Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 120453 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1153 PM CDT FRI APR 11 2014 .SHORT TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 335 PM CDT FRI APR 11 2014 COMPLEX FORECAST WITH MANY CONCERNS CONTINUES IN THE SHORT TERM. FIRST IS WHETHER SMALL CONVECTION CHANCES REMAIN WARRANTED TONIGHT/SATURDAY MORNING ENERN ZONES. WARM FRONT SETTING UP N/NE OF FORECAST AREA THIS AFTN WITH SMALL CU FIELD MARKING LOW LEVEL CONVERGENT ZONE. MOISTURE REMAINS SPARSE...ALTHOUGH SOME MID 30S DWPTS CNTRL NEBR COULD FEED INTO BOUNDARY THROUGH EARLY TONIGHT BEFORE STRENGTHENING LOW LEVEL JET FEEDS IN SOMEWHAT HIGHER MOISTURE BY MORNING. APPEARS FRONT WILL REMAIN MOSTLY TO THE NORTH OR EAST OF THE REGION OVERNIGHT AND LIMITED MOISTURE COULD PUT ANY ELEVATED ACTIVITY FARTHER REMOVED FROM FA...I.E. PARCELS TAKING LONGER TO SATURATE IN LIFT. MOST SHORTER TERM MODELS HAVE BACKED OFF ON GENERATING PCPN OVER THE AREA BUT DID LEAVE IN SMALL POPS LATE TNGT THROUGH SAT MORNING MAINLY IA ZONES. MOISTURE/SOME LOWER CLOUDS LIKELY TO SPREAD INTO SERN ZONES SATURDAY BEFORE MIXING OUT IN THE AFTN. ALTHOUGH A WEAK BOUNDARY SLIPS SWD TO NEAR OMA/LNK DURING THE AFTN...MAIN COLD FRONT AND BETTER THERMAL GRADIENT WAS FARTHER N WITH LOW LEVEL CONVERGENCE ALONG BOUNDARY IN OUR FA FAIRLY WEAK. IT DOES APPEAR DWPTS WILL LOWER AGAIN NRN ZONES WITH MIXING WITH AN INCREASED FIRE DANGER RISK NORTH. AN ELEVATED MIXED LAYER STILL FORECAST TO SET UP OVER BOUNDARY KEEPING MOST OF THE AREA CAPPED UNTIL AFTN HEATING ATTEMPTS TO WEAKEN IT...ESPECIALLY SERN ZONES. FOR INSTANCE NAM FORECAST SOUNDING WEAKENED CAP AT FNB BUT KEPT A FAIRLY STRONG ONE IN PLACE AT KOMA/KLNK. 12Z 4KM WRF DOWNPLAYED ANY CONVECTION THROUGH 00Z SUNDAY WHILE 12Z ECMWF KEYED ON SWRN IA BY 00Z...FAIRLY CONSISTENT WITH PRIOR RUN. ALTHOUGH GFS/NAM HINTED AT SOME DEVELOPMENT BY 00Z...THEIR MAIN FOCUS WAS MORE WITH/ALONG STRENGTHENING LOW LEVEL JET SATURDAY EVENING. ADJUSTED FORECAST SLIGHTLY TO DELAY CHANCES TIL MID AFTN AND WITHHELD LIKELY POPS UNTIL THE EVENING HOURS SPREADING LIKELY/CATEGORICAL POPS FROM FAR E THEN WSW THROUGH THE EVENING. DEEP SHEAR ENOUGH TO PROVIDE A CONDITIONAL SEVERE THREAT WHEN/IF STORMS DEVELOP. DOES APPEAR SOME POTENTIAL FOR SIGNIFICANT RAINS SRN ZONES NEAR LOW LEVEL JET FOCUS. AS UPPER TROUGH BEGINS MOVING EAST ON SUNDAY...STRONG FRONTOGENETICAL FORCING COULD SET UP DECENT PRECIPITATION BAND/BANDS AIDED BY TROUGHS RELATIVELY SLOW MOVEMENT AND MODEST MOISTURE GETTING PULLED INTO SYSTEM. QUESTION SHIFTS...UNFORTUNATELY GIVEN TIME OF YEAR...TO PHASE. NAM ESPECIALLY COOLS BOUNDARY LAYER OFF SIGNIFICANTLY POINTING TO SLEET/SNOW MORESO THAN RAIN NWRN ZONES. USING BLEND OF WARMER ECMWF AND COLDER NAM KEPT PRECIP FOR NOW A RAIN/SNOW MIX SUN AFTN NWRN 1/2 OR SO THEN SPREADING R/S OVER REST OF ZONES SUN NIGHT WITH SNOW ON NWRN FRINGE. ALSO ADJUSTED HOURLY TEMPS SUNDAY FOR STEADY/FALLING NW WITH EARLY HIGH SE. SPEED OF SYSTEM AND CONVECTION EVOLUTION LIKELY TO CAUSE FUTURE ADJUSTMENTS. GENERALLY DISCOUNTED NAM FOR MONDAY WITH SLIGHTLY SLOWER/SHARPER TROUGH KEEPING LINGERING PRECIP ACROSS SRN ZONES INTO THE AFTN AS ECMWF/GFS OFFERED LITTLE SUPPORT. NONETHELESS...CONTINUED COOL WITH MUCH BELOW NORMAL TEMPS. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 335 PM CDT FRI APR 11 2014 MODERATING TEMPERATURES IN TUE/WED PERIOD AS NEXT TROUGH APPROACHES...ALTHOUGH GFS WAS A LITTLE S OF ECMWF. THIS NOT ONLY BROUGHT COOLER READINGS BACK INTO NWRN ZONES ALREADY BY WED BUT ALSO PUT BAROCLINIC ZONE INTO REGION WITH SOME PRECIP THREAT. FOR NOW KEPT WED DRY AND BOOSTED TEMPS SERN ZONES WHERE BOTH MODELS SUGGESTED 60S. WITH FAIRLY COLD AIR FEEDING IN BEHIND TROUGH...MENTIONED R/S MIX NW ZONES AS H85 TEMPS DROP TO AT LEAST -5 C...ALTHOUGH PRECIP COULD BE ENDING AS COLDER AIR ARRIVES. MODEL BLEND INDICATED SMALL POPS TO BE CONTINUED INTO FRIDAY AS ANOTHER WAVE CROSSES PLAINS...AND THERE WERE MAINTAINED. BUT CONFIDENCE PRETTY LOW REGARDING THIS. && .AVIATION...
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(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1149 PM CDT FRI APR 11 2014 MVFR CIGS ARE LIKELY TO DEVELOP BETWEEN 12Z AND 18Z AT KLNK AND KOMA AS LOW LEVEL MOISTURE WORKS NORTH FROM KANSAS AND OKLAHOMA OVERNIGHT. A COLD FRONT DROPPING SOUTH THROUGH EASTERN NEBRASKA WILL PASS KOFK BY 18Z...SWITCHING WINDS TO THE NORTH THERE WITH SPEEDS NEAR 12KT. THE FRONT WILL ONLY SLOWLY DRIFT SOUTH THROUGH THE AFTERNOON...AND LIMP THROUGH KLNK AND KOMA AREAS BETWEEN 00Z AND 06Z. SCATTERED SHOWERS OR THUNDERSTORMS ARE POSSIBLE ALONG THE FRONT AFTER 21Z...BUT IT APPEARS MOST ACTIVITY WILL DEVELOP SOUTH OF KLNK AND KOMA TAF SITES AND REMAIN SOUTH THROUGH THE END OF THE TAF PERIOD.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...CHERMOK LONG TERM...CHERMOK AVIATION...DERGAN

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