Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 192037 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 337 PM CDT Sun Mar 19 2017 .SHORT TERM...
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(tonight through Wednesday) Issued at 335 PM CDT Sun Mar 19 2017 Surface low located over north central Nebraska late this afternoon, with attendant cold front moving across South Dakota and dryline bisecting the state. Modest boundary layer moisture available, but with only weak convergence along dryline, so little if any diurnal development. Better dynamic forcing will be delayed until this evening, along with enhanced isentropic ascent, thus cannot discount isolated-widely scattered tsra development along warm front, that will be located across extreme eastern part of the CWA. Continued slight chance PoPs for extreme southeast Nebraska and southwest Iowa. The rest of the forecast area will remain dry at least through Monday evening. Low level cold advection will keep temperatures 15 to 20 degrees cooler than those seen today, especially if narrow band of stratus develops along H8 front as depicted by short term models. Next chance for precipitation arrives overnight Monday. Weak shortwave moving around base of eastern Canada vortex drops southward from northern Rockies. Vorticity somewhat channeled initially, which may limit precipitation development until pre-dawn hours. Short range models have a slightly warmer temperature profile, and most locations should experience mainly liquid precipitation. Due to warmer temperature profiles, lowered snow ratios slightly and thus accumulating snow totals. Temperatures may need to be lowered in suceeding forecasts, but Tuesday looks to be a rather cool and raw day. Precipitation exits the area by Tuesday evening Upper H5 ridge builds into central Plains Tuesday evening, but another weak short wave will overtop the ridge, giving the area yet another chance for precipitation on Wednesday. Low level cold advection will keep temperatures at or below for the onset of precipitation, thus another chance of wintry mix. For now kept precipitation type rain and snow. .LONG TERM...(Wednesday night through Sunday) Issued at 335 PM CDT Sun Mar 19 2017 Medium range models consistent in placing upper ridge ver the area at the start of the extended period, then solutions depart with spread among the operational and ensembles. At time, operational GFS the fastest in moving H5 low out into southern plains Thurs/Fri, while EC/Can and GEFS members all a little slower and drop center of low a little further south. At least temperatures a little more clear cut, and precipitation type appears to be liquid.
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&& .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 132 PM CDT Sun Mar 19 2017 VFR conditions are expected through the TAF period. South to southeast winds 10 to 20 kts to become variable then northeast at KOFK this evening around 02Z...and after 06Z aft KOMA and KLNK. Some of the models are hinting at some stratus Monday morning after 12Z and will assess in future forecasts. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Fortin LONG TERM...Fortin AVIATION...Zapotocny

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