Decatur, IN Weather

Key Messages

- Areas of fog are possible north of US-30 this morning. Some locally dense fog may be possible in far NW Ohio and southern Michigan.

- Warm, dry and pleasant weather will continue well into next week with highs around 70 and lows in the 40s.

Discussion

Issued at 130 AM EDT Fri Oct 23 2026

Fog is the main forecast concern again this morning. Light NNE flow off Lake Huron supporting widespread dense fog over parts of SE MI and continuing to expand SW with time. Models split on exactly how far SW this fog gets but there is a decent chance our NE counties could get clipped. A few HRRR and RAP runs have also indicated additional fog development possible around KFWA and points SE. Low forecast confidence precludes any proactive headline decisions for now but will continue to monitor satellite/surface obs closely through the early morning and issue advisories or SPS's as necessary. Otherwise, incredibly high amplitude/short wavelength ridge continues to build over the Great Lakes through the weekend with strong AVA/subsidence maintaining high pressure across the Lower Great Lakes/northeast CONUS. Surface winds slowly veer to a more SE and eventually S/SW direction tonight through the weekend. That coupled with some increasing high clouds from upstream trough/front should limit the fog threat for Sat AM though some patchy fog can't be ruled out for our eastern zones. High temps likely reach the low 70s again today given sunny skies (outside of morning fog/stratus) and deep mixing. Leaned on the warmer and drier side of guidance for today which gives afternoon RH values around 35 percent. This is not low enough for a substantive fire wx concern (especially given very light wind) but imagine finer fuels are starting to get pretty dry. Similar story over the weekend. Sunday's highs will be a little warmer given increasing SW flow/light WAA but dewpoints also creep up a bit as well. Strong ridge holds firm over the Ohio Valley this weekend as upstream surface front stalls and washes out well to our NW. Our next chance of rain doesn't arrive until next Thu and even that is highly questionable as numerous solutions show this front stalling to our NW as well. Real rainfall chances don't arrive until around Halloween but that is far enough out that many things could still change. Main story is that warm, dry and pleasant fall weather will continue well into next week.

Aviation

Issued at 130 AM EDT Fri Oct 23 2026

Amplification of flow has led to maintenance of expansive low level ridge axis from the Great Lakes to the Ohio Valley. Surface anticyclone will maintain its dominance across the region as a result with a continued weak easterly low level flow profiles. This easterly flow has been conducive for fog development particularly downwind of the eastern Great Lakes. Higher res guidance continues to suggest far NW Ohio and SE Lower Michigan at greatest risk of dense fog overnight, but will need to watch for possibility of some patchy fog developing in KFWA vicinity in the 09Z to 14Z timeframe. Confidence remains somewhat low for KFWA and will limit mention to TEMPO MVFR vsbys with the 06Z TAFs. Otherwise, VFR conditions and light winds will continue through this period.

Iwx Watches

IN...None. OH...None. MI...None. MARINE...None.