textproduct: Marquette

KEY MESSAGES

- Warmer than normal temperatures are favored through early next week.

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

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

DISCUSSION

Issued at 221 AM EDT Thu May 14 2026

Early this morning model upper level analysis and GOES water vapor imagery showed an upper level ridge over the central U.S. ahead of an upper level shortwave trough that was closing off over northwestern Montana. Surface observations showed winds had diminished over the U.P and temperatures were in the low 30s over the interior with 40s the lakeshores with clear skies.

Today the upper level low over the northern Rockies will track northeast into the Canadian prairies and a decaying upper level ridge will push across the Upper Great Lakes. Under the ridge there will be abundant sunshine and weak gradient flow. Temperatures will be much warmer with highs in the 60s and 70s for inland areas and 50s near the lakeshores. Deep mixing and dry low to mid levels will result in low afternoon humidity of 20-25% over the interior west. Winds will begin to increase over the west late in the day but expect gusts to remain below 15 mph until evening.

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 /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 123 AM EDT Thu May 14 2026

VFR prevails for most of the forecast period at all terminals, with mostly clear skies overhead. That said, a period of MVFR/IFR fog is expected at CMX early Thursday morning before lifting again by mid morning. A batch of light rain showers moves into the western UP towards the end of the forecast period, impacting mainly IWD and CMX before 06Z, but restrictions are not expected. Winds are turning light and variable tonight, then shift to the S or SE by Thursday afternoon.

MARINE

Issued at 221 AM EDT Thu May 14 2026

Winds will remain below 20 kts today with a weak pressure gradient over the lake. Winds become southerly 20-30kt tonight through Friday as a low pressure moves from the Canadian Prairies to Ontario. 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.