textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Wind chills in the teens below zero are expected to continue into this morning. - A Heavy Freezing Spray Warning remains in effect through this morning. - A Winter Weather Advisory is in effect from 9 PM CST this evening until 6 AM CST Wednesday morning, mainly along and south of the Highway 18 and Interstate 94 corridor. Snow accumulations of 2 to 5 inches are expected, with locally higher amounts near the Illinois border area. Snow covered and slippery roads are expected.

- Another Arctic cold front will push east through the area later Wednesday into Wednesday evening, bringing the possibility of locally heavy and fast moving snow showers. The best chances would be southwest and south of Madison. These snow showers may greatly reduce visibility quickly and cause hazardous driving conditions. - Bitter cold temperatures and wind chills are likely Thursday night into the weekend.

UPDATE

Issued 1045 AM CST Tue Jan 20 2026

No major changes in the forecast thus far though I have ticked down snow ratios and QPF, primarily because while the DGZ may be deep the forcing in the DGZ is not overly strong and there are some gusty winds in the highest portions of the DGZ. As for QPF the tick down is largely due to a slight ticked down in the QPF from the CAMs. In either case the snow looks largely expected to impact the southern 2 tiers of counties in the CWA.

In addition, expect another quick round of accumulating snow late Wednesday afternoon through the early evening.

Kuroski

SHORT TERM

Issued 428 AM CST Tue Jan 20 2026

Today through Wednesday night:

Light west winds and temperatures in the single digits below zero will continue to support wind chills in the teens below zero across the area into the morning hours. Winds will shift southwest this afternoon and bring highs into the teens above zero with some weak warm air advection. Clouds will gradually shift into the area later in the day.

A Winter Weather Advisory is in effect from 9 PM CST this evening until 6 AM CST Wednesday morning, mainly along and south of the Highway 18 and Interstate 94 corridor. Models continue to show low pressure shifting east northeast across far northern Illinois later tonight, with the 850 mb low level jet nose pointing northeastward into the Wisconsin/Illinois border area. This area will also see focused warm air advection and a band of 850 mb to 700 mb frontogenesis response develop this evening and linger overnight. Forecast soundings are generally showing fairly deep saturation within the dendrite snow growth zone tapping into the upward vertical motion.

Thus, models have a swath of QPF moving across far southern Wisconsin and the Wisconsin/Illinois border area tonight, exiting Wednesday morning. Snowfall rates from the HREF are generally one quarter to one half inch per hour south, lower to the north. The frontogenesis band may certainly have enhanced snowfall rates of up to 1 inch per hour, depending on where exactly it will set up. There is still uncertainty with where this band will occur.

There is enough confidence in a general 2 to 5 inch snowfall in the southern half of the area to issue the Winter Weather Advisory. Lower amounts are expected further to the north. Snow covered and slippery roads are expected, and the tail end of this event may affect the early morning commute on Wednesday. Further refinements of the heavier swath of snow are anticipated, which may shift a little further north or south of the current forecast.

The snow should taper off west to east by the end of the advisory period, with a temporary lull in the snow activity. Another Arctic cold front will then shift east across the area later Wednesday afternoon into Wednesday evening. This front will have gusty winds along and behind it, with forecast soundings showing saturated and steep low level lapse rates in the dendrite snow growth zone.

The snow squall parameter on the NAM is 3 to 5, with the GFS 1 to 2.5 during this period, with anything over 1 favorable for snow squalls. At the very least, locally heavy and quick moving snow showers may occur in this setup, with snow squall potential. This would bring greatly reduced visibility in a short period of time, leading to hazardous driving conditions. A quick inch of snowfall may occur as well, with the gusty winds perhaps bringing some blowing snow. Will continue to monitor this potential.

West winds with cold air advection behind the front will bring lows into the single digits above zero Wednesday night, with wind chills in the single digits below zero.

Wood

LONG TERM

Issued 428 AM CST Tue Jan 20 2026

Thursday through Monday:

Synopsis: Settling in behind Wednesday evening/night's frontal passage, a renewed surge of Arctic air will move into the western Great Lakes from north central Canada during the Thursday to Friday time frame. It continues to appear that said Arctic air will bring the coldest air of the season-to-date, and perhaps the last several years, to southern Wisconsin through the end of the week. The Thursday night to Sunday time frame will thus be a period to monitor for cold weather headlines in coming forecasts.

