textproduct: Marquette

KEY MESSAGES

- Cooler than normal temperatures through the rest of the work week. Frost is possible the next few nights.

- A dry work week is followed up by light rain this weekend.

DISCUSSION

Issued at 220 PM EDT Tue May 19 2026

The ~1003 mb low pressure analyzed northeast of Lake Superior this afternoon continues departing to Quebec by tonight, forcing the associated cold front the rest of the way across the UP by this evening. High pressure and dry air building in from the west behind this front set up a quiet pattern for the remainder of the work week as it slides over the Great Lakes region. Precipitation does not return until this weekend as a trough over the Plains pivots northeast over the region. Details around this are murky, but impacts likely will be low as instability is nil and probabilities of exceeding 0.5 inches of rain in 24 hours holds at 10% of less. Drier and warmer weather is progged to return early next week with high pressure possibly returning. This quieter period is captured in the CPC precipitation outlooks with near normal for the 6-10 day and slightly below normal for the 8-14 day.

Temps in the 60s to low 70s have been observed ahead of the cold front this afternoon, but this quickly will be replaced by 40s post fropa aside for parts of the south-central that linger in the 50s to low 60s for longer this afternoon/evening. Despite zonal flow developing aloft by Wednesday afternoon, low level CAA into Wednesday yields temps between 5-15F below normal. Lows in the 30s to low 40s tonight will only warm into the 40s to mid 50s for most on Wednesday, save for a few spots reaching low 60s south-central. Temps dip even lower Wednesday night into the upper 20s to upper 30s. While it is still early for growing season, some patchy frost is possible tonight and widespread frost is anticipated Wednesday night. A ridge over the southeast CONUS begins to build late week while a trough deepens over the Rockies. This strengthens southerly flow and WAA increasing temps closer to normal by this weekend with highs in the 50s and 60s and lows in the 40s to low 50s. Patchy frost is possible again Thursday night, but no headlines are planned yet this week given slow start to growing season. In the wake of the weekend system, a strong mid level ridge looks to build over the Midwest, favoring the warming trend to continue into next week. CPC temperature outlooks both show the UP under ~65-70% chances for above normal temps to close out the month.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 700 PM EDT Tue May 19 2026

As cold air advection continues over the terminals through the overnight hours, expect a gradual improvement over the next 24 hours from MVFR to VFR, with the lake effect cloud cover eroding first over IWD this evening as they get back to VFR conditions here around 1 to 2z. As for CMX and SAW, they are looking to bounce around from high-end MVFR to low-end VFR conditions tonight as the lake effect cloud cover move in and out of the area. However, with high pressure ridging moving in on Wednesday, expect the terminals to clear out after 12z. The gusty NW winds early this evening quiet down a tad through the overnight hours, before weakening even more on Wednesday as the high pressure ridge moves in.

MARINE

Issued at 220 PM EDT Tue May 19 2026

Pressure rises and cold air filtering over the lake support west to northwest winds of 20-30 kts into tonight over the east. Winds hold around 20 kts or less this afternoon in the west, remaining below 20 kts after this evening. Winds over the east settle below 20 kts Wednesday morning and likely remain sub-20 kts across the lake through Friday as high pressure persists over the Great Lakes and eastern Canada. Significant wave heights of 4-6 ft over the east hold through tonight, then settle below 4 ft by Wednesday afternoon and likely remain 4 ft or less the remainder of the forecast period. This light wind pattern may even persist into next week with no significant systems on the horizon this weekend and high pressure favored to return next week.

MQT WATCHES/WARNINGS/ADVISORIES

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