textproduct: Duluth

KEY MESSAGES

Listed Chronologically - largest event of the forecast at the end.

- Light snow moves into the Arrowhead this evening and overnight, producing minor accumulations of around 1 to 2 inches in Cook County.

- Dangerous marine conditions develop tonight on Lake Superior with Gale Warnings and Heavy Freezing Spray Warnings in effect.

- A warming trend begins Monday, peaking Tuesday with highs reaching the upper 30s and even the mid 40s across the Northland.

- A potent storm system targets the region Wednesday night into Thursday, bringing strong winds and a messy mix of rain and snow.

DISCUSSION

Issued at 128 PM CST Sun Dec 14 2025

Arctic high pressure is slowly shifting away from the region this afternoon. Temperatures will struggle to climb out of the single digits across much of the Northland for the rest of the day. Despite the sunshine, wind chills remain biting, hovering between 10 and 20 degrees below zero. If you are heading out, continue to dress in layers. As the high center drifts east, we will see winds turn southwesterly, marking the beginning of a significant pattern change.

A weak weather disturbance tracks across Ontario tonight, clipping the Arrowhead region. This will bring a quick shot of snow to areas north of the Iron Range, with the tip of the Arrowhead potentially seeing up to 2 inches of accumulation. Elsewhere, clouds will increase but precipitation should remain sparse. Southerly surface winds will be gusty and prevent temperatures from bottoming out as severely as previous nights.

The big story for the start of the work week is the warm up. Forecast guidance pushes warmer air into the region starting Monday, with highs reaching the teens and 20s. By Tuesday, an Alberta Clipper passing well to our north will allow even warmer air into the area, likely pushing temperatures into the 30s to mid 40s. This will feel significantly milder than recent days.

This warmth sets the stage for a dynamic mid-week system. A strong low pressure system is expected to impact the region Wednesday night through Thursday. With mild air in place, precipitation may start as rain or a wintry mix before transitioning to snow. Strong winds are also likely with this system, making for hazardous travel conditions. Plenty of moisture content streaming from the anonymously rich Pac NW moisture stream. One thing to keep an eye on is if it taps into the Gulf moisture before it impacts the Northland or after it passes to the east of us. That's the largest variable in the equation that we need to figure out as it will drastically change the QPF expected from this system. The good news is that the signal for this system is pretty consistent among guidance, so its likelihood of occurrence is high just don't know the specifics on QPF amounts and the temperature profiles. In addition to the precipitation potential, a lot of guidance is suggesting storm force wind gusts on Lake Superior with this system with a 70 kt 850 mb LLJ wrapping around the system which is extremely strong with a 30 year return interval in NAEFS climatology.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 536 PM CST Sun Dec 14 2025

A strong wave is moving across the Northland this evening, with mid and high level clouds and gusty southwest winds. With a strong LLJ this evening, surface wind gusts of 20-30kts will be possible, before winds diminish slightly overnight. LLWS is possible, mainly at INL, as the LLJ is strong and surface winds slightly weaker than other terminals. Winds further diminish Monday, as high pressure arrives from the northwest.

BKN to OVC skies will persist, with VFR cigs lowering to MVFR at INL and HIB after 06Z, which will gradually improve through Monday morning. Elsewhere, heights will remain at VFR.

MARINE /FOR NEAR SHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 128 PM CST Sun Dec 14 2025

Conditions deteriorate rapidly this evening across western Lake Superior. Southwesterly winds will increase significantly, creating dangerous conditions for mariners. Gale force gusts of 35 to 40 knots are expected tonight. Combined with the bitter cold air, heavy freezing spray will develop, capable of rapidly accumulating ice on vessels. Wave heights will build to 4 to 8 feet, with occasional waves over 10 feet along the North Shore. Winds diminish Monday morning but likely ramp up to gales again by Tuesday afternoon.

Storm force winds possible on Thursday!

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...None. WI...None. MARINE...Small Craft Advisory until 6 AM CST Monday for LSZ121. Small Craft Advisory until 9 PM CST this evening for LSZ140>148-150. Gale Warning from 9 PM this evening to 3 AM CST Monday for LSZ140>148-150. Heavy Freezing Spray Warning from 9 PM this evening to 3 AM CST Monday for LSZ145>147-150.