


Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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556 FXUS63 KOAX 160540 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 1240 AM CDT Wed Jul 16 2025 .KEY MESSAGES... - There is a 50-90+% chance of storms mainly after 6 PM, with a 15-40% chance of severe storms within 25 miles of any location; highest in northeast Nebraska. The primary threats are damaging winds and localized flooding. Isolated occurrences of marginally severe hail and/or a brief tornado are also possible. - Additional rounds of storms are possible from Wednesday afternoon into early Thursday, and again Friday afternoon into the weekend. Severe weather will be possible at times, with the threat of flooding increasing with each successive round. - Cooler on Thursday with highs in the lower to mid 70s, but we quickly warm back up with 80s Friday and mid 80s to lower 90s for the weekend into next week. && .DISCUSSION... Issued at 228 PM CDT Tue Jul 15 2025 Late this afternoon through tonight... Separate vorticity maxima observed in satellite data over western SD and eastern WY/western NE as of early afternoon will progress east through SD and NE tonight, ahead of another mid- level disturbance moving through MT. At the surface, early- afternoon mesoanalysis placed a surface front from central SD into western NE. A cumulus-cloud field is beginning to develop along the front in the vicinity of Valentine, with that general location likely being the focus for intense thunderstorm development later this afternoon. Latest CAM data remain in reasonably good agreement in depicting the upscale growth of initially more discrete thunderstorms into a forward-propagating MCS, which moves into the northwest part of our area after 6 or 7 PM, before eventually reaching the Omaha and Lincoln areas between 11 PM and 1 AM. The CAMs all suggest that the MCS will be intense as it moves into our area this evening with the primary hazard being damaging wind gusts of 60-75 mph. Isolated occurrences of marginally severe hail and/or a brief tornado are also possible. However, the models begin to differ on the intensity of the convective system into the overnight hours as it approaches the MO River, largely due to variations in the amount of instability across the warm sector air mass. Recent runs of the HRRR indicate that the southern portion of the MCS will remain the most intense, with a corridor of damaging winds moving through southeast NE between 10 or 11 PM and 2 AM. That signal is supported by some of the other 12z CAMs. Given that the convective system will be progressive, there is some uncertainty on heavy rainfall potential. Any flooding threat will likely be dictated by the areal extent and intensity of the trailing stratiform region, as well as any regenerative storm development on the western flank of the MCS, or atop the gust frontal surface. Wednesday and Wednesday night... The MT short-wave trough mentioned above will progress through the northern Plains, while at the surface, the convectively augmented cool front will continue south through our area. The models have backed off on precipitation potential along the front on Wednesday afternoon, with better potential for showers and thunderstorms within the post-frontal environment Wednesday evening into Wednesday night. A nocturnal low-level jet will strengthen at that time, enhancing lift and moisture flux atop the frontal surface. The combination of MUCAPE of 1000-1500 J/kg and 30-35 kt of effective bulk shear may support some storm organization with the potential for isolated occurrences of hail and wind approaching severe levels, mainly along and south of I-80. Highs on Wednesday will be notably cooler across northeast NE into west-central IA with readings in the 70s. Temperatures will be warmer along I-80 and points south with readings in the 80s. Thursday and Friday... A cooler, Canadian air mass will overspread the entirety of the area on Thursday, in tandem with surface high pressure building through the area, with highs in the 70s. It appears most locations will remain dry on Thursday and Thursday night, with the forecast indicating 20-30% PoPs across portions of southeast NE and southwest IA. On Friday, another low-amplitude disturbance is projected to move through the northern Plains, with a weak surface low tracking along the SD-NE border. The eastward progression of the surface low will encourage the northward advance of the front previously positioned to the south back into our area. That boundary may become the focus for shower and thunderstorm development Friday afternoon into Friday night. Some severe weather appears possible, as does heavy rainfall and potential flooding. It looks like we`ll see warmer temperatures on Friday with highs in the 80s. This weekend... A quasi-zonal, mid-level flow pattern will continue across the north-central CONUS, with embedded disturbances rippling through that regime. That coupled with the presence of a stationary front in or the immediate south of the area will result in continued shower and thunderstorm chances. The risks for severe weather and flooding are expected to continue. Highs in the 80s to low 90s are forecast. Early next week... The 12z global models indicate the gradual strengthening of a subtropical high across the southern and central U.S., especially during the latter half of the work week. That upper- air pattern evolution will support a potentially drier stretch of weather, along with progressively warmer temperatures. Highs in the mid 80s to low 90s are forecast on Monday, with readings warming into the upper 80s to mid 90s on Tuesday. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1232 AM CDT Wed Jul 16 2025 Strong thunderstorms continue to be the main focus of the short-term TAF period, with the strongest gusts ongoing as of the moment at KOMA/KLNK with those speeds getting trimmed down with AMDs within the next hour or so. Behind the main line, rain and thunder is expected to continue through the early morning hours with lower wind speeds expected, before giving way to SCT to FEW coverage of MVFR-level clouds, while KOFK will see MVFR conditions last through much of the day. Clouds do end up increasing in coverage to bring ceiling restriction to KOMA/KLNK by 01/02z this evening, that should clear up around or just after 06z tomorrow evening. There will be some isolated showers in the northerly winds, but they are anticipated to be few and far between, with no mention in the TAF due to the low confidence in timing and location. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Mead AVIATION...Petersen