FXUS63 KOAX 050823
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
323 AM CDT TUE APR 5 2011
.DISCUSSION...
...MAIN FORECAST PROBLEM IS TEMPERATURES SHORT TERM...THEN POPS
WEDNESDAY NIGHT INTO THE WEEKEND...
EARLY MORNING WATER VAPOR LOOP SHOWS A PROGRESSIVE PATTERN OVER
NORTH AMERICA AND OFF THE WEST COAST...WITH LONG WAVE TROF OVER THE
APPALACHIANS AND A DIGGING SHORTWAVE MOVING INTO THE PACIFIC
NORTHWEST. OVER THE PLAINS...STRONG UPPER LEVEL HEIGHT RISES WERE
NOTED ON THE 00Z UPPER AIR ANALYSIS...WITH A 230 METER RISE OVER
BOULDER AT 300 MB. AT THE SURFACE...HIGH PRESSURE WAS CENTERED OVER
TEXAS WITH A RIDGE AXIS EXTENDING NORTH THROUGH EASTERN NEBRASKA
WHERE WINDS WERE CALM AND DEWPOINTS WERE IN THE TEENS AT 08Z.
THIS PATTERN SUPPORTS QUIET WEATHER THROUGH WEDNESDAY...WITH SOME
CONCERN FOR ELEVATED FIRE DANGER CONDITIONS MAINLY IN THE SOUTHERN
HALF OF THE FORECAST AREA THIS AFTERNOON AS WINDS INCREASE. WE DID
LOWER THE FORECAST MAX TEMPERATURES TODAY BASED ON 850 TEMPERATURES
APPEARING TO BE SLIGHTLY COOLER THAN EARLIER EXPECTED...BUT STILL
WELL INTO THE 60S MOST AREAS.
TONIGHT THE MODELS ARE IN REASONABLE AGREEMENT INDICATING LEE SIDE
CYCLOGENESIS TAKING PLACE OVER THE WESTERN HIGH PLAINS RESULTING IN
A TIGHTENING BAROCLINIC ZONE OVER NEBRASKA AND AN EVENTUAL COLD
FRONTAL PASSAGE BY 12Z WEDNESDAY. ANY VERTICAL MOTION GENERATED AS
A RESULT WILL HAVE VERY LITTLE MOISTURE TO WORK WITH AND ONLY AN
INCREASE IN CLOUD COVER IS EXPECTED...BUT ENOUGH TO KEEP WEDNESDAY
MORNING LOWS IN THE 40S. HIGHS ON THURSDAY WILL BE LIMITED BY THE
COOL AIR ADVECTION BEHIND THIS FRONT AND LEANED TOWARD A CONSENSUS
RESULTING IN MID 50S TO MID 60S.
BEYOND WEDNESDAY...THE PLAINS WILL BE HIGHLY INFLUENCED BY A
DEEPENING LONGWAVE UPPER TROF OVER THE WESTERN US. THIS WILL
EFFECTIVELY OPEN THE GULF TO ALLOW RICHER MOISTURE RETURN INTO THE
PLAINS FOR THE LATER PART OF THE WEEK AND INTO THE WEEKEND. ABOVE
MENTIONED COLD FRONT IS EXPECTED TO RETREAT BACK TO THE NORTH AS A
WARM FRONT THURSDAY...REMAINING TO OUR SOUTH ON THURSDAY BUT
EVENTUALLY REACHING NEBRASKA AND IOWA PERHAPS FRIDAY NIGHT. VARIOUS
MODEL SOLUTIONS SHOW POOR AGREEMENT ON THE DETAILS OF TIMING AND
STRENGTH OF THE BAROCLINIC ZONE AS IT MOVES NORTH INTO THE CENTRAL
PLAINS. OF THE DETERMINISTIC SOLUTIONS...THE 00Z NAM IS THE SLOWEST
WHILE THE 00Z GEM IS THE FASTEST...BRINGING THE WARM FRONT TO NEAR
THE MISSOURI-IOWA BORDER BY 18Z THURSDAY WHICH IS 200 MILES NORTH OF
THE NAM SOLUTION. GEM APPEARS TO BE MORE OF AN OUTLIER AND HAVE
FOLLOWED A SCENARIO CLOSER TO THE NAM AND GFS...KEEPING THE SURFACE
WARM FRONT TO OUR SOUTH THURSDAY AND BRINGING IT INTO OUR SOUTHERN
COUNTIES LATE THURSDAY NIGHT. DESPITE THE DISAGREEMENT ON THE
DETAILS...THE MODELS GENERALLY DO AGREE ON ENOUGH MOISTURE AND LIFT
FOR RAIN OVER MUCH OF THE AREA WEDNESDAY NIGHT INTO THURSDAY
NIGHT... THEN AGAIN DURING THE WEEKEND. SOME THUNDER POTENTIAL WILL
EXIST MAINLY IN THE SOUTHERN PARTS OF THE FORECAST AREA...SEE SWODY3
FOR DETAILS.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
NO SIGNIFICANT AVIATION ISSUES ARE FORECAST. VARIABLE AMOUNTS OF MID
LEVEL CLOUDINESS WILL OCCUR TODAY...BUT VFR CONDITIONS ARE EXPECTED
OVER THE NEXT 24 HOURS.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
DISCUSSION...NIETFELD
AVIATION...MILLER