textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Another Arctic cold front will push east through the area later this afternoon and evening, bringing a locally heavy and fast moving snow band. The snow band may greatly reduce visibility quickly and cause hazardous driving conditions for the evening commute. Snowfall accumulations of 1 to 2 inches are expected, with some potential for a narrow band of 2 to 3 inches west of Madison. In addition, gusty west northwest winds behind the front will cause some blowing snow tonight.

- Flurries/light snow may linger on Thursday. - Bitter cold temperatures and wind chills are likely Thursday night into the weekend. An Extreme Cold Watch remains in effect from 12 AM CST Friday until 12 PM CST Saturday for 30 below zero and colder wind chills.

UPDATE

Issued 1035 AM CST Wed Jan 21 2026

Keeping an eye on an approaching area of snow from the west. Current guidance suggests that snow showers will move from west to east over southern WI between 3pm and 8pm, with some potential for a more intense localized F-gen band of snow to occur somewhere over the area. Current guidance suggests the f-gen band will move through Iowa and far western Dane Counties, where some higher snow totals between 2-3 inches may occur this afternoon and evening. Elsewhere, 1-2 inches are expected this evening with the highest totals near 2 inches along the I-94 corridor.

CMiller

SHORT TERM

Issued 434 AM CST Wed Jan 21 2026

Today through Thursday:

The Winter Weather Advisory remains in effect until 6 AM CST this morning for areas along and south of the Highway 18 and Interstate 94 corridor. The west to east band of low level frontogenesis response has pushed east northeast through southern portions of the area, and should gradually push east northeast out of the area over the next few hours.

The rest of the area should see the light snow end from west to east during this time period as well, with the main differential CVA and low level jet nose shifting to the east. Another half inch to inch of snowfall may occur within the frontogenesis response band, with lower amounts elsewhere. Snow covered and slippery roads are expected, and may affect the early morning commute.

There should be a lull in the precipitation this morning into early this afternoon, as winds shift southwest and start to increase.

An Arctic cold front is then expected to shift east across the area later this afternoon and evening, with gusty west northwest winds behind it developing. A potent 500 mb shortwave trough will accompany the front, with forecast soundings saturating in the low levels with steep lapse rates within the dendrite snow growth zone.

There is some weak instability along the front possible, and the snow squall parameter from various models continues to be between 1 and 2 or more as the front moves through the area. Thus, there is the potential for intense snow showers or snow squalls to occur during this period, mainly between 4 PM this afternoon and 10 PM CST this evening. A quick inch or two of snow accumulation could occur within the more intense snow showers.

Rapidly decreased visibility and brief heavy snowfall rates are possible with these intense/convective snow showers. In addition, the gusty west northwest winds behind the front will bring some blowing snow into tonight. This will affect the evening commute. The day shift may need to consider a Winter Weather Advisory for this period, given the possible impacts. Snow squall potential will also need to be monitored.

There is some potential for more snow showers Thursday afternoon, with yet another Arctic cold front moving southeast through the area. Added 20 percent chances for snow showers for Thursday afternoon, and may need higher PoPs in later forecasts if another convective snow shower setup occurs.

Wind chills may drop into the 10 to 15 below zero range later tonight into Thursday morning period, with the gusty winds and lows in the single digits above zero.

Wood

LONG TERM

Issued 434 AM CST Wed Jan 21 2026

Thursday night through Tuesday:

Synopsis: An area of upper low pressure will drive into the western Great Lakes Thursday afternoon into Friday, progressing east into the Saint Lawrence Valley by early Saturday morning. An attendant surface wind response will act to drive the strongest Arctic front of the recent cold snap through southern Wisconsin in the process, delivering the chilliest temperatures and wind chills of the season-to-date Thursday night through Saturday morning.

Overnight temperatures will fall into the 10 below to 20 below zero range during this time frame, with minimum wind chills plummeting to between 30 below and 40 below zero across the region. An Extreme Cold Watch remains in effect for all of southern Wisconsin between 12 AM CST Friday and 12 PM CST Saturday, with eventual Extreme Cold Warnings anticipated in coming forecasts.

