Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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437 FXUS63 KIWX 160452 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 1252 AM EDT Sun Jun 16 2024 .KEY MESSAGES... - Hot and increasingly humid conditions to dominate much of the forecast with heat indicies either side of 100 degrees and warm overnight lows. Greatest concerns exist Wednesday through Saturday. - Showers/storms are possible Sunday night into Monday as is a trend towards somewhat cooler conditions. - The hot and dry pattern will likely set the stage for a return to drought conditions for some areas. && .DISCUSSION... Issued at 230 PM EDT Sat Jun 15 2024 The big picture forecast is pretty straight forward for much of the upcoming 7 days with heat and humidity becoming a concern as summer settles in with a vengeance. Despite this, there are some details that lead to challenges in terms of handling of the greatest periods of concern and related headlines. The center of a stronger upper level ridge will situate over the Carolinas Sunday, remaining in place and expanding its influence to locations further and further NW with time through the upcoming week. Heights of 586 to 590 dm will edge in for Sunday through Tuesday resulting in highs climbing to near or just above 90. Model blend is running quite high wrt to highs on Monday with mid 90s seeming unrealistic given the lack of significantly dry conditions and noted upper level heights and low temperatures profiles. Have lowered a few degrees for both Monday and Monday night to account for this. While still quite warm, this causes some challenges wrt headlines as heat indices (based on a 65 degree dewpoint) would also be in the low to mid 90s. Further increasing concerns is the fact that 700 mb temps (area looked at for capping of the unstable airmass) will generally be 8 to 10 degrees C, which while still strong, can allow some cu development and even widely scattered showers/storms in what will be a rather unstable environment. No strong signals as to triggers this far out that would increase confidence of anything developing like some models indicate, but a subtle disturbance passing through at the right time could allow for some development. Extensive collaboration took place with surrounding offices and given some of the concerns for Monday and Tuesday, no heat related headlines will be issued with continued emphasis on social media posts and the HWO to cover. Those outside should not focus on the lack of headlines with regards to ensuring you take plenty of breaks and remain hydrated. Upper level heights begin to increase starting Wednesday and really take hold Thursday through at least Saturday ((592-596 dm), suggesting highs in the low to mid 90s and no chances for precipitation. This combined with dewpoints in the mid 60s or higher leads to a greater likihood for heat headlines as heat indices reach at least 95 to 100 and possibly higher along with warm overnight lows resulting in a lack of cooling for those with no or ineffective means to cool. Med range models do agree on a trough approaching the area Sunday night into Monday which may bring a chance for some showers and thunderstorms along with somewhat cooler temperatures. More than enough to worry about before we get there, but have left the slgt chc to chc pops in place. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 1247 AM EDT Sun Jun 16 2024 A large surface ridge over the east CONUS coast will continue to retreat east as an upper level system and associated front organize upstream. Winds will veer to the south this morning as the upstream system approaches. Conditions will remain very dry in the low to mid levels preventing showers or storms from forming. Otherwise, VFR conditions will prevail during this TAF period. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Excessive Heat Watch from Monday morning through Friday evening for INZ007>009-017-018-025>027-032>034. Air Quality Alert until midnight EDT tonight for INZ020. OH...Excessive Heat Watch from Monday morning through Friday evening for OHZ001-002-004-005-015-016-024-025. MI...None. MARINE...None. && $$ DISCUSSION...Fisher AVIATION...Skipper