FXUS63 KOAX 032030
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
330 PM CDT TUE MAY 3 2011
.SHORT TERM...TONIGHT.
MAINLY CLEAR SKIES THROUGH MOST OF THE PERIOD WITH INCREASING
MID TO HIGH LEVEL CLOUDINESS AS COLD FRONT APPROACHES.
.LONG TERM...WEDNESDAY THROUGH TUESDAY.
TEMPERATURES AND PRECIPITATION CHANCES SHOULD BE THE MAIN FORECAST
CONCERNS THE NEXT FEW DAYS. PATTERN WILL REMAIN FAIRLY COOL WITH AT
OR BELOW NORMAL TEMPERATURES THROUGH THURSDAY...THEN EXPECT
TEMPERATURES TO BE AT OR ABOVE NORMAL.
LARGE SCALE PATTERN CURRENTLY FEATURES A MID TROPOSPHERIC TROUGH
FROM THE GREAT LAKES REGION INTO THE SOUTHERN PLAINS...WITH ANOTHER
BACK OVER THE NORTHERN AND CENTRAL ROCKIES. THESE WILL BOTH MOVE
EASTWARD THE NEXT FEW DAYS. TROUGH TO OUR WEST WILL BRING A COLD
FRONT THROUGH THE LOCAL AREA WEDNESDAY AND WEDNESDAY EVENING. THIS
COULD TRIGGER SOME SHOWERS AND THUNDERSTORMS...BUT INSTABILITY IS
FORECAST TO BE WEAK. SO SEVERE STORMS ARE NOT EXPECTED. BEST STORM
CHANCES SHOULD BE FROM ABOUT 21Z WEDNESDAY TO 03Z THURSDAY AND HAVE
TRIED TO REFLECT THAT IN GRIDS. SURFACE BASED CAPE VALUES FROM THE
12Z NAM AND 12Z GFS GENERALLY REMAIN BELOW 700 J/KG. THE FRONT IS
EXPECTED TO PUSH SOUTHEAST OUT OF THE FORECAST AREA BY MIDNIGHT
WEDNESDAY NIGHT...BUT SOME SHOWERS COULD LINGER NORTH OF THE FRONT
IN SOUTHEAST NEBRASKA AND SOUTHWEST IOWA. FOR NOW DID NOT INCLUDE
ANY MENTION OF SHOWERS THURSDAY MORNING...BUT WILL HAVE TO MONITOR
THAT. IT DOES APPEAR THAT THE ATMOSPHERE WILL DESTABILIZE THURSDAY
AFTERNOON WITH 500 MB TROUGH OVER THE AREA AND 500 MB TEMPERATURES
OF -22 DEGREE CELSIUS OR COLDER.
TEMPERATURES AFTER THAT SHOULD MODERATE...WITH HIGHS MAINLY IN THE
70S FROM FRIDAY INTO MONDAY AS THE FLOW ALOFT BECOMES A BIT MORE
ZONAL THROUGH SUNDAY. A FAST MOVING LOW PRESSURE SYSTEM COULD BRING
A FEW SHOWERS OR WEAK THUNDERSTORMS FRIDAY INTO FRIDAY NIGHT.
BOTH THE 12Z GFS AND 12Z ECMWF ARE IN DECENT AGREEMENT THAT A 500 MB
TROUGH WILL DIG OVER THE WESTERN UNITED STATES SUNDAY AND MONDAY...
THEN MOVE OUT INTO THE PLAINS BY TUESDAY. THERE ARE SOME TIMING
DIFFERENCES...BUT THE PATTERN SUGGESTS A STORMIER PATTERN AS WARM
AND MOIST ARE GETS PULLED NORTH AHEAD OF THE TROUGH AND FRONT. AT
THIS POINT...WILL GIVE THE 12Z ECMWF SOLUTION A BIT MORE WEIGHT THAN
THE GFS. SO...HIGHS COULD REACH AROUND 80 BY MONDAY OR TUESDAY...
DEPENDING ON SPEED OF COLD FRONT.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD AT ALL TAF SITES AS
WEAK HIGH PRESSURE MOVES SLOWLY EAST AND THE NEXT COLD FRONT
APPROACHES FROM THE NORTHWEST. WINDS WILL INCREASE AFTER 12Z AS
THE SURFACE GRADIENT TIGHTENS BETWEEN THE TWO WEATHER FEATURES.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...FOBERT
LONG TERM....MILLER
AVIATION...FOBERT