FXUS63 KIWX 220619 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 219 AM EDT Sat Aug 22 2026 .KEY MESSAGES... - 30-60% chances for scattered rain and storms arrive tonight through Saturday. An isolated strong storm capable of gusty winds and brief heavy rain is possible west of US-31 late this evening and east of I-69 Saturday afternoon. - Dangerous swimming conditions expected for southeast Lake Michigan beaches on Saturday and Sunday with High Swim risks both days. Northwest winds will gust to 30 mph with waves of 3 to 5 feet. - Dry weather returns Sunday and Monday with below normal temperatures and low humidity. && .DISCUSSION... Issued at 132 PM EDT Fri Aug 21 2026 An upper level low over the Hudson Bay will be the focus of the forecast for the next 36-48 hours, as the attendant cold front with this system sweeps through our area and brings periodic chances for rain and storms tonight through early Sunday. Mainly dry conditions are expected to continue this afternoon, however, isolated showers and storms remain possible through sunset east of I-69 with a leading 500 mb shortwave associated with the upper level low. Scattered cumulus development is already noted on visible satellite imagery this afternoon. Isolated showers are also likely in the vicinity of Lake Michigan this afternoon where a dying convection complex from upstream is moving in. Into this evening, with the cold front still back in Wisconsin and the upper level trough expected to begin to dig into the Great Lakes, we will have to watch what additional development there is upstream over southern Wisconsin and northern Illinois. CAMs are in fairly good agreement in a cluster of storms developing this evening to our northwest and diving southeast after sunset. Given that shear and instability will wane after sunset, these storms should be diminishing by the time they reach northwest and north central Indiana tonight. Can't rule out an isolated gusty storm or two but not expecting much if any severe threat. Locations along and east of I-69 will remain dry until daybreak Saturday. Showers gradually become more numerous as the front pushes eastward and as the upper level trough amplifies during the morning and early afternoon hours on Saturday. Have maintained PoPs between 30-60% on Saturday, with the highest chances in northwest Ohio. With the front expected to come through between the morning and early afternoon hours, this is not the most favorable diurnal timeframe for storms. Again, can't rule out an isolated strong storm or two (especially in northwest Ohio) as a corridor of up to 1500 MLCAPE could develop east of I-69, but the likelihood of organized severe weather tomorrow is low given marginal shear of 20-30 kts and poor low/mid level lapse rates. With a tightening pressure gradient and strong cyclonic flow on the backside of the departing front on Saturday evening, I wouldn't be surprised if widely scattered lake effect showers develop downwind of Lake Michigan for several hours late Saturday into early Sunday. Winds will be breezy out of the northwest through the remainder of the weekend with northwest winds gusting as high as 25 to 30 mph. The aforementioned frontal passage is expected to stir up southern Lake Michigan, generating large waves and dangerous currents throughout the weekend. Northwest, onshore flow with northwest winds gusting to 30 mph will allow for waves to build to 3 to 5 feet with strong currents expected. High Swim Risks will be in place both days this weekend. Beach Hazards Statements will need to be issued this afternoon for Berrien and La Porte counties at least for Saturday. There will be a lull in winds and possibly waves overnight before dangerous conditions ramp up again into Sunday, with additional headlines likely needed. Heed beach flags/lifeguards and stay out of the water! High pressure builds into the Great Lakes and Midwest regions again by Sunday, giving us the first taste of fall as temperatures and dewpoints fall to comfortable levels. Temperatures will be slightly below normal on Sunday and Monday with highs in the low to mid 70s with northwest flow behind the cold frontal passage. A few crisp nights are ahead Sunday night and Monday night with lows in the low to mid 50s. With much drier air building in, dewpoints only in the 50s will make for several nice days! Another cold front moves in Wednesday with low chances (20-30%) for rain/storms maintained. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 156 AM EDT Sat Aug 22 2026 Expect predominantly VFR to MVFR conditions at the terminals, with quick periods of IFR possible. A cold front will pass from west to east through the period, with potential for showers, storms, and BR/Fog development. So far this evening has been fairly quiet with respect to t-storm activity along the cold front just west of Lake MI. Have tempos in for any showers/storms and 3-5SM BR, first at KSBN then at KFWA. MVFR ceilings move in behind the front and then eventually break to VFR by mid-late afternoon. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Beach Hazards Statement from 10 AM CDT this morning through Sunday evening for INZ103. OH...None. MI...Beach Hazards Statement from 11 AM EDT this morning through Sunday evening for MIZ177-277. MARINE...Small Craft Advisory from 11 AM this morning to 11 PM EDT this evening for LMZ043-046. && $$ DISCUSSION...Johnson AVIATION...MCD