textproduct: Gaylord

KEY MESSAGES

- Some precipitation chances Sunday/Sunday night??

- Increasing heat to start the week...potentially very hot Tuesday.

- Increasing precipitation chances for the latter half of the week.

DISCUSSION

Issued at 314 PM EDT Sat Jul 11 2026

Pattern Synopsis/Forecast: Large scale pattern starting to amplify as a burgeoning ridge expands northeastward from the southwestern U.S...while -PNA troughing digs southward off the west coast. Building ridge upstream has backed upper level winds northwesterly across the Great Lakes...suppressing mid/high clouds farther south. Small but well-defined vorticity center/mid level thermal trough digging southeast to the east of Lake Superior...another PV anomaly riding along the northern edge of the developing ridge across far western South Dakota/Nebraska. Pocket of drier air sitting over the upper Lakes...though 1.50+ inch precipitable water values not far away across Missouri/Illinois/Indiana/Ohio. Not much low level flow across the upper Lakes today with a ridge of high pressure extending across the upper Midwest and into Ontario. Stationary front runs from the southern Plains east-northeast across Indiana/Ohio and off the mid Atlantic coast.

Upstream ridge will continue to expand across the Plains this weekend with rising heights across the Great Lakes. 594+dam 500mb heights forecast to expand across Michigan Monday (+2 to +3 sigma 500mb height anomaly)...with an impressive ~600dam at the center of the ridge over Minnesota. Heights expected to start getting suppressed across the region by Wednesday with an equally impressive for mid July upper low developing over Quebec (-3 sigma height anomaly). This will edge stronger northwest flow aloft into Michigan...and should take the edge off the early week heat. Upper Lakes will probably settle in between the upper low over Atlantic Canada ridging to the west and south for the latter half of next week.

Main issue for this week as far as hot weather potential goes (and resultant precip chances) will be where the main convective corridor sets up. Some baroclinicity creeps in from the north as early as Tuesday...with a slow moving/stationary boundary possibly draped across the forecast area for midweek. As mentioned above this should knock temperatures back a bit with low level cold advection. Boundary may linger in some for through the rest of the week...a consequence of being stuck between two air masses.

Primary Forecast Concerns:

Some precipitation chances Sunday/Sunday night??: Anticipate that there will be convection in the vicinity of Lake Superior Sunday morning within a zone of low/mid level warm advection along with a pair of short wave troughs that will sweep across the lake in northwest flow Sunday. Lead short wave trough passes through eastern Upper prior to sunrise...not sure if there won't be at least some scattered showers with it. Trailing short wave trough drops into Lake Superior/western Upper early Sunday afternoon...where diurnal heating and increasing dew points expected to result in MLCAPE of 1500+ J/kg across central Upper. Combination of increasing instability...passing short wave trough...and any semblance of a Lake Superior breeze enough for chancy PoPs north of the Bridge. This short wave trough expected to move into northern Lower by early evening...but minimal instability here so not expecting this feature to kick anything off farther south. However... with persistent warm advection and elevated instability across Upper Michigan Sunday night expect a continued chance for thunderstorm development into eastern Upper. North to northwest steering flow should push some of this into far northern Lower as well.

Increasing heat to start the week...potentially very hot Tuesday: Temperatures will continue to be on the rise Sunday with highs continuing to climb through the 80s. Monday may be one of those days that starts with a bit more cloud cover (or even some residual showers)...but more afternoon sun should get temperatures going quickly so reasonably confident in most areas away from the lake influence warming into the 90 to 95F range. But Tuesday is the most intriguing day...as it probably has a legit chance of some spots across northeast Lower breaking 100F with downsloping westerly winds (could be a hot/breezy afternoon). At the same time dew points may be substantially lower than our last warm weather spell a couple of weeks ago. This by itself could keep this as "just" a potential Heat Advisory event despite warmer temperatures (current maximum heat indices forecast for Tuesday are the same as the forecast maximum temperatures). But a drier boundary layer and lack of Cu development would help create a deeper mixed layer especially with 850mb temperatures in the +24C vicinity. Bottom line is that Tuesday will very likely be the warmest day of the summer thus far. Still a chance for highs in the 90-95F range Wednesday especially the farther south you go...then a bit cooler still for Thursday/Friday (though probably still above normal depending on cloud cover).

Forecast versus record highs for Monday/Tuesday are as follows:

KANJ: Mon 90/92 (2006)...Tue 89/92 (1983) KGLR: Mon 91/92 (1995)...Tue 93/96 (1955) KHTL: Mon 93/107 (1936)...Tue 95/101 (1936) KTVC: Mon 89/100 (1936)...Tue 96/98 (1995) KAPN: Mon 93/106 (1936)...Tue 98/102 (1983) KPLN: Mon 87/94 (2005)...Tue 92/93 (1977)

A few records in the lower-mid 90s that could be in jeopardy...and a few dust bowl era records that are going to be tougher to crack in the "modern forested" northern Michigan (for lack of a better term).

Increasing precipitation chances for the latter half of the week: Would like to think that as the heat breaks there should be increasing thunderstorm chances starting about Wednesday or so. But there doesn't appear to be much of an appetite for rain in the forecast until around Friday. So if the forecast is going to be adjusted in the coming days it could be toward a higher rain threat starting midweek.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 102 PM EDT Sat Jul 11 2026

VFR. Diurnal cumulus field will remain roughly 5,000ft this afternoon before clearing tonight. Light north to northeast winds this afternoon go calm tonight, turning south to southwest Sunday... perhaps gusting over 15kts by late morning.

APX WATCHES/WARNINGS/ADVISORIES

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