textproduct: Marquette

KEY MESSAGES

- A round of showers and isolated thunderstorms are expected in the west and south tonight, and second round is expected tomorrow afternoon and evening in the central UP.

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

DISCUSSION

Issued at 347 PM EDT Fri Jun 19 2026

Cyclonic flow orbiting the persistent Hudson Bay/Nunavut low continues to dominate weather patterns in the UP. As a distinct mid- level shortwave embedded within this flow propogates ESE'ly from from northern MN today, GOES Day Cloud Phase Distinction shows low- level stratus clouds topped by glaciating higher moisture moving into the very western part of the CWA. Otherwise, diurnal cumulus formation with moderate coverage spreads across the central UP. Despite increased insolation today, CAA is suppressing high temperatures; the UP remains mostly in the 60's well into this afternoon, with a few locations in the south and east reaching 70 or above.

As the MN shortwave tracks easterly this evening, chances of convective precipitation spread west to east across the CWA. While CAMs show weak simulated radar returns beginning at 21Z, precise tracks and QPF amounts vary. With HREF 6-hour QPF distributions showing amounts between 0" and 0.5" for tonight into Saturday morning for the west and central UP, be prepared to expect a sudden burst of rain should a cell track above you.

Tomorrow afternoon will bring a similar story, though with diurnally- driven PoPs rather than synoptic, in the western, central and southern UP. Again, CAMs show weak radar returns beginning in Ontonagon/Keweenaw Counties around 14Z and progressing southeastward toward Delta County into Saturday night. With a couple hundred j/kg of HREF MUCAPE present between Lake Superior and the WI border and similar QPF distributions to Friday, be prepared again for passing thunderstorms and showers on Saturday afternoon and evening if you are in these areas. Sunday looks to be drier and still cool.

Looking ahead to next week, although the current perpetual troughing and steering jet streak deteriorate and move east beginning on Monday, another low forms nearly immediately in its wake over Ontario, though ensembles indicate that heights associated with this will be less anomalously low. That said, the cooler pattern continues. The ECMWF'S EFI within the WFO MQT domain shows anomalously cold (<-0.7) Tmax and Tmin for Days 1-7, except for Day 2, when values are simply slightly less negative (-0.67 for Tmax and -0.57 for Tmin). Additionally, days 4-7 for Tmax and days 5-7 for Tmin show a nonzero SoT, indicating possibility (albiet with low confidence) of more 'extreme' values for these fields. So, although a pattern disruption is expected early next week, surface temperatures are expected to remain roughly the same as they have been through this coming week.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 220 PM EDT Fri Jun 19 2026

VFR conditions and generally light winds, save for breezy gusts 15- 20 kts at CMX, prevail through the rest of the afternoon and evening. A batch of light showers presses into the far western UP this eveningm hweverm VFR cigs and vis are expected to remain. Conditions fall to MVFR and IFR at IWD overnight through daybreak tomorrow.

MARINE

Issued at 347 PM EDT Fri Jun 19 2026

After winds decrease tonight, light winds mostly <15 kts on Lake Superior and the Bay of Green Bay are expected through Sunday. Between tonight and tomorrow, steady WNW'ly gradient flow will give way to fluctuating patterns as a surface low tracks across the UP tonight. Ahead of this minor low, winds will first back southerly, then veer westerly once more. Generally W'ly to WNW'ly flow is expected on Lake Superior and Bay of Green Bay through Sunday, going toward N'ly on Monday. According to GLERL, Lake Superior surface temperatures have increased to above 50F in the nearshore zones, but remain as cold low 40s offshore in the western and eastern basins. The northern part of the Bay of Green Bay shows surface water temps in the low 60s.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Beach Hazards Statement until 5 PM EDT this afternoon for MIZ006.

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