textproduct: Duluth

KEY MESSAGES

- A Freeze Warning has been issued for tonight for areas from Duluth to Brainerd on north, where temperatures will drop into the lower 30s and threaten sensitive vegetation. A Frost Advisory has been issued for areas to the south.

- Cool temps continue through midweek with a warming trend into the weekend.

- Near-critical fire weather conditions may develop on Thursday due to relative humidity dropping to 25 percent and gusty south winds up to 20 mph.

UPDATE

Issued at 234 AM CDT Wed May 20 2026

For the overnight hours and early this morning, a blanket of cloud cover is helping to moderate our temperatures. Because of this, temperatures will not get quite as low as previously forecast. However, despite this slight moderation, most areas within the current headlines will still see those frost and freeze conditions. Make sure tender plants and sensitive vegetation remain protected through the early morning hours.

DISCUSSION

Issued at 252 PM CDT Tue May 19 2026

For the rest of this afternoon, chilly and cloudy conditions will persist across the Northland with scattered rain showers/sprinkles. Temperatures tonight will highly depend on the cloud cover. Satellite imagery shows a cellular nature to the clouds, which have broken out best over north-central Minnesota, but the cumulus field still extends well to the west and south. This creates a classic spring conundrum for overnight low temperatures when the mean of guidance is near freezing. High confidence exists for clearing and colder temperatures in the southwestern sections of our region, while lower confidence remains for the Arrowhead and northwest Wisconsin. Am least confident (40-60%) in getting below 35 degrees over northwest Wisconsin due to the cloud cover, so have issued a Frost Advisory for all of northwest Wisconsin and Pine County in Minnesota. Around the Brainerd Lakes, I have the most confidence they will clear out and have gone below guidance with min temps around freezing. Farther north and into the Arrowhead, confidence in cloud cover lowers again, but the incoming air is cold enough I still have high confidence in freezing temperatures. A Freeze Warning has been issued tonight for areas from Duluth to Brainerd and northward, where temperatures will drop into the lower 30s.

Wednesday will give us a sunny and milder day with afternoon high temperatures in the upper 50s to lower 60s, with cooler conditions near Lake Superior. Clear skies Wednesday night will allow for rapid cooling once again, leading to another night of patchy frost across the area with lows in the mid 30s. Frost Advisories are possible, even likely Wednesday night into Thursday morning. On Thursday, high pressure departs to the east, bringing sunny skies, southerly winds warmer temperatures which continue into Friday. Highs both days should get into the 60s with upper 50s near Lake Superior.

Rain chances return Friday night through Saturday as an upper level trough moves out of the Northern Plains and across the Great Lakes. Mostly cloudy skies and damp conditions will keep Saturday highs in the mid 50s to mid 60s. Upper level ridging to our west and southerly flow across the region will bring a surge of much warmer temperatures to the region for the rest of the Memorial Day weekend. I expect highs on Monday to be well above normal. However, this will be a fairly active pattern with shortwaves likely to dive through this upper level pattern, and we also have some chances for afternoon and evening showers and thunderstorms.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 608 AM CDT Wed May 20 2026

VFR conditions expected today. Winds will be light and variable until a lake breeze moves into DLH this afternoon and leads to some brief gusty winds out of the east to southeast. Winds will settle again in the evening and overnight.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 234 AM CDT Wed May 20 2026

Northwest winds will gradually back to the southeast and east across Western Lake Superior today, remaining below ten knots with waves of one foot or less. East winds will persist on Thursday, gradually increasing to 10 to 15 knots while waves remain below three feet. Stronger winds and building waves are anticipated by Friday and Saturday as a low pressure system approaches.

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

FIRE WEATHER

Issued at 234 AM CDT Wed May 20 2026

Northwest winds early this morning will remain light and variable today under high pressure. Minimum relative humidity this afternoon will drop below 30 percent for much of the Northland, with some areas seeing below 25 percent in northeast Minnesota. A lake breeze will move inland from Lake Superior in the early afternoon, leading to a quick wind shift, a shot of cold air, and rising relative humidity values in a short amount of time. Fire weather concerns significantly increase on Thursday. Gusty south winds up to 20 mph will combine with minimum relative humidity values falling to 25 percent. The most critical conditions are expected from the northern border southward through the Brainerd Lakes. Moisture returns by Friday, bringing humidity values above 30 percent.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Freeze Warning until 8 AM CDT this morning for MNZ010>012- 018>021-025-026-033>037. Frost Advisory until 8 AM CDT this morning for MNZ038. WI...Frost Advisory until 8 AM CDT this morning for WIZ001>004- 006>009. MARINE...None.