textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Pockets of elevated fire weather conditions continue through this afternoon, particularly west of I-41.

- Periods of showers and thunderstorms expected Monday night into Tuesday. A few severe storms are possible.

- Active weather continues into the second half of next week, with multiple chances for snow then rain Thursday into Saturday.

UPDATE

Issued 620 PM CDT Sat Mar 28 2026

Quiet conditions tonight with modest south to southwest winds and partly cloudy skies under the western wide of the high pressure. Low pressure will push toward the area overnight into Sunday morning with the warm front well to the north of the CWA. Increased high clouds with the approaching low but quiet conditions will continue.

Kuroski

SHORT TERM

Issued 215 PM CDT Sat Mar 28 2026

Rest of Today through Sunday night:

Synopsis/Mesoanalysis: High pressure is centered over Indiana early this afternoon, resulting in generally south to southwest surface winds across southern Wisconsin. Broad warm advection is ongoing regionally along the back side of the high, with deep isentropic ascent in the 925-700 mb layer responsible for the mid-upper clouds moving in from the Upper Mississippi Valley. Mid-upper clouds will linger across the area into Sunday afternoon, with clearing working in from the west by Sunday evening. Vacating high pressure will allow the surface front currently over North Dakota to gradually work into northern Wisconsin Sunday evening, where it remain through the conclusion of the short term period. The boundary's gradual approach will maintain south-southwesterly winds in southern Wisconsin, allowing for much milder temperatures tomorrow afternoon. Pockets of elevated fire weather conditions continue across the area through the remainder of this afternoon.

Rest of Today through Sunday: Continue to monitor for pockets of elevated fire weather conditions through the rest of this afternoon as winds increase & sunny skies allow for deep mixing of the boundary layer. Greatest potential for pockets of elevated fire weather conditions is to the west of I-41, where low level mixing will be deepest & minimum relative humidities will drop the furthest. Fuels, which remain on the moist side areawide, will preclude more widespread elevated fire weather potential. Have thus held off on any Special Weather Statements in the afternoon forecast update. Will need to monitor for additional pockets of elevated fire weather conditions Sunday, though modest moisture returns should keep potential lower than today.

Quigley

LONG TERM

Issued 215 PM CDT Sat Mar 28 2026

Monday through Saturday:

Synopsis: The frontal boundary moving into northern Wisconsin through Sunday evening/the conclusion of the short term period will linger over the same general vicinity through the day on Monday into Monday night. Through a likely combination of synoptic and mesoscale processes, the front's southward progress will pick up on Tuesday, with the boundary vacating the region by mid-afternoon. Periods of showers and thunderstorms will accompany the approaching/passing front, with activity likely focusing during the Monday evening/night and Tuesday afternoon time frames. Broad overlap of sufficient instability and wind shear will support some potential for a few strong to severe storms during the Monday evening through Tuesday time frame. Trends will continue to be monitored in coming updates. Cooler conditions will prevail behind the departed cold front Wednesday into Thursday, with moderation in surface temperatures occurring Friday into Saturday. Periods of precipitation will return Thursday through Saturday as a pair of disturbances cross the western Great Lakes. Precip could start as light snow on Thursday, with warming temperatures allowing for a changeover to rain Friday into Saturday.

Monday night: Will be monitoring for round 1/2 of showers and thunderstorms with a surface front lingering just to the north of the area. Any thunderstorm development will be elevated, as a stout EML near/above the 850 mb level will leave the surface layer capped through the overnight period. Anticipate that the aforementioned EML/capping will hinder any convective development through early evening, though an increasing low level jet & affiliated isentropic ascent could provide enough lift to trigger elevated showers & storms moving deeper into the overnight hours. While far from a certainty, available global & mesoscale guidance currently suggests that the best LLJ dynamics & isentropic ascent will be positioned along & north of I-94/US-18, which is where likely (~60%+) precip probabilities have been maintained in the afternoon forecast update. Could see additional shifts in the placement of the LLJ & associated lift over coming forecast cycles, so anticipate some further movement in the corridor of best shower/storm potential in coming updates. Forecast soundings depict anywhere between 500-1500 J/kg of MUCAPE with the potential corridor(s) of storm development, which would overlap with sufficient deep layer shear to support some organized convection capable of large hail & perhaps a few stronger wind gusts. Increasing precipitable water values would also be supportive of heavy downpours in any convection. Widespread flooding potential remains low as of this forecast, though trends will continue to be monitored.

