Marine Weather and Tide Forecast for Grand Marais, MN

DISCUSSION
Issued at 202 AM CDT Mon Aug 3 2026

Current Conditions/Today:

High pressure is jaunting off to the southeast allowing for broad southerly winds and warm air advection to take hold of the region.
Radar this morning shows a few light echoes cruising across northern MN, but no reports of rain reaching the ground with this activity.
More vigorous activity is expected later this morning as a strong low level jet is expected to develop across the Northern Plains which will increase the chances of some elevated storms to develop in the Red River Valley. Strong instability (1000-2000 J/kg of MUCAPE) with a bulk shear of 40-50kts could lead to severe storms that generate large hail. The current suite of high res guidance favors this being farther west outside of our CWA where the HRRR is highlighting some swaths of higher updraft helicity. High res guidance has come into better agreement with the recent runs suggesting that this morning activity will largely stay west of the region and possibly clip into Koochiching during the afternoon hours. Still need to keep a watchful eye out west this morning as the severe risk is still categorized as a marginal (level 1 out of 5).

Activity is expected to ramp back up in evening. Despite the morning storm activity, the region will see ample recovery with southerly flow promoting warm advection and pushing MLCAPE upwards of 1000- 2000 J/kg. A cold front will move east through the late afternoon and evening period triggering convection. Bulk shear will still be bountiful with an upper level jet rounding and upper level low moving into Manitoba. Supercells will be possible capable of producing large hail and damaging winds. A tornado can't be ruled out at this time, but the better streamwise vorticity looks to be over the Red River Valley, which then fades as the storm mode becomes more linear as it tracks into our CWA Showers and storms will continue to move across the region through the overnight period with the severe risk fading in the early morning hours. Thereafter, showers and a few weaker storms will continue through the region Tuesday as the cold front pushes west to east.

Mid week:

High pressure over the region for Wednesday temperatures staying in the 70s. Temperatures will slowly increase through the end of the work week with intermittent rain chances possible as the upper level pattern turns more zonal.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
Issued at 626 AM CDT Mon Aug 3 2026

Showers and storms have formed on the nose of a low level jet over the Red River Valley this morning. This activity may impact INL at times. Southerly winds will be increasing today with gusts in the afternoon over 20 kts. A cold front will advance out of the west bringing strong to severe storms this evening and overnight. As the front passes over the terminals expect winds to shift to out of the west

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/
Issued at 202 AM CDT Mon Aug 3 2026

Light winds today as surface high pressure departs to the southeast.
Southwest winds will increase tonight as a cold front approaches from the west. Small Craft Advisories have been issued for wind gusts up to 25-30 kts. With the cold front, expected showers and storms to enter western Lake Superior after midnight. This activity will clear to the east Tuesday morning. Westerly winds will filter in behind the front with additional Small Craft Advisories likely being needed.

For the open water discussion, refer to the NWS Marquette Area Forecast Discussion at weather.gov/mqt.

FIRE WEATHER
Issued at 202 AM CDT Mon Aug 3 2026

Slightly elevated fire weather concerns for today. High pressure has departed to the southeast. Wind speeds are expected to increase out of the south today ahead of an approaching cold front. Gusts of 20- 25 mph will be possible. Min RHs remain in question, not expecting very dry conditions but some of the high res guidance would suggest dropping into the upper or mid 30s for RH. However, extensive cloud cover ahead of the approaching system may keep those RHs slightly higher. Strong to severe storms are expected to enter from the west this evening. Storm strength is expected to wane in the early morning hours with activity exiting the region Tuesday morning. As the front crosses the Northland, expect a wind shift from out of the south to out of the west.

See the Fire Weather Forecast product for a more thorough breakdown of fire weather conditions.

DLH WATCHES/WARNINGS/ADVISORIES
MN...None.
WI...None.
MARINE...Small Craft Advisory from 10 PM this evening to 8 AM CDT Tuesday for LSZ121-144>148-150.
Small Craft Advisory from 1 AM to 8 AM CDT Tuesday for LSZ140.