textproduct: Marquette

KEY MESSAGES

- Temperatures will be closer to average for the holiday weekend along with notably drier air as dew points fall back into the 50s to low 60s.

UPDATE

Issued at 244 AM EDT Sat Jul 4 2026

Early this morning RAP analysis and GOES water vapor imagery showed a high amplitude upper level ridge north of Lake Superior, over Ontario and extending north into Nunavut. Underneath the ridge relatively zonal flow was in place across the northern U.S. with multiple shortwaves embedded in the flow. Radar showed light echoes over the western U.P. as decaying convection continued to push eastwards from MN. Otherwise it was cloudy over much of the U.P. The aurora was trying to provide a light show but overall clouds were in the way of viewing through there were breaks around Isle Royale where the webcams were picking it up. High pressure building in from Ontario was bringing cooler air into the area and light northerly flow. Temperatures were in the low to mid 60s and could fall into the 50s over the central and north before sunrise.

Today's forecast looks to be on track with highs in the 70s to low 80s, cooler along Lake Superior with onshore northerly flow. Models are in good agreement that an upstream shortwave will track south of the area today, keeping the U.P. mainly dry except for a few isolated showers this afternoon in the far west. Overall it should be a pleasant day with light winds.

DISCUSSION

Issued at 233 PM EDT Fri Jul 3 2026

Afternoon water vapor imagery and RAP analysis reveal upper level high pressure centered over the Blue Ridge mountains, with zonal flow over the Midwest and Great Lakes. Embedded shortwaves throughout the region are remaining outside of the UP, but associated high cloud cover is continuing to stream into the area at times. Closer to home, lake breeze development has become apparent on radar and visible satellite, with plenty of cumulus popping away from the lakeshores. Some storms are already developing along the Superior lake breeze over Luce county, and it would not be surprising to see agitated cu and eventually showers/storms develop westward as well. Scattered showers and storms become more likely over the central and southern UP as the Superior lake breeze continues to move inland and potentially interacts with the Lake Michigan boundary. SBCAPE is already analyzed to be in excess of 2000j/kg across the UP, with several hundred j/kg of DCAPE. Still, shear is quite lacking. So, organized severe convection is not expected, but a stronger gust is not out of the question as storms collapse again. Will also note that SPC has removed us from the Marginal risk.

Otherwise, we are enjoying a pleasantly sunny summer day, with temperatures ranging in the lower to mid 80s for most away from the lakeshores. Temperatures are expected to peak slightly higher in the mid/upper 80s inland, highest over Menominee county, while the lakeshores only peak in the 70s (or even lower nearest to Superior).

The rest of the holiday weekend, temperatures moderate some as high pressure centered over Hudson Bay extends ridging southward and allows a cooler airmass to sink southward. Still, temperatures won't exactly turn cold, with highs ranging in the 70s to lower 80s and lows mainly in the 50s. Meanwhile, yet another shortwave will be moving out of the Plains and towards the Great Lakes Saturday. Much of the deterministic and ensemble guidance favors a weaker wave that stays more to our south, somewhere over WI, while the GFS is both stronger and more north with this wave. NBM in turn keeps the better PoPs south of our borders, with just chance PoPs over the UP Saturday evening into Sunday. If this batch can move over the UP, we aren't exactly looking at a washout; a tenth to quarter-inch would be the more likely scenario, but higher amounts would be possible Temperatures trend warmer again into next week as ridging recovers, and though drier weather is favored, diurnal instability presents almost daily chances for some convection. There are hints for another trough and cold front to sweep through sometime midweek, which brings better chances for convection in the Wed-Thurs timeframe.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 717 AM EDT Sat Jul 4 2026

VFR conditions will prevail through the TAF period. High pressure building south out of the Hudson Bay will bring light easterly winds to the area today. Mid to high level cloudiness can also be expected as it gets sheared off of convection well south and west of the area and advected over the U.P. A few isolated showers are possible around IWD, particularly over the next few hours and again staring in the afternoon. However, confidence and coverage is too low to include in the TAF this afternoon and tonight.

MARINE

Issued at 233 PM EDT Fri Jul 3 2026

Afternoon satellite reveals at least some lingering patchy fog over the open waters, and available webcams show this is dense at times. Otherwise, dense fog is becoming more widespread in the nearshores off the western UP, so fog headlines will go up there. Otherwise, quiet weather persists today with variable winds coming in below 15kts. Weak winds to start off increase out of the northeast Saturday afternoon and evening as another trough moves through the Great Lakes, with gusts up to 20-25kts over the western arm of the lake. This may also bring some showers and storms over the lake Saturday into Sunday, though confidence is low. Northeast winds gradually decrease Sunday, and remain light into next week. Dry weather becomes favored after Sunday, but daytime instability nevertheless leads to at least some potential for afternoon showers and storms.

MQT WATCHES/WARNINGS/ADVISORIES

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