FXUS63 KIWX 150547 AFDIWX Area Forecast Discussion National Weather Service Northern Indiana 147 AM EDT Thu Oct 15 2026 .KEY MESSAGES... - Cooler conditions for tonight with a break in the greater rain shower coverage expected into Thursday morning. More showers and thunderstorms are expected Thursday into Thursday night. - There is a Marginal Risk of severe storms (mainly wind) along and south of US Route 24 for Thursday evening. Confidence in severe weather is low. - Turning much cooler and windy for Friday with some lake effect rain showers expected. && .DISCUSSION... Issued at 317 PM EDT Wed Oct 14 2026 Surface cold frontal boundary has cleared southern portions of the forecast area this afternoon. The low level baroclinic zone is not expected to make much more additional southward progress into this evening as broad upper troughing across southern Ontario/Great Lakes region pushes east allowing some induced short wave upper ridging to build into the region downstream of larger scale cut- off low. Some isolated showers are possible through late afternoon/early evening with weakening frontal zone across the south, but otherwise prospects for additional rainfall tonight look to be on the low side given southward frontal push and break in stronger short wave forcing. Water vapor this imagery this afternoon depicts two features that will be watched over the next 48 hours including a cut-off upper level low across SW CO and a more progressive vort max spilling down eastern side of western Canadian upper trough. Present indications still suggest a phasing of these features Thursday evening across the Corn Belt and Upper Midwest. Isentropic progs of 300-305K layer do indicate a rapid uptick in isentropic forcing toward late morning/midday. This evolution will allow the higher level theta-e air to return northward, particularly by Thursday evening. Showers with some embedded storms are expected to accompany this stronger advective push Thursday afternoon. Despite the strong advection, a strong low level inversion will develop in response and thus sensible warming at the surface likely to be more limited keeping highs in the 60s (possibly return of some low 70s late day/toward evening across the south). Severe weather is not expected during the day Thursday given weak mid/upper level forcing outside of the strong advective forcing and due to the elevated nature of the instability. For Thursday night, the aforementioned upstream facing should begin to induce cyclogenesis of associated low pressure, however some subtle but important trends in guidance have been noted. A subtle trend of slightly more positive tilt with the upper trough appears to be suggesting sfc low deepening rates will be a little less impressive and more delayed than earlier indications. Robust shear profiles will develop ahead of primary low/sfc cold front but northward extent of a quality narrow warm sector remains uncertain, especially considering the trend of less rapid sfc feature deepening. There does still appear to be a narrow temporal window for weak near sfc instability across the south depending on extent of warm frontal progression, but hi res ensemble means still support best surface-based and mixed-layer CAPE remaining across central/southern IN. Only minor changes were made to SWODY2 with a Marginal Risk of severe storms persisting south of US 24, and mainly for the evening hours Thursday. Some isolated wind/tornado risk is possible where some weak MLCAPE can overspread given background low and deep layer shear, but current parameter space would tend to be more supportive of isolated severe threat southwest/south of local area from southern IL into central IN. Another limiting factor for severe potential could be more delayed impressive dynamics due to the weak positive tilt of this system. Otherwise, some brief locally heavy rain is possible with highly anomalous 1.75+ inch PWATs working into the area ahead of the overnight cold frontal passage. Friday still appears to be blustery/windy day with strong cold advection on the back side of this system. This should lead to development of lake effect rain showers and a potential of mixing down some stronger wind gusts. With deepening rates of this system perhaps a bit weaker than earlier indications and some suggestion of a Great Lakes modification of secondary low level trough late in the day, guidance has backed off a bit on gust magnitude during the day, but would suspect some gusts to 30 to 35 mph would be possible. A few gusts approaching 40 mph appear most likely near immediate Lake Michigan shoreline. Given cold advection, temperatures are not likely to move much from morning levels with near steady temps in the 50s expected. No major changes have been made to the long term forecast as below normal temperatures will continue through the weekend. Low temperatures in the 30s are still on track with a potential of patchy frost. The Friday night potential remains somewhat more uncertain as some lingering lake effect clouds could persist across the west, while winds may not full decouple across the east. Saturday night still appears to be best chance of patchy frost depending on extent of southwest return flow with departing high pressure. Mid/upper level flow is still progged to rapidly deamplify early next week which will result in conditions warming to above normal levels into the lower 70s toward the end of the period. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 138 AM EDT Thu Oct 15 2026 Cigs have been varying between roughly 2 kft and 3kft at both sites. Upstream obs suggest this will continue on and off through the night. Main focus will shift to chances for showers, storms and a trend to MVFR and possibly IFR cigs as an area of low pressure approaches with a strong cold front arriving after 00Z. Models continue to vary on overall coverage and location of best chances for precip with some signals of more favorable setup for showers at KSBN and maybe a slightly better chance for thunder at KFWA. Have continued to stay somewhat reserved in flight impacts before the cold front, with a likihood of further changes as the picture hopefully clears. In the wake of the front, CAA will usher in plenty of stratus and lake effect cloud cover just outside this period. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...None. OH...None. MI...None. MARINE...Gale Watch from Friday morning through late Friday night for LMZ043-046. && $$ DISCUSSION...Marsili AVIATION...Fisher