


Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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593 FXUS63 KIWX 100601 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 201 AM EDT Thu Jul 10 2025 .KEY MESSAGES... - Dry for the rest of the overnight with potential of patchy fog development. The fog may be locally dense. - There is a Moderate Swim Risk for southeast Lake Michigan beaches this morning. - Hot and humid by the weekend with chances for rain/storms. && .DISCUSSION... Issued at 223 PM EDT Wed Jul 9 2025 A cold front is located from Grand Rapids southwest towards Des Moines, and it will slowly sink south and east this afternoon and evening. Ahead of the front, destabilization is already occurring across our forecast area. A growing cumulus field is evident on visible satellite imagery and showers have been percolating throughout the area already today. Because of cloud cover across much of the area, temperatures have struggled to get out of the 70s today. Scattered multicell clusters of showers and a few storms are ongoing east of IN 49, while a lake shadow is keeping conditions dry along the lakeshore. Additional diurnally driven showers and storms will be possible until sunset. Much like setups over the past few weeks, it will be feast or famine for storms. Some locations may get nothing while others get several inches of rain in a short amount of time. The Storm Prediction Center has maintained a Marginal Risk (level 1 of 5) for the far northeast portion of the forecast area, meaning a few storms could be strong to severe today. The setup for severe weather appears fairly unimpressive as there is ample instability for storms to work with (2000-2500 J/kg SBCAPE), but no source of lift (until the front arrives) and little to no shear in place as vertical wind profiles are unidirectional out of the southwest. Confidence in severe weather is very low. Given ample low level moisture (dewpoints in the 70s) and high PWATs of 1.5-1.75", flooding is a much more likely scenario today than severe weather. Backbuilding will be possible with low level low from the west/southwest parallel to the boundary and slow Corfidi upshear winds. Precipitation rates should be very efficient today given long, skinny CAPE profiles, a deep warm cloud layer, and PWATs above the 75th percentile of normal. WPC has much of the area in a Marginal Risk (level 1 of 4) for localized flash flooding, which definitely is plausible given the favorable environment. Additionally, there is a High Swim Risk for southeastern Lake Michigan beaches today through early Thursday. As winds switch from the southwest to northwest/north along the lakeshore behind the cold front, waves will build to 3 to 4 feet. Strong rip, structural, and longshore currents will all be possible, especially on the north side of piers. Stay out of the water! winds will shift to be coming from the northwest after the front passes through and skies will start to clear out. Forecast soundings show an inversion developing tonight as well as a stable airmass moves in. With mostly clear skies, light winds, and residual ground moisture, patchy ground fog may develop Thursday morning. Confidence is medium in fog developing, but low as to the extent of visibility impacts. Thursday will be dry as high pressure briefly builds into the Upper Great Lakes region for 24-36 hours. An upper level ridge expands across the southwest and central US this week and progresses eastward. Heat and humidity will build across the Midwest as the upper level ridges expands and WAA increases later in the week. Depending on where the periphery of the ridge sets up and how much destabilization occurs, we could see some showers/storms on Friday. Better chances for rain/storms arrive by the weekend as another cold front moves through, although long term models disagree on exact timing and positioning. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 149 AM EDT Thu Jul 10 2025 A weak sfc cool front has become more diffuse across extreme NE Indiana/NW Ohio early this morning. Residual low level moisture and near sfc moisture source from yesterday`s rainfall will likely yield a zone of most preferred fog formation immediately in the wake of this low level front from west central Indiana through KFWA vicinity extending into NW Ohio. Have maintained previous TEMPO IFR mention at KFWA in the 10Z-13Z timeframe, with a potential of some shorter-lived vsby restrictions at KSBN. A weak intrusion of low level dry air behind the front should limit the overall potential at KSBN. Mainly dry weather is expected through the remainder of the period, with VFR conditions prevailing. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Beach Hazards Statement until 1 AM CDT early this morning for INZ103. OH...None. MI...Beach Hazards Statement until 2 AM EDT early this morning for MIZ177-277. MARINE...None. && $$ DISCUSSION...Skipper AVIATION...Marsili