Some temperature and wind chill moderation will occur Saturday night through Monday, though portions of the area could continue to approach/meet Cold Weather Advisory thresholds during the overnight periods. Advisory level cold may finally break by the Monday night/Tuesday time frame. With Arctic high pressure being the predominant surface feature, precipitation chances appear low through most if not all of the long term period.

Thursday Night through Saturday: A bitterly cold air mass remains on track to settle into southern Wisconsin, leading to frigid and potentially dangerous conditions for those caught outdoors without proper layers/winter clothing. The coldest overall time frame appears to be Thursday night through Friday morning, when the core of a -25 to -30 degree 850 mb air mass will be drifting overhead, though wind chills are expected to remain near or below Extreme Cold Warning thresholds into Saturday morning.

An Extreme Cold Watch thus remains in effect for all southern Wisconsin counties between 12 AM CST Friday and 12 PM CST Saturday, with Extreme Cold Warnings anticipated over the next 12 to 24 hours. Current forecast from the NBM remains reasonable, showing widespread wind chills between 30 below and 40 below zero Thursday night/Friday morning and near/just below 30 below zero Friday night/Saturday morning. Will nevertheless be monitoring for additional downward trends in coming forecasts, particularly during the Thursday night/Friday morning period.

If at all possible, limit time outdoors Thursday night through Saturday morning, as it will take little time for frostbite to set in on unexposed skin. If being outside is absolutely necessary, be sure to dress in multiple layers and limit any areas of unexposed skin.

Saturday Night through Tuesday: Temperatures and wind chills should climb away from Extreme Cold Warning thresholds on Saturday afternoon, though additional periods of wind chills near or below Cold Weather Advisory thresholds will linger during the overnight periods Saturday night into Sunday and Sunday night into Monday. Will thus be monitoring for additional cold weather headlines as this part of period draws closer.

Expect dry conditions for the majority/all of southern Wisconsin, though global ensemble and deterministic model guidance hints at lake effect snow band development over western Lake Michigan Saturday night through Sunday morning. Whether the band materializes, and whether low level flow would steer it into southeast Wisconsin, remain uncertain.

Have thus maintained slight chance to chance precip probs (about 15 to 25 percent) near the lakeshore in the overnight update, with the understanding that values will continue to fluctuate (or drop out entirely) over coming forecasts. Will continue to watch trends.

Quigley

AVIATION

Issued 1040 AM CST Wed Jan 21 2026

MVFR ceilings will persist into tonight with ceilings lowering as a fast moving area of snow moves over southern WI between 21Z and 03Z Thurs. Some of the snow may be briefly heavy from Madison, westward. Immediately following the snow, strong northwest winds will between 25 and 30 knots overnight, easing before 12Z Thursday.

CMiller

MARINE

Issued 434 AM CST Wed Jan 21 2026

Weak low pressure around 30.0 inches will move across southern Lake Michigan this morning, with increasing westerly winds behind it this afternoon. Stronger west to northwest winds are expected late this afternoon and this evening, behind a passing Arctic cold front, as a more organized low pressure system around 29.6 inches moves across Lake Superior.

Gale force gusts are expected over the southern half of the open waters of Lake Michigan, where a Gale Warning is in effect later this afternoon into early Thursday morning. Gusty west to northwest winds Thursday will will turn mainly northwest Friday, as strong high pressure around 31.0 inches builds into the northern Great Plains. A few gale force gusts may occur during this period over the open waters.

A Small Craft Advisory is in effect for the nearshore waters of Lake Michigan from later this afternoon through Friday afternoon, for gusty west to northwest winds.

Arriving Arctic air and elevated wave heights will support additional periods of heavy freezing spray Wednesday night into Friday night across the open waters of the lake. A Heavy Freezing Spray Warning is in effect for this period.

The high will shift into Wisconsin by Saturday, with gradually lighter winds across Lake Michigan.

Wood

MKX WATCHES/WARNINGS/ADVISORIES

WI...Extreme Cold Watch...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066- WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...midnight Friday to noon Saturday.

LM...Gale Warning...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777- LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...3 PM Wednesday to 6 AM Thursday.

Heavy Freezing Spray Warning...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876- LMZ878...9 PM Wednesday to 3 AM Saturday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...3 PM Wednesday to 6 PM Friday.