textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A Winter Weather Advisory remains in effect until 9 am CDT for freezing rain north of I-94. Additional accumulations up one tenth of an inch are possible. - Strong to severe thunderstorms are possible this afternoon into the evening, with all hazards possible.

- Additional chances for rain and strong thunderstorms Friday afternoon into Saturday.

- Easterly to southerly wind gusts will reach gale force over the northern two thirds of the lake today into tonight.

UPDATE

Issued 711 AM CDT Thu Apr 2 2026

Freezing rain continues across northern portions of the forecast area early this morning. Road temperatures are in the 33 to 37 degree range in the north, so the main concern for icing remains on elevated surfaces such as bridges and overpasses. Temperatures will warm enough between 7 and 9 am to bring an end to the freezing rain, with steady rain expected into early afternoon.

No significant changes with the threat for severe storms this afternoon and evening. With the low tracking across the northwest forecast area this evening, the warm sector is still expected to sneak into southern Wisconsin for a few hours. Still on track to see MU CAPE of 500 to 1000 J/kg late afternoon into early evening along with plenty of shear. Maintained messaging for all severe hazards possible later today.

Latest Temps were bumped down a touch for today given the low track is a bit farther south than originally anticipated, Northwest areas may not get out of the 40s, with 60s still expected in the south.

DDV

SHORT TERM

Issued 1227 AM CDT Thu Apr 2 2026

Overnight through Thursday night:

Rain is spreading into southern WI and temperatures are sitting between 32 and 34 degrees north of a line from Lone Rock to Madison to Watertown to West Bend, with temps 35 to 37 south of there. Freezing rain on elevated surfaces is beginning in Sauk County already and the Winter Weather Advisory remains in effect for the northern two tiers of counties.

Rain will taper off and become more showery in nature during the early afternoon as the warm front lifts through southern WI. The 00Z models came in with a little more southerly low track than the previous runs, so I lowered the max temperatures a notch, especially toward central WI.

As for our severe threat tomorrow, the low level shear will be very strong, and there still looks like there will be a brief window where a portion of southern WI gets into the warm sector and taps into higher instability. The HREF still has this area with less than 1000 j/kg MUCAPE, but in this high-shear environment, we can see sneaky severe with lower instability. The persistent easterly winds off Lake Michigan will keep conditions cooler near the lake, and it will not be until late afternoon before winds may become SSW there. With the surface low tracking from roughly Mineral Point to Madison to Sheboygan and a delay in winds becoming southerly along the lake, this will shrink our area for discrete, low- topped supercells during the late afternoon hours. Thinking Green, Rock and Walworth counties have the best chance for this, with the potential for the area to reach into southern Dane, Jefferson and Waukesha Counties. Of course, this can change as we get closer to the time and see how the front plays out.

The actual cold front will track across southern WI from 7 PM to 10 PM, and this will likely bring a line of storms. The 0 to 3 shear vectors will be strong and perpendicular to the line, so favorable for QLCS tornadoes. The northern part of this line should zipper up and coincide with the passage of the surface low, so much of our forecast area could see a brief threat for severe storms. The only area that may miss out on this line of storms would be Sauk, Marquette, Green Lake, Fond du Lac and Sheboygan counties.

Cronce

LONG TERM

Issued 1227 AM CDT Thu Apr 2 2026

Friday through Thursday:

Cold frontal passage and a brief wave of high pressure Friday morning, with morning temperatures in the upper 30s to low 40s. Although skies may briefly clear under high pressure and allow temperatures to rise, expecting phasing between the cold front and a developing warm frontal feature from low pressure in the central Plains to lead to increasing easterly winds into the afternoon hours. This will bring colder, dense air from Lake Michigan into southern Wisconsin. Current forecast is for temperatures to remain in the low 50s in most areas, but temperatures may rise quickly toward the 60s in southwestern Wisconsin due to low pressure lifting northeastward into eastern Iowa and bringing a wave of surface WAA. Regardless, expecting developing convection to remain elevated with a very strong inversion in the mid-levels. Low pressure is expected to fully occlude as it progresses into eastern Iowa Friday evening, leading to a strong 850-700 mb warm front over southern Wisconsin while surface temperatures remain cold (upper 30s to low 40s).

