textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Widespread rain expected tonight. Some rain-snow mix is possible at times, mainly north of I-94, with any accumulation remaining light (1 inch or less) if applicable. Snow showers along the cold front are possible late tonight into Friday morning, and may cause a brief drop in visibility and slick spots on the Friday AM commute.

- A High Wind Warning is in effect 4 AM to 4 PM CDT Friday. West to northwest winds with gusts up to 60 MPH are expected behind a cold front.

- A Storm Force Wind Warning is in effect for the southern half of Lake Michigan tonight through Friday due to gusty winds ahead of and behind the cold front. Gales are expected for the rest of the lake.

- Confidence is increasing for significant accumulating snow, blowing snow, and wintry mix Saturday night through Monday afternoon. A Winter Storm Watch has been issued. There does remain some uncertainty with the exact track of the low along with resultant precipitation types and totals. Pay close attention to the forecast if planning travel during this time frame.

UPDATE

Issued 700 PM CDT Thu Mar 12 2026

Forecast remains largely on track with rain gradually pushing in tonight with some snow mixing in toward central WI. The primary slug of precip will push through starting the next few hours through around 2am. Thereafter there will be increasing concerns for snow behind that precip. A few models suggest a wave of precip that may be either snow or rain right behind the primary slug of precip. If it is snow there will be some concern for a snow squall type feature but if it is largely rain concerns would be limited. With a brief break behind that there will be a better chance for snow showers behind the front correlated with the surface low and TROWAL. Snow squall concern with that is more limited given the more broad brushed nature of it in CAMs but it could be convective which might increase concern should it become banded and more intense. There is a slight concern for some freezing drizzle behind the front as well given some loss of ice in soundings.

The other concern continues to be the wind, which on the high end will be near severe level winds, which is why the High Wind Warning is in effect. The primary concern for higher winds continues to be after 9z but there is some concern for Advisory type winds early this evening particularly with any precip loading. The southerly high end winds are more uncertain however given the lack of mixing potential outside of precip loading.

Kuroski

SHORT TERM

Issued 305 PM CDT Thu Mar 12 2026

Tonight through Friday night:

A clipper system will track eastward across northern WI overnight, with both the WAA this evening into tonight and CAA late tonight into Friday morning leading to precip chances (80-95% and 20-40% respectively). As the associated clouds push in from the west this afternoon, we may see some virga as low level dry air evaporates the initial precip. Forecast soundings indicate we should begin to see surface precip sometime after 7 PM this evening (starting with Lone Rock / WI Dells / Montello) and spreading southeastward to reach the MKE metro no later than 1 AM Friday. Though the LLJ's warm nose (as seen on forecast soundings) does not exceed the freezing mark and we're fairly confident in the presence of cloud ice through the WAA phase, the lowest ~2,000 ft of the atmosphere should remain above freezing (particularly for the southern half of the CWA), same with the surface temperatures. As such, this is predominantly a rain event, with some wet snow mixing in (mainly further north towards central / east-central WI). For the CAA phase of the event (late tonight into Friday morning), we're expecting to lose most (if not all) of that shallow above-freezing layer, though cloud ice is a bit less certain. With strong FGEN and small (but noticeable) positive buoyancy energy along the front, we can't rule out convective snow showers or weak snow squalls along it. We're only affording it 20-40% precip chances given that the coverage would be scattered at best, but the main window for this activity would be 4 AM to 9 AM Friday (for nearly all of the CWA except far southwestern WI), though east-central WI could observe a second round of showery activity as late as mid-day Friday. When all is said and done, we're looking at slushy accumulations of only a fraction of an inch possible, with locally higher totals around 1 inch possible towards east-central WI. Any localized convective snow showers / squalls would be capable of dropping this ~1 inch of snow in a quick ~1 hour window. A few slick spots will be possible for the Friday AM commute, especially further north.

