Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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621 FXUS63 KIWX 131734 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 134 PM EDT Thu Jun 13 2024 .KEY MESSAGES... - Hot today with chances for severe storms late today through early tonight. Damaging winds and large hail are the greatest threats. - Dry, cooler and less humid Friday and Saturday. - Hot & humid Sunday through Thursday; highs around 90 to 95 with afternoon heat indices 95 to possibly as high as 105. Storms possible each day, mainly late afternoons & evenings. && .DISCUSSION... Issued at 313 AM EDT Thu Jun 13 2024 The third day of return flow was underway; however, deeper moisture had not yet made it into the forecast area. But despite the lack of deeper moisture, an EML intrusion was just off to the west. Steep mid level lapse rates will favor severe storms, especially west of Highway 31 where the bulk of a slight risk for severe storms is indicated by SPC. It looks like the best window for storms is from 20Z to 04Z (4pm to midnight EDT). Some weak capping at the base of the EML is likely to help storms to be initially more focused along the south moving front over Lower Michigan. The latest/06Z run of the HRRR appears on track in this regard with convection initiating near the Michigan border by 6pm and then spreading rapidly south during the evening. Given BUFKIT profiles, it appears damaging winds are the greatest threat from storms late today and this evening. Large hail, locally heavy rainfall and an isolated tornado are all possible. After tonight, cooler and less humid air will be over the area Friday and Saturday. By Sunday, the heat will return followed by the humidity arriving Sunday night and Monday. Precipitable water values will be substantial with values at times above 2.0 inches from Monday through Thursday. In this environment and during this time of year, believe storms will be highly diurnal in the 19Z to 02Z window (3pm - 10pm EDT). Large CAPES topping over 3000 J/Kg at times and relatively weak shear should limit severe potential to locally heavy rainfall. Concurrently, the tropical plume of moisture is expected to arrive early next week with the hot conditions. These combined factors are expected to cause afternoon heat indices to reach near 100F to 105F. Will continue to message this heat hazard. && .AVIATION /18Z TAFS THROUGH 18Z FRIDAY/... Issued at 128 PM EDT Thu Jun 13 2024 An active TAF period is anticipated amid the risk for severe thunderstorms, especially at KSBN. Cumulus clouds are developing over Illinois and southern Michigan ahead of a cold front located near the WI-IA-IL lines. Severe thunderstorms are expected to develop near the Michigan state line and drop south. Strong wind gusts, hail, and heavy rain are the primary concerns. Synoptic wind gusts abate behind these thunderstorms, through wind gradually veers through the night behind the cold front. There is a non-zero chance of MVFR ceilings tonight amid post- frontal stratus. Probabilities are generally near 30% or so, per the in-house blend. Therefore, retained the mention at KSBN but avoided the introduction of such ceilings at KFWA for the time being. Satellite trends will be monitored. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...None. && $$ DISCUSSION...Skipper AVIATION...Brown