Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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768 FXUS63 KOAX 011743 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1143 AM CST Wed Mar 1 2017 .UPDATE... Issued at 622 AM CST Wed Mar 1 2017 Updated the forecast to include a mention of flurries between Omaha and Sioux City early this morning. && .SHORT TERM...(today through Friday) Issued at 301 AM CST Wed Mar 1 2017 In the wake of the strong low pressure system that raked areas to the east with severe weather, conditions will be much more benign today and through the next week. Subjective 00Z upper-air analysis indicates upper-level trough from SK through MT/WY/CO to the AZ-NM border. 500mb height falls of up to 70m were noted in the central Plains to southern High Plains. A 125kt southwesterly jet streak extended from southwest TX through eastern KS. with weaker winds behind the trough. An 850mb low was centered in IA, with the cold front at 00Z extending through southeast NE to central KS and a warm front across northern IL to northern IN, and with 8C+ dewpoints as far north as southern MI ahead of the low/front. Surface low at 08Z was centered in northern IL to southwest MI, with surface cold front extending through IL to south central MO to southeast OK. Main forecast concerns through Friday are temperature and wind fluctuations. Colder air is in place behind the exiting low, which should bring temperatures back to near-normal both today and tomorrow. May see some instability-type returns on radar this afternoon, but given dry lower levels, think it will be tough to get measurable precip, and have kept mention at sprinkles. Also think that the sprinkles could be mixed with a stray sleet/snow pellet given low-level instability and cooler mid-levels, but tagging it as "flurries" didn`t feel quite right, and we don`t have an option for non-measurable sleet in the forecast grids. Have bumped up winds for this afternoon, as well, with lingering rather tight pressure gradient and good mixing. With the system moving east on Thursday, the potential for light precipitation behind it also should slide east of the area. Have increased winds on both Thursday and Friday, and have dropped afternoon dewpoints (both toward MOS grids), as favorable mixing conditions continue. Temperatures will remain near normal (i.e. cooler) on Thursday as a shortwave around the back of the upper- level trough brings reinforcing cold air. The surface high should slide through on Thursday night, with return flow finally arriving by Friday morning. Gusty winds will return on Friday, this time out of the south, and with temperatures moderating. With lower dewpoints and gusty winds, may need to keep an eye on fire weather conditions on Thursday and Friday, though current relative humidity forecast is around the mid-20s to mid-30s at the lowest (in southeast to central NE). .LONG TERM...(Friday night through Tuesday) Issued at 301 AM CST Wed Mar 1 2017 Southwesterly to westerly low- to mid-level winds will bring much warmer temperatures on Saturday and Sunday. With a weak upper-level trough slowly digging into the Rockies by Sunday, a surface low is progged to develop somewhere around western NE/western KS, inducing a dryline in central NE to central KS and a fair amount of low-level moisture return on Sunday. Still may need to worry about fire weather concerns on Saturday, but moisture return should mitigate that risk on Sunday. Upper-level trough remains progged to exit across the central Plains on Monday/Monday night. With surface low sliding from NE into SD/MN, the CWA appears to remain dry-slotted, with precipitation well north and/or east of the area. Blends do spit out a small sliver of rain in the far eastern CWA, to which I`ve included a thunder mention... because if it does rain, it`s likely to be in the form of at least isolated thunderstorms. Little cool-down is progged behind the system, with temperatures remaining well above normal on Tuesday. && .AVIATION...
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(For the 18Z TAFS through 18Z Thursday afternoon) Issued at 1143 AM CST Wed Mar 1 2017 Low/Mid-level cyclonic flow persists across northeast Nebraska and northwest Iowa. MVFR ceilings persist at KOFK and KOMA and expect these conditions to continue into mid-afternoon, until H8 ridge axis builds into the region and should help dissipation of cloud cover. VFR conditions expected at KLNK through TAF period. Syncing of low/mid level flow is maintaining surface pressure gradient, thus expect gusty northwest winds to continue until aforementioned H8 ridging builds into area at all three TAF locations. By 00Z VFR conditions expected at all TAF sites, and winds will slacken below 10 kts.
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&& .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ UPDATE...DeWald SHORT TERM...Mayes LONG TERM...Mayes AVIATION...Fortin is the U.S. government's official web portal to all federal, state and local government web resources and services.