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.

UPDATE

Issued 920 PM CST Mon Jan 19 2026

Forecast remains on track this evening. High pressure is moving in from the Northern Plains, and will allow winds to continue to taper through the overnight hours. Under mostly clear skies, this will result in another night of very chilly conditions across southern Wisconsin. Lighter overall winds will keep wind chills 5-10 degrees above last night's readings in most locations, with all of the area on track to get through the overnight without any cold weather headlines. Will nevertheless be monitoring wind chill trends over northern counties, where a few locations could see wind chills briefly dropping to near -20 through daybreak.

Quigley

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 920 PM CST Mon Jan 19 2026

VFR flight categories prevail through the majority of the period at all southern Wisconsin terminals. Winds will continue to taper overnight as high pressure moves in from the west. The high will progress eastward tomorrow, allowing winds to shift out of the southwest by the afternoon hours. Mid-level clouds will thicken during the late afternoon hours ahead of an approaching disturbance. Said disturbance will bring chances for SN near the end of the 30 hour period at KMKE, and just beyond the current 24 hour period at all other fields. Have thus accounted for SN potential at KMKE in the 00Z forecast, with mentions becoming necessary at other terminals in the coming 06Z update. Expect VIS reductions to accompany SN, which will likely lead to periods of at least MVFR flight categories Tuesday evening.

Quigley

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...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.

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