textproduct: Milwaukee/Sullivan

KEY MESSAGES

- A cold front will drop southward through the region Today, bringing scattered rain showers and cooler temperatures behind it. A few rumbles of thunder are possible in southern WI towards the WI/IL border.

- Cooler conditions will persist Friday, with scattered snow showers possible Friday afternoon and evening (15-40% chance). Highest confidence towards east-central WI.

- Return to warmer temperatures for this weekend into early next week.

- Trending more active early-mid next week, with multiple chances for showers and thunderstorms

UPDATE

Issued 653 AM CDT Thu Mar 26 2026

Rain has develop across central Wisconsin and northern Iowa this morning. These showers are developing behind the cold front where the better mid level fgen and WAA resides. The weak southwest winds overnight have kept temperatures mild and dewpoints up. The rain showers currently out on radar will continue east across the state and will scrape around the edges of our forecast area. These showers will be fairly light this morning, but this isnt the show for us just yet.

Mid level Fgen is expected to slowly shift south overtime behind the sfc cold front. We can see the winds direction change and some colder air start to move in along the front which is stretched roughly from Mauston to Oshkosh to Manitowoc. This weak boundary will slowly pull south throughout the morning. As it does so the sfc WAA will come to an end and temperatures will start to fall. Far south and southwestern Wisconsin will have the warmest temperatures of the day and therefore the most instability. This will be the area to keep an eye on as we head into the late morning and afternoon when the mid level forcing is overhead. This will be the area with the best potential for a few rumbles of thunder as the precipitation expands across southern Wisconsin. Not expecting any stronger storms here as we just wont have enough time to destabilize here in Wisconsin prior to the cold front passing.

Patterson

SHORT TERM

Issued 1025 PM CDT Wed Mar 25 2026

Today through Saturday:

High pressure building into the western Canadian provinces will force a cold front southward across the region this morning, with northeasterly winds arriving behind it. Some 700mb FGEN / WAA well north of the surface front may yield some light sprinkles of rain in portions of central and east-central WI from around dawn this morning through mid morning (mainly north of a Lone Rock to Juneau to Sheboygan line, 10-30% chances). The surface front completes it's passage later this morning, with northeast winds then intensifying into this afternoon. 30-40 MPH gusts are possible along the Lake MI shoreline. These winds will propel the surface cold front south of I-80 in Illinois.

As cold advection sharpens and FGEN strengthens aloft this afternoon, we expect scattered rainshowers to develop overhead (45-80% rain chances). Though we still cannot rule out a few rumbles of thunder south of I-94, probabilities have declined since the past forecast iteration. If a storm or two were to become locally strong, some small hail would be possible. Severe storms are not expected in our region with this setup. Rain shower activity confines further south into early this evening, leaving dry weather and gusty north winds for Tonight.

Light northerly CAA continues into Friday, turning northwest into Friday afternoon as the aforementioned high pressure kicks into the Dakotas. -15 to -20 Celsius air at the 700mb level moves overhead into Friday afternoon, sharpening the surface to 700mb lapse rates to dry adiabatic and allowing for sufficient surface-based buoyancy to create open-cellular convective snow showers, which (based on lapse rates / positioning of cold air aloft) will be most concentrated towards east-central WI Friday afternoon and evening. Though surface air temps will be above freezing Friday afternoon (highs in the mid 30s east-central WI to low 40s southwest WI), we expect them to drop into the evening. Though frontogenesis is too weak / disorganized to merit a substantial threat for squalls, we do expect popcorn- style convective snow showers to develop, and if low-level RH is high enough for the snow to reach the ground, we could see some pockets of reduced visibility, and perhaps even slick spots or rapid minor accumulations if surface temperatures allow. Depending on the choice of model, you could wind up with mostly virga (evaporates before reaching the ground). We'll continue to monitor as Friday draws closer.

Dry weather looking likely into Saturday with a southwesterly breeze. Temperatures begin a gradual upward trend from then onwards.

Sheppard

LONG TERM

Issued 1015 PM CDT Wed Mar 25 2026

Saturday Night through Thursday:

Synopsis: Centered over the southern plains at the beginning of the period, subtropical ridging will break down over the Gulf of Mexico Sunday into the beginning of next week. Breakdown of the ridge will allow for interaction/phasing of the polar and subtropical jet streams through the early week period, with one upper speed max extending from southern California to the western Great Lakes to Quebec by the mid-week time frame. A cold front is progged to move through the area during the day Monday, likely stalling over northern Illinois by Monday evening. The boundary will attempt to work back north into the area as a warm front Tuesday into Wednesday as low pressure develops in the central plains. Said area of low pressure will migrate east Wednesday night into Thursday, allowing the boundary to become cold frontal once more & shunting it through/south of the area. The presence of the waffling surface front, in addition to the strengthening and periodically divergent flow aloft, will thus result in more active conditions during the early to mid week period across southern Wisconsin. Absence of any deeper cold air pushes will keep temperatures mild, with all rain being favored during periods of active weather. Thunderstorms may mix in with the rain. Any stronger storm potential remains uncertain at this time, with trends being monitored over coming updates.

