textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Bitterly cold wind chills between 20 and 30 below continue through mid-day areawide. Wind chills as low as 35 below continue through sunrise in east-central Wisconsin.

- A lake effect snow band will come close to the southeast Wisconsin shore late tonight into Sunday afternoon. If the snow band comes ashore, accumulating snow would be possible from Milwaukee and points south.

- Additional periods of wind chills in the 10 to 20 below range continue during the overnight periods into next week. Cold Weather Advisories are possible Sunday night.

SHORT TERM

Issued 346 AM CST Sat Jan 24 2026

Today through Sunday Night:

Synopsis/Mesoanalysis: A broad area of high pressure is centered over the Upper Mississippi Valley this morning, resulting in variable to light northwesterly winds over southern Wisconsin. With skies remaining mostly clear through the first half of the overnight, efficient radiational cooling has occurred in the presence of the advancing surface high, with the majority of locations reporting air temperatures in the teens below zero as of 3 AM CST. While far lighter relative to yesterday, the variable to light northwesterly winds are combining with the frigid air temperatures to support widespread wind chills in the -20 to -30 range early this morning. Readings as low as -35 have been reported in east-central Wisconsin, where northwesterly winds have remained a touch stronger. The aforementioned wind chills will continue through this morning, with cold weather headlines remaining in effect until Noon CST across all of southern Wisconsin. Broad high pressure will continue to build over the northern CONUS today, with two defined/closed areas of high pressure forming over the Northeast & Upper Mississippi Valley this evening. With Lake Michigan positioned between the two surface highs, convergent low level winds will allow for development of a lake effect snow band over central parts of the lake tonight. The snow band will work west Sunday morning, pulling near southeast Wisconsin before moving away Sunday afternoon & evening. If the snow band makes it on shore, it would pose some potential for accumulating snow from Milwaukee and points south. A much stronger area of low pressure will move from the Southeast into the Ohio Valley Sunday morning & afternoon, bringing small chances for light snow or flurries south of I-94 & US-18. Minimal if any accumulation is expected in this activity.

Rest of Overnight through This Morning: Headline-level wind chills will continue through this morning areawide. Given ongoing obs & short term forecast trends, have thus maintained all headlines through their scheduled end times in the overnight update. Extreme Cold Warning thus remains in effect through 6 AM CST in east-central Wisconsin, and will be replaced by a Cold Weather Advisory until 12 PM CST following the 6 AM CST expiration time. Everywhere else, a Cold Weather Advisory remains in effect until 12 PM CST. Continue to dress in layers if needing to be outside through this morning.

Tonight through Sunday: Will be monitoring for some snow potential (particularly after midnight) as a lake effect snow band evolves over western Lake Michigan & a storm system passes south of the region. If dry low level air can be overcome, the larger storm system could bring some light flurries or snow showers to areas mainly south of I-94 & US-18, with minimal (if any) accumulation expected. A more impactful scenario could materialize if the aforementioned lake effect snow band makes it onshore in southeastern Wisconsin, however, as it would pose greater potential for enhanced hourly snowfall rates & accumulation from Milwaukee and points south. Whether the band makes it ashore remains highly uncertain as of this forecast, with available model solutions ranging from the band remaining over the lake to coming on land for multiple hours. However far the band makes it, anticipate that it will make its closest pass to southeast Wisconsin between ~6 AM-2 PM Sunday, with low level winds pushing it east later Sunday afternoon. Given the wide range of potential outcomes regarding the lake effect band, have held off on any headlines in the overnight forecast, but will be closely watching trends through today. If a scenario favoring accumulating snow becomes favored, Winter Weather Advisories may become necessary.

Sunday Night: Anticipate widespread wind chills between -10 and -20. Will be monitoring for potential Cold Weather Advisories in later forecasts, as probabilistic guidance is indicating increasing potential (60% or greater) for wind chills colder than -20 by daybreak Monday morning.

Quigley

LONG TERM

Issued 346 AM CST Sat Jan 24 2026

Monday through Friday:

Overall a pretty boring long term here. The upper level pattern is dominated by ridging in the western CONUS and a trough across the eastern CONUS. Under this pattern the central CONUS and Great Lakes Region will have 500 mb lows and shortwaves pivoting down from Manitoba and Saskatchewan before these lows kick out to the Atlantic coast. The upper levels will be a juxtaposed with sfc, as high pressure systems move into the Plains, Great Lakes Region, and Ohio River Valley. What this translates to is overall is weak flow a the sfc, more cold/dry air moving in and weak lift aloft. The weak lift aloft will struggle to overcome the low dewpoints (moisture) and subsidence at the sfc.

