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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS63 KOAX 161107
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
607 AM CDT THU MAY 16 2013

.AVIATION...
-- Changed Discussion --
12Z TAFS FOR KOFK...KOMA AND KLNK.

ALTHOUGH PREVAILING VFR CONDITIONS WERE FORECAST FOR TAF SITES
THROUGH 17/12Z...SEVERAL ISSUES WILL NEED MONITORING. FIRST IS
EXPANDING AREA OF MOISTURE/LOW CLOUDS JUST N OF KS BORDER SW OF
BEATRICE AT 11Z THIS MORNING. ALTHOUGH BULK OF THESE CLOUDS
SHOULD REMAIN SW OF TAF SITES TODAY BEFORE MIXING OUT THIS
MORNING...SOME OF THE RESIDUAL MOISTURE ON NE SIDE COULD ALLOW FOR
A BRIEF PERIOD OF CIGS BELOW FL030 THIS MORNING AT KLNK AND
POSSIBLY KOMA. IN ADDITION...A WEAK FRONT IN SERN NEBR WILL BE
LIFTING NORTH TODAY COINCIDENTAL WITH A DISTURBANCE TRACKING
ACROSS NEBRASKA. THESE FEATURES COULD BRING TSTM DEVELOPMENT
JUST ABOUT ANYWHERE DURING THE TAF VALID PERIOD AND IN ANY
STRONGER SHOWERS/STORMS...CONDITIONS COULD CONCEIVABLY DROP INTO
IFR CATEGORY BRIEFLY. COVERAGE WAS EXPECTED TO BE MORE
CONCENTRATED LATE THIS AFTERNOON THROUGH LATE EVENING AND
ESPECIALLY OVER NERN NEBR.

CHERMOK
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&&

.PREV DISCUSSION... 
-- Changed Discussion --
/ISSUED 402 AM CDT THU MAY 16 2013/

DISCUSSION...

MAIN FORECAST CONCERNS CENTER AROUND THUNDERSTORM CHANCES NEXT FEW
DAYS.

00Z UPPER AIR ANALYSIS ALONG WITH LATEST WATER VAPOR IMAGERY SHOWS
A CLOSED LOW OVER CENTRAL OKLAHOMA WITH BELT OF THE WESTERLIES
EXTENDING FROM THE WESTERN STATES INTO THE NRN PLAINS. THERE IS A
PIECE OF SHORTWAVE ENERGY WITHIN THE WESTERLIES OVER NORTHERN
COLORADO. AT THE SURFACE...A QUASI STATIONARY FRONT EXTENDS FROM
WEST TO EAST ACROSS FAR SOUTHEAST NEBRASKA AND INTO EXTREME
SOUTHERN IOWA AND NORTHERN MISSOURI. THERE REMAINS QUITE A
DEWPOINT GRADIENT ALONG THIS BOUNDARY WITH LOWER 60S TO THE SOUTH
AND 40S TO THE NORTH. THIS BOUNDARY WILL PUSH NORTH AS A WARM
FRONT TODAY BRINGING THE HIGHER SFC DEWPOINTS ALONG WITH IT. MIXING
TO AROUND 800MB TODAY PUTS MUCH OF THE FORECAST AREA INTO THE 80S.

THE ABOVE MENTIONED COLORADO IMPULSE WILL CONTINUE TO MOVE
NORTHEAST THROUGHOUT THE DAY. WE EXPECT SHOWERS AND ISOLATED
THUNDERSTORMS TO CONTINUE AHEAD OF IT THROUGH WESTERN NEBRASKA
AND EVENTUALLY INTO NORTHEAST NEBRASKA. INSTABILITY WILL BE
INCREASING ACROSS THE REGION AS MOISTURE CONTINUES TO PUSH NORTH
WITH THE WARM FRONT. WILL CONTINUE THE CHANCE OF THUNDERSTORMS ALONG
AND NORTH OF THE FRONT FROM LATE THIS AFTERNOON INTO TONIGHT AS
MID LEVEL LAPSE RATES INCREASE AHEAD OF THE IMPULSE. THE STORMS
SHOULD EVENTUALLY MOVE NORTHEAST OF THE AREA LATER TONIGHT ALONG WITH
THE MID LEVEL IMPULSE. BEHIND IT...WEAK MID LEVEL RIDGING WILL
MOVE OVERHEAD AND SHOULD KEEP FRIDAY DRY. TEMPERATURES WILL REMAIN
MILD WITH HIGHS IN THE LOWER TO MID 80S AND A GUSTY SOUTHEASTERLY
WIND.

PATTERN BECOMES MUCH MORE ACTIVE INTO THE WEEKEND AS A WESTERN
TROUGH ADVANCES TOWARD THE FOUR CORNERS REGION BY SATURDAY. AHEAD
OF THIS...SEVERAL IMPULSES WILL EJECT OUT AHEAD OF THIS FEATURE
WHILE SOUTHERLY MOIST FLOW INCREASES ACROSS THE SOUTHERN PLAINS.
AS THE DYNAMICS COME TOGETHER TO OUR WEST SATURDAY...STORMS ARE
EXPECTED TO FOCUS ALONG A LEE SIDE SURFACE TROUGH FROM THE
DAKOTAS INTO WESTERN NEBRASKA. THIS ACTIVITY WILL ADVANCE EASTWARD
INTO A FAIRLY CAPPED ENVIRONMENT WHICH SHOULD WEAKEN BY EVENING.
UNCERTAINTY REMAINS ON JUST HOW FAR EAST THE ACTIVITY WILL
SPREAD...BUT A STRENGTHENING SOUTHERLY LOW LEVEL JET WILL BE
AIDING IN SUSTAINED OVERNIGHT ACTIVITY.

MUCH STRONGER UPPER LEVEL SUPPORT WILL EJECT OUT OF THE UPPER
TROUGH AND INTO OUR REGION SUNDAY AFTERNOON WHERE A MOIST AND
UNSTABLE AIRMASS WILL RESIDE. A SURFACE BOUNDARY IS PROGGED TO
MOVE EAST ACROSS THE REGION DURING PEAK HEATING AND SHOULD BE THE
FOCUS FOR POTENTIALLY SEVERE THUNDERSTORMS AS DEEP BULK SHEAR
INCREASES.

COOLER TEMPERATURES IN STORE FOR EARLY NEXT WEEK AS A NORTHERN
PLAINS LOW KEEPS THE AREA IN NORTHWESTERLY FLOW.

KERN
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&&

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

$$