Tuesday: Will be watching for a possible round 2/2 of showers and thunderstorms as the main cold front moves through southern Wisconsin. Whether or not a second round of development can occur will depend on how quick the front moves through, in addition to the amount of cloud cover lingering in the wake of overnight/early morning showers & storms. If the front lingers into the afternoon & peak heating of the day, the chances for more showers & storms would increase, particularly in southeast Wisconsin where the boundary will pass the latest. In the event enough instability was realized for convection, shear would remain sufficient to support a few more strong to severe storms. Remaining uncertainties regarding evolution of the cold front/destabilization along it---which will likely be heavily influenced by round 1/2 of activity---make it difficult to offer further details at this time, with trends being monitored closely in coming forecasts.

Thursday through Saturday: Additional precipitation chances return ahead of two more disturbances. Could see some snow at the outset of precipitation on Thursday, with steady warm advection allowing for a changeover to all rain Friday-Saturday. Will offer more details regarding precip totals & any thunder potential as this portion of the period draws closer.

Quigley

AVIATION

Issued 645 PM CDT Sat Mar 28 2026

The lake breeze has pushed through some areas near the lake with southeast winds early this evening but generally over the next few hours the lake breeze will weaken and winds will shift back southwest. Winds will remain light to modest with some winds aloft bringing LLWS concerns 2kft up from the southwest at about 40 kts. this may last into early Sunday morning. Otherwise skies will clear out over the next few hours with mostly high clouds over southern WI in the TAF period. No other TAF concerns are expected at this time.

Kuroski

MARINE

Issued 215 PM CDT Sat Mar 28 2026

Widespread gales are not anticipated across the open waters through the duration of the forecast period. Currently centered over Indiana, 1034 mb high pressure will advance into the Mid-Atlantic this afternoon through tonight as 1006 mb low pressure builds into the northern Great Plains, resulting in increasing south to southwesterly winds across Lake Michigan. Widespread 20-25 knot gusts are expected over the northern half of the waters, with a few gusts to 30 knots possible over the far northern lake. Breezy southwest winds will continue through tomorrow as a cold front begins to approach the waters from the north. The front will gradually advance south across Lake Michigan Sunday night through Tuesday. This will result in generally east-northeast winds across the northern half of the lake with southerly winds further south. A few gales are possible over southeastern Lake Michigan Monday night, but aren't expected to be widespread. Periods of showers and thunderstorms will accompany the slow-moving front, with a few stronger storms possible Monday night and once again on Tuesday. Large hail would be the primary threat in any stronger storms.

Winds will trend northerly behind the departing cold front Tuesday evening through Wednesday. Will be monitoring trends for a few gusts approaching gale force Tuesday evening/night, with the current expectation being for any such gusts to be isolated. 1040 mb high pressure will shift from Ontario to Quebec through the late week time period as 1010 mb low pressure builds into the Ohio River Valley, allowing winds to trend east-northeasterly. Additional rain and snow will accompany the approaching/passing area of low pressure Thursday into next weekend.

Southerly winds and wave heights will increase in nearshore zones this afternoon, with readings exceeding Small Craft Advisory conditions from Port Washington and points north. A Small Craft Advisory has thus been issued between 4 PM and 10 PM CDT from Port Washington north to Sheboygan in the mid-day forecast update. Winds and waves are expected to remain below advisory thresholds further south. Winds will gradually taper as they veer southwesterly through the overnight, with a larger offshore wind component also allowing wave heights to trend downward. Thus don't anticipate the need for any Small Craft Advisories beyond 10 PM CDT, though trends will continue to be monitored through this afternoon & evening. Additional periods of Small Craft Advisory conditions are likely moving into next week. Will assess the need for headlines as this part of the period draws closer.

Quigley

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Small Craft Advisory...LMZ643 until 10 PM Saturday.