Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 222038 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 338 PM CDT TUE APR 22 2014 .SHORT TERM...
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(TONIGHT THROUGH FRIDAY) ISSUED AT 330 PM CDT TUE APR 22 2014 MAIN FORECAST CONCERN WILL BE CENTERED AROUND THUNDERSTORM CHANCES THROUGH THURSDAY MORNING. MID/UPPER LEVEL TROUGH AXIS EXTENDS ACROSS THE INTERMOUNTAIN WEST WITH IMPRESSIVE 130M HEIGHT FALLS OUT AHEAD OF IT. THIS TROUGH WILL CONTINUE TO MOVE EAST AND AHEAD OF IT...A DEEPENING LEE SIDE SFC LOW WILL EXTEND ACROSS THE HIGH PLAINS BY 12Z WED. AHEAD OF ALL OF THIS...STRONG LOW LEVEL SOUTHERLY FLOW WILL BRING BOTH WARM AND MOIST AIR ADVECTION INTO THE REGION. AN FEW RADAR RETURNS ARE SHOWING UP UNDER THE ACCAS FIELD OVER CENTRAL NEBRASKA THIS AFTERNOON. THE HRRR HAS PICKED UP ON THIS BUT WITH LITTLE UPPER LEVEL SUPPORT IN THE AREA JUST YET...THINK THESE WILL FADE AS THEY APPROACH A MUCH DRIER AIRMASS THIS EVENING. NOCTURNAL 850MB WINDS ON THE ORDER OF 50-60KTS ARE FORECAST OVERNIGHT WHICH WILL HELP ADVECT +8 TO +10C DEWPOINTS INTO THE AREA BY WED AFTERNOON. WILL CONTINUE OVERNIGHT/EARLY MORNING TSTM CHANCES IN ASSOCIATION WITH THE STRENGTHENING LLVL JET. A TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN THE RETREATING HIGH PRESSURE CURRENTLY OVERHEAD NOW AND THE APPROACHING HIGH PLAINS LOW WILL BRING QUITE GUSTY WINDS TO THE AREA WED MORNING AND THROUGH THE EARLY AFTERNOON. WITH COORDINATION FROM SURROUNDING OFFICES...WILL HOIST A WIND ADVISORY FOR PORTIONS OF OUR WEST AND NORTH FROM 15-21Z. EXPECT A LULL IN TSTM ACTIVITY DURING THE LATE MORNING/EARLY AFTERNOON HOURS WEDNESDAY. THE SFC LOW WILL BE ENTERING INTO WESTERN KANSAS BY 00Z THU WITH COLD FRONT PUSHING THROUGH CENTRAL NEBRASKA. THE GREATEST INSTABILITY WILL EXIST OVER NORTH CENTRAL KANSAS AND SOUTH CENTRAL NEBRASKA AT THIS TIME WITH BULK 0-6KM SHEAR ON THE ORDER OF 50KTS. CONVECTION IS LIKELY TO DEVELOP ALONG/AHEAD OF THE COLD FRONT AND SPREAD EAST THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS WITH LARGE HAIL AND DAMAGING WINDS AS THE PRIMARY HAZARDS. PW`S BY EARLY EVENING DO INCREASE TO AROUND 1.50" SO THE POTENTIAL EXISTS FOR SOME HEAVIER RAINFALL AMOUNTS. THE UPPER TROUGH IS FORECAST TO SWING THROUGH CENTRAL NEB BY 12Z THURSDAY WITH THE SFC COLD FRONT WELL INTO IOWA BY THAT TIME. LINGERING POST FRONTAL PCPN IS QUITE POSSIBLE IN OUR EASTERN COUNTIES IN THE MORNING. BROAD/WEAK UPPER RIDGING WILL MOVE OVERHEAD ON FRIDAY WITH STRONG SOUTHERLY FLOW SO WE SHOULD BE ABLE TO WARM INTO THE LOW 70S FRIDAY. .LONG TERM...(FRIDAY NIGHT THROUGH TUESDAY) ISSUED AT 330 PM CDT TUE APR 22 2014 GLOBAL MODELS ARE CONSISTENT IN MOVING A TROUGH ACROSS THE ROCKIES AND INTO THE CENTRAL PLAINS THIS WEEKEND. THE MODELS DIVERGE TO SOME DEGREE AS TO HOW QUICKLY TO MOVE THE TROUGH OUT OF THE AREA WITH LITTLE IN THE WAY OF AN UPSTREAM KICKER. THE 00Z ECMWF IS HOLDING ONTO THIS TROUGH INTO THE DAY ON MONDAY AS THE SLOWEST SOLUTION. AHEAD OF THE SYSTEM MODIFIED GULF AIR WILL BE ADVANCING NORTHWARD ON SATURDAY. MOST OF THE DAY ON SATURDAY SHOULD BE DRY BUT A COLD FRONT WILL MOVE INTO NORTHEAST NEBRASKA BY AFTERNOON AND THIS COULD BE THE IMPETUS OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS BY AFTERNOON. AS LARGER-SCALE FORCING INCREASES ON SATURDAY NIGHT...ALONG WITH STRONGER LOW LEVEL WARM-AIR ADVECTION WE SHOULD SEE AN INCREASE IN THE AREAL EXTENT OF THE PRECIP...AND LIKELY POPS APPEAR WARRANTED AT THIS TIME. THE 00Z GFS/GEM WOULD THEN SHIFT THIS FORCING/PRECIP SOUTH OF THE AREA BY SUNDAY NIGHT WHILE THE ECMWF WOULD CONTINUE SOME THREAT INTO MONDAY. ALTHOUGH THE SLOWER SOLUTION OF THE ECMWF ISN`T OUT OF THE QUESTION...GIVEN THE LIMITED SUPPORT WILL CONT WITH A DRY FORECAST FOR SUNDAY NIGHT THROUGH TUESDAY. TEMPERATURES WILL WARM INTO THE 70S FOR MOST AREAS ON SATURDAY AHEAD OF THE COLD FRONT...BUT WITH THE PRECIP AND CAA ON SUNDAY TEMPERATURES WILL LIKELY HOLD IN THE 60S. TEMPERATURES SHOULD BE ON THE INCREASE FOR MON/TUE AS A WESTERN US RIDGE DEVELOPS EAST INTO THE CENTRAL US.
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&& .AVIATION...
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(18Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1212 PM CDT TUE APR 22 2014 GENERALLY LOOK FOR VFR CONDITIONS THROUGH THE PERIOD. CEILINGS MAINLY ABOVE 5000 FEET COULD DEVELOP LATER TONIGHT WITH -SHRA ACTIVITY. DID NOT MENTION -TSRA IN TAFS FOR NOW...SINCE COVERAGE MAY BE LIMITED. DECIDED TO ADD IN LOW LEVEL WIND SHEAR FOR TONIGHT AS WINDS ALOFT BELOW 2000 FEET INCREASE INTO THE 40 TO 50 KNOT RANGE OR MORE.
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&& .OAX WATCHES/WARNINGS/ADVISORIES...
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NE...WIND ADVISORY FROM 10 AM TO 4 PM CDT WEDNESDAY FOR NEZ011-012- 015>018-030>034-042>044-050-051-065-066-078-088-089. IA...WIND ADVISORY FROM 10 AM TO 4 PM CDT WEDNESDAY FOR IAZ043.
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&& $$ SHORT TERM...KERN LONG TERM...MILLER AVIATION...MILLER

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