FXUS63 KOAX 252102
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
302 PM CST SAT DEC 25 2010
.SHORT TERM...TONIGHT THROUGH TUESDAY.
SHORT TERM FORECAST CHALLENGES WILL PRIMARILY BE CLOUDS AND
TEMPERATURES.
AT 20Z...SFC HIGH PRESSURE WAS CENTERED OVER SOUTHEAST SOUTH
DAKOTA AND EXTENDED SOUTH INTO ERN NEBRASKA. CLOUDS CONTINUE TO
DOMINATE WITH IFR/MVFR CIGS ACRS THE REGION. SINCE 17Z HOWEVER
THERE HAS BEEN SOME THINNING OF THE CLOUDS AND A STRIP OF
CLEARING FM FARGO NORTH DAKOTA SOUTH TO SIOUX FALLS. MEANWHILE IN
WRN NEB...WESTERLY FLOW HAS ERODED CLOUDS FROM THE WEST WITH THE
CLEARING LINE FROM WEST OF AINSWORTH TO WEST OF LEXINGTON.
DO NOT HAVE A GOOD FEEL FOR THE CLOUDS TONIGHT AS LOW LEVEL RH
REMAINS HIGH IN THE SFC TO H95 LAYER WITH WEAK HIGH PRESSURE.
THINK THERE WILL BE PLACES THAT WILL CLEAR OUT...BUT THEN FILL
BACK IN WITH STRATUS AND PATCHY FOG AND ALSO SOME FLURRIES.
CLOUDS OR A LACK OF CLOUDS WILL PLAY HAVOC WITH THE TEMPERATURES
OVERNIGHT WITH SOME SNOW COVER AND VERY COLD TEMPERATURES IN
PLACE. THE MODELS HAVE MOSTLY OVERDONE THE CLEARING THIS PAST WEEK
AS PERIODS OF LOW LEVEL RH HAVE KEPT US IN THE CLOUDS. WILL
CONTINUE TO HOLD ON TO MOSTLY CLOUDY AS THE PREVALENT SKY
CONDITION...HOWEVER THINK THAT THERE WILL BE SOME LOCATIONS THAT
WILL SCATTER OUT FOR A TIME. WITH CLOUDS...TEMPS WOULD HOLD IN THE
10 TO 15 DEG RANGE...HOWEVER WITH BREAKS OR CLEARING FOR A TIME
WOULD DROP IN THE SINGLE DIGITS.
SFC HIGH PRESSURE WILL SHIFT EASTWARD INTO MINNESOTA AND IOWA
SUNDAY AND IT SHOULD STILL BE COLD WITH HIGHS IN THE TEENS AND
20S. AGAIN THE LOW LEVEL RH WILL MAKE IT A TOUGH CALL AS FAR AS
THE CLOUDS AND FOR NOW WITH BETTER MIXING HAVE PARTLY CLOUDY IN
THE WEST...BUT STILL KEEP PARTLY SUNNY GOING FARTHER EAST. STILL
LOW CONFIDENCE IN THE CLD FCST SUNDAY NIGHT. MONDAY INTO TUESDAY...THE
SHORTWAVE TROF SHOULD SPREAD INCREASING MID CLOUDS AND MODERATE
TEMPERATURES. HIGHS MONDAY SHOULD TOP OUT IN THE 20S AND 30S...AND
WARM FURTHER FOR TUESDAY WITH HIGH IN THE 30S AND A FEW 40S.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY.
THE PRIMARY CONCERN DURING THE PERIOD WILL BE A POTENTIAL STORM
THAT COULD AFFECT US THE LATTER HALF OF THE PERIOD ON FRIDAY AND
SATURDAY. ALTHOUGH ITS IMPORTANT TO STRESS THAT MODEL SOLUTIONS
CONTINUE TO PROVIDE NUMEROUS ALTERNATIVES OF WHAT WILL EVENTUALLY
HAPPEN...THUS CONFIDENCE REMAINS OVERALL LOW ATTM.
