Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 272340
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
640 PM CDT WED AUG 27 2014

.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 302 PM CDT WED AUG 27 2014

...HEAVY RAINFALL AND POSSIBLE FLOODING IN THE MAIN CONCERN IN THE
SHORT TERM...

EARLY AFTERNOON WATER VAPOR IMAGERY INDICATED A POTENT UPPER LEVEL
SYSTEM OVER THE CNTRL ROCKIES. THIS SYSTEM AND ASSOCIATED 60 KT
H3 JET AND 30-40 M H5 HEIGHT FALLS WILL MOV NEWD OVER THE SHORT
TERM BRINGING CONTD PERIODS OF SHOWERS AND THUNDERSTORMS TO THE
REGION. PERSISTENT 850-700 MB WAA ACTING THE ON THE ERN EDGE OF
THE MID-LEVEL MOISTURE GRADIENT HAS ALLOWED FOR PERSISTENT
SHOWERS AND A FEW THUNDERSTORMS THIS AFTN FOR MAINLY ALONG AND E
OF THE RIVER. MODELS ARE GENERALLY IN GOOD AGREEMENT THAT THIS
AREA OF RAINFALL WILL GENERALLY WEAKEN BY EVENING AS THE BETTER
FORCING FOR ASCENT ASSOCIATED WITH THE UPPER LEVEL SYSTEM AND
INCREASING LOW-LEVEL JET. THUS WILL INITIALLY FOCUS THE HIGHEST
POPS IN THE WRN FA IN THE EVNG. THIS FORCING SHOULD LEAD TO
INCREASING SHOWERS AND THUNDERSTORMS OVER CNTRL AND WRN NEB
THROUGH THE EVENING. MODELS...ESPECIALLY THE CAMS...INDC THAT AN
ORGANIZED MCS WILL TRACK EWD INTO ERN NEB AND WESTERN
IOWA...MAINLY AS WE GET TOWARD LATE EVENING AND INTO THE OVERNIGHT
HOURS.

THERE REMAINS SOME UNCERTAINTY TO THE EXACT TRACK OF SAID
SYSTEM AND THUS WHERE THE HEAVIEST RAINFALL WILL FALL WITH MODEL
SOLUTION RANGING FROM THE NRN TO SRN CWA. CURRENTLY FEELING IS
THAT THE AREA BETWEEN I80 AND HIGHWAY 20 WILL BE THE MOST LIKELY
AREA. DESPITE THE UNCERTAINTY IN THE PLACEMENT OF HEAVY RAINFALL
THERE IS PRETTY HIGH CONFIDENCE THAT HEAVY RAINFALL WILL OCCUR
GIVEN THE 1.8-2.0 IN PWATS AND CLOUD BEARING SW UNIDIRECTIONAL
FLOW LEADING TO BACKBUILDING. THUS WILL CONT TO MENTION HEAVY
RAINFALL IN THE FORECAST. FF GUIDANCE INDCS THAT DESPITE SPOTTY
HEAVY RAINFALL THE LAST TWO NIGHTS THAT MOST AREAS OF THE CWA CAN
STILL TAKE A GOOD RAINFALL BEFORE MORE THAN ISO FLOODING WOULD
OCCUR. THUS WE WILL HOLD OFF ON A FLASH FLOOD WATCH ATTM. OF
COURSE THERE ARE A COUPLE OF NARROW CORRIDORS OF THE CWA THAT ARE
MORE SUSCEPTIBLE TO FLOODING DUE TO RECENT RAINS...AND THESE WILL
HAVE TO BE MONITORED CLOSELY. ONCE CONFIDENCE IN THE EVENTUAL
TRACK OF THE MCS INCREASES A WATCH MAY BE ISSUED LATER.

CONVECTION SHOULD CONT INTO THU MORNING WTIH THE WRN EDGE OF THE
MCS LIKELY ALONG AND JUST WEST OF THE RIVER AT THAT TIME. BY MID
TO LATE MORNING THE SYSTEM SHOULD MOVE OFF TO THE EAST. THE UPPER
LEVEL SYSTEM WILL BE OPENING UP ON THU WITH A WEAK BOUNDARY IN
THE AREA. GIVEN THE LACK OF A CAPPING INVERSION...FAVORABLE LARGE-
SCALE FORCING FOR ASCENT...AND THE BOUNDARY IN THE AREA WE SHOULD
SEE STORMS REDEVELOP ON THU AFTN...ESPECIALLY OVER THE CTNRL AND
ERN FA. THESE WILL LIKELY CONT INTO THU NIGHT BUT BY THIS TIME THE
THREAT OF MORE WIDESPREAD HEAVY RAINFALL WILL LIKELY BE EAST OF
OUR AREA BY THEN. THIS PATTERN MAY AGAIN DEVELOP ON FRI AFTERNOON
BEFORE THE SYSTEM MOVES OFF TO THE EAST AND DRY WEATHER DEVELOPS
FOR SAT.

.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 302 PM CDT WED AUG 27 2014

ONLY A QUICK BREAK IN ACTIVE WEATHER IS EXPECTED BEFORE THE NEXT
TROUGH AND ASSOCIATED SFC LOW/CDFNT WILL QUICKLY MOV INTO THE
REGION FOR SUNDAY. THIS SYSTEM APPEARS PRETTY DYNAMIC AND MAY LEAD
TO SOME SVR WX FOR SUN ACRS THE CWA AS HIGHLIGHTED IN THE SPC
OUTLOOKS. OTHERWISE ONCE THIS FRONT MOVES THROUGH WED SHOULD SEE
DRY WEATHER AND SEASONABLE TEMPERATURES FOR MON NIGHT THRU THU.

&&

.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 637 PM CDT WED AUG 27 2014

VFR CONDITIONS AT KOMA/KLNK INITIALLY...AND POSSIBLY AT KOFK.
SHOWERS WILL AFFECT KOFK/KLNK INITIALLY AS WELL...THEN BECOMING
PREVAILING BY 04-06Z WITH MVFR CONDITIONS DEVELOPING. THUNDERSTORMS
WILL ALSO BE POSSIBLE LATE IN THE NIGHT 08-15Z AT ALL TAF...THEN
ENDING. VFR CONDITIONS BY LATE MORNING AND AFTERNOON...AND COULD
SEE ADDITIONAL THUNDERSTORMS AT KOMA/KLNK 20-24Z.

&&

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

$$

SHORT TERM...BOUSTEAD
LONG TERM...BOUSTEAD
AVIATION...DEWALD



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