The west to northwest winds behind the cold front are expected to be gusty, and a High Wind Warning has been issued for the entire CWA from 4 AM to 4 PM CDT Friday. Though the worst of the gusts may only last for a fraction of this entire window, the ingredients for gusts up to 60 MPH will be present. Highest confidence in criteria-level gusts is the southwestern two thirds of the region, with the lowest confidence (slightly slower gust potential) towards east-central WI. Downed tree branches and power outages could easily occur.

High temperatures in the upper 30s to low 40s Friday afternoon. As high pressure sags southeastward into the region into Friday evening, wind gusts will rapidly decrease. Clouds might briefly scatter apart Friday afternoon / evening for all or part of the region, but then rebuild into Friday night ahead of the next system.

Sheppard

LONG TERM

Issued 305 PM CDT Thu Mar 12 2026

Saturday through Thursday:

Confidence remains high that a significant winter storm will impact the region this weekend, with a swath of heavy snow likely along with strong winds. As is common with deepening/phasing systems like this, big questions remain with the track of the low and timing of the phasing, which will impact where the swath of heaviest snow sets up. Additionally, models have trended toward taking the 850 mb low farther north into the southern forecast area, bringing an area of warmer air aloft into areas along/south of I-94. This could result in a period of freezing rain, sleet, and rain mixing in for these southern areas. Models are remaining south with the surface low though, with deterministic and ensemble mean tracks roughly through or to the south of Chicago. Given these variables, there remains a fair amount of uncertainty in terms of local wintry precip impacts. That said, this storm has a high impact potential for areas that take the brunt of this system. This is due the potential for prolonged heavy precip rates, period of wintry mix, and strong winds. With the high impact potential and start of the system a little over 48 hours out, opted to go with a Winter Storm Watch for the entire forecast area. Highest confidence in impacts from snow and blowing snow is currently north of I-94, with the higher confidence in wintry mix along/south of I-94. Strong winds will be a concern across southern Wisconsin.

Here are a few things to keep an eye on over the next couple days. The first thing to watch are the surface and 850 mb low tracks. Given the expected transition from rain to mixed precip to very heavy snow over a fairly short distance with this deepening low, any wobble north/south with the low tracks would have a significant impact on local precip types/amounts. As mentioned already, while the surface low track has remained fairly steady, the 850 mb low has been trending northward. Another trend to watch is that models have been slower with the exit of this system, lingering into at least Monday morning with the moderate to heavy snow and blowing snow. This would bring the higher impacts into the Monday morning commute. Lastly, models are often on the high side with storm total liquid equivalent 2-4 days out. Given the current anomalously high storm totals for a winter storm, it will be worth watching if models start coming down with totals in the next 24-48 hours. Give the strength of this system though, liquid equivalent totals of 1-2 inches seem reasonable, maybe not upwards of 3" per 12Z deterministic models.

Colder and drier conditions are expected to settle into the region behind the departing strong low early next week, as high pressure moves in from the northwest. Below normal temps are likely Monday and Tuesday, with temps moderating towards normal by mid-week. Dry weather is expected Mon/Tue, with a chance for rain/snow Tue night into Wed as a shortwave drops through the area.

DDV

AVIATION

Issued 700 PM CDT Thu Mar 12 2026

VFR to IFR conditions are expected through the period. This evening light rain and snow will move in from the west and move east-northeast into Friday morning. Current returns are radar are virga due to dry air near the ground. As the low level moisten light stratiform rain will slow make it to the ground. As low and mid level air moistens mid and low level clouds will develop. Terminals along and north of Interstate 94 can expect ceilings to fall to 1 to 2 kft tonight as the light precip moves through. Areas south of 94 will can expect ceiling around 3 to 4 kft. Light rain will gradually become a rain/snow mix to all snow early Friday morning. Wet slushy snow accumulations of a couple tenths of an inch will be possible. Our southern terminals including JVL and ENW will see little to no accumulations (dusting or less). Snow shower around daybreak have a small chance of becoming convective snow which could result in brief periods of higher rates and lower visibilities (weak snow squall around 30 mins). Precipitation will pull northeast out of the area by late Friday morning. Ceilings will rise at the precipitation moves out leading to a return to VFR conditions.