Deterministic forecasts from the global guidance suite hint at some additional chances for snow Thursday night into Friday, and once again Saturday evening, though their ensemble-based counterparts are drier in both time periods, due to placement uncertainties regarding responsible forcing mechanisms. Will continue to monitor trends and provide additional details should greater agreement on snow during the Thursday night into Friday and/or later Saturday time periods become more apparent.

Thursday through Sunday: A prolonged stretch of bitterly cold to at times dangerous cold is on track to settle into southern Wisconsin. Deterministic forecasts continue to depict an area of 25 below to 30 below zero Fahrenheit 850 mb temps moving into the region from northern Canada, with the core of the Arctic air mass settling overhead Thursday night through Sunday morning.

Ensemble-based statistics illustrate the highly anomalous nature of the incoming air mass, with both the ECMWF and GEFS indicating 850 mb temperatures in the 0.5th to 1st percentile of model climatology from Thursday night through Saturday night. If said percentiles are mapped to the underlying temp/wind chill distributions driving the NBM, they would translate to overnight wind chills near or below Extreme Cold Warning (30 below zero or colder) thresholds both Thursday night into Friday and Friday night into Saturday across most of southern Wisconsin, with additional periods of Cold Weather Advisory conditions (20 below zero or colder) extending into Sunday.

Will continue to be watching trends through the end of the week to see where wind chill forecasts ultimately settle. Regardless of where minimum wind chills ultimately line up, anticipate some sort of cold weather headlines through this part of the period. If possible, try to limit time outdoors. If necessary, dress in plenty of layers and limit exposed skin if needing to be outside.

Quigley

AVIATION

Issued 1050 AM CST Tue Jan 20 2026

Light west winds will shift southwest this afternoon. Middle to high clouds will move in this afternoon ahead of this next system

Snow is expected to spread into the area this evening, generally over most of the area by 03Z to 04Z Wednesday. The snow will continue overnight before ending from west to east by around 12Z Wednesday. Winds will be light during the snow tonight into early Wednesday morning.

Snowfall rates generally around one quarter to one half inch per hour are expected over most of the area, perhaps lower toward Sheboygan. There is a heavier west to east snow band that will set up, with rates of up to 1 inch per hour, but there remains uncertainty with where it will occur and how focused/narrow that band will be. A general 2 to 5 inch snowfall is expected in the southern half of the area, with lower amounts to the north. Fluffy, powdery snow character is expected.

Ceilings should be in the 800 to 1300 foot AGL range during the period of snow tonight into early Wednesday morning, with visibility generally in the 1 to 2 mile range. It may drop to around 1/2 mile within heavier snow bands.

Another round of snow expected late Wednesday afternoon through the early evening with another half inch up to 2 inches expected with temporary VSBY reductions in snow to around a half mile with and another period of at least MVFR CIGS possible.

Kuroski

MARINE

Issued 428 AM CST Tue Jan 20 2026

High pressure around 30.6 inches well southeast of the region will shift east today. Gusty west winds this morning will shift west southwest this afternoon. Elevated waves and Arctic air will continue to lead to areas of heavy freezing spray through this morning. A Heavy Freezing Spray Warning remains in effect until Noon CST today for all of Lake Michigan.

West to southwest winds will continue tonight, with low pressure around 29.8 inches moving across southern Lake Michigan Wednesday morning. West winds are expected behind the low Wednesday afternoon.

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. Gusty west to northwest winds Thursday will will turn mainly northwest Friday, as strong high pressure around 30.9 inches builds into the northern Great Plains. A few gale force gusts may occur during this period.

Winds may reach Small Craft Advisory levels across the nearshore waters of Lake Michigan at times Wednesday night into Friday night.

Arriving Arctic air and elevated wave heights will support additional periods of moderate to potentially heavy freezing spray Wednesday night into Friday night.

Wood

MKX WATCHES/WARNINGS/ADVISORIES

WI...Winter Weather Advisory...WIZ062-WIZ063-WIZ064-WIZ065-WIZ066- WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...9 PM Tuesday to 6 AM Wednesday.

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.