ZONAL FLOW TUESDAY/WEDNESDAY SHOULD LEAD TO A COUPLE OF MILD DAYS
WITH SOUTHERLY FLOW PREVAILING. HOWEVER...A TROUGH THAT IS CURRENTLY
SPINNING IN THE GULF OF ALASKA IS FORECAST TO DIVE INTO THE
NORTHWESTERN CONUS WEDNESDAY...WHEN THE MODELS ARE STILL IN FAIRLY
DECENT AGREEMENT WITH EARLY ON. MEANWHILE...A WEAK SOUTHERN STREAM
FEATURE MOVING EASTWARD OUT OF THE SOUTHERN ROCKIES COULD...COMBINED
WITH A HEALTHY SOUTHERLY FETCH OF LOW LEVEL MOISTURE...GENERATE SOME
PRECIPITATION WEDNESDAY NIGHT...UNFORTUNATELY...DUE TO THE WARMING
ALOFT...THIS COULD RESULT IN A FREEZING RAIN THREAT ACROSS PORTIONS
OF NORTHEAST NEBRASKA...BUT JUST RAIN WITH SURFACE TEMPS ABOVE
FREEZING ALONG/SOUTHEAST OF INTERSTATE 80. THIS COULD LINGER INTO
THURSDAY MORNING BEFORE GETTING SHUNTED NORTH/EAST OF THE REGION BY
THURSDAY AFTERNOON.
FOCUS THEN SHIFTS TO THE REMAINDER OF THE PERIOD THROUGH NEW YEARS
DAY...WHEN FORECAST BECOMES INCREASINGLY DIFFICULT DUE TO VARYING
MODEL SOLUTIONS. GFS REMAINS THE SLOWEST OF ALL MODELS WITH A MUCH
MORE SOUTHWESTERN TROUGH...WITH GFS ENSEMBLE LOOKING SIMILAR TO THE
ECMWF AND GEM...WHICH OFFER A MORE PROGRESSIVE AND SLIGHTLY MORE
NORTHERN TROUGH. OPERATIONAL GFS SEEMS MORE PRUDENT...ALTHOUGH IT IS
AN OUTLIER...GIVEN THE ANTICIPATED STRENGTH AND DIGGING JET STILL ON
THE BACK SIDE...WHICH SHOULD LEAD TO A MORE SOUTHWESTERN AND OVERALL
SLOWER SOLUTION. THE SLOWER STRONGER GFS WOULD GIVE US A DOOZY OF A
STORM THROUGH THE WEEKEND...WITH A SIGNIFICANT THREAT FOR HEAVY
SNOW...EVEN SOME FREEZING PRECIPITATION AHEAD OF IT WITH FREEZING
RAIN OR SLEET...AND COMBINED WITH VERY STRONG WINDS...AND A VERY
PROLONGED 48 HOUR DURATION EVENT. THE ECMWF ON THE OTHER HAND WOULD
FOCUS MORE OF THE ENERGY FURTHER NORTH ACROSS THE DAKOTAS AND JUST
GIVE US A GLANCING BLOW AND A SYSTEM THAT MOVED OUT MUCH QUICKER.
TRENDED THE FORECAST A BIT MORE TOWARD THE MORE PESSIMISTIC SOLUTION
OF THE GFS FOR NOW...AND WILL CONTINUE TO MONITOR LATER MODEL TRENDS
VERY CLOSELY OVER THE NEXT FEW DAYS GIVEN THAT THE UPCOMING HOLIDAY
WEEKEND. STILL ONLY HAVE CHANCE POPS THAT FAR OUT GIVEN MODEL
UNCERTAINTIES THOUGH.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
TRENDS PER SFC OBS INDICATE AREA OF LIFR CIGS WAS EXPANDING OVER
NERN NEB...WHILE GENERALLY MVFR/IFR CIGS PREVAILED OVER THE REST OF
ERN NEB. ATTM MAIN CONCERN IS APPEARS WHERE DELINEATING LINE
SEPARATING LOW CIGS AND VFR CONDITIONS WILL SET UP THIS EVENING. FOR
NOW THINK THAT DIVIDING LINE WILL REMAIN WEST OF KOFK/KOMA/KLNK THRU
THE FCST PD...THUS WILL OPT FOR MAINTAINING IFR CIGS AT ALL SITES.
MAY SEE OCCASIONAL MVFR VSBY AS WELL MAINLY BTWN 26/09Z-13Z...BUT
OPTED NOT TO ADD TEMPO GROUP DUE TO LOW CONFIDENCE. WILL REEVALUATE
AT NEXT ISSUANCE AT 26/00Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY/DEWALD/DEE