Area Forecast Discussion
Issued by NWS Omaha/Valley, NE
Issued by NWS Omaha/Valley, NE
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078 FXUS63 KOAX 151106 AFDOAX Area Forecast Discussion National Weather Service Omaha/Valley NE 606 AM CDT Sat Jun 15 2024 .KEY MESSAGES... - Non severe thunderstorms early this morning, then an additional chance of strong and possibly severe thunderstorms this afternoon. All modes of severe weather would be possible from 4 pm through midnight, mainly along and south of a Columbus to Sioux City line. - Very hot temperatures expected Sunday and Monday with afternoon heat index values 98 to 103 each day. - Daily storm chances exist at least somewhere in our coverage area every day from Sunday night through next week, and especially north of Interstate 80. Each round of storms will have potential for some severe weather and locally heavy rains. && .DISCUSSION... Issued at 357 AM CDT Sat Jun 15 2024 A line of non severe thunderstorms is currently moving through eastern NE early this morning. Wind gusts have ranged from 40 to 55 mph along with some small hail. This line will continue to push into western IA before daybreak, with an hour or two of stratiform rain trailing behind the main line. The rain will end from west to east with the bulk of it over by 10 am. Then there will be a few hour break from late morning through early afternoon, and while most areas will remain dry during this time, there could still be a spotty shower here or there. Meanwhile, we will be waiting for the main shortwave to move off the front range of the Rockies, which will fire strong and possibly severe storms this afternoon. The CAMs honestly provide varying locations for the convective development this afternoon, but the consensus seems to indicate the best severe threat along and south of a line from Columbus, NE to Sioux City, IA. There should be enough recovery time to allow the atmosphere to destabilize before this happens, and when storms develop, they could be quite strong with supercells possible, with all modes of severe weather possible. SPC has placed the area in a slight risk for severe storms, with a 15% chance of wind and hail, and a 5% chance of for an isolated tornado. WPC has also placed eastern NE and southwest IA in the area for excessive heavy rainfall since this area will receive heavy rainfall this morning. Again though, confidence is somewhat low where the axis of storms develop. The severe storm threat could begin by 4 pm and linger through midnight. Any storms that develop will continue to push east and be east of the forecast area by daybreak Sunday. Before the severe storms arrive late this afternoon, high temperatures should the middle to upper 80s, and could even reach the lower 90s along the KS/NE border. And then hot weather is expected to develop Sunday with mostly sunny skies and high temperatures in the middle to upper 90s. Combined with dewpoints in the upper 60s, this will create afternoon heat index values from 98 to 103, and major heat risk. These values are just below official heat advisory criteria, but those with outdoor plans should plan accordingly and stay well hydrated with water and seek the shade whenever possible. Southerly winds at 15 to 25 mph will help, but it will be the hottest day of the year so far. Storm chances come again Sunday night, mainly north of Interstate 80, with a marginal risk of both severe storms and excessive heavy rainfall. Monday brings continued small storm chances north of I80, but realistically, it could even be north of our forecast area. It will be another hot day with high temperatures once again in the lower to middle 90s, and heat index values 97 to 102. Due to the prolonged heat, the heat risk will remain elevated, but again, heat index values remain just below heat advisory criteria. And rain chances continue north of I80 Monday night, but again, based on newer models, any storms could also be north of the area. Another front moves into the region on Tuesday, which brings more thunderstorms, and another chance for severe storms along with heavy rainfall. And storm chances continue every day for the remainder of the week. Highs Tuesday in the upper 80s to lower 90s, but that front could bring cooler temperatures in the upper 70s to upper 80s for Wednesday, but warming back up to the upper 80s to lower 90s again by the end of the week. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 557 AM CDT Sat Jun 15 2024 Strongest of convection now east of TAF sites and continuing in that direction through the day. Trailing stratiform showers are already ending on the western edge of the CWA and those showers will end by about 15Z in Omaha and earlier at LNK and OFK. Some VFR cigs are also trailing the convection and it, too, should wrap up by about noon. Due to the level of uncertainty in this eve`s convection, have not included in TAFs as model guidance is especially disparate in time and space details. Will likely include some evening timing with next TAF issuance. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...DeWald AVIATION...Nicolaisen