textproduct: Marquette

KEY MESSAGES

- Warmer than normal temperatures are favored by the end of this week.

- Low relative humidities paired with gusty winds and warm temperatures Friday and Saturday lead to elevated fire weather conditions.

- Light rain showers Thursday night into Friday. Heavier rain showers as well as strong to potentially severe storms accompany a low pressure early next week.

DISCUSSION

Issued at 305 PM EDT Wed May 13 2026

Afternoon GOES water vapor imagery and RAP analysis place the UP in the wake of the deep mid level trough and surface low over eastern Ontario, but still beneath cold northerly flow. Upstream is a stacked mid level ridge and surface high pressure over the Plains. Northwest winds gusting up to 20-30 mph will taper gradually taper off with the slackening pressure gradient and weakening CAA. Lingering cloud cover also clears out for most outside the far east while temps warm slightly into the mid 40s to upper 50s, coldest near eastern Lake Superior. The colder than normal airmass impacts the UP one more night as high pressure continues to build in from the west. Winds become calm and temps settle into the 30s, coldest interior west where isolated low lying spots may dip into the 20s (~30% chance).

Ridging aloft passes overhead on Thursday while the high begins it's eastward shift over the Great Lakes. Winds remain light with lake breeze influences expected off both Great Lakes. This will moderate temps there in the 50s to low 60s with interior highs in the 60s to low 70s, warmest west. Model soundings indicate a dry profile with steep low lapse rates mixing a very dry airmass down to the surface. Could see a short SPS for elevated fire weather concerns in the west in the afternoon.

High pressure continues shifting east Thursday night, giving way for a shortwave and frontal boundary extending off a passing low to the north. This brings back showers and some embedded elevated storms from the west. Despite PWATs between 1 and 1.25 inches, the forcing is not particularly strong/organized and instability is unimpressive. QPF of a few hundreths up to 0.25 inch are possible. Once in the wake of this round, mostly dry weather is expected on Friday. Temps only settle Thursday night into the 40s to mid 50s. The warming pattern continues on Friday as highs reach into the mid 50s to mid 60s east where there is cooler southerly flow off of Lake Michigan and 70s to low 80s over the west. Also expect breezy winds with a passing low level jet, bringing gusts into the 25-35 mph, strongest where there is downslope acceleration. Additional SPS worthy elevated fire weather concerns are likely in the west in the afternoon. Friday night stays mild and dry in the 50s.

Flow overhead becomes zonal on Saturday with an elongated mid level wave grazing the northern end of the CWA. Limited moisture and forcing mean dry weather likely persists (80% chance). Breezy west winds start the day off, gusting into the 20-30 mph range, but taper off in the afternoon as the jet departs and weak ridging begins building in from the Canadian Prairie. Highs will be in the 60s to mid 70s, warmest south. Once again efficient mixing from dry air aloft presents another SPS day for elevated fire weather conditions. This high pressure influence persists through most of Sunday. Saturday night will be cooler in the upper 30s to 40s, warming up on Sunday into the 50s and 60s; interior west may reach into the low 70s (25% chance). Sunday presents the last day for possibly elevated fire weather conditions interior west as winds pick up in the afternoon when RHs dip into the upper 20s.

Attention turns to a trough over the Rockies that develops a low pressure system anticipated to track somewhere over the Upper Great Lakes Monday night and Tuesday. Ensemble spread in the track is significant among all the suites, but some thunderstorms are possible between Sunday night and Tuesday (30-40% chance). A warm front and shortwave lift in from the south Sunday night bringing the first round of showers and storms to the UP. Instability is marginal, leaving potential for weak embedded storms (<500 j/kg). The later shower and storm potential is where uncertainty is greatest. The ECMWF and its ensemble suite favors the UP getting into the warm sector and thus have higher instability (up to 1000- 2000 j/kg of MUCAPE) compared to the GFS and GEFS which favor a more southeast track of the warm sector (1000 j/kg or less of MUCAPE). Shear in either model is sufficient (at least 30 kts) for stronger and more organized convection. Too many discrepancies remain in the upper pattern progression and surface tracks to nail down details, but will monitor severe potential with the coming forecast packages. Currently the SPC Severe Weather Outlook has a 15% chance along the WI/MI state line area.

What does have higher confidence with this event is widespread precip with possible higher amounts exceeding one inch highlighted by EFI shading to 0.8 over the west with SoT nearing 1. NAEFs moisture transport highlight a strong Gulf connection with values above ~99th climatology percentile across the UP and NBM mean PWATs are between 1.3 and 1.6 inches. Current NBM probabilities of >=1 inch of QPF in 24 hours is 45-55% along the western spine of the UP.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 212 PM EDT Wed May 13 2026

VFR conditions have returned to all TAF sites this afternoon as high pressure strengthens over the region. Nonetheless, northwesterly winds will remain strong into this evening, especially at CMX and SAW, with gusts up to 25 kts. Otherwise, outside of any MVFR fog development at CMX early tomorrow morning, VFR will remain the prevailing flight category.

MARINE

Issued at 305 PM EDT Wed May 13 2026

Lingering northwest winds between 20-30 kts over the east taper off into tonight as high pressure builds overhead; winds remain below 20 kts through Thursday. Wave heights between 4-8 ft over the southeastern waters fall below 4 ft tonight.

The next low tracking across Ontario brings southerly winds of 20-30 kts lakewide Thursday night into Friday. Strongest winds are expected over the east, particularly Friday morning when there is a 20-40% chance for gales to 35 kts. Stable air over the lake will limit stronger mixing from occuring. Winds become westerly between 20-30 kts Friday night, holding through Saturday morning before tapering back down below 20 kts by Saturday night.

Another system early next week brings 20-30 kt winds to the lake Sunday/Monday, but uncertainty in low track and timing is high. Some thunderstorms are anticipated to accompany this system on Monday.

MQT WATCHES/WARNINGS/ADVISORIES

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