Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 260833 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 333 AM CDT FRI JUN 26 2015 .SHORT TERM...(TODAY THROUGH SUNDAY) ISSUED AT 333 AM CDT FRI JUN 26 2015 THE CHANCE FOR THUNDERSTORMS TODAY IS THE PRIMARY FORECAST CONCERN. THEN A GENERALLY DRY AND WARMER WEEKEND...WITH THE EXCEPTION OF A SMALL CHANCE FOR STORMS SUNDAY. NORTHWEST MID LEVEL FLOW ACROSS THE PLAINS WAS NOTED ON EVENING UPPER AIR CHARTS AND SHORT TERM MODEL OUTPUT. A COUPLE OF SHORTWAVES COULD BE IDENTIFIED WITHIN THE FLOW...AND RECENT RAP HEIGHT FORECASTS ALONG WITH WATER VAPOR IMAGERY SUGGESTED ONE WAVE WAS MOVING OUT OF SOUTHEAST NEBRASKA AS OF 3 AM...AND ANOTHER WAS APPROACHING NORTHEAST NEBRASKA FROM SOUTH DAKOTA. BOTH WAVES WERE TRIGGERING SCATTERED SHOWERS AND STORMS...HOWEVER THE STRONGEST WERE IN NORTHERN KANSAS WHERE LIFT WAS MAXIMIZED JUST NORTH OF FRONTAL BOUNDARY EXTENDING FROM KANSAS CITY TO WICHITA. GIVEN NORTHWEST FLOW ALOFT...SOUTHERN STORMS MOVING OUT OF OUR AREA WILL REMAIN THERE THIS MORNING. SHORTWAVE TO THE NORTH WILL GRADUALLY WORK SOUTHEAST TODAY...BUT ABSENCE OF SURFACE BOUNDARY/LOW LEVEL CONVERGENCE SUGGESTS ACTIVITY WILL REMAIN ISOLATED TO SCATTERED IN NATURE. IN FACT...MANY SHORT RANGE MESOSCALE MODELS INCLUDING HRRR AND RAP SUGGEST A DECREASE IN ACTIVITY THROUGH THE MORNING BEFORE AFTERNOON HEATING HELPS BUBBLE UP WIDELY SCATTERED AFTERNOON CONVECTION. SO WILL PLAY THE HIGHEST POPS IN NORTHEAST NEBRASKA THIS MORNING...THEN BROADBRUSH SMALL CHANCES THROUGH THE AFTERNOON ACROSS MUCH OF EASTERN NEBRASKA AND SOUTHWEST IOWA. COULD SEE SOME LINGERING SHOWERS/STORMS IN SOUTHEAST NEBRASKA OR SOUTHWEST IOWA DURING THE EARLY EVENING BEFORE SHORTWAVE PUSHES FARTHER AWAY AND WE LOSE AFTERNOON HEATING. OTHERWISE WE WILL SEE A TENDENCY TOWARD NORTHERLY LOW LEVEL FLOW TONIGHT AND SATURDAY AS HIGH PRESSURE SETTLES ACROSS THE REGION...AND BRINGS SLIGHTLY DRIER AIR INTO OUR AREA. SHOULD SEE PLENTY OF SUNSHINE SATURDAY WITH HIGHS IN THE LOWER 80S AFTER MORNING LOWS IN THE LOWER 60S. SOUTHERLY FLOW WILL RETURN SATURDAY NIGHT AS A SHORTWAVE DIVES INTO MINNESOTA THEN EVENTUALLY IOWA/WISCONSIN/ILLINOIS. SURFACE COLD FRONT WILL FOLLOW THIS WAVE AND SWEEP THROUGH EASTERN NEBRASKA AND SOUTHWEST IOWA ON SUNDAY. CONVECTION SATURDAY NIGHT SHOULD BE CONFINED TO AREAS TO OUR NORTHEAST WHERE STRONG WARM ADVECTION IS REALIZED JUST AHEAD OF MID LEVEL WAVE. ON SUNDAY...AXIS OF BEST LIFT NEAR