Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000 FXUS63 KOAX 220802 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 302 AM CDT Fri Sep 22 2017 .SHORT TERM...
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(Today through Sunday) Issued at 301 AM CDT Fri Sep 22 2017 A significant mid-level trough from the northern Inter-mountain region into Great Basin early this morning will slowly edge east through the Interior West this weekend. Meanwhile, a surface front will remain quasi-stationary from the upper-MS Valley to central High Plains for the next couple of days before advancing southeast into the mid-MO Valley later Sunday into early next week. Strong, southerly low-level flow ahead of the mid-level trough and surface frontal system has allowed an anomalously warm and moist air mass to overspread the region with highs this afternoon warming into the lower to mid 90s. For reference, record highs are 96(1940) at Norfolk, and 99(1937) at both Omaha and Lincoln. When coupled with dewpoints in the upper 60s to lower 70s, afternoon heat indicies will approach 100 degrees. There is some indication in both parameterized and convection- allowing model guidance that the strong boundary-layer heating and the presence of a subtle pre-frontal confluence zone from central into northeast NE could foster isolated storm development late this afternoon into evening. Given the favorable overlap of moderate instability and a vertically veering wind profile, the environment will be supportive of strong to severe storms, conditional on storm initiation and sustenance. Lows tonight are expected to only fall into the lower 70s, owing to the high moisture content and sustained south winds. Record warm minimum temperatures for both September 22 and 23 will be within reach. Those values are: 67(2016) and 69(1958) at Norfolk, 73(2016) and 72(1892) at Omaha, and 75(1937) and 72(1930) at Lincoln. Late this weekend into early next week, ingredients appear to be coming together for a potentially heavy rainfall event, especially across portions of northeast NE. The deep-layer wind field will remain aligned largely parallel to the surface front settling into area, resulting in the potential for a prolonged period of training storms. Antecedent rainfall has been well below normal for the past month generally north of an Albion to Norfolk to Sioux City line, so runoff should be minimal initially in those locations. At some point, we could begin to see some flooding issues on area streams and rivers. To the south of the frontal precipitation, warm and humid conditions will prevail with highs in the mid 80s to around 90 degrees. .LONG TERM...(Sunday night through Thursday) Issued at 301 AM CDT Fri Sep 22 2017 The aforementioned mid-level trough will begin to spread east from the Rockies into the Great Plains Sunday night into Tuesday, supporting a steady southeastward movement of the associated surface cold front through the forecast area. High precipitation chances will exist from Sunday night into Monday night before diminishing on Tuesday with the passage of the front. Storm-total precipitation amounts may range from two to four inches across portions of northeast NE to around an inch over far southeast NE into southwest IA. Locally higher amounts are likely to occur. Afternoon temperatures will fall back into the 60s to lower 70s with the passage of the cold front with generally dry conditions anticipated after Tuesday morning.
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&& .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1140 PM CDT Thu Sep 21 2017 VFR conditions are expected throughout the TAF cycle. Southerly surface winds will gust again after sunrise and through the afternoon hours to close to 25kts. Low-level wind shear is likely through the overnight as well with a strong southwesterly low- level jet. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Mead LONG TERM...Mead AVIATION...Kern is the U.S. government's official web portal to all federal, state and local government web resources and services.