textproduct: Gaylord

KEY MESSAGES

- Strong storms and heavy rain possible on Wednesday

DISCUSSION

Issued at 326 AM EDT Tue Aug 25 2026

PATTERN SYNOPSIS/FORECAST:

569dm 500mb low churning across southern Canada attm, slowly losing a bit of steam as it passes overtop the broad southern stream 598dm ridge centered over New Mexico. Additional perturbations riding up into the PacNW off the Pacific, albeit much less notable than the one over southern Canada. Shortwave ridge axis building over the Upper Great Lakes in the wake of 563dm upper low over Quebec, though a few PV maxima continue to swirl back toward MI in behind this as of 3z as NWly 80kt upper jet departs. Quiet and briefly drying here in the Northwoods with high pressure returning...between plume of moisture associated with the departing low finally pulling out to the east...and next plume of moisture, instability, and attendant convection stretching from the central Plains up around the aformentioned Canadian upper low..along a cold front stretching from occluded low over Manitoba down into the Panhandle of Nebraska, with a warm front over MN. Stationary boundary stretches from western KS to the Carolinas and up into ME; some deeper moisture and convection over the Lower MS Valley and Gulf Coast with this. A little warmer yesterday with increasing sunshine and warm advection aloft; 850mb temps rise into the teens again just to our west.

Ridge axis will move through today...as upstream PV maximum digs into the Upper Midwest tonight into Wednesday, dragging a surface front through the area, giving us a shot at some beefier showers and storms for midweek. This PV max will lift out to our east Thursday morning as a lobe of energy dives SSE from an upper low over Hudson Bay, similar to this past weekend, though it appears this will be translated slightly east from this past weekend's pattern, such that it may not be quite as cool...but we will probably remain a little more cloudy/unsettled. Pattern will begin to flatten out across the northern CONUS as an upper low treks through western Canada...with a shallow ridge axis upstream from us for the end of the week, signaling a potential pattern for activity to ride the ridge toward the Great Lakes for the second half of the week. Quite a bit of uncertainty in the pattern beyond this, with guidance struggling to determine how the pattern across Canada will evolve going into next weekend, though it is possible we may be under the influence of warm advection and could stay somewhat unsettled.

FORECAST DETAILS...

Heavy rain potential Wednesday...Warm advection tonight into Wednesday morning should lead to an increase in shower/storm coverage across the area, with the potential for better convective instability along the cold front/dry slot in the afternoon as clouds attempt to clear out a bit...and then more showers hanging on into the overnight with additional moisture behind the system. Pwats jump toward 1.5in again late tonight into the early morning hours, and hang on through the afternoon, suggesting potential for heavy rain, particularly if storms are slow moving or track over the same areas multiple times. Think the most likely QPF bullseye will be the EUP, closer to the synoptic forcing associated with the sharp PV max digging into the area...and where there may be a potential warm front to focus slow-moving/training activity. Guidance soundings in this area suggest an environment more favorable for heavy rainfall as well, with skinnier CAPE profiles in a moist environment through much of the column. If the PV max digs a little further south into the area, though, this could put more of the area at risk for heavy rain. Attm, probabilistic guidance is starting to come into a little better/stronger agreement (40-80 percent) on the idea of at least an inch of rain across the EUP by Wednesday evening; worth noting that the current bullseye of 1in+ QPF hasn't moved much at all since yesterday morning's package.

Strong storms possible Wednesday...Think we will be fighting a strong warm nose around 800mb (ish) during the day, but there are signals for a combination of diurnal heating and mid-level cooling by the afternoon to try to overcome this as the front crosses the region...allowing elevated instability during the morning hours to potentially become surface based. Greater instability and steeper lapse rates aloft should remain to our south Wednesday...but we are still looking at 500-1500ish joules of instability, whether elevated or not. Additionally, a mid-level jet max associated with the PV maxima suggests an increased shot at deep-layer shear, and will need to keep an eye out for some storm organization and some stronger storms. It appears the boundary may try to drape across the region, turning a little more zonally-oriented with time through the day, with potential for shear vectors at least marginally perpendicular to the boundary at times, and may need to keep an eye out for some discrete cell development through the day.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1050 PM EDT Mon Aug 24 2026

Mostly clear to partly cloudy skies today into this evening under some passing higher level clouds and a few high based cumulus. Concern remains this morning for the possibility for some mist/light fog to develop. Confidence continues to remain low on just how widespread and significant this mist/fog will become. Any fog/mist will quickly mix out after sunrise. Light winds, with some local afternoon lake breeze development expected.

APX WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...None.