textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Wind chills in the teens below zero are expected to continue into Tuesday morning. - A Gale Warning remains in effect for all of Lake Michigan through late this afternoon. A Heavy Freezing Spray Warning remains in effect as well through Tuesday morning.

- Accumulating snow is expected Tuesday night (90% chances), with amounts in the ballpark of 2 to 4 inches. There are 10-40% chances for light snow to linger (or briefly redevelop) Wednesday into Wednesday evening. - Bitter cold temperatures and wind chills are looking likely Thursday night into the weekend.

SHORT TERM

Issued 250 PM CST Mon Jan 19 2026

Tonight through Wednesday:

Breezy west winds continue to gradually subside through this afternoon and evening as high pressure settles into the southern Plains / lower Mississippi Valley, with continued dry weather through tonight and the daytime hours of Tuesday. Thin high altitude cloud cover will move through the region at times tonight, but with periods of clear skies allowing for plenty of radiational cooling (overnight low temps in the single digits below zero tonight) allowing wind chills to remain in the teens below zero into Tuesday morning. Despite plenty of sunshine Tuesday morning, temperatures are slow to respond due to the existing snow cover (high temps in the mid teens Tuesday afternoon, with wind chills in the positive single digits to around 10). Cloud cover then begins to increase Tuesday afternoon ahead of the next system.

A clipper system tracks eastward across the region Tuesday night, with an arrival window of roughly 8 PM to 11 PM CST Tuesday evening. Between then and around daybreak Wednesday morning, roughly 2 to 4 inches of snowfall is expected, with a very light and powdery texture (high SLR). Most models resolve a weak dry slot wrapping into the system (and passing overhead) through the daytime hours of Wednesday, leading to a lull in the snow. We did leave 10-35% chances for continued light snow in the forecast through the daytime Wednesday in case the system's 500mb PVA were to produce some additional light accumulations. 45% light snow chances return on the back side of the clipper system as it's associated cold front swings through Wednesday evening (discussed in the LONG TERM section).

Stay tuned to Tuesday night's snow forecast in case details change. The latest model guidance has trended further and further south with the axis of highest snowfall (placing it more or less overhead), though this trend could certainly continue or reverse.

Sheppard

LONG TERM

Issued 250 PM CST Mon Jan 19 2026

Wednesday night through Monday:

Early in the evening there may be some additional light snow across parts of southern WI as a cold front swings through the region. Some upper level PVA/moisture, closer to around 600mb according to forecast soundings and some additional forcing around 800mb in the DGZ will be the main forcing mechanisms for snowfall in addition to the front. However, by mid evening we will quickly start to see the atmosphere dry out around us as the cold front ushers in a much cooler air mass. Wednesday night may feature some lingering flurries but mostly due to some lingering near surface moisture with the DGZ at or near the surface. Thursday morning forecast sounding actually show an even better chance for flurries given some better low level moisture all right at the surface in the DGZ, despite the high pressure pushing in.

The strongest region of high pressure is not expected to push in until later Thursday/Thursday night. By then we will see the atmosphere dry out significantly as the frigid air mass pushes in with thicknesses in the 485-500dm range Thursday night. Temperatures will fall to the negative teens Thursday night/Friday morning with wind chills in the -25 to -35 range with similar conditions into Friday night/Saturday morning. During the day Friday will also remain frigid with max apparent temps in the -15 to -25 range. This will start to improve, if only gradually, Saturday night as the thicknesses across the region improve to the 505-515dm range by Sunday morning. Temperatures will remain frigid with wind chills Sunday morning in the -20 to -30 range but the gradual shift back toward slightly warmer temperatures will continue into early next week.

Overall the extended includes very little in the way of precipitation due to the extremely dry temperatures and cold with strong high pressure and strong troughing over the region with no moisture in the profile. Precip concerns may return toward early next week but in all likelihood we may very well remain dry beyond as additional bouts of cold and dry air masses swing through the region though there is uncertainty at this stage that may play significant roles in exactly how next week plays out.

Kuroski

AVIATION

Issued 250 PM CST Mon Jan 19 2026

Currently looking at clear skies and VFR across southern WI, with some 10,000 to 15,000 ft SCT/BKN high altitude clouds attempting to push in from the northwest. Dry weather and VFR expected through tonight and the daytime hours of Tuesday. Gradually decelerating west winds tonight, followed by light southwest winds into Tuesday. High altitude clouds gradually increase in coverage and thicken Tuesday afternoon as the next system approaches, though ceilings should remain VFR through at least a few hours after sunset Tuesday evening.

Accumulating snowfall (in the ballpark of 2 to 4 inches) is then expected later Tuesday evening through around dawn Wednesday, with chances for lighter snow and flurries to linger thereafter. Ceilings and visibility will fall as the snow starts, with an arrival window of roughly 8 PM to 11 PM CST Tuesday evening for the snow. Light and powdery snow texture.

Sheppard

MARINE

Issued 250 PM CST Mon Jan 19 2026

Low pressure will move from eastern Ontario today into Quebec this evening. Widespread gales are expected through the rest of the day, with a Gale Warning in effect until 6 PM CST this evening for all of Lake Michigan. Gale Warning in the nearshore until 3 PM CST with Small Craft thereafter until 3 AM CST.

Winds will weaken somewhat this evening into early Tuesday morning, as the low moves far enough away with high pressure remaining south of the region. Winds will shift southwesterly Tuesday afternoon, as the high moves into the Mid-Atlantic. Elevated waves and arriving Arctic air will lead to areas of heavy freezing spray through Tuesday morning. A Heavy Freezing Spray Warning remains in effect until Noon CST Tuesday for all of Lake Michigan.

West to southwest winds will continue into Wednesday, as low pressure passes across the lake. Winds will increase further and shift west to northwest Wednesday night, as another Arctic cold front crosses Lake Michigan. A few gale force gusts may occur on the eastern side of the lake with small craft conditions likely. Arriving Arctic air and elevated wave heights will support additional periods of moderate to potentially heavy freezing spray Wednesday night into Thursday.

Winds will turn north to northwest Friday, as strong high pressure around 30.8 inches builds into the northern Great Plains.

Kuroski

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Gale Warning...LMZ643-LMZ644-LMZ645-LMZ646 until 3 PM Monday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 3 AM Tuesday.

Gale Warning...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563- LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until 6 PM Monday.

Heavy Freezing Spray Warning...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878 until noon Tuesday.