


Area Forecast Discussion
Issued by NWS Northern Indiana
Issued by NWS Northern Indiana
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822 FXUS63 KIWX 132239 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 639 PM EDT Sun Jul 13 2025 .KEY MESSAGES... - Some smoke aloft from Canadian wildfires is expected to spread across the region today and into Monday, particularly across the upper Great Lakes. - Scattered showers and storms this afternoon and evening, especially south of US 24. - A brief reprieve from higher humidity today into Monday but peak afternoon heat indices return into the 90s for Tuesday and Wednesday. - Next chances for rain/storms arrive midweek, especially Wednesday and Thursday in the afternoon and evening. && .UPDATE... Issued at 628 PM EDT Sun Jul 13 2025 Appears that northern edge of theta-e gradient and associated light to moderate rain has been reached near the US-24 corridor. A few lightning strikes have been occurring, with the majority remaining across central IN. Pops have been nudged up to likely in far southern areas given the steady nature of the precip. Shouldn`t hang around more than a few hours with rainfall estimates averaging between 0.25 and 0.5 inches. Some CAMs still try to draw the area a bit further north as it approaches Ft Wayne so have left some lower pops for now and will monitor trends. && .DISCUSSION... Issued at 224 PM EDT Sun Jul 13 2025 The cold front that moved through yesterday has slowed and is currently draped from Toledo, OH southeast to just north of the St Louis metro. There is a low level theta-e gradient across the area today, with the best temperature and moisture found along and south of the US 24 corridor. This area is also where dewpoints are in the upper 60s to low 70s. As the front moves through the rest of our forecast area this afternoon/evening, scattered showers and a few isolated storms should develop across north central Indiana. Much like the set up yesterday, there is some instability for storms to tap into but shear is very low so storms will remain sub-severe. Lightning, briefly heavy rain, and gusty winds to 30-40 mph will all be potential hazards along and south of US 24. Showers will gradually taper off into the overnight hours. Tonight, skies will clear out behind the front and winds will be light and variable. Patchy fog will be possible, especially in areas where showers and storms have moved through over the past 24 hours. Leftover moisture near the surface should help allow for radiation fog to form along and south of US 24 by early Monday morning. In addition, wildfire smoke from Canada continues to drift into across the Upper Great Lakes region. The greatest impacts to air quality are expected across the UP and Northern Lower Michigan, however, the statewide Michigan Air Quality Alert has been expanded through the day Monday. It is possible that smoke aloft gets as far as northern Indiana and far northwest Ohio, making for hazy skies. Surface air quality should not be impacted. Heat and humidity will increase over the next few days, especially on Tuesday. Southerly low level flow and WAA will usher in low to mid 70s dewpoints on Tuesday and Wednesday, with a notable increase in humidity. Highs will be in the upper 80s to low 90s, with peak heat indices in the 90s. Mid range model guidance has been persistent with an active pattern reemerging by midweek. A 500mb shortwave will aid in thunderstorm development as it pivots through the area Wednesday afternoon/evening. Additional shortwaves pivot through Thursday and a cold front sweeps through, with additional showers and storms possible. Our typical summertime pattern of high instability and minimal shear looks to set up once again, so it is too far out to determine whether there will be any severe potential with these storms. By the weekend, dry conditions return with zonal flow over the Upper Great Lakes. && .AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 628 PM EDT Sun Jul 13 2025 At this point will leave VFR conditions in place at both sites as best influx of moisture likely to remain south of KFWA and well south of KSBN. If rainfall can make it into FWA, may need to watch for some ground fog, but decent drying took place which should limit impacts. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...Air Quality Alert until midnight EDT Monday night for MIZ078>081-177-277. MARINE...None. && $$ UPDATE...Fisher DISCUSSION...Johnson AVIATION...Fisher