Generally have ruled out the idea of any freezing precipitation with the occluded front pushing through northern Wisconsin overnight Friday. However, a substantial amount of MUCAPE (1000-1500 J/kg) riding along the 850-700 mb front combined with freezing levels around 12,000 ft and equilibrium levels near 38,000 ft and mid-level lapse rates around 7 degrees C/km gives an environment favorable for large hail growth. 0-6 km southwesterly bulk shear of 50-60 kt also is expected, which will allow for a few individual cells to develop and tap into the favorable environment. Storms will likely become less discrete and more linear as the low propagates through northern Wisconsin, bringing an end to the large hail threat. Cold frontal feature moves offshore into Lake Michigan Saturday morning, with gusty westerly winds and highs in the 50s expected behind the front.

Trends toward a faster ejection of the low have reduced chances for precipitation into Saturday and Saturday night, with generally dry conditions now expected. Lows Saturday night are expected to hover near freezing. Gusty northwesterly winds continue into Sunday as Canadian high pressure builds into the Plains, with highs in the upper 40s to near 50 degrees.

Sunday night, a shortwave progresses through northern Wisconsin and brings slight chances for a mix of rain and snow to southern Wisconsin (~15% chances). Monday, as a reinforcing Canadian High builds into Upper Midwest, continued scattered snow/rain showers are expected along the eastern edges over souther Wisconsin (15-30% chances). High pressure affects southern Wisconsin overnight, bringing lows in the 20s and light winds. High pressure lingers through Tuesday, with winds turning to southerly overnight as high pressure exits and multiple shortwaves begin to build broad ridging over the central Plains. Next chances for precipitation develop Wednesday night into Thursday as low pressure ejects from the High Plains and propagates eastward. Model discrepancy increases during this timeframe, so too early to call for specific hazards and timing, but this period does bear watching for the next storm set-up.

MH

AVIATION

Issued 711 AM CDT Thu Apr 2 2026

Widespread rain will persist into this afternoon, with freezing rain chances winding down between 12Z and 14Z. Visibilities between 2-5 miles are expected during the rain along with ceilings between 300 and 1000 ft. Breezy east to southeast winds will continue today, becoming southerly by late afternoon. Wind shear is expected to develop today as the LLJ moves overhead, winding down by mid-evening.

Thunderstorm chances are expected by mid afternoon, with a higher chance for storms late afternoon into the evening. Some of these latter storms may be severe, with all hazards possible. Breezy westerly winds are likely overnight into early Thursday behind a cold front, with low ceilings likely persisting.

DDV

MARINE

Issued 1227 AM CDT Thu Apr 2 2026

Breezy northeast to east winds will increase through Thursday morning as high pressure of 30.7 remains near James Bay and low pressure of 29.4 inches approaches from the Central Plains. These winds will then reach gale force Thursday morning and through the day as a warm front lifts northward over the lake.

Easterly gales up to 40 kt over the northern third of the lake will continue through the day, while the southern two thirds may see a lull during the afternoon as the warm front slowly moves in. Then low-end southerly gales are expected over the southern two thirds during the evening hours. A Gale Warning with two segments remains in effect, with staggered end times, and it was expanded to include the southern tip of the lake. Thunderstorms are also expected over the southern two thirds of Lake Michigan Thursday afternoon and evening. Winds will abruptly shift to the west behind the cold front Thursday night.

The nearshore areas remain with a Small Craft Advisory, as there is less certainty for frequent gale force gusts.

Beyond, winds become light and variable Friday late morning into Friday afternoon before gusty northeast winds return ahead of a low pressure of 29.8 inches on Saturday.

Cronce

MKX WATCHES/WARNINGS/ADVISORIES

WI...Winter Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056- WIZ057-WIZ058-WIZ059-WIZ060 until 9 AM Thursday.

LM...Gale Warning...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671- LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874- LMZ876-LMZ878 until 1 AM Friday.

Gale Warning...LMZ261-LMZ362-LMZ364-LMZ563 until 9 PM Thursday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 4 AM Friday.