CYCLOGENESIS DEVELOPING ACROSS THE PLAINS
SOUTHERLY FLOW AND WAA SHOULD AGAIN PUSH HIGHS INTO THE UPPER 40S
TO MID 50S...BUT LACK OF DEEP MOISTURE SHOULD PREVENT PRECIP UNTIL
FRIDAY EVENING...ALTHOUGH WILL HAVE TO WATCH FOR AN AREA OF
CONVERGENCE NEAR THE WARM FRONT WHICH MAY BE ALONG THE SD/NE
BORDER REGION BY AFTERNOON.
SURFACE LOW MOVES TO NORTHWEST IOWA FRIDAY EVENING. ISENTROPIC
UPGLIDE AHEAD OF THE COLD FRONT COULD LEAD TO A FEW SHOWERS ACROSS
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA...ALSO WITHIN A WEAK AREA
OF MID LEVEL FRONTOGENESIS...BUT SURFACE TEMPS WILL BE WARM ENOUGH
FOR JUST RAIN. MEANWHILE...COLDER AIR JUST BARELY MAKES IT TO
NORTHEAST NEBRASKA BY MIDNIGHT TOMORROW NIGHT...WHICH COULD LEAD
TO A VERY SMALL WINDOW OF MIXED PRECIPITATION...BUT THE ARCTIC AIR
SURGE IS SUFFICIENTLY STRONG THAT IM FAIRLY CONFIDENT IT WILL BE A
QUICK CHANGEOVER. ITS IMPORTANT TO NOTE THOUGH THAT THE TROWAL
AXIS IS FURTHER NORTH ACROSS SOUTH DAKOTA AND MINNESOTA...SO
AMOUNTS ACROSS NORTHEAST NEBRASKA ARE EXPECTED TO BE VERY LIGHT
FRIDAY NIGHT. AS THE ARCTIC AIR PLUNGES SOUTHWARD...THE QUESTION
SHIFTS TO HOW FAR SOUTH IT WILL MAKE IT BY DAYBREAK SATURDAY.
NAM/GFS SOLUTIONS ARE OFF BY 11-13 DEGREES. SETTLED ON A MODEL
BLEND OF ALL AVAILABLE SUITES.
THE SURFACE LOW CONTINUES TO PUSH EASTWARD ON SATURDAY. THE BEST
TROWAL AXIS AGAIN REMAINS JUST NORTH/EAST OF THE CWFA...THUS WERE
ONLY EXPECTING A GLANCING BLOW AT BEST NORTH AND EAST OF OMAHA.
DUE TO THE ARCTIC PUSH WITH DENDRITIC TEMPS AT H7 OVERSPREADING THE
AREA...WOULD NOT BE SURPRISED TO SEE SOME SCATTERED FLURRIES
ELSEWHERE...BUT OVERALL AMOUNTS WILL LIKELY RANGE FROM JUST A
TRACE IF ANY SNOW NEAR FAIRBURY IN OUR SOUTHWEST...TO LESS THAN AN
INCH NEAR ONAWA IN OUR NORTHEAST. HAVING FALLING TEMPS NEARLY
EVERYWHERE ON SATURDAY. THIS IS A FAIRLY QUICK MOVING
SYSTEM...WITH NO SIGNIFICANT UPPER JET DYNAMICS SUPPORTING
IT...AND ALL PRECIP SHOULD HAVE ENDED BY SATURDAY EVENING. HAD
CONSIDERED THE POSSIBILITY OF SOME LINGERING FLURRIES SATURDAY
NIGHT AS WELL...BUT HELD OFF FOR NOW.
SUNDAY REMAINS COLD AND BREEZY WITH NO SIGNIFICANT WEATHER SYSTEMS
AFFECTING THE LOCAL AREA.
.LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. NORTHWEST FLOW
PREVAILS EARLY IN THE PERIOD WITH VERY COLD HIGH PRESSURE
EXTENDING DOWN THE SPINE OF THE CONUS. THIS WILL RESULT IN ONE
MORE VERY COLD NIGHT...BUT HIGH CLOUDS SPILLING DOWN THE REGION
COULD HELP LOCATIONS FROM DROPPING OFF TOO EXTREME. THE GFS HAS
BEEN CONSISTENT IN DEVELOPING A SWATH OF LIGHT SNOW ON MONDAY
ACROSS THE REGION AND THERE IS SOME SUPPORT FROM THE ECMWF AS
WELL...THUS DECIDED TO ADD SOME SCATTERED FLURRIES TO THE
AREA...BUT NOT EXPECTING ANYTHING SIGNIFICANT AT ALL. BEYOND
THEN....THE RIDGE ACROSS THE ROCKIES BEGINS TO BREAK DOWN IN
RESPONSE TO ANOTHER TROUGH ENTERING THE PACIFIC NORTHWEST. THIS
SHOULD ALLOW MODERATING TEMPERATURES...ALTHOUGH THE ECMWF REMAINS
COOLER THAN THE OPERATIONAL GFS...SO MAY HAVE TO ADJUST MIDWEEK
TEMPS DOWN JUST A BIT.
DEWALD
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
MILD AND DRY PACIFIC AIR MASS MOVING INTO THE AREA THIS AFTERNOON
BEHIND SFC TROUGH CURRENTLY ACROSS EASTERN NEBRASKA. VFR CONDITIONS
EXPECTED AT ALL 3 SITES THROUGH THE PERIOD AS AREA REMAINS IN THIS
AIR MASS. SOME INCREASING MID LEVEL MOISTURE TOWARDS THE END OF
THE FORECAST PERIOD AS NEXT SYSTEM APPROACHES FROM THE WEST.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$