textproduct: Gaylord

KEY MESSAGES

- Showers/storms return today, especially tonight into Saturday and the remainder of the weekend.

- Fall-like conditions Sunday

DISCUSSION

Issued at 315 AM EDT Fri Aug 21 2026

PATTERN SYNOPSIS/FORECAST:

598dm upper ridge centered over the 4 Corners with influence up into the PacNW as 60-80kt upper jet snakes its way around the perimeter of the ridge. Broad troughing across the eastern half of the CONUS/North America with 3-4 notable shortwave trough axes within the flow... one over Saskatchewan, another stretching from western Lake Superior down into the Mid MS Valley, a beautiful PV swirly on water vapor over northern Quebec, and a positively tilted axis into New England. Deepest moisture (pwats in excess of 2in) across the CONUS resides from the SE US up along the Mid Atlantic coast along and ahead of a baroclinic zone stretching all the way back to the OK Panhandle. However, there are some maxima in absolute moisture/pwats associated with the Saskatchewan shortwave trough and the Upper Midwest PV max/trough axis and their attendant surface reflections. Attm, the Upper Midwest/Upper Great Lakes remains in a subtle warm advection regime ahead of the latter feature (a cold front draped from northern MN to northern Nebraska and back up into the Intermountain West), particularly in the lower portion of the atmosphere, though col region over the central Plains suggests we will not be able to tap into the h.o.t. air over the western US/Plains (850mb temps well in excess of 20C). Low-levels across the Upper Great Lakes are quite dry, as evidenced by excellent inverted V sounding through about 700mb on the 0z/21 RAOB here at our office...and thus, clouds/rain continue to struggle, at least as of 4z, to make much eastern headway. However, there is a subtle plume of low-level moisture over IN/OH stretching north toward GRR (cloud bases ~2-3kft) which has some slight appearance of creeping northward attm along what appears to be an inverted trough axis.

First of the perturbations swings through this morning/midday, with Saskatchewan energy skating into the region late this afternoon/evening...and additional reinforcing troughing behind it for tonight into Saturday. This should dig a sharp trough axis over the Upper Great Lakes...as upper low off the West Coast ejects into the PacNW and ridge briefly bulges northward in between. Upper troughing (upper low?) remains over the region into Sunday and Sunday night...keeping things cool and unsettled to wrap up the weekend. This should start to lift out as aforementioned upstream troughing plows across southern Canada and briefly shifts a lobe of the ridge axis into the Upper Midwest to start the week. Still a lot of uncertainty in the timing of the upstream feature...but this generally appears to approach the Upper Great Lakes around midweek, and would expect this to be the next notably active period. Uncertainty increases even further beyond this, in how this troughing evolves going into late week next week, though indications attm are generally pro-troughing across the eastern CONUS/North America, to some degree.

FORECAST DETAILS...

Rain/storm chances today through Saturday...given antecedent low- level dry air mass, suspect showers will be more scattered in nature, at least to start, and therefore may struggle to produce much in the way of appreciable rainfall, at least to start...though low-level dry air could support evaporative cooling and gusty winds with storms. Trough axis approaches this afternoon, and think this will supply enough forcing to drive some convection across northern Michigan for the latter half of the day into the evening hours...though not impossible the better forcing splits around us, particularly focusing just to our south across SW Lower MI...and even further southwest, where instability potential is greater. However, we should get a few hundred Joules or so of CAPE this afternoon, and even more (1000-2000j/kg) along the boundary/dry slot this evening into tonight when better PVA arrives ahead of the next perturbation. Deep-layer shear appears relatively low to marginal here in the Northwoods, which should (in theory) keep things from getting too spicy here, though I wouldn't be entirely surprised to have some rogue stronger storms.

Still seeing that linear uptick in moisture/instability over northern Michigan this morning/early afternoon (may be focused a little more to the west than yesterday's expectations)...and think this is likely related to the boundary driving some convective activity over central WI as of 6z; instability with this feature appears low to marginal, at least initially, and think it suggests at least some showers, if not even some thunderstorms toward midday or so.

Showers for the weekend...diurnal-instability showers, perhaps some rumbles of thunder, are likely into Saturday with that next trough axis skating into the region, especially during the afternoon as we begin to cool aloft. There are some signals for instability to linger into Saturday across the area, and with falling temps aloft, suspect small hail could be in play, especially on Sunday as 850mb temps plummet below 10C across much of the area. We should also generate enough overlake instability to get lake effect rain showers on Sunday (N-NW flow); with reasonably strong pressure gradient in place over the region Sunday, think it will be a brisk/breezy, fall- like day with showers and temps muddling around in the 60s for most, especially inland and beneath cloud cover.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1256 PM EDT Fri Aug 21 2026

Isolated to scattered showers and low chances for TSRA will push across the area through much of the TAF period. Much of this will fall out of a mid-cloud deck, at least today. As we head into evening, some cig/vsby restrictions are possible. Southerly winds will become breezier this afternoon, diminishing tonight, before turning out of the northwest Saturday.

APX WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for LHZ346>348. Small Craft Advisory until 8 PM EDT this evening for LMZ323- 341-342-344>346.