textproduct: Gaylord

KEY MESSAGES

-Showers and thunderstorms move across the Northwoods Monday afternoon through Monday night.

-Seasonably cool temperatures and breezy conditions continue though Wednesday.

-Overall quiet weather returns the rest of the week with little to no additional precipitation.

DISCUSSION

Issued at 247 AM EDT Mon Jul 20 2026

Pattern Synopsis: An elongated 500mb ridging pattern remains positioned over the western two-thirds of the country, with downstream longwave troughing centered over Northern Quebec. An embedded shortwave trough currently over the Manitoba/Ontario border with attached surface low pressure will dig across the Great Lakes Region this afternoon through evening, producing widespread showers and thunderstorms tonight with enough moisture and instability. Latest guidance continues to support enough energy for severe storm potential followed by a frontal passage overnight that will draw a cool northerly air mass into the area.

Aforementioned longwave troughing will extend south of Michigan this Tuesday, returning a cooler Canadian Air mass influence. Temperatures Tuesday, Wednesday and Thursday are expected to remain below normal for late July with highs in the upper 60s to low 70s and breezy northwest flow. Chances of precipitation remain rather limited beyond the midweek as Upstream midlevel subsidence supports surface high pressure. A few embedded weak waves will likely support light periods of scattered showers through the end of the week, but little to no QPF is expected at this time.

Forecast Details:

Today and tonight: The primary concern for the forecast rests on the approaching shortwave moving across Ontario today. Moisture advection ahead of the front will drive dew points into the mid 60s along with moderate instability produced via diurnal heating. Showers and storms will become more widespread tonight. Latest model soundings depict a quasi inverted-V profile with adequate mid- level lapse rates and a strong low-level jet that favors any severe storms producing damaging wind gusts. Severe potential aside, PWAT near climatological maxima and skinny CAPE profiles could create localized heavy rainfall well over an inch for some parts of Northern Lower this evening through the overnight hours.

Tuesday and Wednesday: Cold air advection behind the shortwave will move into the Great Lakes Region as the aforementioned deep mid/upper level trough dips its axis south of Michigan. Boundary layer flow will keep conditions breezy this Tuesday and Wednesday with gusts building around 30 knots. Temperatures will be noticeably cool as highs are only expected to climb into the upper 60s to low 70s. While synoptic moisture will be rather limited behind Monday night's frontal passage, cold 850mb temperatures will interact with the warm lakes to keep low-level cloud cover across the CWA with even one or two locations typically affected by northwest flow observing light showers/drizzle. Thursday through Sunday Outlook:Surface high pressure builds firmly over the Great Lakes region by Thursday. Subsidence aloft will create light winds and temperatures slowly warming through the remainder of the forecast period as the core of the Canadian air mass shifts eastward. High temperatures will return toward the mid- to-upper 70s by Friday and approach climatological normal temperatures around 80 degrees over the weekend. Overall quiet and dry weather will dominate the remainder of the forecast period. However, a few weak, moisture-starved waves pivoting around the northeastern midlevel trough could bring brief periods of scattered showers, with little to no QPF expected.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 537 AM EDT Mon Jul 20 2026

VFR conditions today under some higher based cumulus and upper level clouds from upstream convection. Showers and thunderstorms work into the area this evening. Some of these storms could be strong to severe, producing gusty winds and vis restricting rains. Band of MFR producing low clouds will likely occur immediately following the rain, with these clouds likely mixing out heading toward early Tuesday morning. Southwest winds do become gusty today and tonight, with variable and gusty winds with any thunderstorm activity.

APX WATCHES/WARNINGS/ADVISORIES

MI...Beach Hazards Statement through Tuesday morning for MIZ016-024- 025-031-095-096-098. MARINE...Small Craft Advisory until 8 AM EDT Tuesday for LHZ345. Small Craft Advisory from 2 PM this afternoon to 8 AM EDT Tuesday for LHZ346>349. Small Craft Advisory until 8 AM EDT Tuesday for LMZ323-341-342- 344>346. Small Craft Advisory from 2 PM this afternoon to 8 AM EDT Tuesday for LSZ321-322.