Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 290546 AFDOAX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 1146 PM CST WED JAN 28 2015 .SHORT TERM...(TONIGHT THROUGH SATURDAY) ISSUED AT 315 PM CST WED JAN 28 2015 THE CHANCE OF PCPN ON THE WEEKEND AND TEMPERATURES THROUGH THE PERIOD WILL PROVIDE THE MAIN FORECAST CHALLENGES. A COUPLE OF SHORTWAVE TROUGHS WILL MOVE ACROSS THE REGION DURING THE OVERNIGHT HOURS. 12 HOUR HEIGHT FALLS AT 12Z AT 500 MB WERE AS HIGH AS 100 METERS OVER WYOMING. THIS WAVE WILL MOVE EASTWARD THROUGH EARLY TONIGHT WITH ANOTHER WAVE DROPPING SOUTHEAST FROM THE DAKOTAS AFTER MIDNIGHT. MOISTURE PROFILES ARE NOT SATURATED...BUT THERE MAY BE ENOUGH MOISTURE FOR SOME SPRINKLES OR LIGHT SHOWERS IN OUR NORTHERN AND EASTERN COUNTIES. WILL NEED TO WATCH SURFACE TEMPERATURES SINCE PCPN WILL BE FALLING AS LIQUID AND IF IT DROPS BELOW FREEZING IT MAY CAUSE SOME VERY LIGHT SPOTTY ICING. WINDS WILL ALSO INCREASE LATER TONIGHT AS LOW PRESSURE AT THE SURFACE TRACKS ACROSS IOWA AND INTO NORTHEAST ILLINOIS BY DAYBREAK. TIGHTENING PRESSURE GRADIENT AND DOWNWARD MOMENTUM TRANSFER (GFS SHOWS 925 MB WINDS UP TO AROUND 40 OR 45 KNOTS OVERNIGHT) WILL BE THE MAIN REASONS FOR THE STRONG WINDS. THESE MAY NOT BE CONSTANTLY AT ADVISORY NUMBERS ALL NIGHT...BUT FEEL AT LEAST A COUPLE OF PERIODS OF STRONG WINDS WILL OCCUR. WILL GO AHEAD AND ISSUE A WIND ADVISORY FOR MOST OF OUR FORECAST AREA STARTING MID EVENING IN NORTHEAST NEBRASKA THEN SPREADING THAT SOUTHEAST WITH TIME. THE STRONG NORTHWEST WINDS WILL BRING IN COOLER AIR FOR THURSDAY. THESE WINDS SHOULD REMAIN FAIRLY STRONG IN THE MORNING BUT DECREASE THROUGH THE AFTERNOON AS SURFACE RIDGE AXIS BUILDS INTO THE AREA BY THURSDAY EVENING. WENT WITH HIGHS MOSTLY IN THE UPPER 30S AND LOWER 40S NORTH...LOWER AND MID 40S SOUTH. SOUTHERLY WINDS ARE FORECAST TO INCREASE FRIDAY AS THE RIDGE MOVES EAST LATE THURSDAY NIGHT INTO FRIDAY MORNING. WILL BOOST HIGHS A BIT FOR FRIDAY...TO THE LOWER AND MID 40S BUT EVEN WARMER READINGS APPEAR POSSIBLE IN OUR SOUTHWEST ZONES. DECIDED NOT TO BE TOO OPTIMISTIC AT THIS TIME. THE OPERATIONAL RUNS OF THE 12Z GFS AND 12Z ECMWF HAVE CHANGED IN REGARDS TO POSSIBLE PCPN AMOUNTS FOR THE WEEKEND. THE 12Z GFS ENSEMBLE AND THE 15Z SREF STILL INDICATE SOME POTENTIAL FOR LIGHT RAIN/SNOW. FOR OUR AREA...IN GENERAL...EXPECT THAT THE MAIN FORCING AND MOISTURE WILL STAY TO OUR SOUTH SATURDAY INTO SATURDAY NIGHT. THIS WILL BE ADJUSTED (IF NEEDED) AS WE GET CLOSER. THE MODELS MAY DEVIATE MORE FROM RUN TO RUN OVER THE NEXT FEW DAYS. THIS VARIANCE WILL BE AT LEAST PARTIALLY DUE TO THE COMPLEX FLOW THAT WILL DEVELOP OVER THE NORTHERN PACIFIC...WHICH IS NOT A HIGH DENSITY DATA AREA FOR UPPER AIR OBSERVATIONS IN MOST CASES. .LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY) ISSUED AT 315 PM CST WED JAN 28 2015 ANOTHER WAVE WILL DROP DOWN ACROSS THE DAKOTAS TOWARD THE CENTRAL PLAINS FOR SATURDAY NIGHT...BUT THIS MAY HAVE LARGER IMPACTS IN SOUTHERN MINNESOTA AND NORTHERN IOWA. PCPN CHANGES WILL BE DECREASING SUNDAY AND SUNDAY NIGHT...AND OUR TEMPERATURES SHOULD AS WELL. COLD HIGH PRESSURE WILL BE OVER THE EASTERN DAKOTAS BY NOON SUNDAY...THEN THAT SHOULD MOVE INTO IOWA AND MISSOURI BY MONDAY MORNING. SYSTEM AMPLIFICATION SEEMS POSSIBLE BASED ON THE NORTHWEST FLOW PATTERN FOR SUNDAY...SO WILL NEED TO WATCH THE WAVE SHOWN IN THE NORTHERN STREAM ON SUNDAY. THE CANADIAN MODEL EVEN BRIEFLY SHOWS A CLOSED LOW AT 500 MB NEAR THE SOUTH DAKOTA/MINNESOTA BORDER ON SUNDAY. OTHERWISE WILL WILL BE MAINLY UNDER THE INFLUENCE OF COOL NORTHWEST FLOW EARLY NEXT WEEK. HIGHS WILL BE MUCH BELOW NORMAL SUNDAY INTO MONDAY...THEN SHOULD TREND CLOSER TO NORMAL FOR TUESDAY/WEDNESDAY. KEPT A SMALL CHANCE OF LIGHT SNOW GOING FOR TUESDAY. && .AVIATION...
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(06Z TAFS FOR KOFK...KLNK AND KOMA.) ISSUED AT 1141 PM CST WED JAN 28 2015 MVFR CONDITIONS HAVE OVERSPREAD THE AREA AND SHOULD LAST INTO THURSDAY MORNING. SPRINKLES WILL BE POSSIBLE...BUT NOT SIGNIFICANT ENOUGH TO MENTION. NORTHWEST WINDS 20 TO 30KTS WITH GUSTS 30 TO 40KTS TONIGHT. THE NORTHWEST WINDS SHOULD DROP OFF THURSDAY AS THE STRONGER WINDS ALOFT SHIFT TO THE EAST...GENERALLY DROPPING TO UNDER 15KTS THURSDAY AFTERNOON AND UNDER 10KTS THURSDAY NIGHT.
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&& .OAX WATCHES/WARNINGS/ADVISORIES...
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NE...WIND ADVISORY UNTIL 7 AM CST THURSDAY FOR NEZ015-030>034-042>045- 050>053-065>068. WIND ADVISORY UNTIL 6 AM CST THURSDAY FOR NEZ011-012-016>018. IA...WIND ADVISORY UNTIL 7 AM CST THURSDAY FOR IAZ043-055-056-069-079- 080-090-091.
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&& $$ SHORT TERM...MILLER LONG TERM...MILLER AVIATION...ZAPOTOCNY

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