textproduct: Marquette

KEY MESSAGES

- A batch of rain showers spreads into the area this afternoon, with a few rumbles of thunder possible in the south-central UP.

- Almost daily chances of showers and storms persist into next week. Severe storms are not expected.

- Temperatures remain below normal this week into early next week.

DISCUSSION

Issued at 317 AM EDT Wed Jun 17 2026

Early this morning, water vapor imagery and RAP analysis reveal a shortwave trough exiting the eastern UP, and another, deeper Clipper wave digging into the Northern Plains. Surface low pressure has developed over the Dakotas. Meanwhile, skies are briefly clearing out over the western and central UP, while lower cloud cover and spotty showers linger in the east. Some patchy fog development is already apparent on nighttime microphysics, corroborated by the occasional drop in visibility among surface observations. Patchy fog lingers the rest of the night while temperatures bottom out in the lower to mid 40s for most. Some of our typically cooler spots in the western and north-central UP may fall further into the upper 30s.

As we head into the daytime hours, the Plains wave swings into the Great Lakes, with the associated surface feature moving through southern WI. Isentropic ascent into the UP will allow showers to spread in during the afternoon, though as we remain in the cool sector, confidence in any thunder is low. The initial batch of showers moves out by midnight, but wraparound moisture may keep in some more spotty, light activity the rest of the night and even into Thursday. Guidance continues to waffle somewhat on rainfall amounts, but this depends on the exact track of the surface low today. The current forecast favors widespread totals of 0.25-0.35in over the area, with higher totals around and in excess of a half an inch possible closer to the WI border (NBM and HREF showing around a 50- 70% chance for these higher totals). If a more southerly track pans out, then lower totals can be expected. Meanwhile, the Keweenaw may struggle to crack a tenth of an inch with this round. Otherwise, expect temperatures to rebound into the 60s, with a somewhat breezy day courtesy of the tightening pressure gradient; wind gusts to around 20mph are possible over much of the western and central UP. Thursday turns breezier still as the system swings into Quebec and deepens. Expect widespread NW wind gusts around 20mph, with some higher gusts to 25mph over the eastern UP. Temperatures come in slightly warmer, peaking in the 60s to lower 70s.

Expect below normal temperatures and on-and-off rain chances to continue through the rest of this week and into the next as an upper- level troughing pattern remains overhead via a low near Hudson Bay. During the rest of the week, expect highs to generally be in the 60s with a few spots getting into the lower 70s. Expect the daily shortwave action to continue until a shortwave ridge moves into the central CONUS early next week, breaking down the upper-level troughing pattern overhead. This may give us a day or two of a break in the daily to near-daily precipitation; however, another Clipper low dropping down could bring rain chances back over us by the end of the forecast period.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 105 AM EDT Wed Jun 17 2026

Main aviation concerns are fog potential for the remainder of the night and potential for lower flying conditions due to rain this afternoon and evening. Earlier rainfall has cooled and moistened the lower levels at SAW, and it is here that the fog threat is highest, provided that lower to midlevel clouds clear out. Recent dewpoint depressions of zero have increased confidence in fog, with prevailing IFR and TEMPO IFR reflected in the latest TAF through around 12Z. Aside from the fog, VFR conditions should prevail until at least this afternoon, when an area of rain will spread across the UP from west to east. Best probability of MVFR or lower cigs/vsby is at IWD and SAW, while PROB30s were included for MVFR vsby at CMX due to lower confidence. IFR cigs/vsbys cannot be ruled out at IWD especially after 00Z.

MARINE

Issued at 317 AM EDT Wed Jun 17 2026

Winds are starting off light and variable this morning, but will be on the increase into the daytime hours as a Clipper low tracks out of the Northern Plains,reaching southern WI by the early evening and Lower Michigan late tonight. As this occurs, expect to see winds from the northeast pick up to 20 to 25 knots over the western arm of the lake this afternoon, before dying back down to 20 knots or less again by midnight. While winds behind the low do look to increase from the northwest still over the eastern half Lake Superior on Thursday, the chances for gales have dropped off as only wind gusts of 20 to 25 knots are now expected. The gusty northwest winds look to continue through Thursday night before falling to 20 knots or less again by Friday evening. Expect the calmer winds through the weekend as upper-level troughing keeps bringing weak shortwaves in until early next week.

MQT WATCHES/WARNINGS/ADVISORIES

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