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000
FXUS63 KOAX 252011
AFDOAX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
311 PM CDT SAT MAY 25 2013

.DISCUSSION...

ALTHOUGH TIMING OF HIGHEST CONCENTRATION OF ANY CONVECTION IS THE
MAIN CHALLENGE FOR ANY GIVEN PERIOD WELL INTO NEXT WEEK...PATTERN
LOOKS TO REMAIN ACTIVE WITH PRECIP CHANCES GOOD IF NOT LIKELY MOST
AREAS MOST EVENINGS/OVERNIGHT PDS.

AT 19Z SURFACE BOUNDARY EXTENDED FROM JUST N OF FNB TO JUST SW OF
OLU/BVN WITH RESIDUAL COOL OUTFLOW FROM MORNING CONVECTION
REINFORCING FRONT. CONVERGENCE NEAR BOUNDARY HAD INCREASED CU
FIELD WCNTRL ZONES AND LATEST RAP MESO ANALYSIS PLACED AXIS OF
2000-3000 J/KG ML CAPE ACROSS THAT AREA WITH LITTLE/NO CIN. SO
THERE REMAINS SOME POSSIBILITY OF CONVECTION DEVELOPING NEAR/N OF
THIS BOUNDARY EARLY THIS EVENING...ESPECIALLY AS ANY SUBSIDENCE
EFFECTS OF DEPARTING MCV FROM EARLIER CONVECTION GETS FARTHER
REMOVED. LATER THIS EVENING/OVERNIGHT HIGH PLAINS CONVECTION WILL
PROBABLY MAKE A RUN TOWARD/INTO FA...POSSIBLY CONSOLIDATING MORE
ACROSS NRN ZONES AIDED BY RR ENTRANCE REGION OF WEAK UPPER JET
SEGMENT. HOWEVER...CAN/T RULE OUT ACTIVITY FARTHER S AS WELL SINCE
BOUNDARY MAY NOT MOVE MUCH TONIGHT. LOW LEVEL JET DOES STRENGTHEN
SOME INTO FRONT OVERNIGHT...BUT STRONGEST/MORE CONVERGENT AREA NOT
NECESSARILY FOCUSED ACROSS THE FORECAST AREA...SO CONFIDENCE ON
WIDESPREAD HEAVY RAINFALL NOT VERY GOOD. THAT SAID...SMALL AREA OF
NRN IA ZONES DID PICK UP 1-2+ INCHES OF RAIN LAST NIGHT AND THAT
AREA APPEARS TO HAVE THE HIGHEST CHANCE OF SIGNIFICANT RAINS
TONIGHT AS MOISTURE REMAINS PLENTIFUL WITH PWATS AROUND 1.5
INCHES. THUS ISSUED A SMALL FLASH FLOOD WATCH NE OF OMAHA TO MATCH
UP WITH DMX WHERE HEAVIER RAIN WAS MORE WIDESPREAD.

DECREASED POPS DIURNALLY ON SUNDAY LIKE TODAY ALTHOUGH IT WAS
NOTED THAT FOR SEVERAL RUNS NOW NAM HAD DEVELOPED A SMALL MCS AND
DROPPED IT SE ACROSS FA DURING THE AFTERNOON. FORECAST WAS NOT
BASED ON THAT SCENARIO. ALSO MODELS HINTING AT MORE LOW LEVEL
MOISTURE WITH LOW CLOUDS POSSIBLY LINGERING INTO THE AFTERNOON.
THUS INCREASED SKY COVER. IF CLOUDS HOLD ALL DAY CONVECTIVE
DEVELOPMENT COULD BE ALTERED AS WELL AS HIGH TEMPERATURES.
OTHERWISE...LIKELY POPS MANY AREAS AGAIN WERE MENTIONED SUN NIGHT.
MONDAY POSSIBLY A VERY SIMILAR SCENARIO...ALTHOUGH FINER DETAILS
PROBABLY IMPACTED BY PREVIOUS PERIODS CONVECTION BOTH DAYS.

SOME INDICATION BY MODELS THAT A FRONT...POSSIBLY AIDED BY
OVERNIGHT CONVECTION...WILL PUSH S INTO NRN ZONES ON TUESDAY AS A
STRONGER WAVE EJECTS ACROSS CANADIAN PRAIRIE. COOLING AT H85
MINIMAL FOR THAT AREA...BUT NE WINDS AND POSSIBLE LOW CLOUDS
COULD KEEP MAX TEMPS COOLER AND THIS COULD NEED ATTENTION IN LATER
FORECASTS. OTHERWISE...THIS BOUNDARY AND UPPER TROUGH BEGINNING TO
APPROACH AREA WILL KEEP AREA ACTIVE TUESDAY/TUE NGT. WEDNESDAY
COULD POSSIBLY BE MORE OF A LULL WITH WARMER TEMPERATURES BEFORE
STRONGER ENERGY PUNCHES ACROSS CNTRL PLAINS WED NGT/THURSDAY
INCREASING COVERAGE/CHCS AGAIN. ALTHOUGH SEVERE POTENTIAL WILL
EXIST INTO TUESDAY...THIS STRONGER TROUGH COULD BRING A HEIGHTENED
RISK OF SVR WEATHER TO AREA LATE NEXT WEEK.

CHERMOK


&&

.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.

A WARM FRONT SLOWLY LIFTING OVER THE CNTRL PLAINS WILL BE THE
FOCUS FOR TSRA ACTIVITY OVER ERN NEB LATER TONIGHT. LLVL MOISTURE
WILL CONTINUE STREAMING NWD INTO THE REGION THROUGH THIS EVENING.
THIS ALONG WITH A STRENGTHENING LLVL JET...TSRA ACTIVITY SHOULD
INCREASE SOMEWHAT IN AREAL COVERAGE...MAINLY OVER NERN NEB. DUE
TO SOME UNCERTAINTY THOUGH HOW FAST THE SFC BNDRY WILL
LIFT...HAVE DECIDED TO JUST COVER ALL SITES WITH PROB30 GROUPS
BTWN 26/03Z- 12Z. MEANWHILE...WITH PERSISTENT MOISTURE ADVECTION
EXPECTED...CONDITIONS SHOULD BEGIN DETERIORATING FROM VFR TO IFR
BY OR SHORTLY AFT 26/06Z. GOOD INDICATION FROM MODEL GUIDANCE THAT
MVFR CONDITIONS THEN WILL PREVAIL THE REST OF THE FCST PD.

DEE

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...FLASH FLOOD WATCH FROM MIDNIGHT CDT TONIGHT THROUGH SUNDAY
     MORNING FOR IAZ043-055-056.

&&

$$