Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 201136 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 636 AM CDT Fri Oct 20 2017 .SHORT TERM...
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(Today through Sunday) Issued at 327 AM CDT Fri Oct 20 2017 Greatest concern in the near term is the potential for wind gusts approaching advisory criteria. Forecast soundings depicting deep mixing during the afternoon hours, with effective momentum transfer from H8 to the surface. HRRR, RAP and NAM all indicating potential for gusts 38-42kts. Mitigating factor for maximum momentum transfer to be realized will be due to increase in mid- to high level cloudiness during the afternoon. Increased wind gusts from previous forecasts, but kept speeds just below wind advisory criteria for now. Fire danger will be elevated in areas of cured agricultural vegetation due to increased winds. Another result of deep mixing will be much warmer than normal temperatures for today, with maximum temperatures 15-20 degrees above seasonal normals. Progressive long wave trough will move into the intermountain west by late tonight. Large scale ascent and warm air advection may lead to isolated to scattered thunderstorm develop late this evening into the overnight hours. As trough moves into plains early Saturday, frontal boundary will push into forecast area, thus expect coverage of showers and storm to increase. Bulk shear values in the 35-45kt range and SBCAPE 1000-1500 sufficent to support strong to isolated severe storms, especially south of I-80. Focus of stronger convection appears to be south of the forecast area. Trough moves quickly across plains and front will be through most of the forecast area by late afternoon, thus total rainfall amounts likely will be less than one inch in most locations, with precipitation threat ending by early evening. Low level cold advection in the wake of the front will make for a more typical fall day across the area on Sunday. .LONG TERM...(Sunday night through Thursday) Issued at 327 AM CDT Fri Oct 20 2017 Broad, large scale trough will dominate weather regime through Monday. There`s a slim chance of showers Sunday night into Monday, as jet streak moves around base of trough; however, left forecast dry. More significant short wave will drive trough southward into eastern U.S. Monday, presenting area with another surge of cooler air. Temperatures will rebound somewhat by mid- week as upper level ridging builds into the area from the southwest. Warm- up will be brief, as another progressive short wave sweeps across plains. Right now, there appears little moisture avaiable for precipitation to occur, so expect dry frontal boundary passage, but reinforcement of cooler than normal temperatures for the end of the week.
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&& .AVIATION...
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(For the 12Z TAFS through 12Z Saturday morning) Issued at 629 AM CDT Fri Oct 20 2017 Expect VFR conditions to prevail through 06Z before trending toward MVFR cigs and vsbys as surface cold front approaches from the western high plains. Windy conditions will develop by 15Z with gusts of 40kts possible after 18Z.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Fortin LONG TERM...Fortin AVIATION...Fobert

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