textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Light snow will develop across southern Wisconsin this afternoon and evening, moving west to east (70 to 90 percent chances). Steady light snow will end into the late evening hours, with patchy freezing drizzle (~20% chance) and scattered snow showers (50 to 70% chance) then expected through much of the overnight hours.

- Early Friday morning, an additional wave of steady snow is expected to progress west to east across the region (80 to 90% chance). Best chances for steady moderate snow are north of the I-90/I-94 corridor. After this wave of snow moves through, an additional period of scattered snow showers (40 to 60% chance) and freezing drizzle is expected (20 to 30% chance). Freezing drizzle will end west to east through the morning hours.

- Scattered snow showers are expected to continue Friday afternoon through Saturday (30 to 60% chance). A few showers may become locally heavy Friday afternoon along a frontal passage.

- Below-normal temperatures continue this weekend through the beginning of next week. Coldest temps and wind chills expected Sunday through Tuesday, and may approach Cold Weather Advisory criteria (20 degrees below zero).

SHORT TERM

Issued 413 PM CST Thu Jan 15 2026

Tonight through Friday night:

Low pressure developing across northern Minnesota will dig slightly southeastward tonight, as a shortwave propagates northward from Missouri into southern Wisconsin. Snow has already begun to develop across central Iowa as these features interact, and expectations are for snow to bloom northeastward into southern Wisconsin this evening (best chances of 70 to 90 percent between 6 PM and 10 PM). Around an inch of snow is expected. As snow exits to the east tonight, lower clouds and a dry mid- level punch (within the dendritic growth zone) may result in patchy freezing drizzle (~20% chances). Confidence in freezing drizzle is low during the 10 PM to 3 AM timeframe due to expectations for dry air near the surface (which would prevent freezing drizzle from developing). Weak pockets of moisture within the dendritic growth zone may also result in scattered snow showers during the overnight hours (30 to 60 percent chance).

The developing low pressure system slides into northern Wisconsin into early Friday morning, developing a weak warm frontal feature across southern Wisconsin and increasing the moisture and corresponding precipitation chances across the region. Due to continued dry air in the mid-levels, freezing drizzle chances increase as surface moisture increases during the early morning hours (~3 AM onward). Models diverge in the timing and intensity of a southeastward-moving warm frontal feature Friday morning. However, confidence in pooling of low level moisture and an eventual northwest to southeast moving band of snowfall is high (70 to 90 percent chances). Expecting up to a glaze of icing on untreated surfaces, and an additional inch of snowfall. This band of snow moves offshore into Lake Michigan mid-morning, with freezing drizzle ending as well.

Isolated, intermittent snow showers are then possible through the remainder of the morning hours Friday. Going into the afternoon, a brief period of weak (<50 J/kg MUCAPE) instability may result in some of these snow showers becoming locally intense with lowered visibilities and a quick few tenths of an inch of snow. A cold front will bring a return to Arctic air during the later afternoon hours, and showers along this frontal passage are most likely to produce the local enhanced rates. Temperatures will fall quickly from near freezing to the low 20s Friday evening, with lows in the low teens expected by daybreak Saturday. Low pressure occludes and sits across eastern Lake Superior through Friday night, allowing for continued flurries and light snow showers through the remainder of the overnight hours (convective snow showers will weaken after sunset).

MH

LONG TERM

Issued 413 PM CST Thu Jan 15 2026

Saturday through Thursday:

The occluded surface low will still be over the Upper Great Lakes on Saturday. A little shortwave rounding the base of the upper trough will slide through northern IL or southern WI on Saturday. One more round of light snow or flurries should overspread srn WI Sat afternoon.

That upper low will finally open up and push eastward Saturday night into Sunday, which will allow the Great Lakes surface low to exit. The next surface low, tied to a modest mid level shortwave trough dropping out of Manitoba, will cross the Upper Great Lakes on Sunday. The associated surface trough/cold front is expected to swing across srn WI Sunday afternoon-evening and this may pack a punch in terms of strength of an arctic front and strength of the shortwave. This one will be watched for its snow squall potential.

So our next round of arctic air will be overhead Monday. The forecast high is in the single digits and lows Mon nt should be below zero. Gusty westerly winds will keep wind chills low Monday through Tuesday morning as well. Wind chill values may dip below -20F (Wind Chill Advisory criteria) in a few spots early Monday morning and again early Tuesday morning. This period looks dry, but flurries would be possible with any low clouds within this cyclonic flow, and also with any subtle shortwaves.

Temperatures will rebound a little bit on Tuesday as another upper wave approaches. This would strengthen the baroclinic zone between the sfc low approaching from Alberta and the high sitting over the central Plains. An area of warm air advection will bring a swath of snow to WI, although there is still uncertainty about where - northern WI or southern WI. This would occur Tue nt-Wed AM. Yet another round of snow is possible over the Midwest Thursday afternoon-night.

Cronce

AVIATION

Issued 413 PM CST Thu Jan 15 2026

VFR ceilings will gradually lower through tonight, with light snow progressing west to east late this evening into tonight and resulting in lowered visibility (~4 SM) and approximately an inch of accumulations. Southwesterly winds are expected to continue throughout tonight, becoming gusty around 20 kt. Late tonight into early Friday morning, patchy freezing drizzle and isolated snow showers may develop in southwest Wisconsin, spreading eastward into southeastern Wisconsin around sunrise. 700-1500 ft ceilings are expected with this activity. A glaze of ice and traces of snow are possible.

Chances for freezing drizzle and snow increase (~30% chance and 70-90% chance, respectively) into the early morning hours Friday as winds shift westerly. Expect an additional inch of snow and up to a glaze of ice. Snow is expected to progress northwest to southeast through the morning hours Friday. Snow chances diminish (30-50%) and freezing drizzle ends, but additional MVFR snow showery activity is expected through at least Friday evening.

MH

MARINE

Issued 413 PM CST Thu Jan 15 2026

Breezy southwesterly winds will continue to build over Lake Michigan through the evening ahead of an approaching cold front. Front will push across Lake Michigan overnight with breezy westerly winds setting up into the weekend as low pressure digs down from northern Manitoba through western Ontario before settling over Lake Superior/northern Lake Michigan by Friday evening. A Small Craft Advisory is in effect from this evening through Friday evening for southern Wisconsin nearshore regions due to these winds. The low pressure will meander around this area into Saturday with westerly winds continuing across the lake. Then the low pressure will gradually weaken as it shifts east Saturday evening allowing winds to briefly weaken overnight into Sunday as high pressure slides south through the Central Plains.

Winds are then expected to shift more southwesterly and increase for Sunday as another low pressure system deepens as it tracks into the Lake Superior region Sunday afternoon/evening. The associated cold front will sweep across Lake Michigan as the low pressure quickly pushes east into Monday. Expecting stronger northwesterly winds to develop behind the departing low and cold front Sunday night through Monday. There will be a potential for gales during this timeframe and will monitor to see if this gale trend continues. Winds hazardous for small craft are expected in southern Wisconsin nearshore regions. Otherwise, low pressure kicks east later Monday with another high pressure building into the region for Tuesday.

Given the colder Arctic airmass settling over the area and brisk winds, expect freezing spray concerns across Lake Michigan this weekend and continuing into the next week as well with even colder temps.

Wagner

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...8 PM Thursday to 9 PM Friday.