Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 120851 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 251 AM CST Tue Dec 12 2017 .SHORT TERM...(Today through Thursday) Issued at 250 AM CST Tue Dec 12 2017 We will remain in a prevailing northwest flow pattern aloft today into tonight ahead of the next vigorous short-wave trough which will move through the mid-MO Valley tomorrow (Wed). In the low levels, winds will back to westerly today, allowing for downslope-induced warming to erode the cooler air mass which filtered into the region behind yesterday`s (Mon) cold front. While some warm-advection-related clouds could linger, afternoon highs should range from around 50 in the west to 40-45 across our southwest IA counties. Tonight into Wednesday, the next strong cold front (associated with the disturbance mentioned above) will advance through the northern Plains and mid-MO Valley. Mild overnight temperatures and late morning/early-afternoon highs on Wednesday will give way to falling mercury by mid afternoon. Winds will be quite strong again from the northwest and a wind advisory may become necessary. While we will indicate a low-probability chance of precipitation across our northeastern counties, better potential will remain to our east. Additionally, we could see a brief window of elevated fire weather conditions along the Kansas border Wednesday afternoon where a favorable overlap of strong winds and warmer/drier air will reside. On Thursday, yet another short-wave trough and related cold front will track from the northern High Plains into the region. It currently appears that this system will contain a bit more moisture, translating to a more meaningful chance of precipitation. Model forecast soundings indicate light snow as the initial precipitation type, changing over to light rain by afternoon as the boundary layer warms. Our official forecast will indicate accumulations approaching a half inch over portions of northeast NE, tapering to trace amounts south toward I-80. The NAM and GFS solutions depict a swath of 1.0-1.5" snow accumulation across our area, so this is something we will continue to monitor. .LONG TERM...(Thursday night through Monday) Issued at 250 AM CST Tue Dec 12 2017 Latest medium-range model guidance is now in better agreement in indicating that a multi-stream trough will track from the British Columbia and Pacific Northwest coasts on Friday into the Great Plains later Saturday into Sunday. Ahead of this system, we will see continued mild conditions Friday into Saturday with highs in the 40s to lower 50s. About the only model that shows QPF across our area is the ECMWF, and we will include slight-chance PoPs Saturday afternoon into Saturday night. Thereafter, we could see some amplification of a broader-scale trough from central Canada into the north-central U.S. early next week. Confidence in that scenario remains low with our forecast indicating continued above-normal temperatures. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1120 PM CST Mon Dec 11 2017 VFR conditions expected thru the fcst pd. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Mead LONG TERM...Mead AVIATION...DEE is the U.S. government's official web portal to all federal, state and local government web resources and services.