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000
FXUS63 KOAX 241138
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
638 AM CDT FRI MAY 24 2013

.AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK. MID CLOUDS WILL
PREVAIL THROUGH THE PERIOD WITH WINDS INCREASING TO ABOUT 15 KNOTS
GUSTING TO 25 KNOTS BY 15Z. MID LEVEL IMPULSE COULD TRIGGER
ISOLATED THUNDERSTORMS BY 21-02Z.

DEWALD

&&

.PREV DISCUSSION... /ISSUED 342 AM CDT FRI MAY 24 2013/

DISCUSSION...
LOOKS LIKE QUITE THE ACTIVE WEATHER PATTERN WILL DEVELOP OVER THE
MIDDLE OF THE COUNTRY TODAY AND REMAIN IN PLACE THE NEXT 7 DAYS.
UPPER LOWS/TROUGHS MOVING TOWARD THE EAST COAST AND ALONG THE WEST
COAST WILL KEEP OUR PART OF THE WORLD UNDER WEAK RIDGING AT LEAST
THROUGH SUNDAY. THEN MORE SOUTHWESTERLY FLOW TAKES OVER AS WESTERN
TROUGH MOVES A LITTLE EAST. DESPITE WEAK RIDGING ALOFT...SEVERAL
IMPULSES WILL MOVE OVERHEAD WHICH WILL TRIGGER OFF-AND-ON EPISODES
OF POTENTIAL PRECIPITATION OVER THE WEEKEND.

AT LOWER LEVELS...MOIST SOUTHERLY FLOW AT THE SURFACE THROUGH AT
LEAST 850MB IS FORECAST TO OVERSPREAD ALL OF THE PLAINS LATER TODAY
AND PERSIST THROUGH MUCH OF NEXT WEEK. 850 DEW POINTS WERE ALREADY
10-14C FROM SOUTHWEST KANSAS THROUGH THE TEXAS PANHANDLE...AND THIS
AIR SHOULD BE MOVING INTO WESTERN NEBRASKA TODAY THEN SPREAD EAST
THROUGH WESTERN IOWA TONIGHT. AT THE SURFACE...EASTERLY FLOW WAS
KEEPING DEW POINTS IN THE 40S THIS MORNING...BUT 60S DEW POINTS IN
THE SOUTHERN PLAINS WILL SURGE NORTH AND BECOME ENTRENCHED OVER OUR
CWA ON SATURDAY.

SO WITH MOISTURE BECOMING INCREASINGLY FAVORABLE FOR PRECIPITATION
AND WEAK IMPULSES MOVING OVERHEAD...REALLY CAN NOT RULE OUT AT LEAST
SMALL CHANCES FOR SHOWERS/THUNDER AT ANY TIME THROUGH THE HOLIDAY
WEEKEND. FOR TODAY...MOISTURE WILL NOT BE AS ROBUST...BUT DECENT MID
LEVEL WARM ADVECTION WILL BE SWEEPING THROUGH EASTERN NEBRASKA DURING
THE DAY WITH INITIAL SURGE OF MID LEVEL MOISTURE. ALREADY SEEING
SIGNS OF THAT WARM ADVECTION AS MID LEVEL CLOUDS HAVE EXPANDED FROM
WESTERN INTO CENTRAL NEBRASKA. ONLY PRECIPITATION NOTED SO FAR WAS IN
NORTHWEST KANSAS...BUT SHORT RANGE AND MESOSCALE MODELS ARE ALL
HINTING AT HIT-AND-MISS CONVECTION SPREADING INTO EASTERN NEBRASKA
DURING THE DAY. SO WILL MAINTAIN SMALL CHANCES IN OUR WEST THIS
MORNING...WITH BETTER CHANCES IN THE AFTERNOON AS SOUTHERLY FLOW
BECOMES MORE ROBUST.

PERHAPS THE BEST CHANCES FOR CONVECTION THROUGH THE WEEKEND WILL
COME DURING THE NIGHTTIME HOURS AS LOW LEVEL JET DYNAMICS CONTRIBUTE
TO FORCING. AFTERNOON INSTABILITY WILL CERTAINLY INCREASE EACH DAY
THROUGH MONDAY...AND ANY UPPER IMPULSE COULD RELEASE THAT
INSTABILITY. BUT NAILING DOWN THOSE IMPULSES WITH MUCH MORE THAN A
DAY OR SO LEAD TIME IS NEARLY IMPOSSIBLE. SO FORECAST WILL REFLECT
CHANCES FOR THUNDERSTORMS EACH OF THE NEXT SEVERAL DAYS...WITH
MORE LIKELY POPS COMING DURING THE EVENING AND OVERNIGHT HOURS.

HEAVY RAIN MAY OCCUR WITH ANY OF THESE CONVECTIVE EPISODES AS WELL.
PRECIPITABLE WATER VALUES ARE FORECAST TO COME CLOSE TO 1.5
INCHES...WHICH IS WELL ABOVE NORMAL LEVELS FOR THIS TIME OF YEAR.
PLUS FREEZING LEVELS APPROACHING 13000 FT SUGGEST WARM CLOUD DEPTH
COULD ENHANCE RAINFALL PRODUCTION. WILL HAVE TO WATCH HOW AND WHERE
THINGS DEVELOP OVER THE NEXT COUPLE OF DAYS TO FINE TUNE ANY
POSSIBLE FLOODING CONCERNS.

THE REST OF THE WEEK TUESDAY THROUGH THURSDAY MAY BRING BETTER
CHANCES FOR SEVERE STORMS IN THE CENTRAL PLAINS. WESTERN UPPER
TROUGH SHOULD BE PUSHING INTO THE PLAINS WITH STRONGER MID LEVEL
FLOW AND SLIGHTLY COOLER AIR ALOFT SPREADING INTO THE PLAINS.

DERGAN

&&

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

$$