textproduct: Duluth

KEY MESSAGES

- Winter Weather Advisory continues for Iron County, WI. Expect an additional 1-4" between 2 PM and midnight tonight.

- Flurries and a few stronger snow showers are expected this afternoon over northeast Minnesota and inland portions of northwest Wisconsin.

- Clipper system Tuesday will bring a short period of snow. Snowfall rates may be heavy at times Tuesday with visibility less than 1/4 mile. Winter Storm Watch issued for southern Cook County.

DISCUSSION

Issued at 327 PM CST Sun Feb 22 2026

A broad 300 mb cutoff low was located over the central Great Lakes this afternoon. Several lobes of vorticity were evident on GOES-East water vapor imagery. An area of channelized vorticity was located over Minnesota and is forecast to propagate southeastward through this evening. Morning stratus has given way to partial clearing over north-central and central Minnesota east into the I-35 corridor. Another area of stratus was over the Arrowhead and was advancing southwestward. Lake-effect snow continued over portions of northwest Wisconsin. In the areas where partial clearing developed, a small amount (10-30 J/kg) of surface-based instability was found. GOES-East Band 2 imagery revealed horizontal convective rolls over those areas. The rolls are too shallow to produce sustained light snow although flurries are likely. With a few more hours of sunshine ahead instability may become sufficient for the convection to deepen more persistent light snow showers.

Lake-effect snow continues through tonight and will gradually weaken in intensity. An additional 1 to 4 inches of snow are forecast for northern Iron County through early Monday morning. As high pressure drifts southeastward across the Northland, look for drier air, weakening winds, and increased shear over western Lake Superior to taper the snow down to flurries. Winter Weather Advisory remains in effect until midnight for Iron County. Light snow showers and flurries will persists downstream of Lake Superior into this evening for the remainder of northwest Wisconsin.

High pressure will drift farther eastward on Monday with winds turning southerly. A convergence band of light snow may develop over western Lake Superior in response to the changing wind direction and gradually strengthening flow ahead of a Monday night and Tuesday clipper. The band of snow will migrate northward and produce light snow along portions of the North Shore from near Two Harbors to Grand Marais. Accumulation during the afternoon and early evening will be light, less than an inch.

A fast-moving clipper will move through the region Monday night and Tuesday. NAEFS ensemble mean sea level pressure will be anomalously low by Tuesday evening and will approach the 5th percentile of CFSR climatology. NAM and RAP 3-hour pressure change is forecast to be 6 to 9 millibars as the low passes over northern Minnesota. Strong frontogenesis is forecast to accompany the system and will provide enhanced forcing for ascent from early Tuesday morning through early Tuesday afternoon. NAM is slower and better organized than the other models while the GFS features a faster and less amplified system. The NAM solution has similarities to the ECMWF and the Canadian GPDS. ECMWF ensembles feature a tight cluster in low pressure centers while the GEPS and GEFS have less agreement. All models feature a fast-moving low and a stripe of accumulating snow for northern Minnesota into northwest Wisconsin.

Southerly winds will produce onshore flow from Grand Marais to Grand Portage Tuesday which will generate additional orographic ascent in addition to the dynamic forcing of the clipper. We expect several hours of 1+ inch per hour snow rates in those areas. Snow ratios will be in the 12-16:1 range during that time, closer to climatological averages for late February than last week's system. Thus the snow consistency will be lighter and less dense. Snow rates of 1+ inch per hour are likely elsewhere farther west as the frontogenesis moves eastward. Widespread visibility of less than 1/4 mile are likely during the period of the heaviest snow Tuesday morning. We issued a Winter Storm Watch for southern/lakeshore portions of Cook County with this forecast package. Favorable forcing, temperature profiles, and lake-enhancement suggest total snow in that area of 3 to 8 inches. NBM probabilities of more than 6 inches of snow are maximized east of Grand Marais and extend to near Grand Portage. If winds don't veer as much Tuesday, the axis of heaviest snow would shift farther south along the shore. Areas farther inland and over portions of northwest Wisconsin will likely need a Winter Weather Advisory with later updates.

Snow is expected to taper off quickly as the compact system departs the region late Tuesday afternoon and Tuesday evening. Another shortwave trough will move out of the northern Rockies and into the Plains Wednesday. That wave is expected to produce another swath of light snow as it passes. The latest forecasts generally keep that snow farther south and may miss the Northland completely. For now we continue to carry snow chances generally south of US-2 in Minnesota and Wisconsin Wednesday afternoon through early Thursday morning.

The Northland will remain under an active weather pattern through next weekend. A thermal gradient will wobble north and then south as several shortwave troughs pass over the region for the second half of next week through next weekend. Temperatures will trend warmer Thursday and Friday and then likely cooler next weekend. There will be additional chances of light snow through the period, though no major storm systems appear on the horizon.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 1202 PM CST Sun Feb 22 2026

MVFR stratus over terminals will continue to mix out. Still expect snow showers to develop and be accompanied by MVFR ceilings and visibility. Opted for TEMPOs where confidence is higher while maintaining PROB30 elsewhere. High pressure over Manitoba will propagate southeastward through the region tonight and Monday with a period of VFR conditions expected. A fast- moving clipper will bring a period of MVFR to IFR visibility Monday night and Tuesday (24.06Z until 24.22Z).

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/

Issued at 327 PM CST Sun Feb 22 2026

North winds this afternoon will veer north-northeasterly tonight and gradually weaken as high pressure builds in from the west. Wind gusts of 25 to 30 knots (with occasional gales to 35 knots near Grand Marais) will slowly dwindle tonight. Conditions remain hazardous for smaller vessels. In addition to the winds and waves, heavy freezing spray is likely north and east of the Apostle Islands. A fast-moving clipper system will move across the region Monday night and Tuesday. Winds will be strong both ahead of and behind the system. Gales of 35 to 40 knots may develop along portions of the North Shore Tuesday morning. The greatest chance of gales will be from Silver Bay to Grand Portage.

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

DLH WATCHES/WARNINGS/ADVISORIES

MN...Winter Storm Watch from late Monday night through Tuesday afternoon for MNZ021. WI...Winter Weather Advisory until midnight CST tonight for WIZ004. MARINE...Small Craft Advisory until 8 AM CST Monday for LSZ140. Small Craft Advisory until midnight CST tonight for LSZ141>146. Small Craft Advisory until 6 AM CST Monday for LSZ148-150. Heavy Freezing Spray Warning until 6 AM CST Monday for LSZ150.