Marine Weather and Tide Forecast for Cornucopia, WI

DISCUSSION
Issued at 342 PM CST Mon Jan 19 2026

Colder air arrived and will be with us for a while. There will be a few days during the next week or two where temps warm up while still remaining below normal. Wednesday will be one example when we are /only/ 7 to 12 degrees below normal for high temps (forecast temps middle single digits in the Arrowhead to teens above zero in central MN east through the St. Croix Valley). Next Monday may be only around 10 degrees below normal, too. The airmass moving in for Thursday and Friday appears to be the coldest the Northland has experienced since 2021.
Fortunately the coldest air will be short-lived arriving Thursday night and departing Saturday. Actual air temperatures will approach -40 in northern Minnesota and around -30 in central Minnesota and northwest Wisconisn. A prolonged period of cold weather alerts will be needed.

A weak trough will pivot through the region tonight. Thin stratus was producing light snow showers and flurries over northeast Minnesota, northwest Ontario, and southeast Manitoba today and will continue to generate a few snowflakes tonight.
Overnight skies will eventually clear starting over central and north-central Minnesota which should allow for radiational cooling. Nudged temperatures below the NBM guidance for tonight closer to the 50th percentile (which was several degrees colder than the deterministic NBM). The 25th percentile is colder again by 2 to 5 degrees. Depending on how quickly clouds depart and winds weaken, some areas may dip into the 30s below zero tonight. Dangerous wind chills of -25 to near -40 are forecast tonight. Cold Weather Advisories remain in effect for the Northland until noon Tuesday.

A weak clipper will pass through the region Tuesday night and Wednesday and will bring a brief period of warmer temperatures with highs Wednesday in the single digits to middle teens above zero. That system will have little moisture for snow. Despite the limited moisture, it's likely most of the area will see at least a few flakes. Accumulation should be less than an inch.

The Arctic surge begins to arrive Thursday. High temperatures will range from the low single figures above zero in northwest Wisconsin to around -10 degrees in north-central Minnesota, 20 to 30 degrees below normal. Overnight lows Thursday night will range from the middle 20s below zero along the South Shore to near 40 below zero in north-central Minnesota. Highs Friday will be in the teens below zero except along the South Shore where single digits below zero are forecast. Friday night will be the coldest of this stretch with lows generally from -25 to -42.
Looking back through the archives, this seems to be the coldest temperatures the Northland experienced since January and February 2021. Extreme Cold Warnings will likely be needed for the dangerous cold and wind chills.

Temperatures trend slightly warmer for the weekend while staying well below normal. A clipper Sunday night and Monday will bring a slight chance of light snow and will help Monday be the second warmest day of the next 7. The longer range outlooks continue to indicate below normal temperatures out to early February. There will likely be some warmer days during that stretch. Additional Arctic outbreaks remain possible as the Arctic Oscillation (AO) remains in it's negative phase into early February. Ensemble guidance points to the AO phase trending toward neutral during the first week in February which would help keep Arctic air closer to the pole.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
Issued at 1124 PM CST Mon Jan 19 2026

VFR conditions with clear skies are largely expected through much of the first 12 hours of this TAF period. There will be off and on MVFR stratus decks moving through the Range and Arrowhead into 12-15Z this morning and may affect HIB periodically. Lake effect snow showers will bring both MVFR visibility and ceilings to the Bayfield Peninsula and snowbelts into Tuesday daytime. A clipper to the south builds VFR ceilings back in 18Z and afterward through 00Z. As lower level moisture saturates areas in the far southern parts of the Northland around and after 00Z, BRD and HYR may see MVFR ceilings. A light dusting of snowfall is forecast though at least for those terminals to end this TAF period. A trace may also impact DLH and HIB as well though too so light snow was placed in those terminal TAFs too on the pessimistic side of this southern clipper.

MARINE /FOR NEARSHORE WATERS OF WESTERN LAKE SUPERIOR/
Issued at 342 PM CST Mon Jan 19 2026

Gusty west winds veer northwesterly tonight and gradually weaken. Small Craft Advisories for most of the waters expire at 10 PM tonight. Areas from Grand Portage to Silver Bay is in effect until 10 AM Tuesday and the Outer Apostle Islands runs until 4 PM Tuesday. Heavy freezing spray will remain a risk along the South Shore until 10 PM tonight. Gusty winds return Wednesday night and Thursday. The risk of heavy freezing spray will increase once again as will the risk to smaller vessels.
Bitterly cold Arctic air will pour over the waters Thursday night through Saturday morning which may create sea smoke, snow showers, reduced visibility, and icing conditions.

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

DLH WATCHES/WARNINGS/ADVISORIES
MN...Cold Weather Advisory until noon CST Tuesday for MNZ010>012- 018>021-025-026-033>038.
WI...Cold Weather Advisory until noon CST Tuesday for WIZ001>004- 006>009.
MARINE...Small Craft Advisory until 10 AM CST Tuesday for LSZ140>142.
Cold Weather Advisory until noon CST Tuesday for LSZ142.
Small Craft Advisory until 4 PM CST Tuesday for LSZ150.