textproduct: Duluth

KEY MESSAGES

- Fog is expected again tonight. Dense fog possible at the Twin Ports off Lake Superior. A Dense Fog Advisory is in effect for the Twin Ports until noon Thursday.

- A Colorado low will bring a mix of precipitation, with a few rumbles of thunder possible during the day. Snowfall expected Friday night.

- A roller coaster of temperatures continue throughout this week.

UPDATE

Issued at 541 PM CST Wed Mar 4 2026

Fog and low stratus rolled southeastward off of Lake Superior within the past hour. Visibility dropped to less than 1/4 mile at DYT and 1/4 mile at SUW. DLH was at 1/16 mile as of 530 PM. We issued a Dense Fog Advisory for the Twin Ports area until noon Thursday. We will likely need to expand the advisory later tonight. The timing and area of the extension is yet to be determined. Radiational cooling and daytime max dewpoints in the middle to upper 30s should result in fog becoming widespread later tonight. The main question is whether surface winds will remain strong enough to mix the boundary layer.

DISCUSSION

Issued at 228 PM CST Wed Mar 4 2026

Weather conditions across the Northland will remain relatively quiet through this afternoon as fog from this morning continues to dissipate. However, this clearing will be short-lived. As winds turn to the northeast off Lake Superior tonight, moisture will become trapped near the surface. This will cause patchy dense fog and freezing fog to reform across much of the region, with the most significant visibility reductions expected near the head of Lake Superior and the Twin Ports.

Fog will likely linger through much of Thursday morning before slowly lifting. Temperatures on Thursday will stay mild inland, but the North Shore will see much cooler conditions due to the onshore breeze. Our attention then shifts to a powerful spring storm system developing over Colorado. This low-pressure system will track toward the Great Lakes, bringing a variety of weather hazards to our region starting late Thursday night and continuing through Saturday morning.

Rain will spread over the area early Friday morning. In northwest Wisconsin and as far west as the Brainerd Lakes, enough instability may exist for a few rumbles of thunder Friday afternoon and into the evening. Along the higher terrain of the North Shore, a layer of warm air aloft could lead to a period of freezing rain before temperatures fall, but latest trends show that window becoming short, so a clean transition from rain to snow is more likely with this system as colder air moves in Friday night. While many areas are expected to see 1 to 3 inches of slushy accumulation, we are closely monitoring the potential for a narrow band of heavy snow depending on the track and the strength of the system. If this band develops, some areas in northern Minnesota could see up to 8 inches of snow by Saturday morning. Additionally, the combination of rain and melting snow will create significant runoff, leading to ponding of water in low-lying areas where the ground remains frozen.

Conditions will turn cooler on Saturday, though temperatures will stay above freezing. Another warm-up is expected early next week, with highs returning to the 40s and 50s on Sunday and Monday. A more significant cold air mass is then projected to settle over the area by the middle of next week, bringing temperatures back closer to seasonal normals along with continued chances for active weather.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 541 PM CST Wed Mar 4 2026

Warm temperature for most locations once again today pushed afternoon dewpoints into the middle and upper 30s. Radiational cooling tonight should support low stratus and fog development at the terminals. Onshore winds from Lake Superior brought saturated marine layer air into the Twin Ports during the past hour. DLH reported 1/16 mile visibility. Expect the poor conditions to persist through the night perhaps into Thursday afternoon. Elsewhere the concern is mainly IFR/LIFR ceilings. Winds may remain strong enough to limit fog potential.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 228 PM CST Wed Mar 4 2026

Relatively quiet conditions will persist through this afternoon on western Lake Superior with waves under 2 feet. Fog is expected to redevelop tonight across western Lake Superior. Some areas may be dense. Northeast winds will increase significantly tonight and Thursday to 20 to 25 knots with gusts up to 30 knots. A Small Craft Advisory is in effect this evening until tomorrow afternoon. Waves will build to 4 to 8 feet, especially along the North Shore and the Twin Ports.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Dense Fog Advisory until noon CST Thursday for MNZ037. WI...Dense Fog Advisory until noon CST Thursday for WIZ001. MARINE...Small Craft Advisory until 4 PM CST Thursday for LSZ121- 140>148-150.