FXUS63 KOAX 051953
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
253 PM CDT TUE APR 5 2011
.SHORT TERM...TONIGHT THROUGH FRIDAY.
MAIN CHALLENGE/CONCERN IN SHORT TERM WILL BE ON THURSDAY AS
POTENTIAL EXISTS FOR WIDESPREAD PRECIPITATION WITH INCREASING
CONVECTIVE POTENTIAL LATER THAT EVENING. BEFORE THEN...SHORTWAVE
ENERGY WILL BE RACING ACROSS NORTHERN PLAINS TONIGHT DRIVING A
MOSTLY DRY COLD FRONT ACROSS THE FORECAST AREA. SINCE SURFACE TO
H85 DEW POINTS WERE QUITE DRY...LEFT IN ONLY SLIGHT CHANCE POPS
FAR N LATE TONIGHT CLOSER TO WHERE SOME MID LEVEL MOISTURE IS
EXPECTED...ALTHOUGH PROBABLY NOT MUCH MORE THAN SPRINKLES.
OTHERWISE EXPECT AN INCREASING AREA OF MID CLOUDS TNGT INTO
WEDNESDAY MORNING THEN A DECREASING AREA OF MID CLOUDS TO LINGER
INTO MIDDAY WEDNESDAY MAINLY CENTRAL ZONES ON WEDNESDAY. HOWEVER...
ENOUGH AFTERNOON SUNSHINE SHOULD EXIST TO COMBINE WITH MODEST
COOL ADVECTION TO ALLOW TEMPERATURE RECOVERY TOWARD COOLER MET
GUIDANCE VALUES AT LEAST. INCREASING SHOWER CHANCES THEN EXPECTED
LATE WEDNESDAY NIGHT AND ESPECIALLY THURSDAY AS UPPER TROUGH
APPROACHES PULLING SURFACE TO H85 MOISTURE NORTHWARD. CONVECTIVE
CHANCES APPEAR TO INCREASE MARKEDLY IN THE LATE AFTERNOON OR EARLY
EVENING FAR SE ZONES AS WARM FRONT BULGES NWD.
HOWEVER...TEMPERATURE FORECAST WAS BASED ON FRONT REMAINING SOUTH
OF SERN NEBR/SWRN IA WITH WIDESPREAD CLOUDINESS AND HIGH SHOWER
CHANCES KEEPING TEMPERATURES ON THE COOL SIDE...ESPECIALLY FROM
THE OMAHA/LNK VICINITY NWD. CONVECTION AND/OR TROUGH SHOULD THEN
PUSH FRONT BACK S OF FORECAST AREA FRIDAY WITH THAT DAY MOSTLY DRY
AND IN RECOVERY MODE. SOME INDICATION THAT TEMPERATURES COULD WARM
NICELY IF MIXED TO H85...HOWEVER...WITH ENE SURFACE FLOW THIS IS
NOT CERTAIN. ALSO 12Z NAM 2M TEMPERATURES WERE QUITE COOL...40S N
TO AROUND 60 S...THUS DID NOT GET TOO CARRIED AWAY ON WARMER
READINGS JUST YET.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY.
UNCERTAINTIES EXISTED BETWEEN 12Z GFS AND 00Z ECMWF ON HOW FAST
AND HOW STRONG A TROUGH AND ASSOCIATED COLD FRONT CROSS FORECAST
AREA ON SUNDAY...WITH ECMWF SLOWER. QUICK GLANCE AT 12Z ECMWF ALSO
SHOWED A SLOWER SOLUTION...ALTHOUGH PERHAPS A LITTLE QUICKER THAN
ITS 00Z COUNTERPART. HOWEVER...BEFORE THEN AS THE UPPER TROUGH
APPROACHES...A WARM FRONT...OR SOME SEMBLANCE OF ONE...WILL
ATTEMPT TO LIFT NORTH ACROSS EASTERN NEBRASKA/WRN IOWA FRIDAY
NIGHT INTO SATURDAY. WITH A DECENT AGREEMENT BETWEEN THE TWO
MODELS...ADJUSTED MOST TEMPERATURES UPWARD SATURDAY. SINCE THERE
COULD BE A DOUBLE STRUCTURED WARM FRONT ON SATURDAY...WITH THE
HOTTEST ONE TO OUR SOUTH...LEFT IN MODEST POPS S AND EAST DUE TO
EITHER MORNING CONVECTION AS INCREASINGLY HIGHER H85 THETA E AIR
ADVECTS NWD IN THE MORNING E OR AFTERNOON CONVECTION DVLPS NEAR
EITHER POSSIBLE WARM FRONTS ACROSS FAR N AND FAR S.
WITH BIG DIFFERENCES IN TIMING OF TROUGH/FRONT ON SUNDAY BETWEEN FASTER
12Z GFS AND SLOWER 00Z/12Z ECMWF...MADE LTL CHANGES TO
TEMPERATURES. THIS REFLECTS A SOMEWHAT HIGHER CHANCE OF A COOLER
FORECAST SINCE 00Z GFS ENSEMBLE MEAN SUPPORTED COOLER 12Z
OPERATIONAL GFS RUN. ALSO LEFT IN MODESTLY HIGH POPS. BOTH MODELS
HAD TROUGH PAST FORECAST AREA BY MONDAY AFTERNOON WITH DECENT
DRYING/MIXING AND RECOVERING H85 TEMPS. THUS BOOSTED READINGS
TOWARD 12Z MEX WHICH MAY PROVE CONSERVATIVE. NEXT FRONT APPEARS IT
WILL BE PUSHING INTO FORECAST AREA BY DAY 7 ALTHOUGH CONFIDENCE
NOT THE BEST. BLENDED SURROUNDING OFFICES WITH A ADJUSTED MEX FOR
THEN AND LEFT FORECAST DRY AT THIS TIME.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
COLD FRONT OVER THE NORTHERN PLAINS WILL MOVE SOUTH INTO THE AREA
AFTER 00Z WITH INCREASING MID LEVEL CIGS EXPECTED. OTHER THAN WIND
SHIFT TO THE NORTH BEHIND THE FRONT NO SIGNIFICANT AVIATION ISSUES
ARE FORECAST WITH VFR CONDITIONS OVER THE NEXT 24 HOURS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...RED FLAG WARNING UNTIL 5 PM CDT THIS AFTERNOON FOR NEZ078-088-
089-092-093.
IA...NONE.
&&
$$
CHERMOK/FOBERT