Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 281745 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1245 PM CDT THU MAY 28 2015 .SHORT TERM...(TODAY THROUGH FRIDAY NIGHT) ISSUED AT 303 AM CDT THU MAY 28 2015 SUBJECTIVE 00Z UPPER AIR ANALYSIS INDICATES WEAK WEST- SOUTHWESTERLY UPPER- LEVEL FLOW ACROSS THE CENTRAL US...WITH A FEW RIPPLES...AND WITH AN UPPER- LEVEL TROUGH NOTED IN ID/MT EXTENDING INTO THE DESERT SOUTHWEST. NO NOTABLE 500MB HEIGHT FALLS WERE ANALYZED IN THE CONUS..THOUGH BROAD HEIGHT RISES UP TO 100M WERE NOTED FROM THE MO RIVER VALLEY TOWARD THE GREAT LAKES. AN AXIS OF 850MB 8C+ DEWPOINTS EXTENDED NORTHWARD THROUGH THE HIGH PLAINS...WITH A DRY POCKET UNDER MID- LEVEL RIDGING FROM EASTERN NEB/EASTERN DAKOTAS INTO IA/WESTERN GREAT LAKES. HINTS OF AN EML ALSO MADE AN APPEARANCE...WITH 10C+ TEMPERATURES AT 700MB IN NM/SOUTHERN TX. SURFACE TROUGH AXIS AT 07Z EXTENDED ALONG THE HIGH PLAINS. MAIN FORECAST CONCERNS ARE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY THROUGH FRIDAY NIGHT. AREAS OF CONVECTION HAVE BEEN REMAINED SCATTERED...WITH NONE IMMINENTLY THREATENING THE CWA. SHORT-RANGE MODELS CONTINUE TO INDICATE SHOWERS AND THUNDERSTORMS MOVING INTO AT LEAST THE SOUTHERN CWA YET THIS MORNING...AND HAVE KEPT A CHANCE IN THE SOUTHWEST TO WESTERN CWA...THOUGH CONFIDENCE IS LOW. INSTABILITY IS WEAK IN EASTERN NEB...AND THINK STORMS WOULD BE WEAKENING. WITH THOUGHT THAT PRECIPITATION COVERAGE MIGHT BE LOWER THAN PROGS...HAVE INDICATED TEMPERATURES ON THE WARMER SIDE OF GUIDANCE TODAY. DO THINK SHOWERS/THUNDERSTORMS WILL DEVELOP IN THE CWA THIS AFTERNOON/EVENING AS SHORTWAVE KICKS ACROSS THE REGION...THOUGH STILL THINK BETTER INSTABILITY WILL BE WEST AND SEVERE WEATHER POTENTIAL WILL BE LIMITED. CONVECTION SHOULD CONTINUE TONIGHT AT LEAST IN SOME SENSE...PERHAPS IN BROKEN AREAS AS IS ONGOING THIS MORNING...AND CURRENT POPS MIGHT BE A BIT ON THE AGGRESSIVE SIDE. CONVECTIVE EVOLUTION BECOMES EVEN MORE UNCERTAIN ON FRIDAY. UPPER=LEVEL TROUGH WILL EJECT ACROSS THE PLAINS ON FRIDAY...WITH SURFACE COLD FRONT PUSHING OUT OF SD FRIDAY AFTERNOON/EVENING. MAY BE SOME ONGOING SHOWERS/THUNDERSTORMS IN THE MORNING OR THROUGH THE DAY...WITH LITTLE TO HOLD IT BACK...AND THAT ACTIVITY WOULD WEAKEN INSTABILITY. FRONTAL PASSAGE WILL BRING HIGHER CHANCES FOR SHOWERS AND THUNDERSTORMS FRIDAY AFTERNOON/EVENING...WITH MUCH MORE COOL AND STABLE AIRMASS BEHIND THE FRONT. HAVE SPED TIMING OF FRONTAL PASSAGE JUST A BIT MORE...BUT DID HOLD ONTO SLIGHT CHANCES OF SHOWERS THROUGH 12Z SATURDAY IN THE SOUTHERN CWA BEHIND THE FRONT. .LONG TERM...(SATURDAY THROUGH WEDNESDAY) ISSUED AT 303 AM CDT THU MAY 28 2015 BEHIND THE FRONT...COOLER AND DRIER WEATHER WILL SPILL INTO THE CENTRAL PLAINS FOR THE WEEKEND. UPPER-LEVEL RIDGE WILL BUILD EASTWARD INTO THE CENTRAL US INTO EARLY NEXT WEEK...KEEPING WEATHER DRY AND BRINGING MODERATING TEMPERATURES AS LOW- TO MID- LEVEL FLOW RETURNS TO SOUTHERLY. GFS AND ECMWF BOTH HOLD AN UPPER- LEVEL TROUGH/WEAK UPPER LOW IN THE SOUTHERN/SOUTHEASTERN US INTO EARLY NEXT WEEK. MOISTURE FROM THE GULF MAY DIVERT TOWARD THAT FEATURE...WITH SOME RETURN FLOW MOISTURE ADVECTED INTO THE HIGH PLAINS...AND DRIER AREA BETWEEN FOR MUCH OF THE CENTRAL PLAINS. RIDGE BREAKS DOWN TO SOUTHWESTERLY FLOW AROUND WEDNESDAY AS UPPER- LEVEL TROUGH DIGS INTO THE WESTERN US...WITH CUTOFF UPPER LOW HOLDING ITS PLACE. FIRST EJECTING SHORTWAVE MAY BRING ACTIVE WEATHER TO THE NORTHERN PLAINS ON TUESDAY NIGHT/WEDNESDAY...BUT THAT BATCH LOOKS TO STAY NORTH OF THE CWA. NEXT WAVE AROUND WEDNESDAY NIGHT/THURSDAY LOOKS MORE LIKELY TO BRING ACTIVE WEATHER TO THE AREA. && .AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1227 PM CDT THU MAY 28 2015 AVIATION FORECAST REMAINS DIFFICULT WITH SPOTTY CONVECTION IN THE FORECAST THROUGH THE PERIOD. SURFACE LOW CENTERED OVER EAST COLORADO AS OF 17Z WAS PUMPING MOISTURE FROM THE SOUTH INTO EAST NEBRASKA AND WESTERN IOWA. HAVE ADDED VCSH TO KLNK AND KOMA AND NOT INCLUDED THUNDER AT THIS TIME. VFR TO MVFR EXPECTED AT ALL THREE TAF SITES FOR THE MOST PART THROUGH THIS FORECAST PERIOD. THOUGH A STRAY THUNDERSTORM MAY HAVE TO BE DEALT WITH...HAVE NOT ATTEMPTED TO BRING ORGANIZED THUNDERSTORMS INTO THE FORECAST UNTIL AROUND 12Z...ESPECIALLY AT KOMA AND KLNK...WHEN ACTUAL COLD FRONT WILL BE APPROACHING FROM THE WEST. EXPECT SHOWERS AND THUNDERSTORMS ASSOCIATED WITH THE COLD FRONT TO MOVE ACROSS TAF SITES BETWEEN 15Z AND 18Z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...MAYES LONG TERM...MAYES AVIATION...MEYER

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