SHORTWAVE AND SURFACE REFLECTION WILL STILL LIE WELL TO OUR EAST AND NORTHEAST IN MINNESOTA AND IOWA...BUT COULD SEE A FEW SHOWERS OR STORMS NEAR AND EAST OF THE NEBRASKA/IOWA BORDER AS COLD FRONT SWINGS SOUTHEAST. SHOULD SEE NICE WARMING ON SUNDAY AS SOUTHWEST FLOW AHEAD AND NORTHWEST FLOW BEHIND FRONT WILL PROMOTE DECENT MIXING. HIGHS THEN SHOULD EASILY REACH THE MID AND UPPER 80S. .LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY) ISSUED AT 333 AM CDT FRI JUN 26 2015 GENERAL MID LEVEL FLOW PATTERN CHANGES ONLY A LITTLE DURING THE WEEK. BROAD HIGH PRESSURE WILL REMAIN OVER THE SOUTHWESTERN STATES THROUGH THE PERIOD. MEANWHILE UPPER LOW IN THE EASTERN GREAT LAKES EARLY IN THE PERIOD WILL LIFT TO THE NORTHEAST...LEAVING BROAD TROUGH BEHIND OVER THE EASTERN HALF OF THE COUNTRY. IN BETWEEN THESE FEATURES...FLOW IN THE CENTRAL PLAINS WILL SHIFT FROM NEARLY NORTHERLY TO NORTHWESTERLY BY MID WEEK. SEVERAL IMPULSES RIDING OVER WESTERN RIDGE WILL ENTER THE PLAINS...BRINGING OFF AND ON THUNDERSTORM CHANCES TO OUR REGION. GFS AND ECMWF ARE IN FAIRLY GOOD AGREEMENT WITH THIS OVERALL PATTERN CHANGE...BUT DIFFER ON TIMING OF PRECIPITATION-PRODUCING SHORTWAVES. HOWEVER BOTH MODELS ARE RELATIVELY SIMILAR IN DROPPING A MORE SIGNIFICANT SHORTWAVE INTO THE PLAINS ON TUESDAY...INCREASING THUNDERSTORM CHANCES IN EASTERN NEBRASKA AND WESTERN IOWA TUESDAY NIGHT AS ATTENDANT SURFACE LOW AND FRONTAL SYSTEM MOVE THROUGH THE REGION. WILL HAVE THE HIGHEST PRECIP CHANCES AT THIS TIME...THOUGH STILL ONLY IN THE CHANCE CATEGORY AS MOISTURE RETURN AFTER SUNDAY COLD FRONT WILL BE SLOW TO OCCUR. SHOULD SEE MINIMAL RAIN CHANCES BEHIND THIS SYSTEM ON WEDNESDAY AND THURSDAY...BUT GIVEN UNCERTAINTY IN SMALL-SCALE MID LEVEL FEATURES...CAN NOT RULE OUT A STRAY STORM OR TWO. OTHERWISE EXPECT TEMPERATURES TO AVERAGE 60S AND 80S FOR LOWS AND HIGHS THROUGH THE PERIOD. && .AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1200 AM CDT FRI JUN 26 2015 SHORTWAVE STILL MOVING THROUGH TONIGHT AND FRIDAY WILL RESULT IN SPOTTY SHOWERS AND A FEW THUNDERSTORMS. MAINLY HAVE VFR CIGS WITH SOME PERIODS OF SHOWERS THROUGH 18Z. DUE TO THE SPOTTY NATURE OF THE THUNDERSTORM WILL HAVE TO MONITOR AND ADD IF NEEDED FOR THE THUNDER THREAT. SOME PATCHY MVFR VSBYS MAY TRY TO DEVELOP BY MORNING. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. && $$ SHORT TERM...DERGAN LONG TERM...DERGAN AVIATION...ZAPOTOCNY

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