The main times to note will be Tuesday with the passage of a cold front and Wednesday with some limited moisture return and sfc convergence. Tuesday dry air looks to win out so as the cold front passes. Little to not POPS with this front, but it will bring a return of CAA (thankfully this too will be weak and mostly usher in drier air). For Wednesday, there will be shortwave trough aloft moving down from Canada, but the one discrepancy is what will be occuring at the surface. Guidance is fairly split here on the strength of the sfc high that will be parked over the Great Lakes and Plains. Some deterministic and ensemble members have a mid level shortwave providing a bit more lift, but the overall lift is weak and moisture is low. Kept the average among guidance which has 20% chance POPs or less, but overall confidence is low on anything overcoming the low level dry air. If we do get precip, temperatures will be cold enough for snow and accumulations will be low with little impact. The only other thing worth noting in the extended is temperatures will slowly climb up. Highs in the single digits Monday will be in the teens by midweek and looking just beyond the extended shows a glimmer of highs in the 20s.

Patterson

AVIATION

Issued 346 AM CST Sat Jan 24 2026

VFR flight categories prevail through the majority of the period at all southern Wisconsin terminals. Currently building in from the Upper Mississippi Valley, high pressure will move across the region today, maintaining the weakening trend in winds that is already ongoing early this morning. Weak low pressure remains forecast to develop over southern Lake Michigan this evening through tonight, which will bring a slight increase in northerly winds nearing the end of the period. Expect winds to be strongest in east-central and southeast Wisconsin. Affiliated with said low, a lake effect snow band is forecast to develop over western Lake Michigan this evening. The band should remain over the open waters of Lake Michigan through the majority of the overnight hours, though it could approach southeast Wisconsin near & after daybreak Sunday. Will thus be monitoring trends for potential -SN mentions at southeast Wisconsin aerodromes in later forecasts. A much larger area of low pressure will move from the southeastern United States to the Ohio River Valley during the day Sunday, bringing increasing low-mid level clouds to southern Wisconsin. Could see some -SN from this system to the south of I-94 & US-18, though low forecast confidence has precluded any mentions in the 06Z update. Will continue to monitor trends over coming updates. Thickening low level clouds will accompany the passing area of low pressure, with CIGs expected to remain at/above FL030 at this time.

Quigley

MARINE

Issued 346 AM CST Sat Jan 24 2026

Winds will continue to taper across Lake Michigan today as 1040 mb high pressure moves in from the west. Wave heights will likewise decrease with wind speeds, resulting in rapidly diminishing heavy freezing spray potential through sunrise. The Heavy Freezing Spray Warning will thus expire as scheduled at 3 AM CST this morning. Low pressure of 1034 mb remains forecast to form over the southern waters today, bringing lake effect snow potential to the southern half of Lake Michigan from this afternoon through tonight. The low's development will bring increasing northeast winds tonight through Sunday. Winds are expected to remain below gale thresholds.

Winds will trend northwesterly to westerly Sunday night into Monday as 1002 mb low pressure moves into the northeastern United States and 1040 mb high pressure builds into the central Great Plains. A brief period of southwest winds is forecast Monday evening/night as 1036 mb high pressure builds into the Ohio River Valley. Winds will then shift back to west-northwesterly Tuesday morning as 1032 mb high pressure builds into the northern Great Plains. Periods of 25- 30 knot gusts are anticipated from Sunday night through Tuesday morning, with a few gusts approaching gale force possible over southern Lake Michigan Monday night. Will continue to monitor trends for possible headlines in coming forecasts. The breezier conditions will be accompanied by areas of moderate to heavy freezing spray Sunday night into Tuesday. A Heavy Freezing Spray Watch has been issued between 6 PM CST Sunday and 6 PM CST Tuesday given this potential.

Increasing winds and waves will likely lead to Small Craft Advisory conditions in nearshore zones Sunday evening into Monday morning. A brief lull in conditions is possible Monday afternoon, prior to advisory-level conditions returning Monday night through Tuesday. Headlines will likely become necessary during this portion of the period in coming forecasts. Winds and waves will subside through the day Wednesday, with additional Small Craft Advisory conditions possible Wednesday night into Thursday.

Quigley

MKX WATCHES/WARNINGS/ADVISORIES

WI...Extreme Cold Warning...WIZ046-WIZ047-WIZ051-WIZ052-WIZ058- WIZ059-WIZ060 until 6 AM Saturday.

Cold Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ058- WIZ059-WIZ060 until noon Saturday.

Cold Weather Advisory...WIZ056-WIZ057-WIZ062-WIZ063-WIZ064- WIZ065-WIZ066-WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072 until noon Saturday.

LM...Heavy Freezing Spray Watch...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876- LMZ878...6 PM Sunday to 6 PM Tuesday.