FXUS63 KOAX 312025
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
325 PM CDT THU MAR 31 2011
.SHORT TERM...TONIGHT.
MORNING RUN OF NAM AND CMC SEEM TO BE IN DECENT AGREEMENT LAYING
LIGHT PRECIPITATION MAINLY ON THE WESTERN PERIPHERY OF THE COUNTY
WARNING AREA THROUGH RIDAY MORNING IN ASSOCIATION WITH RELATIVELY
WEAK NORTHWEST FLOW IMPULSE DROPPING OUT OF THE DAKOTAS. MEANWHILE
THE GFS IS FOCUSING PRECIPITATION OVER ENTIRE COUNTY WARNING AREA.
NEVERTHELESS...FORCING PRIMARILY THERMALLY DRIVEN WITH STOUT 295K
ISENTROPIC UPGLIDE PROGGED. LOWEST CONDENSATION PRESSURE DEFICITS
EXPECTED LATER ON TONIGHT...THUS WILL GO WITH HIGHER CHANCES FOR
PRECIPITATION AFTER MIDNIGHT. OTHERWISE COLD AIR ADVECTION REGIME
EXPECTED TO DOMINATE OVERNIGHT.
.LONG TERM...FRIDAY THROUGH THURSDAY.
THE PRIMARY FORECAST CONCERNS DURING THIS PERIOD ARE CHANCES FOR
PRECIPITATION FRIDAY MORNING...THEN AGAIN FROM SATURDAY NIGHT
THROUGH MONDAY NIGHT.
STRONG MID AND UPPER TROPOSPHERIC FLOW REMAINS IN PLACE FROM THE
PACIFIC INTO SOUTHERN BRITISH COLUMBIA...THEN IT CURVES SOUTHEAST
INTO WESTERN KANSAS. A JET MAX OF 175 KTS WAS NOTED IN SOUTHERN
ALBERTA AT 12Z VIA A SATELLITE DERIVED WIND NEAR 32,000 FEET. A FAST
MOVING DISTURBANCE IN THAT FLOW COULD BRING A LITTLE LIGHT RAIN TO
PARTS OF THE AREA FRIDAY MORNING...THEN EXPECT MAINLY DRY CONDITIONS
FRIDAY AFTERNOON AND EVENING. MODELS HINT AT SOME LIGHT PRECIPITATION
FRIDAY NIGHT INTO SATURDAY MORNING...BUT FOR NOW LEFT CHANCES AT
14 PERCENT OR LESS. THERE IS FAIRLY IMPRESSIVE VERTICAL MOTION IN
THE 700 TO 500 MB LAYER ALONG WITH SOME FRONTOGENETICAL FORCING...
BUT MOISTURE BELOW 850 MB IS SOMEWHAT LIMITED.
BY 12Z SATURDAY...A 500 MILLIBAR RIDGE SHOULD BE OVER THE EASTERN
ROCKIES AND HIGH PLAINS REGION...WITH A STRONG TROUGH EXTENDING
FROM THE PACIFIC NORTHWEST TO JUST OFF THE COAST OF CALIFORNIA. LOW
PRESSURE AT THE SURFACE WILL START TO ORANIZE IN WYOMING SATURDAY
INTO SATURDAY NIGHT...WITH INCREASING INSENTROPIC UPGLIDE AND
INCREASING LOW LEVEL MOISTURE. 850 MILLIBAR WINDS INCREASE INTO THE
40 TO 50 KNOT RANGE SATURDAY NIGHT AS ELEVATED INSTABILITY INCREASES.
SO EXPECT SOME ISOLATED THUNDERSTORMS TO OCCUR ACROSS PARTS OF
SOUTHEAST NEBRASKA AND SOUTHWEST IOWA SATURDAY NIGHT INTO SUNDAY
MORNING. HOWEVER...BEST COMBINATION OF FORCING AND SIGNIFICANT
850 TO 500 MILLIBAR LAYER MOISTURE IS TO OUR NORTH AND EAST. SO...
EXPECT HEAVIEST PRECIPITATION SATURDAY NIGHT THROUGH SUNDAY TO BE
NORTH AND EAST OF OUR FORECAST AREA. THE CHANCE FOR THUNDERSTORMS
CONTINUES SUNDAY AND SUNDAY EVENING FOR MUCH OF THE AREA.
LOW PRESSURE AT THE SURFACE MOVES OUT ACROSS THE PLAINS SUNDAY NIGHT
INTO MONDAY...WITH COLDER AIR WRAPPING INTO OUR AREA WITH NORTH
WINDS AS THE LOW MOVES INTO NORTHERN MISSOURI. MODEL DIFFERENCES ARE
FAIRLY DRAMATIC BY 12Z MONDAY IN REGARDS TO LOCATION OF THE SURFACE
LOW. THE 12Z ECMWF WAS MUCH FASTER THAN THE 12Z GFS. AT THIS TIME...
FEEL THE BEST SOLUTION IS PROBABLY THE 12Z GFS ENSEMBLE MEAN. WHAT
THIS MEANS IS THAT SOME LIGHT SNOW OR A RAIN/SNOW MIX MAY OCCUR
MONDAY AND MONDAY NIGHT...UNTIL THE MAIN 500 MB TROUGH AXIS SHIFTS
EAST OF OUR LOCAL AREA AND SUBSIDENCE DEVELOPS. AT THIS POINT...
ANY SNOW ACCUMULATIONS ARE EXPECTED TO BE LIGHT. THE AFWA GLOBAL
ENSEMBLE 6 HOUR PROBABILITIES FOR AN INCH OR MORE OF SNOW REACH
10-30 PERCENT FOR PORTIONS OF THE AREA SUNDAY NIGHT INTO MONDAY.
HIGHS SHOULD BE MOSTLY 55 TO 60 FRIDAY AND SLIGHTLY WARMER THAN THAT
SATURDAY. HIGHS SUNDAY SHOULD REACH THE UPPER 50S TO MID 60S NORTH
AND MID 60S TO LOWER 70S SOUTH. DEPENDING ON CLOUD COVER AND MIXING...
SUNDAY COULD END UP BEING QUITE A BIT WARMER...BUT WILL STAY SOMEWHAT
CONSERVATIVE ON SUNDAYS HIGHS FOR NOW SINCE A LOT DEPENDS ON THE
EXACT LOCATION OF THE WARM FRONT.
&&
.AVIATION...
TAF SITES KOFK/KOMA/KLNK
18Z TAFS
MAIN AVIATION ISSUE THIS FORECAST PERIOD IS MVFR/-RA ALL SITES
01/08Z-12Z TIMEFRAME. MODEST LOW LEVEL BOUNDARY LAYER MOISTURE
WILL ACCOMPANY AN UPPER DISTURBANCE DROPPING OUT OF THE NORTHERN
PLAINS WITH POSSIBLE SCATTERED PRECIPITATION RESULTING. VFR
CONDITIONS ALONG WITH NORTHWEST WIND GUSTS AROUND 25 KNOTS AFTER
01/12Z THE REST OF THE FORECAST PERIOD.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE
LONG TERM....MILLER
AVIATION...DEE