Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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855 FXUS63 KOAX 032320 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 520 PM CST Sat Dec 3 2016 .SHORT TERM...(tonight through Tuesday) Issued at 256 PM CST Sat Dec 3 2016 Isentropic ascent on the 285-295 K surfaces ahead of a positively titled shortwave trough /located from eastern SD into central NEb per afternoon water vapor imagery/ continues over eastern Nebraska and western Iowa. This forcing is expected to continue this evening until the axis of the trough shifts east after midnight. For the most part the precipitation has fallen as light snow with some light rain on the western and southern edge. The majority of the light snow is melting on contact this afternoon, but in a narrow band from LNK to the southern OMA metro area the rates have overcome the melting, and up to a half inch has been reported. In this band we may see up to an inch or slightly more before the precipitation shifts off to the east. We will slightly see some slick spots on roads, especially secondary roads within this band. Temperatures through the event are expected to be near or slightly above freezing, which should help mitigate some of the impacts. Once the trough shifts to the east we will see clearing skies on Sunday with winds become west and northwest through the day, which should lead to decent mixing and warmer temperatures with highs climbing into the 40s for many areas. Another shortwave trough will quickly move through the northern Plains on Monday allowing for a strong cold front to sweep through the CWA late in the day and into Monday evening. Moisture will be limited to the southern Plains associated wtih the ejection of the current closed low, but strong low-level frontogenesis may allow for some flurries or a brief period of light snow across western Iowa just behind the front. .LONG TERM...(Tuesday night through Saturday) Issued at 256 PM CST Sat Dec 3 2016 The global models are now in good agreement for mid to late week, and confidence in the sensible weather is much higher today. The front on Monday night should continue south into the southern Plains while additional jet energy quickly shifts through the Great Basin. This will translate east through the Plains along the preexisting strong thermal gradient. This should lead to a zone of stronger frontogenesis and a band of light snow in the Plains for late Tuesday night and into Wednesday. Currently is appears that this band will mostly be south of the FA, but we will continue to indicate some low-chance pops over the southern CWA due to the uncertainty in the placement at this range. The more significant story though is expected to be the cold air with a second cold front that will move through the area on Tuesday night. This will bring the coldest air of the new season to the region to end the work weekend into the weekend. Both the GFS and EC indicate the next shortwave trough and associated chance for precipitation, likely in the form of light snow, is expected toward next weekend. && .AVIATION...
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(For the 00Z TAFS through 00Z Sunday evening) Issued at 520 PM CST Sat Dec 3 2016 Mosaic radar data as of 23z revealed a band of light to occasionally moderate snow located along and just to the south of I-80 where observed visibilities were 3/4 to 1 1/2 miles. Expect similar snow rates at KLNK and KOMA for the next few hours before the broader-scale precipitation shield begins to shift east ahead of a mid-level trough translating across the northern and central Plains. Even with the cessation of precipitation tonight...ceilings and visibilities are not likely to increase owing to fog formation which will persist into Sunday morning. Conditions should begin to improve thereafter as a weak front moves through the area. At KOFK, IFR ceilings are likely to persist into early Sunday with some visibility restriction due to fog.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM... LONG TERM... AVIATION...Mead

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