Monday through Monday night: Global guidance currently depicts an early day cold front passage in southern Wisconsin, with a northeast wind shift off Lake Michigan helping to shove the boundary south of the state line by Monday afternoon. Solutions show the front stalling over the northern Illinois vicinity during the evening & overnight hours, with the 925-850 mb front lagging over the southern half of Wisconsin. Combined with an increasing nighttime low level jet, could thus see an increasingly favorable environment for elevated showers & storms across the area Monday evening & night. Have maintained precip probabilities from the NBM in the evening update, as they reflect the generally increasing potential for precip through the overnight period. Expect these probabilities to sharpen & increase to more precise locations in later updates as confidence in specific areas of shower/storm development increases. Will need to monitor trends regarding stronger storm potential in coming updates given increasing MUCAPE & shear beneath the upper jet, though remaining uncertainties regarding the exact placement of boundaries & the low level jet make it too early to offer any specifics in this forecast.

Tuesday through Thursday: Expect active conditions to continue with a surface front in the vicinity & persisting dynamic flow aloft. While the NBM depicts continuous precipitation probabilities during this time frame, there will be dry periods mixed in with the bouts of shower & thunderstorm activity. These finer scale timing details will be sorted out as this portion of the period draws closer. Similar to Monday evening/night, it remains too early to offer specifics on any stronger storm potential given remaining uncertainties on surface front evolution/timing. Will also need to monitor for any trends regarding heavy rainfall given the potential for multiple rounds of showers/storms during this time frame.

Quigley

AVIATION

Issued 653 AM CDT Thu Mar 26 2026

VFR to IFR conditions are expected through the period. Light winds predominately out of the southwest will persist through sunrise this morning as a cold front slowly moves south down the state. This cold front is currently along a line from Mauston to Oshkosh to Manitowoc. North-northeast winds are expected behind the cold front later this morning into the afternoon. These northerly winds will initially be light as the front passes then they should quickly increase becoming breezy. Gusts of 20 to 30 kts (~ 25 to 35 MPH) will be possible behind the cold front this afternoon through tonight. Winds are expected to be at their strongest along Lake Michigan. Ceilings will slowly fall to around 1-3 kft late this morning into the afternoon as rain develops across southern Wisconsin. Can't rule out a couple rumbles of thunder across far southern Wisconsin late this morning through this afternoon. Not anticipating any stronger storms to develop. Since thunder are small and any rumbles of thunder will be scattered/intermittent left the mention of thunder out of the TAFs. Once the rain has cleared later this afternoon the MVFR ceilings are expected to linger into the evening hours before clearing from west to east. VFR ceilings will return tonight as the cloud deck begins to clear. As we near the end of the TAF period winds will start to diminish and become lighter. Winds will be shifting from north-northeast to north then northwest by mid Friday morning.

Patterson

MARINE

Issued 1015 PM CDT Wed Mar 25 2026

Open Waters / Synopsis:

A weak backdoor cold front will sag southward across the lake overnight through Thursday morning, with a southwest breeze ahead of it and light north winds behind it. Low pressure strengthens to 29.4 inches over the central Great Plains on Thursday, with a trough of low pressure around 29.7 inches extending northeastward through Illinois / Indiana (south of the aforementioned cold front). Meanwhile, high pressure around 30.7 inches builds into southern Canada. The tightening pressure gradient will cause north winds to accelerate across the lake Thursday afternoon, achieving gale force over the southern two thirds of the lake late Thursday afternoon through late Thursday night. A Gale Warning is in effect.

North winds gradually subside in a north to south manner Friday as the aforementioned high pressure builds into the midwest. Light northwest winds expected into Friday night as the aforementioned high pressure passes southwest of the lake, with winds gradually backing south through Saturday. Modest southerly winds take hold for much of the rest of the weekend as high pressure exits east into the Atlantic and broad low pressure develops over the Plains.

Nearshore Zones:

A Gale Warning is in effect for all nearshore zones late Thursday afternoon through late Thursday night. North gales up to 35 knots are expected, with the highest confidence in achieving gale force further south (mainly south of Port Washington). Waves will peak in the 5 to 11 foot range, with the highest waves further south and further offshore (closer to the open waters). Lingering waves will likely necessitate a Small Craft Advisory from when the Gale Warning expires (late Thursday night) through all of Friday morning, perhaps into Friday afternoon for southern zones.

Sheppard

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Gale Warning...LMZ080-LMZ366-LMZ565-LMZ567-LMZ643-LMZ644- LMZ645-LMZ646-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779- LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...5 PM Thursday to 5 AM Friday.