FXUS63 KOAX 091821
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
121 PM CDT MON MAY 9 2011
.UPDATE...
UPDATED FOR DRIER DEWPOINTS AND WARMER TEMPERATURES THIS AFTERNOON AND
TO TWEAK WINDS AND CLOUDS.
&&
.DISCUSSION...
DRIER DEWPOINTS IN THE 30S AND 40S ARE WORKING INTO THE WESTERN
PORTIONS OF THE FORECAST AREA AND TEMPERATURES WERE IN THE 90S
AT SEVERAL SPOTS INCLUDING SOUTHWEST IOWA. MADE NECESSARY ADJUSTMENTS
TO DECREASE DEWPOINTS WITH THE DRYLINE WORKING EAST AND RAISED
TEMPERATURES OVERALL WITH MOST LOCATIONS IN THE 90S...EXCEPT FOR
THE FARTH NORTH. CLEARING HAS ALSO OVERSPREAD ALL BUT THE FAR
NORTHEAST PORTION OF THE FORECAST AREA.
&&
.PREV DISCUSSION... /ISSUED 332 AM CDT MON MAY 9 2011/
DISCUSSION...
TEMPERATURES THE NEXT COUPLE OF DAYS THEN INCREASING PRECIPITATION
CHANCES AT MID WEEK ARE THE PRIMARY FORECAST CONCERNS.
CONVECTION THAT FIRED IN SOUTH CENTRAL SOUTH DAKOTA SUNDAY EVENING
CONTINUED TO PUSH EAST INTO SOUTHWEST MINNESOTA THIS MORNING. A FEW
SHOWERS WERE NOTED JUST NORTH OF NORTHEAST NEBRASKA...AND COULD SEE
A STRAY SHOWER IN OUR FAR NORTHERN COUNTIES BEFORE SUNRISE.
OTHERWISE TEMPERATURES TODAY COULD BE A BIT TRICKY AS WIDESPREAD
STRATUS/STRATO CU HAS FORMED OVER MOST OF EASTERN NEBRASKA THIS
MORNING...JUST NORTH OF A WARM FRONT DENOTED MOST CLEARLY BY 10
DEGREE HIGHER DEW POINTS TO THE SOUTH OF THE BOUNDARY. THAT WARM
FRONT IS FORECAST TO LIFT NORTH THROUGH THE CWA DURING THE DAY...BUT
COULD REMAIN NEAR NORTHERN CWA THROUGH THE AFTERNOON. EXPECT CLOUDS
TO MIX OUT LEAVING MOSTLY SUNNY SKIES AS THE FRONT MOVES NORTH.
TEMPERATURES OVER MOST OF THE CWA SHOULD HIT THE UPPER 80S TO NEAR
90...WITH NORTHERN SECTIONS OF NORTHEAST NEBRASKA AND WEST CENTRAL
IOWA POSSIBLY HOLDING IN THE LOWER 80S.
EVEN WARMER TEMPERATURES ARE EXPECTED TUESDAY AS SOUTHEAST LOW LEVEL
FLOW BECOMES SOUTHWESTERLY IN THE AFTERNOON. DOWNSLOPE WIND
COMPONENT IS EXPECTED TO PROVIDE ADDITIONAL COMPRESSIONAL WARMING TO
PUSH HIGHS ABOVE SIMILAR MODEL OUTPUT NUMBERS. THUS MANY AREAS WILL
REACH THE LOWER 90S...WITH NORTHEAST NEBRASKA HOLDING IN THE 80S
WHERE MIXING WILL BE LESS DUE TO LIGHTER WINDS.
PRECIPITATION CHANCES MONDAY AND TUESDAY WILL BE MINIMAL AS MID
LEVEL CAP AND LACK OF SURFACE/MID LEVEL TRIGGERS INHIBIT
DEVELOPMENT. HOWEVER PRECIPITATION CHANCES INCREASE BEGINNING
TUESDAY NIGHT AS UPPER TROUGH PUSHES INTO THE PLAINS. AGAIN THIS
MORNING MODELS ARE ADVERTISING THIS TROUGH ENTERING THE PLAINS IN
TWO PIECES. THE FIRST PIECE WILL EJECT INTO THE NORTHERN PLAINS
TUESDAY NIGHT...PUSHING A COLD FRONT INTO OUR CWA THEN. CONVERGENCE
ALONG THE FRONT IS MINIMAL...BUT WILL PROVIDE A FOCUS FOR ANY
SHORTWAVE EJECTING THROUGH SOUTHWEST FLOW ALOFT. BETTER PRECIP
CHANCES COME WEDNESDAY INTO WEDNESDAY NIGHT AS SECOND PIECE OF THE
TROUGH TRAVELS INTO THE CENTRAL PLAINS. PLENTY OF MOISTURE WILL
STILL BE RESIDENT ON WARM SIDE OF NEARLY STATIONARY COLD FRONT AS
COOLING ALOFT ROLLS OVERHEAD. EXPECT BEST CHANCE FOR STORMS TO BEGIN
WEDNESDAY AFTERNOON WITH UPPER TROUGH PROVIDING MID LEVEL LAPSE
RATES NEAR 8 C/KM AND SURFACE-BASED CAPE OF 2500 J/KG. 0-6KM BULK
SHEAR OF 40KTS ALONG WITH AFOREMENTIONED INSTABILITY SUGGESTS
SEVERE STORMS ARE POSSIBLE AT LEAST THROUGH WEDNESDAY EVENING.
AS UPPER TROUGH LIFTS NORTHEAST LATE WEDNESDAY NIGHT AND
THURSDAY...COVERAGE OF PRECIPITATION WILL DECREASE...BUT COOL AIR
ALOFT WILL MAINTAIN A CHANCE FOR SHOWERS AND ISOLATED STORMS AT
LEAST THROUGH THURSDAY. MEDIUM RANGE MODELS ARE STILL WORKING OUT
THE DETAILS ON MOVING TROUGH THROUGH THE PLAINS. OPERATIONAL GFS AND
ECMWF BOTH SUGGEST A SLOW PROGRESSION TO THE EAST...KEEPING SMALL
SHOWER CHANCES IN THE FORECAST THROUGH FRIDAY. COOLER TEMPERATURES
WILL RESULT WITH 60S FOR HIGHS A GOOD BET THURSDAY AND FRIDAY.
DERGAN
AVIATION...
TAF SITES KOFK/KOMA/KLNK
06Z TAFS
INFLUX OF LLVL MOISTURE ALREADY ALLOWING FOR FORMATION OF MVFR CIGS
IN ERN NEB THIS MORNING. EXPECT THAT MVFR CIGS SETTLE IN AND
PREVAIL AT ALL TERMINALS THRU ABOUT 09/14Z. ALSO...DEEPENING SFC LOW
INVOF NEB PANHANDLE WILL RESULT IN SE WIND GUSTS AROUND 25KT DURING
THE AFTERNOON HOURS. OTHERWISE VFR CONDITIONS PREVAILING REST OF
FCST PD.
DEE
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
ZAPOTOCNY