Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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607 FXUS63 KOAX 182030 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 230 PM CST Wed Jan 18 2017 .SHORT TERM...
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(tonight through Saturday) Issued at 200 PM CST Wed Jan 18 2017 A couple of weather systems will bring drizzle or rain to the area in the short term. The first system was spinning across the front range of the Rockies near the CO/KS border and will lift northward across the area through early Friday. Low level moisture across the southern Plains will quickly stream northward tonight with dewpoints remaining the the lower to mid 30s overnight. This should result in an area of low stratus developing in northeast NE, and maybe a slightly higher MVFR deck along/south of I80. Given the cool ground and high dewpoints, fog will also likely develop, and the question is how dense will the fog be. SREF and various short range models suggest it could be locally dense north of I80, but will hold off any advisory for now and see how it develops. It`s also within this axis that the Nam was hinting at some patchy drizzle as well. Temps may hold right around freezing, but not sure the low level moisture is deep enough, and whether there would be enough lift to generate any precipitation. It`s something else that we`d have to monitor for potential development and add to the forecast later on if necessary. Cloudy skies continue Thursday into Thursday night, with low level moisture depth increasing sufficiently to support drizzle just about everywhere. Fortunately, temperatures will be in the 40s Thursday, and remain in the lower to mid 30s Thursday night. Added fog back to the weather grids for Thursday night with most guidance suggesting fog and potentially pretty low visibility and very low, essentially surface based clouds. The first wave moves out Friday, but the clouds and patchy drizzle remain, and may even begin to increase to Friday evening as the next stronger wave approaches. By this time, we do have a little deeper moisture to work with, which may finally result in measurable precipitation, mainly along and north of I80, but again, due to warm temperatures aloft, in the for of rain. This second system does have a surface circulation associated with it, and some colder air tries to wrap around on the northwest side, but it may not be soon enough. Weather grids do have a wintry mix in northeast NE late Friday night for an hour or two, but the dynamics and lift associated with the low are likely just ahead of the colder air, except for just a couple of counties. Most of Saturday will dry, save for the handful of counties on our far northern border where lingering precip chances exist Saturday morning. Highs Saturday still in the 40s. .LONG TERM...(Saturday night through Wednesday) Issued at 200 PM CST Wed Jan 18 2017 Late in the weekend, a fairly strong closed low moves well south of the region through the southern Plains into the lower Mississippi River valley. Focus shifts to the next trough moving onto the west coast, which eventually moves across the Rockies and brings us a chance of rain and snow by Tuesday into Wednesday. GFS has remained fairly consistent in showing a pretty substantial winter storm setting up for somewhere on the Plains, with rain chances ahead of it and snow and windy conditions behind it. Most recent ECMWF now substantially disagrees with the GFS solution, which is the first departure from consistency for that model in the last couple of days. And it`s just outside the window of the Canadian model. Thus, the details of how the weather will unfold next week are somewhat uncertain. We`ll still have 40-60% of precipitation Tuesday through Wednesday, with rain and snow, but given model disparity, overall confidence is a little low right now in the details. As always, stay tuned. We`ll continue to watch closely.
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&& .AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1135 AM CST Wed Jan 18 2017 Deteriorating conditions are on tap later tonight given combination of wet ground along with gradual influx of llvl moisture into ern Neb. At this point expect conditions to fall into MVFR territory during the early evening hours before dropping to IFR twd 10z-12z Thurs morning. Expect some improvement to MVFR then around mid morning. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...DeWald LONG TERM...DeWald AVIATION...DEE

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