textproduct: Marquette

KEY MESSAGES

- Dry weather persists through Wednesday with above normal temperatures.

- Elevated fire weather conditions today across the west and central UP due to relative humidity values between 20-25%, warm temperatures, and gusts 15-20 mph.

- Next chances of showers and thunderstorms is between early Thursday to late Friday, but uncertainty in the details is high. Additional chances for convection linger into the weekend.

DISCUSSION

Issued at 350 PM EDT Mon Jun 1 2026

Another clear-sky day unfurls this afternoon on the lee side of a persistent upper-level omega block. GOES-East bands 9 and 10 show dry low-level air across the western UP, and very dry air in the low- and mid-levels in the east, with continued dry air pushing southwesterly toward the CWA. Correspondingly, RH's have been plummeting since this morning in many locations across the UP, with values commonly between 20-25% this afternoon, though some sites are seeing values either above or below this range. Bolstered by northeasterly gradient flow, radar reflectivity shows a lake breeze from Lake Superior progressing due south and reaching Gwinn at approximately 1830Z. Behind the lake breeze front, observations show that this marine-modified air brings some relief to very dry surface conditions, with RH's in the 70's and above. The 15-20 mph breezes which instigated the fire-SPS have materialized in the west and east UP, and are expected to decrease tonight.

Aloft at the mid-levels, the omega block is still firmly in place, with a closed low situated directly over Montana, the ridge center straddling northern Minnesota, and the lee trough center over Nova Scotia. This pattern is expected to budge only incrementally until Tuesday morning when it begins to break down; after this point, ensemble guidance suggests that the main ridge will de-amplify with higher thicknesses collapsing progressively southeastward over the region until Wednesday night. This means high pressure will continue to dominate at the surface through this decay process, with dry, backing gradient flow and light winds at the surface. Thus, expect widespread very dry afternoon RH's in the low 20's Tuesday and Wednesday afternoons prior to the next pattern shift. High temperatures increase each day until Wednesday; highs reach the mid- 80s in the interior west and low 80s in the east tomorrow, and high 80s in the interior west and low 80s elsewhere on Wednesday. Fire weather concerns are limited, however, due to lack of wind. Take care to hydrate proactively, and check burn bans.

Ensemble guidance indicates that Wednesday night into Thursday will bring about the final collapse of the decaying ridge from the omega block as the Montana low propagates eastward, reaching Ontario by midday Thursday. At this point, however, deterministic models suggest the low will dissipate as ridging builds in quickly behind it into Friday. Although the passage of this low coincides with a plume of anomalously high PWAT reaching the UP from the Gulf as shown by the LREF and ECWMF EFI, guidance suggests minimal synoptic forcings at this time. From a buoyancy standpoint, however, the LREF shows above up to 70% probability of 250 J/kg of MUCAPE entering the western UP early Thursday morning, and 10-20% probability of 1000 J/kg of MUCAPE in the CWA Thursday evening. Between Thursday and Friday, LREF shows 30-40% chance of 6-hour precipitation greater than 0.1", with higher accumulations in the western UP. So for Thursday and Friday, chances exist of a wetting rainfall accumulations and a thunderstorm or two, but the threat of severe weather is minimal.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 112 PM EDT Mon Jun 1 2026

SKC and P6SM conditions for all sites throughout this TAF period. Winds out of the north-northeast to east-northeast continue at 5-10 kt through this evening before becoming light and variable overnight, with southeasterly winds around 5 kt resuming at SAW early tomorrow afternoon. A lake breeze may increase winds and make them variable direction tomorrow afternoon, but the lake breeze would arrive after 18Z.

MARINE

Issued at 350 PM EDT Mon Jun 1 2026

High pressure over the Great Lakes will keep winds below 20 kt through Wednesday, with the exception of some gusts around 20 kt through this evening as northeasterly winds funnel into the western arm toward the Twin Ports. The high shifts east Wednesday night into Thursday with southerly wind gusts around 20 kt. There will be a slight chance of thunderstorms ahead of a weakening disturbance Wednesday night into Thursday night.

MQT WATCHES/WARNINGS/ADVISORIES

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