textproduct: Gaylord

KEY MESSAGES

- Air Quality Alert remains in effect through Saturday

- Showers/thunderstorms tonight/Saturday with passing cold front

- Stronger thunderstorm threat possible Monday

- Cooler weather settles in Tuesday/Wednesday.

DISCUSSION

Issued at 309 PM EDT Fri Jul 17 2026

Pattern Synopsis/Forecast: Broad typical summertime ridging encompasses much of the CONUS...with the notable exception of a strong upper low (-3 sigma 500mb height anomaly) over Atlantic Canada. Troughing off the west coast as well...part of a larger split long wave trough (weak +EPO/-PNA look). Broad upper level low circulating beneath the broad CONUS ridge over Texas...and causing all of the flooding issues across the Hill Country. Pacific- dominant (southern branch) west-northwest upper level flow across the Great Lakes...with a couple of upper level short wave troughs/height falls in the northern branch flow across northern Saskatchewan/Manitoba/ northwest Ontario. Mid level short wave trough across Manitoba extending south into North Dakota/ Minnesota...with low/mid level warm advection ahead of it. Strong east-west low level moisture gradient across the upper Lakes this morning...~20C 850mb dew point change from drier Lower Michigan west into Wisconsin. More importantly from an air quality perspective.. 850/700mb winds are backing from northwest to southwest which hopefully will nudge of the near surface smoke east/northeast later today and improve things a bit. Broad area of surface high pressure encompasses much of the eastern CONUS...1008mb surface low over northern Minnesota with a trailing cold front back across the Dakotas and a warm front extending southeast into the Ohio Valley/mid Atlantic. Upstream northern branch short wave trough digs southeast and across the upper Lakes Saturday. Associated surface wave will pass east of Lake Superior by Saturday morning and drag a cold front across Michigan. Back into the northwest flow aloft Sunday with ridging building back into central Canada and surface high pressure settles in over the Great Lakes/Midwest. Split short wave trough off the west coast today will propagate inland across Canada this weekend... flattening the ridge and eventually sending stronger height falls and a cold front across the state sometime in the Monday night/ Tuesday time frame. This will eventually evolve into a long wave trough getting carved out across eastern Canada and the northeast quadrant of the CONUS for the latter half of next week.

Primary Forecast Concerns:

Air Quality Alert remains in effect through Saturday: Have definitely seen an improvement in visibility this afternoon...along with some lowering AQI values though still in the Unhealthy to Very Unhealthy category. KAPX VWP showing low/mid level winds backing to the west/southwest today...and bringing in some better conditions from the other side of Lake Michigan though better air quality is still closer to the Mississippi River. Winds remaining from the southwest through tonight...along with precipitation helping scrub the lower atmosphere to some degree...should allow conditions to continue to improve (at least across northern Lower). Cold front passage Saturday morning will swing winds back around to the northwest (with gusts 20-30mph)...with trajectories from the smoke region over northwest Ontario so expecting a return of thicker smoke and reduced air quality again starting late Saturday afternoon and probably lingering into Sunday. Air Quality Alert from EGLE has already been extended through Saturday.

Showers/thunderstorms tonight/Saturday with passing cold front: Scattered convection has been developing along the low level moisture gradient this afternoon across northern Michigan to the east of the warm front pressing eastward across Wisconsin/western Upper. May get a lull in this convection by early evening with passage of a short wave trough at 700mb...but anticipate additional thunderstorm development ahead of approaching cold front. Heavy rainfall a possibility across eastern Upper and the Tip of the Mitt counties; axis of 1.75+ inch precipitable water values and K Indices near 40 suggest an environment supportive of heavier downpours though convection should be progressive. Good bit of deep layer shear in place as well tonight (30-40+kts 0-6km bulk shear) with MUCAPE around 2000J/kg also suggestive of at least a large hail threat with stronger embedded cells. Think convection will mostly be south of the Bridge Saturday morning as cold front sinks southeast across northern Lower...with some low clouds and maybe some drizzle across eastern Upper through midday Saturday. Remaining convection (and later threat) expected to move into southern Lower by early Saturday afternoon. Stronger thunderstorm threat possible Monday: Probably more like later Monday/Monday night ahead of next digging short wave trough and thermal ridge...accompanied by stronger westerly flow/shear. Already in the Day 4 15% outlook from SPC so an evolution worth monitoring.

Cooler weather settles in Tuesday/Wednesday: Behind Monday's system looking at another push of colder with the potential for 850mb temperatures dropping below +10C. Looks potentially windy during midweek especially Wednesday with strong cold advection...and warm lakes which looks marginally interesting from the perspective of kicking off some lake induced showers Tuesday night/Wednesday.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 132 PM EDT Fri Jul 17 2026

Widespread visibility restrictions should continue to improve through the issuance period as wind directions shift more southerly and shower/storm chances increase region-wide. Scattered showers are noticed on radar currently, with additional showers expected later on tracking north to south, with the potential for some stronger storms to develop into tonight. Within any stronger storms, conditions may deteriorate (particularly visibilities) with heavy rain and gusty winds being the main threats. Otherwise, light winds into this evening, with southwest winds becoming a bit gusty later tonight, and shifting northwest as we head into Saturday (remaining gusty) and potentially bringing that smoke right back into the region as we progress through Saturday.

APX WATCHES/WARNINGS/ADVISORIES

MI...None. MARINE...Small Craft Advisory from 5 AM Saturday to 5 AM EDT Sunday for LHZ347-348. Dense Smoke Advisory until 11 PM EDT this evening for LMZ323- 341-342-344>346. Small Craft Advisory from 5 AM Saturday to 5 AM EDT Sunday for LSZ321.