Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 261725
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1225 PM CDT TUE AUG 26 2014

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 315 AM CDT TUE AUG 26 2014

...LOCALLY HEAVY RAIN POSSIBLE THROUGH THURSDAY...
THE SHORT TERM FORECAST PROBLEMS CONTINUE TO BE LOCATION OF
LOCALLY HEAVY RAIN EACH DAY.

THE 00Z OAX SOUNDING HAD A PWAT AROUND 1.4 INCHES AND 1100 J/KG
OF ELEVATED INSTABILITY WITH STEEP MID LEVEL LAPSE RATES. THE
RADAR WAS FAIRLY QUIET UNTIL AROUND 04Z WHEN STORMS BEGAN TO FIRE
AROUND YORK...EXPANDING NORTHEAST TOWARD WAHOO AND FORT CALHOUN.
THE LATEST RADAR MOSAIC HAS THE CLUSTER OF STORMS PUSHING EAST AND
SOUTHEAST FROM OVER SOUTHEAST NEBRASKA INTO WESTERN IOWA...WITH
ADDITIONAL RE-DEVELOPMENT FROM COLUMBUS TO TEKAMAH AND SOLDIER
IOWA. THIS UPTICK IN STORMS GENERALLY COINCIDED WITH THE
INCREASING LOW LEVEL JET AND RESULTANT DIFFERENTIAL THETA-E
ADVECTION ALONG WITH FAVORABLE RIGHT ENTRANCE REGION JET SUPPORT
AND MID LEVEL OMEGA. LOCALLY HEAVY 2 TO 4 INCH RAINS PROBABLY FELL
IN A NARROW BAND BASED ON RADAR...WITH THE HEAVIEST IN A LINE FROM
YORK TO NEAR WESTON...BENNINGTON AND PERSIA IOWA.  OTHER GENERAL
.5 TO 1.5 INCH AMOUNTS FELL ACROSS PARTS OF THE AREA...WITH NOT
MUCH IN FAR NORTHEAST NEBRASKA OR FAR SOUTHERN NEBRASKA SO FAR.

THE H5 PATTERN REMAINS FAVORABLE FOR STORM DEVELOPMENT WITH A TROF
OVER THE WESTERN U.S. PIECES OF ENERGY EJECT INTO THE PLAINS AND A
GENERAL WARM ADVECTION PATTERN WILL REMAIN IN PLACE.  THE SURFACE
FRONTAL BOUNDARY TO THE SOUTH OF THE FORECAST AREA WILL REMAIN
THERE THROUGH WEDNESDAY MORNING THEN MAY TRY TO LIFT NORTH INTO
SOUTHEAST NEBRASKA WEDNESDAY AFTERNOON WITH THE BOUNDARY STILL IN
THE AREA THURSDAY AFTERNOON. THE MID LEVEL TROF FINALLY MOVES INTO
THE CENTRAL PLAINS BY FRIDAY. PWATS ACTUALLY INCREASE TO AROUND 2
INCHES TONIGHT AND REMAIN HIGH THROUGH THURSDAY.

WILL MONITOR RADAR TRENDS...BUT EXPECT WITH THE VEERING WINDS THE
CLUSTER OF STORMS TO CONTINUE TO PUSH INTO SOUTHWEST
IOWA...HOWEVER CONTINUED RE-DEVELOPMENT IS EXPECTED OVER THE
FORECAST WITH PERSISTENT WARM AIR ADVECTION...ALBEIT NOT AS
FOCUSED. THERE SHOULD BE DECREASING DIURNAL TREND...HOWEVER WARM
AIR ADVECTION INCREASES AGAIN BY LATE AFTERNOON AND OMEGA
INCREASES SUBSTANTIALLY OVERNIGHT. WE LOOK FOR THE PATTERN TO
REPEAT OVER THE NEXT TWO NIGHTS. THE LOW LEVEL JET STRENGTHENS
EACH NIGHT AND CONDITIONS ARE FAVORABLE FOR STORMS TO RE-DEVELOP.
THE WARM CLOUD DEPTHS REMAIN AROUND 4KM DEEP AND PWATS VERY HIGH.
LOCALLY HEAVY RAIN IS LIKELY EACH NIGHT. THE HEAVIEST RAIN MAY
ONLY BE A COUNTY OR TWO WIDE AND EXTEND ACROSS PARTS OF THE
FORECAST AREA...SO THIS WILL BE TOUGH TO PIN DOWN. THE
DIFFERENTIAL THETA-E ADVECTION...MAY BE FARTHER NORTH TONIGHT...SO
THIS MAY BE HELPFUL TO SPREAD AROUND THE LOCALLY HEAVY RAIN.
WEDNESDAY...AREAS ALONG AND NORTH OF I80 ARE STILL FAVORABLE FOR
HEAVY RAIN. THERE IS A STRONG SHORTWAVE AND LIFT OVER THE FRONT IN
THE AFTERNOON. THERE IS A SPEED MAX THAT MAY ASSIST IN LIFTING
THIS AREA OF HEAVY RAIN NORTH OF THE FORECAST AREA BY THURSDAY
MORNING. WHILE HEAVY RAIN WILL BE THE MAIN RISK...DIFFERENTIAL
HEATING WILL CONTRIBUTE TO INSTABILITY AND THERE WILL BE SOME DEEP
LAYER SHEAR TO WORK WITH...THUS ISOLATED STRONG TO SEVERE STORMS
WILL BE POSSIBLE.

.LONG TERM...(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 AM CDT TUE AUG 26 2014

PRECIPITATION CHANCES CONTINUE THURSDAY NIGHT...LINGER FRIDAY AND
PUSH EAST FRIDAY NIGHT THROUGH SATURDAY. STILL SOME MODEL TIMING
DIFFERENCES ON HOW QUICK TO EXIT THE PRECIPITATION WITH THE EC A
LITTLE FASTER. SATURDAY NIGHT THROUGH SUNDAY LOOKS MAINLY DRY.
ANOTHER TROF OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES WILL
INCREASE RAIN CHANCES FOR SUNDAY NIGHT DRAGGING A FRONT INTO THE
AREA MONDAY. HIGHS SHOULD TOP OUT IN THE 70S AND 80S.

&&

.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1216 PM CDT TUE AUG 26 2014

VFR CONDITIONS EARLY IN THE TAF PERIOD. THUNDERSTORMS DEVELOPING
SOUTHWEST OF KLNK COULD AFFECT THAT LOCATION 20-24Z AND KOMA
22-02Z. OTHERWISE...EXPECTING ADDITIONAL NOCTURNAL THUNDERSTORM
DEVELOPMENT AT ALL TAF SITES...ESPECIALLY 04-12Z. MVFR CONDITIONS
COULD DEVELOP BY 10Z AND BEYOND AS WELL.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&

$$

SHORT TERM...ZAPOTOCNY
LONG TERM...ZAPOTOCNY
AVIATION...DEWALD


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