textproduct: Marquette

KEY MESSAGES

- Another system brings breezy conditions and additional chances for showers across Upper Michigan today. There is a slight chance (15%) for thunderstorms in the far eastern U.P. this afternoon.

- Benign weather with cooler than normal temperatures expected the rest of this week and beyond.

DISCUSSION

Issued at 353 AM EDT Mon May 4 2026

The upper level pattern this morning remains dominated by persistent large scale troughing which encompasses much of central and eastern Canada as well as the Great Lakes region. The latest in a series of embedded shortwaves within this feature is noted over northwest Ontario this morning, and this will bring another chance of showers from west to east across Upper Michigan as an attendant surface low cross north of Lake Superior today. A somewhat potent 50 kt low level jet moving in ahead of this feature will produce breezy conditions, particularly along the Keweenaw where southwest to westerly winds could gust as high as 40 mph at times. Rainfall amounts will once again be minimal as abundant dry air in the lower levels of the atmosphere helps to limit QPF values to a few hundredths of an inch in most locations. Much like yesterday, a cold front passing through the area this afternoon will provide a focus for a slight chance of thunderstorms in the east, but chances will be limited to around 15% as latest SREF guidance can only muster around 200 J/kg MUCAPE given the moisture starved environment.

Shower activity winds down by this evening as the system departs to the east. This will usher in a cooler and drier period for most of the rest of the week, with only minor diurnal rain chances (up to 20%) on Thursday. Limited fire weather concerns will be the focus of the weather impacts during the midweek period as NBM RHs fall to around the 30 percent mark during the afternoon hours of Tuesday and beyond, and NBM wind gusts are around 15 kt (or 15-20 mph) during those times. Sustained cool northerly flow will keep temperatures below normal, with highs generally in the mid-50s or below and lows in the 20s for the interior and around freezing at the shores of the Great Lakes.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 124 PM EDT Mon May 4 2026

VFR conditions prevail through the TAF period amid gusty west to northwest winds behind a cold front. Wind gusts of 25-40 kt will be common through this evening (highest at CMX). CMX is reporting MVFR cigs on the 17Z ob, and can expect those cigs intermittently through around 20Z. A stray shower cannot be ruled out through the rest of the daylight hours, but associated vsby/cig restrictions are not expected. Winds gradually diminish overnight tonight.

MARINE

Issued at 353 AM EDT Mon May 4 2026

A passing system accompanied by a 50 kt low level jet will bring stronger southwest winds on Lake Superior today, shifting westerly behind an associated cold front in the afternoon. While gusts will reside in the 25-30 kt range across most of the lake, have opted to hoist a Gale Warning along the Keweenaw and adjacent open waters this afternoon. Hi-res guidance suggests slightly stronger gusts to 35-40 kt in these areas where decreasing low level stability should allow some of the stronger winds to mix down to the surface. Additionally, strong pressure rises behind the cold front should sustain some of these higher gusts through late afternoon into early evening. Waves look to build to 5-7 ft across much of the lake today as a result, locally building to 7-9 ft north of the Keweenaw this afternoon. Small craft headlines linger into Tuesday as westerlies hold at 20-25 kt. Winds drop back below 20 kt by Tuesday night and generally remain light through the rest of the week in the absence of any significant systems tracking through the Great Lakes.

MQT WATCHES/WARNINGS/ADVISORIES

Upper Michigan... None. Lake Superior... Gale Warning until 8 PM EDT this evening for LSZ243-244-264- 266.

Lake Michigan... None.