textproduct: Marquette

KEY MESSAGES

- Temperatures remain hot this afternoon with heat indices well into the 90s and even exceeding 100F in some spots. Little relief is expected tonight as lows only range in the 60s to lower 70s.

- Smoke from upstream wildfires sinks into the Great Lakes tonight into Wednesday. An Air Quality Alert has been issued for Wednesday.

- Temperatures moderate from Wednesday onward, with precipitation chances returning late in the week.

DISCUSSION

Issued at 256 PM EDT Tue Jul 14 2026

Early afternoon RAP analysis has the UP on the northern perimeter of an impressive midlevel ridge centered over the Midwest, with 500mb heights flirting with 600dam. Visible satellite reveals clear skies over the UP...with the exception of smoke from wildfires over Ontario that is moving over Superior and beginning to reach our shores. Under sunny skies, temperatures have already climbed into the lower to mid 90s so far, and should peak in the mid and upper 90s (or even near 100F) for most. This yields peak heat indices this afternoon well into the 90s and possibly exceeding 100F. Thus, our heat headlines will continue. Meanwhile, a weak cold front has kicked off a narrow band of thunderstorms over far northern MN, but will note that recent radar and satellite trends already show this current batch weakening. Still, the SE-moving cold front and any remnant thunderstorm boundaries could allow for additional storm development. Storms may graze the western UP closer to 00Z, but confidence is low given weak forcing and dry air to overcome. If storms can develop, however, they could put down a good wind gust (a potential betrayed by inverted-V soundings and steep DCAPE near 1500j/kg).

Any thunderstorm activity wraps up by 06Z, but skies won't be looking exactly clear the rest of the night as smoke continues to spread over the UP. HRRR smoke model shows extensive near-surface smoke over the UP by early Wednesday morning, lingering through the rest of the day. The Michigan Department of Environment, Great Lakes, and Energy has therefore issued an Air Quality Alert for Wednesday. Meanwhile, temperatures tonight only come in slightly cooler than last night, bottoming out in the 60s to lower 70s before we rebound well into the 80s for most. Menominee county stands the best chance at seeing highs in the lower 90s, while areas closer to the Superior shoreline may not even break out of the 70s. With another hot day and poor air quality for Wednesday, consider limiting strenuous outdoor activity. At least some patchy smoke lingers over the area through Wednesday night.

Temperatures will continue to moderate towards more "normal" summer heat the latter half of the week as the upper ridge is flattened out by persistent strong troughing over eastern Canada. This will yield highs generally in the 70s to low 80s near Lake Superior and into the mid/upper 80s inland Thursday onwards. Overnight lows will also return closer to seasonal norms, ranging in the 50s and 60s by Wednesday night and onwards. The forecast remains dry through Thursday, but the flattening of the upper level flow will pave the way for the next system bringing a higher chance for widespread rain and thunderstorms back to the area Friday and into the weekend. Do not see signals for any significantly impactful weather in the long term forecast at this time.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 137 PM EDT Tue Jul 14 2026

VFR conditions are expected through this evening. Winds will still be gusty at CMX and SAW to start the TAF period but will become light and northerly as the evening progresses. Thereafter smoke from wildfires in northern MN/northwest Ontario will push into the area. There is uncertainty as too how thick the smoke will be and the extent of impacts to vsby. Could not rule out MVFR conditions by Wednesday morning.

MARINE

Issued at 256 PM EDT Tue Jul 14 2026

SW winds continue to gust up to 20-30kts over the western portions of the lake this afternoon, highest between the Keweenaw and Isle Royale, with gusts up to 20 kts over the eastern half of the lake. Winds should fall back into the evening while shifting more to the W/NW as a weak cold front passes through. Winds remain below 20kts Wednesday through Thursday as ridging recovers over the area. Winds may become elevated to near/above 20kts at times Friday through the weekend with a series of shortwaves moving through, also bringing a potential for thunderstorms. Otherwise, afternoon satellite reveals patchy fog over the eastern half of the lake, which may be dense at times. As wildfire smoke from Ontario drifts over Superior this evening through at least Wednesday evening, some drops in visibility will remain possible.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Extreme Heat Warning until 10 PM EDT /9 PM CDT/ this evening for MIZ001>007-009>014-084-085.

Lake Superior... None. Lake Michigan... None.