221 FXUS63 KOAX 242047 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 347 PM CDT Tue Aug 24 2021 ...Updated Forecast Discussion... .DISCUSSION... Issued at 346 PM CDT Tue Aug 24 2021 Main forecast concern going forward remains heat and shower/storm chances. Early afternoon analysis showed an outflow boundary along a line including Columbus, NE, to Harlan, IA. Additional sporadic showers and storms were developing along said boundary through much of the day as well as just ahead of some weak shortwave energy sliding through north-central Nebraska. For tonight, expect additional development along an incoming cold front as a low level jet strengthens and a slightly stronger shortwave moves in (currently seen in northeast Colorado). Latest guidance suggests MUCAPE values of right around 2000 J/kg on either side of midnight, roughly when initiation is progged by most short term CAMs. That said, tend to lean toward slightly earlier initiation given the aforementioned incoming shortwave energy and low level jet. In that case, would expect a little bit more instability, but deeper layer shear still looks fairly weak, so not anticipating much in the way of storm organization. Still, can't rule out some stronger to severe storms along the boundary, given favorable low level shear and decent instability. Damaging wind and localized heavy rain would likely be the main threats. The aforementioned cold front will remain oriented roughly west to east near or across the area through the next several days, providing a focus for more thunderstorm potential each day. Expect sufficient instability for stronger to severe storms through at least Thursday, with shear likely being the main question mark in regards to a more widespread severe weather threat. Regarding heat, clouds and showers have kept heat index values in check across northeast Nebraska, so elected to cancel portion of the Heat Advisory. For Wednesday, the front looks to remain over far southern portions of the forecast area, keeping most under easterly to northeasterly surface flow. Still looks to be warm, but not quite as favorable for Heat Advisory criteria, at least for areas north of the boundary. Clouds/showers/storms could limit heat as well, so confidence in temperature forecast isn't super high. For now, going with a Heat Advisory for those areas south of the boundary where winds are more likely to be southerly. Heat looks to continue into at least Saturday, with widespread highs in the 90s and heat index values over 100, though boundary location and associated clouds/precip will play a large role each day. Eventually expect the front to sweep through the area and provide at least some brief relief Sunday/Monday, as high temperatures look to "only" be in the 80s those days. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1220 PM CDT Tue Aug 24 2021 VFR conditions are expected for the most part with a chance for thunderstorms moving through parts of the area this afternoon and again overnight (04-10z) . Conditions in and around thunderstorms could be variable down to IFR at times in addition to gusty and variable surface winds. Forecaster confidence on these thunderstorms is low. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...Heat Advisory until 8 PM CDT this evening for NEZ030>034-042>045- 050>053-065>068-078-088>093. Heat Advisory from noon to 8 PM CDT Wednesday for NEZ066-068-078- 088>093. IA...Heat Advisory until 8 PM CDT this evening for IAZ043-055-056-069- 079-080-090-091. && $$ DISCUSSION...CA AVIATION...Kern