textproduct: Marquette

KEY MESSAGES

- Temperatures approaching freezing this morning likely will result in frost away from the Great Lakes. Frost Advisories are in effect.

- Elevated fire weather conditions are possible (40-60% chance) this afternoon as winds gusts increase to 20-25 mph with humidities falling into the 20s and highs in the upper 50s and 60s.

- Dry weather through tonight is followed up by light rain this weekend.

UPDATE

Issued at 303 AM EDT Fri May 22 2026

The going forecast remains mostly on track this morning as GOES-East Nighttime Microphysics RGB imagery shows just a few areas of high cirrus streaming in from the west and southwest. This with slightly stronger winds than this morning have slightly reduced the efficiency of radiational cooling, yet once again, 5Z RTMA temps are pacing multiple degrees cooler than hourly NBM temps, so the forecast min temps this morning will resemble something closer to the 10th percentile, and just based on pattern recognition, it would not be surprising if the NBM was underdispersed in that regard once again. Will keep the ongoing Frost Advisories, though the westward extent of frost is somewhat uncertain given that some solutions do show frost into southern Houghton County.

The first aspect of impactful weather once the frost melts will be the potential for particularly dry weather today with increasing wind gusts. Despite the aforementioned cloud cover in the morning period, a consensus of model solutions shows clearing trends in the daytime hours today. This will help temperatures to continue a warming trend with forecast highs in the mid 60s with efficient mixing of very dry air aloft (HREF mean 850mb RHs in the central UP are ~20% and model soundings show 800mb RHs even lower than that). That said, if the cloud cover remains overhead and reduces the efficiency of mixing, RHs may not fall as much as yesterday. This forecast will reflect minimum RHs in the mid 20s% range away from the cooler Great Lakes shores, but there are mechanisms for both drier and more moist solutions. The wind forecast is also somewhat uncertain as hi res guidance shows potential for wind gusts of 25-30 mph in the interior west today while the rest of guidance is closer to 20 mph. These uncertainties combine to muddy the fire weather forecast today. Will issue an SPS for elevated fire weather conditions to be on the safe side given past instances of both wind gusts being higher than forecast and RHs falling below model guidance, though there is at least some uncertainty present. Conditions should remain well below critical thresholds.

The aforementioned higher wind gusts are more certain to occur over the lower-friction waters of the Great Lakes, which will make for potentially hazardous conditions in some nearshore zones this evening and tonight ahead of the Memorial Day weekend as well as moderate-to-high rip current risk for the beaches of Schoolcraft County west of Manistique and for the beaches near Big Bay on Saturday, though up to 30 percent chances of precipitation may make beach conditions suboptimal in the first place. Check the forecast before heading out for your holiday plans!

Beyond this weekend, confidence in impactful weather is too low to deviate from the NBM.

DISCUSSION

Issued at 312 PM EDT Thu May 21 2026 Amended at 303 AM EDT Fri May 22 2026

High pressure over the Upper Great Lakes gradually builds into Quebec/New England through this weekend, but holds ridging over the CWA into Saturday. This continues dry weather for most through tonight. Lows this morning will not be quite as cold as the previous morning due to less optimal placement under the high pressure, a slight increase in low level moisture from last night, and light southeast winds instead of calm ideal conditions. That said, lows are expected in the 30s, coldest east. There is a 10-30% chance for low lying areas, particularly in the east, to dip into the upper 20s. Opted to hoist a Frost Advisory from 12 to 8 am EDT (11 pm to 7 am CDT) for all except the far western counties/Keweenaw. Friday brings borderline to possibly elevated fire weather conditions (40-60% chance, highest southwestern UP). Afternoon highs will be warmer, peaking in the upper 50s and 60s. Mixing brings RH down into the 20s with winds gusting up to 20-25 mph in the afternoon-early evening hours.

Attention then turns to the troughing pivoting from the Plains, moving over the Upper Midwest/Great Lakes late Friday night and Saturday. The broader trough is composed of two main waves. The more rigorous one over the Northern Plains remains MN westward and the weaker trough emanating from the Southern Plains remains southeast, tracking over the Lower Great Lakes. These features both bring weak low pressure systems with them, but the best lift remains outside the CWA. Isentropic ascent and minimal PVA scraping the west and southeastern edges of the UP will squeeze out a few hundreths of QPF into Saturday night. Probabilities for at least 0.25 inches of rain have fallen to 10-15% across the CWA except the far western spine of the UP where 20-40% remains given its proximity to the more vigorous trough.

A trailing shortwave trough on Sunday yields a 15-30% chance for showers and weak thunderstorms with a few hundred J/kg of MUCAPE available, likely less than 500 J/kg (60-75% chance), and bulk shear struggling to reach 25-30 kts. Instability increases (~50% chance for up to 1000 J/kg of MUCAPE) alongside better bulk shear up to ~30 kts supporting 15-30% chance of showers and storms in the afternoon on Memorial Day with a transient shortwave. Around 15% PoPs on Tuesday are a result of a clipper system to the north, but shear drops off to 25 kts or less as instability continues to grow. Then high pressure develops, favoring dry weather into the latter part of next week. Expect highs to warm back into the 70s to mid 80s for most early next week, cooler 60s by the lakeshores. Lows rise into the mid 40s to 50s. Forecast confidence quickly falls off by late next week as models struggle to resolve a closed low that develops over the west CONUS.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 134 AM EDT Fri May 22 2026

VFR conditions continue throughout the period as a high pressure leaves the Great Lakes this evening and a low approaches from the Northern Plains. Winds remain out of the SE through the period, becoming gusty beginning this afternoon. Some spotty LLWS is possible, but confidence in the timing/location details is too low to include in the TAFs at this time.

MARINE

Issued at 312 PM EDT Thu May 21 2026 Amended at 303 AM EDT Fri May 22 2026

Easterly winds mainly hold 20 kts or less through this morning with high pressure overhead. This high pressure shifts northeast from Lake Superior through Saturday while a low pressure over the Central Plains lifts north over MN and another low pressure lifts from the Southern Plains to the Lower Great Lakes. These features straddle Upper Michigan and Lake Superior with troughing Saturday night and Sunday as they continue toward Canada. Easterly winds increase to 20-30 kts by Friday evening lakewide. Winds settle to 20 kts or less over the west half by Saturday morning, but east half winds remain elevated between 15-30 kts Friday night through Saturday. Winds fall off Saturday night as the low pressures dissipate, likely remaining below 20 kts through much of next week as high pressure returns to the Great Lakes.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... Frost Advisory until 8 AM EDT /7 AM CDT/ this morning for MIZ004>007-010>014-085.

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