Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 041107
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
607 AM CDT FRI SEP 4 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 344 AM CDT FRI SEP 4 2015

WARM TEMPERATURES AND CHANCES FOR MAINLY LATE NIGHT/EARLY MORNING
THUNDERSTORMS THROUGH THE WEEKEND ARE THE PRIMARY FORECAST CONCERNS.

STRONG SHORTWAVE LIFTING NORTHEAST FROM THE HIGH PLAINS INTO SOUTH
DAKOTA NOTED ON WATER VAPOR IMAGERY WAS TRIGGERING SCATTERED
CONVECTION ACROSS A GOOD PART OF NEBRASKA FROM NORTHWEST TO SOUTH
CENTRAL. ISOLATED CELLS WERE POPPING UP HERE IN THE EAST AS WELL.
EXTRAPOLATION OF CURRENT PRECIPITATION...ALONG WITH SUPPORT OF
SEVERAL SHORT RANGE HI-RES MODELS SUGGEST MUCH OF EASTERN NEBRASKA
AND PARTS OF WESTERN IOWA WILL SEE AT LEAST ISOLATED SHOWERS/THUNDER
THIS MORNING. EXPECT CONVECTION TO GRADUALLY WEAKEN/DIMINISH BY MID
TO LATE MORNING AS SHORTWAVE LIFTS FARTHER AWAY AND LOW LEVEL JET
WEAKENS. ASSOCIATED CLOUDS MAY HINDER WARMING A BIT THIS
MORNING...BUT PLENTY OF SUNSHINE THIS AFTERNOON AND A RELATIVELY
WARM START SUGGEST HIGHS IN THE UPPER 80S AND LOWER 90S WILL AGAIN
BE REALIZED.

LITTLE CHANGE TO OVERALL PATTERN IS EXPECTED TONIGHT INTO SATURDAY
AS UPPER LOW IN THE NORTHWEST U.S. BEGINS TO BOTTOM OUT NEAR
WA/OR/ID BORDER...KEEPING SOUTHWEST FLOW ALOFT ACROSS THE PLAINS.
AGAIN LOW LEVEL JET IS EXPECTED TO IGNITE ELEVATED CONVECTION OVER
PARTS OF OUR AREA LATER TONIGHT. LAYER THETA-E PROFILES POINT TO A
SOUTH CENTRAL TO NORTHEAST NEBRASKA LINE FOR BEST PRECIP CHANCES
BETWEEN MIDNIGHT AND NOON...WITH CONVECTION AGAIN WANING AS LOW
LEVEL JET DIMINISHES. LOW LEVEL ATMOSPHERE SHOULD REMAIN UNCHANGED
AS WELL...SO HIGHS AGAIN AT OR ABOVE 90 ARE FORECAST.

BY SATURDAY NIGHT AND SUNDAY...NORTHWEST UPPER LOW WILL BEGIN
EJECTING TO THE NORTHEAST INTO SOUTHERN SASKATCHEWAN BY SUNDAY
AFTERNOON...RESULTING IN LOWERING HEIGHTS IN THE PLAINS. SURFACE
FRONT THAT WILL PERSIST NEAR THE HIGH PLAINS INTO SATURDAY WILL
FINALLY BEGIN A PUSH SOUTHEAST...REACHING EASTERN NEBRASKA SUNDAY
AFTERNOON. COMBINATION OF COOLER AIR ALOFT OVER SURFACE CONVERGENCE
ALONG FRONTAL ZONE...AND WARM/MOIST LOW LEVEL AIR AHEAD OF THE
BOUNDARY...WILL RESULT IN SCATTERED CONVECTION IGNITING SUNDAY
AFTERNOON AND EVENING. SURFACE-BASED CAPES SHOULD EXCEED 2000 J/KG
DURING THE HEAT OF THE DAY WITH BULK 0-6KM SHEAR OVER
30KT...SUGGESTING SOME STRONG STORMS ARE POSSIBLE. EXACT TIMING OF
FRONT AND QUALITY OF MOISTURE PROFILE IS STILL IN QUESTION REGARDING
SEVERE PROBABILITIES IN OUR AREA AS MODELS CURRENTLY KEEP BETTER
DYNAMICS/MOISTURE JUST TO OUR NORTH. BUT STILL A GOOD CHANCE FOR
THUNDERSTORMS OVER MOST OF EASTERN NEBRASKA SUNDAY AFTERNOON AND
EVENING.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 344 AM CDT FRI SEP 4 2015

CONVECTION TIED TO SUNDAY AFTERNOON FRONTAL SYSTEM WILL CONTINUE
INTO SUNDAY EVENING ACROSS AT LEAST SOUTHEAST NEBRASKA AND SOUTHWEST
IOWA. THIS FRONT SHOULD CLEAR OUR SOUTHEAST CWA BY MONDAY
MORNING...HOWEVER ANOTHER SHORTWAVE ROLLING OFF THE ROCKIES WILL
INDUCE A QUICK RETURN FLOW SCENARIO ACROSS THE PLAINS FOR MONDAY
AFTERNOON/EVENING. AFTER THAT WAVE PASSES MONDAY NIGHT...A GENERAL
DOWNWARD TREND IN PRECIP CHANCES AND TEMPERATURES WILL FOLLOW FOR
THE REST OF THE WEEK. A FEW OVERRUNNING SHOWERS ARE POSSIBLE ON
TUESDAY...BUT THE MAIN WEATHER STORY THEN WILL BE COOLER
TEMPERATURES AND DRIER LOW LEVEL AIR. HAVE HIGHS IN THE 80S FOR THE
MOST PART ON MONDAY...DROPPING INTO THE 70S BY WEDNESDAY AND
THURSDAY.

&&

.AVIATION...(12Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 606 AM CDT FRI SEP 4 2015

SPOTTY SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE AREA THIS
MORNING...POSSIBLY AFFECTING KOFK AND KLNK EARLY ON IN THE PERIOD.
OTHERWISE MAINLY VFR CONDITIONS ARE EXPECTED...WITH SOUTHERLY WINDS
INCREASING THIS AFTERNOON BEFORE DYING DOWN SHORTLY AFTER 00Z THIS
EVENING.

&&

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

$$

SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...KG



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