textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Widespread fog with visibilities around 1-2 miles expected through this morning, with patchy dense fog possible. Dense fog is possible again overnight into Friday morning.

- Light rain or drizzle is possible through this morning across southeastern Wisconsin (~40 percent chance). - Moderate to briefly heavy rainfall rates are possible Friday into Friday night, with embedded thunderstorms expected. A few strong to potentially severe storms may be possible Friday evening into Friday night. - Very mild Friday and again Monday and Tuesday.

- Rain with perhaps a few embedded thunderstorms Tuesday into Tuesday night, with snow developing Tuesday night into Wednesday.

SHORT TERM

Issued 1256 AM CST Thu Mar 5 2026

Today through Saturday:

Light easterly winds near Lake Michigan will bring in continued low stratus and fog. Although confidence is high in widespread fog development across southeastern Wisconsin into far south- central Wisconsin, visibilities in the 1/2 to 1/4 mile categories (dense fog) have considerably less confidence. Areas to the south within the core of low pressure have certainly seen dense fog develop, but in southern Wisconsin, farther away from the core and mainly advection off Lake Michigan driven, thinking only patchy dense fog is possible at this time. Still, with very low stratus, and dew points near the temperatures, could still see stratus build down to the surface by daybreak, primarily in Ozaukee to Waukesha to Rock Counties south and eastward.

Low stratus and patchy fog remain in place throughout the remainder of today and tonight as southern Wisconsin remains in light easterly flow within a seasonably warm airmass. Conditions will improve through the day, with highs in the 40s to low 50s. Overnight, as temperatures begin to fall again, patchy dense fog becomes likely again. Widespread dense fog is possible late tonight into Friday morning.

Friday morning, gusty southerly winds develop as a warm front lifts through southern Wisconsin and brings a round of showers and thunderstorms (80-100% chances). As this round of storms progresses eastward into midday, more widespread thunder activity is possible as MUCAPE values increase into the 750-1000 J/kg range. With a strong warm nose, the majority of this activity will remain elevated, so strong to severe storms are not expected during the morning hours.

Although capping remains in place in the low levels through much of Friday afternoon, expecting temperatures to rise into the mid to upper 60s across all of southern Wisconsin as stiff southerly winds continue. If any sunlight is able to enhance the warming, this capping whittles away quickly and creates a surface-based thunderstorm. Regardless of capping, MUCAPE of 1000-1500 J/kg, 700-500 mb lapse rates of 7-8 degrees C/km, bulk shear of 40-50 kt, and freezing levels near 700 mb will all allow for hail potential in stronger storms. Any storms that do become surface based will also be capable of producing gusty and damaging winds, although these will likely much more isolated.

Storm coverage will become more isolated into the late afternoon and evening hours Friday as the warm front lifts north into northern Wisconsin. A cold front and associated pre-frontal convection will then form the basis for the next round of thunderstorms late Friday night into early Saturday morning. MUCAPE will be lower (currently progged at 500-750 J/kg), but bulk shear increases to 50-60 kt and a LLJ as high as 60 kt noses into southern Wisconsin along with the front. In other words, dynamic forcing is great, while instability may prevent storms from tapping into the dynamics and becoming strong to severe.

Cold front completes its progression through southern Wisconsin by daybreak Saturday, with some lingering rain and storms into this period. Lingering lighter showers may continue into Saturday afternoon, but not anticipating any additional strong or severe storms. Highs in the 50s are expected.

MH

LONG TERM

Issued 1256 AM CST Thu Mar 5 2026

Saturday night through Thursday:

High pressure builds back into the region Saturday night as low pressure exits, bringing clearing skies and lows in the mid to low 30s. Light winds will gradually turn southwesterly into Sunday morning as a low pressure system pivots through southern Manitoba into the Hudson Bay. This will result in warming temperatures to near 60 degrees, potentially all the way to Lake Michigan as a strong offshore component is expected. Winds remain southwesterly through Sunday night, with lows in the 40s expected. Southwesterly winds continue into Monday, bringing highs in the upper 60s, and perhaps a few places nearing 70 degrees.

More uncertainty in the forecast develops Monday night, as model solutions diverge on strength and therefore timing of a shortwave propagating across the northern Plains into the Upper Midwest. The GFS prefers a faster, stronger solution across northern Minnesota, dragging a weak front through southern Wisconsin during the early evening hours. Euro and Canadian prefer a weaker solution, phasing with a developing low in the Montana Rockies and allowing it to eject eastward into the Upper Midwest during this same time frame. With these solutions at play, GFS brings precipitation into southern Wisconsin as early as Monday night, while the Euro and Canadian hold off until Tuesday afternoon into Tuesday night. Have kept NBM PoPs in for this forecast cycle due to this uncertainty, with high confidence (70% or higher) in Tuesday night precipitation. Depending on timing and strength of this system, the back side may see a rain snow mix to a brief period of snowfall into Wednesday morning. Precipitation may still linger into Wednesday afternoon if stronger solutions prevail, as wrap- around precipitation will continue for several hours as low pressure slowly moves out (30-40% chances).

Model solutions continue to show an amplified pattern through late week, with confidence high in a low pressure system propagating through the Upper Midwest in some capacity on Thursday, but low confidence in exact placement and timing. Therefore, continued with NBM output through late week.

MH

AVIATION

Issued 1256 AM CST Thu Mar 5 2026

Light easterly winds off Lake Michigan will continue to bring in IFR stratus through this morning and even throughout much of the day into tonight. Widespread fog is expected from MKE to JVL southward this morning, with patch dense fog (1/4 SM) possible. Visibilities will improve briefly during the midday to afternoon hours, before lowering again after sunset and spreading farther inland. Ceilings and lowered visibilities are only expected to begin to lift into Friday morning as gusty southerly winds develop and scour out the low lying clouds. However, going into Friday morning, a round of rain and thunderstorms is expected to develop.

MH

MARINE

Issued 1256 AM CST Thu Mar 5 2026

Weak low pressure around 29.9 inches over southern Illinois will progress through the Ohio Valley today as high pressure around 30.7 inches lingers over the Hudson Bay, bringing increasing easterly winds. Warm airmass will allow for dense fog (less than 1 NM) across southwestern portions of the Lake, with potential to spread through the remainder of the southern third of the lake through today into late tonight. Fog is expected to continue through Friday morning, before winds shift to southerly and become gusty ahead of low pressure of 29.4 inches developing in the central Plains. Conditions may become hazardous for small craft during this time. Rounds of rain and thunderstorm, with a few storms becoming strong to severe, will progress through the Lake Friday afternoon through Friday night as low pressure progresses northeastward into Lake Superior. Late Friday night into Saturday morning, a cold front will progress southeastward through the Lake, bringing a final round of rain and storms and turning winds to northwesterly. Winds remain light and northwesterly through Saturday night. Winds turn back southwesterly into Sunday morning as low pressure develops in the Plains.

MH

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Dense Fog Advisory...LMZ644-LMZ645-LMZ646-LMZ671-LMZ673-LMZ675- LMZ777-LMZ779 until 6 AM Friday.