FXUS63 KOAX 132102
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
302 PM CST SUN FEB 13 2011
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
TEMPERATURES STILL THE PRIMARY FOCUS IN THE SHORT TERM WITH WIND
A CONCERN THIS EVENING.
WESTERLY FLOW HAS RESULTED IN SOME SIGNIFICANT WARMING ACROSS THE
REGION THIS AFTERNOON WITH TEMPERATURES IN THE 60S IN WESTERN
PARTS OF THE CWA AND AROUND 70 IN CENTRAL NEBRASKA.
INITIAL CONCERN WILL BE STRENGTH OF THE LOW LEVEL INVERSION AND ITS
ABILITY TO KEEP STRONGER WINDS REPORTED OUT WEST FROM MAKING IT
DOWN TO THE SURFACE. MAIN FOCUS APPEARS TO BE BETWEEN LINCOLN AND
NORFOLK ALONG WESTERN EDGE OF THE SNOW FIELD. WILL HOLD OFF ON
ANY ADVISORY HEADLINES FOR NOW AS RUC FORECAST SOUNDINGS TEND TO
MAINTAIN THE INVERSION WITH WINDS APPROACHING CRITERIA FOR A SHORT
TIME PRIOR TO 00Z.
COOLER AIR SPREADS INTO THE AREA TONIGHT ON THE BACKSIDE OF GREAT
LAKES CLIPPER BUT TEMPERATURES STILL ABOVE NORMAL FOR MONDAY. WARMER
AIR RETURNS MONDAY NIGHT INTO TUESDAY AS HIGH SHIFTS EAST AND
SURFACE TROUGH MOVES INTO THE NORTHERN PLAINS. NARROW BAND OF LOW
LEVEL MOISTURE ALSO GETS PULLED UP AHEAD OF THE TROUGH TUESDAY AND
TUESDAY NIGHT WITH MAIN AXIS PLACED EAST AND SOUTH OF THE CWA.
HOWEVER...MODELS PULL THIS MOISTURE AXIS BACK TO THE NORTHWEST ON
WEDNESDAY IN ADVANCE OF NEXT SYSTEM DEVELOPING OVER THE NORTHERN
ROCKIES. PRIMARY IMPACT EXPECTED TO BE INCREASE IN LOW CLOUDS FOR
EASTERN AREAS AS MOISTURE LAYER REMAINS RATHER SHALLOW AND ITS
RESULTING AFFECT ON TEMPERATURES.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
VERY WARM TEMPERATURES WILL BEGIN EXTENDED PERIOD AS MUCH OF THE
SNOW COVER SHOULD BE GONE BY THIS TIME AND A SHORT WAVE TROUGH WILL
BE EJECTING NORTHEAST TOWARD WESTERN SOUTH DAKOTA. WITH DECENT
AGREEMENT BETWEEN 12Z GFS/00Z ECWMF...CONFIDENCE IS RELATIVELY HIGH
AND THE SET UP FAVORABLE FOR STRONG MIXING...ESPECIALLY WRN/SRN
FORECAST AREA. STRONG SW COMPONENT TO SFC/BOUNDARY LAYER WINDS
SHOULD NOT ONLY MIX/SHOVE ANY LOW CLOUDS NE OF FORECAST AREA BUT
ALSO POSSIBLY MIX TEMPERATURES TOWARD 850 MB. ALTHOUGH DID NOT
RAISE TEMPERATURES QUITE THAT HIGH...AS COMPROMISE OF +11 C FROM 12Z
GFS AND +16 C FROM 00Z ECMWF WOULD SUGGEST READINGS WELL INTO THE
70S...DID RAISE INTO UPPER 60S/AROUND 70 S AND SW. THIS TROUGH WILL
DRIVE A MODERATELY STRONG COLD FRONT QUICKLY SE THROUGH FORECAST
AREA...A BIT QUICKER THAN PREVIOUS RUNS...AND THUS ALTERED
TEMPERATURES/PCPN TYPE TO REFLECT THIS. I.E...LOWERED TEMPS THU
NGT/FRI AND MENTIONED R/S MIX THURSDAY NIGHT NORTH WITH ANY PCPN
LINGERING FRIDAY PROBABLY JUST SNOW. AFTER THAT FRONT
STALLS/ATTEMPTS TO RETURN NORTH AS IT APPEARS NEBRASKA WILL BECOME
MORE UNDER INFLUENCE OF SOUTHERN STREAM...UPPER HEIGHTS START
INCREASING AS ANOTHER TROUGH APPROACHES. THUS KEPT IN SMALL
PRECIPITATION CHANCES SOUTH SATURDAY AND EXTENDED THIS CHANCE INTO
SUNDAY. TEMPERATURE PROFILE FROM BOTH 12Z GFS AND 00Z GFS ENSEMBLE
MEAN WERE A BIT WARMER THAN EARLIER AND WOULD SUGGEST A MIX IF NOT
JUST RAIN SOUTH SO MENTIONED RAIN/SNOW MIX FOR SAT AND SUNDAY
DAYTIMES.
NO CHANGE FROM YESTERDAYS THINKING ON ICE JAM SITUATION AND THAT
DISCUSSION FOLLOWS..
ICE ON THE RIVERS SHOULD BE ABLE TO BREAK UP AND OUR SNOWPACK SHOULD
QUICKLY MELT AWAY. HOW THIS WILL ALL PLAY OUT AND IF/WHERE THERE
COULD BE ANY ICE JAMS ON THE RIVERS IS IMPOSSIBLE TO FORECAST AT
THIS POINT...BUT SOMETHING PEOPLE WITH INTERESTS ALONG THE PLATTE
AND ELKHORN RIVERS SHOULD BE AWARE OF FOR THE NEXT COMING WEEK. FOR
NOW WILL HIGHLIGHT IN THE LATEST HWO.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS ARE EXPECTED THRU THE PD WITH THE MAIN CONCERN
CENTERING AROUND LLVL WIND SHEAR THRU THE END OF THE TAF PD. WK SFC
TROF MOVING ACROSS ERN NEB TODAY WL TURN WEST/SOUTHWEST WINDS AROUND
TO THE NORTHWEST BY THIS EVENING. SNOW COVER ACROSS EXTREME ERN NEB
HAS KEPT A SMALL INVERSION OVER THE AREA WHICH HAS REDUCED MIXING
POTENTIAL. MOMENTUM TRANSFER INCREASES LATER THIS EVENING AS
NORTHWEST 850MB WINDS ARE FORECAST AROUND 75KTS OR SO WITH SFC WINDS
LIKELY GUSTING TO NEAR 35KTS OR SO. WINDS ARE EXPECTED TO DIMINISH
AFTER 12Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT/CHERMOK/KERN