Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 270445 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1145 PM CDT FRI SEP 26 2014 .SHORT TERM...(TONIGHT THROUGH MONDAY) ISSUED AT 300 PM CDT FRI SEP 26 2014 TEMPERATURES AND TIMING CHANCES FOR SPOTTY PCPN WILL PROVIDE THE MAIN FORECAST CHALLENGES IN THIS PERIOD. CURRENT LARGE SCALE PATTERN FEATURES A TROUGH AT 500 MB EXTENDING FROM WESTERN CANADA TO OFF THE CALIFORNIA COAST. A RIDGE STRETCHED FROM MEXICO INTO THE GREAT LAKES REGION. A COUPLE OF VERY WEAK CUT OFF LOWS WERE EMBEDDED IN THE RIDGE. THE LOW DOWN OVER WEST TEXAS SHOULD HAVE LITTLE IMPACT ON OUR AREA...BUT THE ONE THAT WAS NEAR THE BORDER OF IOWA AND MISSOURI EARLY THIS AFTERNOON IS OF SOME CONCERN. VERY SPOTTY PCPN DID DEVELOP LAST NIGHT/EARLY THIS MORNING OVER PARTS OF SOUTHWEST IOWA AND SOUTHEAST NEBRASKA... SOMEWHAT IN ASSOCIATION WITH THAT LOW. A GENERAL BLEND OF THE SHORT TERM MODELS SHOWED THAT THIS FEATURE WILL PROBABLY DRIFT WESTWARD (RETROGRADE) INTO OUR AREA TONIGHT AND LINGER ACROSS WESTERN IOWA INTO SUNDAY. DID NOT INCLUDE ANY POPS FOR THIS EVENING...BUT NEXT SHIFT WILL HAVE TO MONITOR THAT. THERE WERE A FEW ISOLATED ECHOES JUST TO OUR EAST AS OF 3 PM. ADDED SOME LOW POPS FOR SHOWERS/THUNDERSTORMS MAINLY OVER ABOUT THE SOUTHEAST HALF OF THE FORECAST AREA FOR LATER TONIGHT AND INTO SATURDAY MORNING. POINT FORECAST SOUNDINGS SHOW WEAK INSTABILITY BUT SOME POSITIVE CAPE MAINLY IN SOUTHWEST IOWA. SPC DAY 1 OTLK ALSO HAS THAT AREA WITH POTENTIAL FOR THUNDER. AGAIN...IF THESE OCCUR...THEY SHOULD BE VERY SPOTTY AND PROBABLY DISSIPATE BY MID MORNING SATURDAY. FOR NOW KEPT THE REST OF SATURDAY AND SATURDAY NIGHT DRY. AS LOW LEVEL WARM AIR ADVECTION INCREASES ON SUNDAY...WE COULD ALSO SEE SLIGHTLY MORE COVERAGE OF SHOWERS AND THUNDERSTORMS. THE 12Z NAM MAY HAVE BEEN A BIT OVERDONE WITH COVERAGE AND PCPN AMOUNTS...BUT CHANCES SEEMED HIGH ENOUGH TO ADD SOME LOW POPS SUNDAY. OTHERWISE...WILL WILL HAVE TO WAIT UNTIL THE SYSTEM OVER THE ROCKIES MOVES IN FOR BETTER CHANCES FOR MORE WIDESPREAD PCPN NEXT WEEK. HIGHS SATURDAY/SUNDAY/MONDAY WILL BE MAINLY IN THE UPPER 70S AND LOWER 80S WITH LOWS MAINLY MID 50S TO LOWER 60S. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) ISSUED AT 300 PM CDT FRI SEP 26 2014 AT THE BEGINNING OF THIS PERIOD...A CLOSED LOW OVER THE ROCKIES SHOULD HAVE STARTED TO OPEN UP TO MORE OF A NEGATIVELY TILTED WAVE. LARGE SCALE LIFT/FORCING FOR ASCENT INCREASES ACROSS THE WESTERN PARTS OF THE AREA MONDAY NIGHT BUT GETS BETTER FOR ALL OF THE FORECAST AREA ON TUESDAY. BUMPED UP POPS JUST A BIT FOR THIS...WITH LATEST ECMWF AND GFS IN DECENT AGREEMENT ON TIMING. FRONT WILL WEAKEN A BIT AND STALL MID WEEK. MODEL DIFFERENCES START TO GROW BY DAY 6 AND DAY 7...WITH THE GFS BEING A BIT WARMER THAN THE ECMWF. STAYED FAIRLY CLOSE TO AN EVEN BLEND FOR NOW. WILL HAVE TO LINGER AT LEAST SOME LOW POPS INTO THURSDAY NIGHT...UNTIL THE FRONTAL BOUNDARY FINALLY PUSHES OFF TO THE SOUTHEAST. WENT DRY ON FRIDAY FOR NOW. && .AVIATION...
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(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1145 PM CDT FRI SEP 26 2014 SCT-BKN MID CLOUDS HAVE BEEN SPREADING NORTH ALONG THE MISSOURI RIVER WITH RADAR SHOWING SOME RETURNS SOUTH OF KOMA. MAIN ACTION IS EXPECTED TO REMAIN EAST OF THE AREA FEATURES SLOWLY SPREADING NORTH IN ASSOCIATION WITH THE UPPER LOW. VFR CONDITONS ARE EXPECTED TO PREVAIL THROUGH THE PERIOD AT ALL THREE SITES. MAY HAVE TO KEEP AN EYE ON KOMA FOR POSSIBLE INCREASE IN DEVELOPMENT THROUGH 12Z BUT LOW CONFIDENCE AT THIS POINT.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...MILLER LONG TERM...MILLER AVIATION...FOBERT

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