textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Areas north of the I-94 corridor may observe a glaze of freezing rain accretion late this evening into Thursday morning, mainly on elevated surfaces. Highest potential is toward central WI. Slick spots are possible for the Thursday AM commute. - Thunderstorms are possible Thursday afternoon and evening (level 2 out of 5 severe threat). All Hazards are possible.

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

UPDATE

Issued 656 AM CDT Wed Apr 1 2026

The forecast generally looks on track through this afternoon. Quiet weather is likely, with no significant updates to the forecast anticipated. The focus on the short term weather remains on the potential for a wintry mix or precipitation late this evening into early Thursday morning. The latest couple of model runs are showing a little colder wet bulb temps during this period, especially along/north of I-94. This would lead to an increased potential for a wintry mix, with possibly some sleet and snow at first, transitioning to mainly freezing rain in the north. While we have been messaging the wintry mix mainly north of I-94, this trend in models would suggest the potential for at least a couple hours of freezing rain along the I-94 corridor, with locations farther south remaining just rain. Areas north of I-94 continue to have the best potential for a prolonged period of freezing rain.

There is less confidence in the impacts of any potential freezing rain due to the road temps possibly remaining above freezing. Road temps along/north of I-94 are in the mid to upper 30s this morning with air temps in the low to mid 30s. Thus maintained the mention of mainly elevated surfaces (such as bridges and overpasses) having the best chance for some icing. Additionally, wet-bulb temps will be right around the freezing mark, which isn't particularly efficient for ice accretion.

Despite the uncertainties, a Winter Weather Advisory may eventually be warranted for portions of the forecast area if models continue to trend colder and confidence in freezing rain continues to rise.

DDV

SHORT TERM

Issued 1100 PM CDT Tue Mar 31 2026

Tonight through Thursday night:

High pressure nudges in tonight as the base of the high strengthens and pushes into eastern Ontario into Wednesday. Into the upper levels it largely looks like zonal flow but the large scale look appears to be in an area of weak ridging, particularly into the day Wednesday. Into the day Wednesday we will see predominantly northeast flow and we warm up a bit of a boundary/front feature develops and spreads down the lake. It appears to be a bit of a backdoor cold front type feature but in effect will just keep temperatures in eastern WI from increasing much. This will be as temperatures to the west increase into the mid to upper 40s thus just creating a fairly strong temperature gradient across the CWA. Otherwise no precipitation is expected Wednesday though we cannot rule out a brief period of light precip across parts of southern WI Wednesday morning as a result of a little shortwave energy aloft in the presence of some moisture. Given drier low to mid levels this would likely appear as virga but we cannot completely rule out a few flakes/sprinkles.

Into Wednesday night there will be increasing chances for precip as a strong low develops over the central plains associated with a strong shortwave lifting into the midwest. In addition, a strong LLJ will nudge in with strong WAA and plenty of moisture throughout the column. Very high chances (>80%) for precip overnight into Thursday morning for the vast majority of the CWA. Late Wednesday night into Thursday with strong WAA will create a warm nose and with temperatures near freezing toward central WI it remains a possibility that we could see a period of freezing rain. The northward progression of this system has reduced the overall risk for extensive freezing rain potential but there remains chances for some light icing across central WI. Warmer temperatures recently may reduce the potential impacts for roads as road temperatures may remain above freezing

Into Thursday morning there will be a chance for a dry slot to slide into parts of southeast WI as some models support this idea. However, there will be chances for storms much of the day Thursday as CAMs suggest scattered storm potential even for the morning. The better chance will be during the afternoon and evening, however. Most of southern WI is in a slight risk for Thursday likely due to a combination of increasing instability ahead of the cold front/low. The forcing along the front is suggestive of early evening storms with instability of upwards of 1500J/kg along with very strong shear 0-6km of 40-45kts and 0-1km of upwards of 40kts as well. Very high 0-1km SRH appears possible as well with strong low level turning. Still plenty of questions with the severe risk, but all hazards will be possible with this risk. Risk for storms will push out by the late evening as the system swings out, with weak high pressure and dry air aloft pushing into the area overnight.

Kuroski

LONG TERM

Issued 1100 PM CDT Tue Mar 31 2026

Friday through Wednesday:

A brief period of respite Friday morning as low pressure exits into Quebec, followed by additional precipitation developing Friday afternoon along a frontogenetic region arising from the phasing of the cold front from the previous system and the developing warm front from a newly ejecting low in the central Plains.

