FXUS63 KIWX 230602 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 202 AM EDT Sun Aug 23 2026 .KEY MESSAGES... - 20-30% chances for scattered lake effect rain showers downwind of Lake Michigan tonight through Sunday. - Dangerous swimming conditions persist through the weekend on southern Lake Michigan. - Below normal temperatures and much lower humidity Sunday through Tuesday. && .DISCUSSION... Issued at 1237 PM EDT Sat Aug 22 2026 A typical early fall-like weekend is ahead with clouds, showers, breezy conditions, and cooler temperatures. A low pressure system is located over northern Lower Michigan with its attendant cold front positioned just west of IN-15 currently. Scattered showers and isolated storms can be seen on radar this afternoon, especially along and east of I-69, where a 500 mb shortwave is aiding in convective development as the front pushes east. Can't rule out an isolated strong storm or two (especially in northwest Ohio) as there is an area of 1500 J/kg MLCAPE and 700 J/kg DCAPE across northern Indiana and northwest Ohio but the likelihood of organized severe weather is low given marginal shear of only 20 kts and poor low/mid level lapse rates. In addition to showers and storms, a deepening pressure gradient on the backside of this system is expected to generate gusty northwest winds throughout this afternoon and evening. Northwest winds will be sustained around 10 to 15 mph with gusts as high as 25 to 30 mph until sunset. Northwest cyclonic flow and delta Ts of ~14C (water temps ~24C, 10C at 850mb tonight) should produce at least a weak lake effect response tonight with scattered showers overnight into Sunday morning in the vicinity of Lake Michigan. Showers should gradually increase in coverage across northern Indiana downwind of Lake Michigan into the afternoon on Sunday. It will be breezy again out of the northwest on Sunday and then light winds return Monday and Tuesday as the pressure gradient eases. Did bump up cloud cover and lower temps for tomorrow as this pattern typically produces more lake effect clouds downwind of Lake Michigan than the NBM picks up on. Dangerous swimming conditions are ongoing for southeast Lake Michigan beaches and are expected to continue through Sunday. A Beach Hazards Statement is in effect for La Porte and Berrien counties through 11 PM EDT Sunday. High swim risks are expected both days with northwest winds generating 3 to 5 ft waves. Strong rip and structural currents are also expected! If your weekend plans include heading to the beach, heed all warnings from lifeguards and stay out of the water! A dry, continental airmass from central Canada moves in later Sunday as high pressure builds across the Midwest and Great Lakes. Much lower humidity and several days of slightly below normal temperatures will make for refreshing early fall-like days Sunday through Tuesday with highs in the mid 70s and dew points only in the low to mid 50s! Get the pumpkin spice lattes ready for the crisp mornings ahead as lows Monday and Tuesday morning will only be in the low 50s! Wednesday is a bit warmer (highs 75 to 80 degrees) and features the next chance for rain and storms. A similar setup, although not as pronounced as today, is likely with another upper level trough over the Great Lakes and a surface cold front sweeping through. At this time, have maintained 20-50% chances for scattered rain and storms Wednesday, with the highest chances in the evening. && .AVIATION /06Z TAFS THROUGH 06Z MONDAY/... Issued at 151 AM EDT Sun Aug 23 2026 Predominantly VFR conditions at the terminals this period, with MVFR ceilings/vis possible during shower activity this morning (KSBN) and possibly this afternoon (KFWA). Some of guidance hinting at some BR development at KFWA early but left out for now given winds are slightly stronger than models depict. Stronger W-NW winds return this afternoon, with gusts up to around 20-25 knots possible. Confidence in shower activity impact either terminal is fairly is low-a lot of the guidance is pretty widely scattered in terms of areal coverage. However, felt confident to at least put a mention for KSBN given upstream showers over Lake MI with incoming trough. Added a prob30 to KFWA for later this afternoon. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Beach Hazards Statement through this evening for INZ103. OH...None. MI...Beach Hazards Statement through this evening for MIZ177-277. MARINE...Small Craft Advisory until 11 PM EDT this evening for LMZ043- 046. && $$ DISCUSSION...Johnson AVIATION...MCD