Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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056 FXUS63 KOAX 180835 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 335 AM CDT Fri Aug 18 2017 .SHORT TERM...
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(Today through Sunday) Issued at 335 AM CDT Fri Aug 18 2017 A shortwave trough over SD early this morning will translate east into MN today ahead of an amplifying upstream impulse and associated upper-level jet streak which will track from the eastern Dakotas into the mid-MS Valley by tonight. Forcing for ascent attendant to the former has fostered a loosely organized MCS over the mid-MO Valley, which will likely decrease in areal coverage as it continues southeast across our CWA this morning. An isolated strong storm is possible, though severe weather is not anticipated. A weak cool front will move through the area this afternoon with winds shifting to northwest with its passage. It appears that generally weak convergence along this boundary will limit the potential for the redevelopment of storms later today. High pressure will build south into the mid-MO Valley tonight, potentially leading to patchy fog. This is especially the case across eastern parts of the forecast area where surface winds will remain light through 12z/Saturday. A quasi-zonal, mid-level flow pattern is forecast to develop across the northern tier of states this weekend, supporting southerly low-level winds, increasing moisture content and warmer temperatures. The low-level warming/moistening will yield a low- probability chance of showers and thunderstorms Saturday night into Sunday. .LONG TERM...(Sunday night through Thursday) Issued at 335 AM CDT Fri Aug 18 2017 The primary focus in the long-term period is weather conditions for the total-solar eclipse on Monday. Latest medium-range model guidance is consistent in suggesting that a subtropical-branch shortwave trough over CO Sunday night will be drawn northeast into the mid-MO Valley on Monday where it will be entrained into a belt of higher-momentum flow present across the north-central states. Forcing for ascent associated with this feature will likely foster scattered clouds and at least an isolated chance of showers and thunderstorms across southeast NE and southwest IA on Monday afternoon. From Monday night into the middle of next week, considerable amplification of a mid-level trough is forecast from eastern Canada into the Great Lakes. This upper-air pattern evolution will support the movement of a cold front through the forecast area Monday night into Tuesday when a good chance of measurable precipitation will exist. The cold front will usher a cooler, continental air mass into the region with near or slightly below- normal high temperatures expected through the middle to latter part of the upcoming week.
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&& .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1117 PM CDT Thu Aug 17 2017 Radar mosaic was showing a line of TSRA extending from SE SD into n-cntrl Neb quickly moving to the SE. Feel somewhat confident enough...given radar trends...to go with prevailing TSRA at KOFK between 08Z-10Z with conditions quickly improving to VFR. As far as KOMA/KLNK...appears that the SRN flank of intense storms may miss both TAF sites with areal coverage of convection relatively small. Therefore will go with VCTS between 11Z-15Z. VFR thereafter. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Mead LONG TERM...Mead AVIATION...DEE

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