The new low will propagate northeastward into the Upper Mississippi Valley overnight Friday, allowing for the warm front to dominate. Ensemble member low locations indicate strong agreement that southern Wisconsin will be within the warm sector of this low throughout Friday night, keeping precipitation rain. Thunderstorms are expected with MUCAPE building into the region Friday afternoon and continuing into the early overnight hours. Current model depictions indicate the potential for a brief negative tilt to the trough as it rounds the southern side of a surface high over the Hudson Bay. Some GFS ensemble members paint enough instability throughout the overnight hours to bring some concern for an isolated severe storm even overnight. Into early Saturday morning, expect the low to eject into Lower Michigan, bringing a cold front through southern Wisconsin and bringing an end to any severe threat.

Some model-to-model timing discrepancies develop going into Saturday, with faster moving models showing low pressure quickly propagating into Quebec and cutting off precipitation across Wisconsin. However, models that show the slight negative tilt would allow for a deeper, slower moving system and wrap-around cold rain showers through Saturday. Kept NBM PoPs due to uncertainty in this period. Overnight Saturday, as low pressure does exit into Quebec and Canadian Prairies high pressure builds southward through the Plains, expect lows in the upper 20s to low 30s.

Dry conditions expected through Sunday under a cooler airmass, with highs in the mid 40s to near 50 degrees and lows in the upper 20s to low 30s again. Into Monday, a reinforcing shot of cold air follows a clipper system through the northern Great Lakes region. Temperatures are trending cooler, with highs in the ups to low 50s expected. If temperatures continue to trend cooler, snow may mix in with rain at times (20-30% chances of precipitation) as the clipper progresses southeastward through the region. By the overnight hours Monday, remaining precipitation will transition into snow showers (20-30% chances) as temperatures fall into the upper 20s to low 30s.

Cold high pressure builds back in on Tuesday, with highs in the 40s and lows in the upper 20s. As the progressive upper level pattern continues, low pressure will develop in the lee of the Rockies Tuesday night into Wednesday, shifting winds back to southerly across southern Wisconsin and bringing a return to temperatures in the 50s.

MH

AVIATION

Issued 656 AM CDT Wed Apr 1 2026

Lower ceilings between 1500 and 2500 ft should generally retreat west to east this morning, possibly hanging on in the east into the afternoon. Periods of mid and high level clouds will persist through the day. Breezy east to northeast winds gusting 20 to 25 knots are likely today into tonight.

Widespread precipitation and lower ceilings (500-1500 ft) will move in from the south later this evening into tonight. The precip is likely to be all rain south of I-94, with a wintry mix transitioning to period of freezing rain north of I-94. There is a chance for at least a couple hours of freezing rain along the I-94 corridor tonight. All rain is then expected across the forecast area by mid-morning Thursday as warmer conditions continue to move in from the south. There remains some uncertainty with the potential impacts of the freezing rain tonight into early Thursday given current pavement temps of mid to upper 30s along/north of I-94 as well as air temps right around the freezing mark tonight. Elevated surfaces will have the highest chance of seeing some icing.

DDV

MARINE

Issued 1100 PM CDT Tue Mar 31 2026

Northerly winds become brisk into Wednesday as a high pressure around 30.5 inches builds over Ontario. High pressure will strengthen into the day Wednesday to 30.6 inches as it pushes toward eastern Ontario with a bit of a front sliding down the lake with northeastern winds behind it.

Breezy easterly winds are then expected Wednesday night into Thursday between high pressure of now 30.7 inches east of James Bay in Canada, and low pressure of 29.4 inches lifting from the Central Plains into Wisconsin. Gusts appear more likely to reach gale force over far northern Lake Michigan on Thursday and thus a Gale Watch has been issued Thursday morning through most of the afternoon. The breezy easterly winds will shift southerly from south to north across the lake Thursday afternoon into the evening with the passage of a warm front, then followed by the cold front with winds shifting westerly late Thursday night. Precipitation is expected Wednesday night through Thursday with a chance for some ice toward far northern parts of the lake, particularly Thursday morning. Then expect some storm chances primarily over the southern half of the lake Thursday afternoon and evening as the 29.5 inch low pushes through the northern lake Thursday night.

Small Craft Advisory in effect through at least much of Thursday night for waves 5-8ft and gusty winds from 15-20kts with gusts up to 30 kts. Winds will turn from the north to east back to the south over the course of the next 48 hours.

Kuroski

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 4 AM Friday.

Gale Watch...LMZ261-LMZ362-LMZ364-LMZ563...7 AM Thursday to 5 PM Thursday.