textproduct: Marquette

KEY MESSAGES

- High temperatures today and Tuesday will be 5 to 10 degrees above average, generally in the low to mid 80s. Humidity will be on the rise Tuesday with dew points in the 60s.

- Scattered showers and thunderstorms develop Tuesday afternoon and evening.

- Showers and thunderstorms become more widespread Tuesday night into Wednesday.

UPDATE

Issued at 236 AM EDT Mon Jul 6 2026

Early this morning RAP surface analysis showed high pressure over Northern Quebec, near James Bay, extending southwest over the Upper Great Lakes. This was bringing clear skies and light winds to the U.P. Temperatures had fallen into the 40s and 50s with the coolest readings over the northern half of the U.P.

A sunny and warm summer day is on tap for the U.P. with afternoon temperatures rising 5 to 10 degrees above average, reaching into the mid 80s. A surface ridge overhead will result in light winds today with a weak pressure gradient in place. This will be optimal conditions for lake breezes to form this afternoon, dropping temperatures back down into the upper 60s along the immediate Lake Superior shoreline and 70s along Green Bay and Lake Michigan.

DISCUSSION

Issued at 106 PM EDT Sun Jul 5 2026

Early afternoon water vapor imagery and RAP analysis reveals weak troughing over the eastern UP/lower MI slowly moving east, while drier air associated with ridging is advancing toward the western UP. At the surface, a ridge of high pressure extends southwest over Lake Superior/UP from a center over Hudson Bay. Expect the ridge to further assert itself through tonight over the local area as the trough exits east. With a drier airmass, good radiational cooling is expected tonight, with lows away from the immediate shorelines falling into the upper 40s and low 50s. For Monday, the high continues to shift east, resulting in weak return flow, with highs mainly in the low to mid-80s.

Next period of potentially impactful weather looks to be in the Tuesday afternoon through Wednesday timeframe. This will occur as mid/upper level zonal flow strengthens modestly across the northern tier of the CONUS, and a weak low-level boundary becomes strung out from central Ontario through Lake Superior and the UP, southwestward into the northern Plains. Meanwhile, modest SW flow in the 925-850 mb layer will help to boost PWATs up to 1.5-1.75 inches, or +1 to +2 sigma per the NAEFS. Expect scattered showers and storms to develop Tuesday afternoon and evening along the low-level front, with best coverage over the west half. Modest midlevel lapse rates should keep SBCAPE around 1000 J/kg or less with deep-layer shear around 25 kt or less, which should limit the severe weather threat overall. However, the potential for multiple rounds of convection along the stalled boundary, along with relatively slow storm motions, will result in a heavy rain threat with the most widespread coverage of showers and storms by Wednesday. Modest instability values are a limiting factor, however. Latest NBM probs of exceeding 2" of rain in 48 hours are 20-30% in the west and central UP.

Dry and seasonable weather is favored to end out the week Thu/Fri in the wake of Wednesday's system as high pressure builds in again from the north.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 127 AM EDT Mon Jul 6 2026

High pressure promotes VFR conditions under mostly clear skies through the period at Upper Michigan terminals. Winds generally out of the east to northeast turn light tonight, and remain below 10kts Monday.

MARINE

Issued at 106 PM EDT Sun Jul 5 2026

High pressure will result in light winds through Monday night. The high shifts east for Tuesday as warmer and more moist air arrives. This is likely to result in periods of rain and thunderstorms from late Tuesday into Wednesday night. Areas of fog will be possible during this time as well, especially where it rains. Winds remain less than 20 kt throughout the week.

MQT WATCHES/WARNINGS/ADVISORIES

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