Strong gusty winds will accompany this passing system through the TAF period. South to southwest winds will increase late this evening into tonight. The gusty southerly winds will be sustained 15 to 25 kts with gusts of 30 to 40 kts. Winds will turn to westerly early Friday morning and then northwesterly by mid morning and remain strong. West to northwest sustained winds of 20 to 25 kts with gusts of 35 to 50 kts. Winds will remain strong through Friday morning and slowly diminish through the afternoon. Light northwest winds are expected Friday night.

Kuroski

MARINE

Issued 305 PM CDT Thu Mar 12 2026

Very active conditions are anticipated across the open waters from tonight through the beginning of next week. Currently in the northern Great Plains, 990 mb low pressure will approach and cross the northern half of Lake Michigan tonight through Friday morning. Southerly winds will quickly increase as the low approaches tonight, ultimately veering westerly to northwesterly as it moves into Ontario Friday evening. Widespread gale force gusts remain forecast across the northern half of the open waters, where a Gale Warning remains in effect between 10 PM CDT tonight and 10 PM CDT Friday evening. Even stronger gusts are expected across the southern half of the open waters, where confidence has increased in widespread storm force gusts in this forecast. A Storm Warning has thus been issued for southern Lake Michigan between 10 PM CDT tonight and 10 PM CDT Friday evening. It's possible that winds could decrease below storm thresholds prior to the current 10 PM CDT Friday expiration of the Storm Warning. If necessary, any early cancellations will be handled as winds decrease Friday evening. Areas of rain and snow will accompany passing low pressure tonight. Areas of light to occasionally moderate freezing spray are possible over northern Lake Michigan Friday afternoon.

Winds will taper away from headline thresholds later Friday night through Saturday as 1024 mb high pressure builds into the northern Great Plains & ultimately crosses the open waters. East-northeast winds will steadily increase Saturday night through Sunday as a second area of 994 mb low pressure forms in the central Great Plains. The low will progress over or just south of the southern Lake Michigan Sunday night as it deepens toward 986 mb, resulting in a northerly wind shift. Winds will shift out of the northwest Monday as the low continues into Ontario. Expect another prolonged period of gale, if not storm force gusts across all of the open waters as the low approaches & shifts east of Lake Michigan early Sunday morning through Monday, with headlines becoming necessary within the next 12-24 hours. Prolonged snow is expected Saturday night through Monday, some of which could be heavy. Sleet or freezing rain could mix in with snow over southern Lake Michigan Saturday night into Sunday. Freezing spray potential will increase Monday behind the departing low, with areas of moderate to heavy freezing spray possible. Trends will be monitored in coming forecasts for potential headlines.

Storm force gusts are expected in nearshore zones tonight through Friday. A Storm Warning has thus replaced the previous Gale Warning in all nearshore zones between 10 PM this evening and 10 PM Friday evening. Gusts may decrease below storm thresholds prior to the current 10 PM CDT Friday Storm Warning expiration, with any early cancellations being handled as winds decrease Friday evening. Another prolonged period of gale or storm-force gusts is expected Sunday morning through Monday as a second area of low pressure moves through the western Great Lakes. Expect that headlines will become necessary over the next 12-24 hours. Areas of moderate to potentially heavy freezing spray are possible Monday afternoon.

Quigley

MKX WATCHES/WARNINGS/ADVISORIES

WI...High Wind Warning...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066- WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...4 AM Friday to 4 PM Friday.

Winter Storm Watch...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057- WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066- WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...7 PM Saturday to 4 PM Monday.

LM...Storm Warning...LMZ080-LMZ643-LMZ644-LMZ645-LMZ646-LMZ669- LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ870-LMZ872-LMZ874- LMZ876-LMZ878...10 PM Thursday to 10 PM Friday.

Gale Warning...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565- LMZ567-LMZ868...10 PM Thursday to 10 PM Friday.