FXUS63 KIWX 071043 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 643 AM EDT Thu May 7 2026 .KEY MESSAGES... - Frost Advisory early today far southern Lower Michigan. - Scattered to numerous showers at times through Sunday. - A gradual warming trend the rest of the week with highs around 70 by Saturday. && .DISCUSSION... Issued at 345 AM EDT Thu May 7 2026 Chilly temperatures were over the region early this morning where patchy to areas of frost are expected. A Frost Advisory remains in effect over all of far southwest Lower Michigan where some clouds over most areas were still holding temperatures above 40 degrees as of 3 AM EDT. A large upper low was over southern Hudson Bay. 500 mb height anomalies were in the vicinity of negative 400 meters per GFS. Impulses associated with this system were helping to generate light showers. A strong impulse will top the upper level ridge early next week and bring showers and a slight chance for thunderstorms from Tuesday into Wednesday. The atmospheric environment will have very limited instability all of the way through the middle of next week with maximum CAPE values generally less then 400 J/Kg. Low-topped convection is likely, but ELs will be quite low - generally under 15K. No severe thunderstorms are expected. && .AVIATION /12Z TAFS THROUGH 12Z FRIDAY/... Issued at 640 AM EDT Thu May 7 2026 Primarily VFR conditions expected through this forecast valid period, with possible exception being any heavier shower activity later this afternoon/evening. An upper level short wave across northeast Iowa will dig across the southern Great Lakes region through mid afternoon, but will have meager moisture to work with. As this short wave begins to pull off to the east, a zone of stronger isentropic ascent and moisture advection will try to shift into northern Indiana with warm-front like feature across northern Illinois. Dry subcloud layers should limit instability but given strength of low level frontogenesis forcing and potential of some very weak sfc-based instability late afternoon/early evening, would expect scattered shower development in possibly a narrow corridor from NE IL into northern IN. Both terminals appear vulnerable to some window for shower potential, with the window looking to be of shorter duration at KSBN late afternoon/early evening before stronger 925-850mb fgen forcing slips to the south. Cannot completely discount some isolated thunder given strength of frontal forcing and weak instability, but confidence in thunder at terminals is very low. Potential of showers should diminish at KFWA closer to midnight tonight as forcing mechanisms drop south of the terminal. Otherwise, boundary layer averaged winds this afternoon of around 15 knots could promote some gusts into the 15 to 20 knot range at both KSBN and KFWA during peak mixing hours. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...Frost Advisory until 8 AM EDT this morning for MIZ078>081-177- 277. MARINE...None. && $$ DISCUSSION...Skipper AVIATION...Marsili