textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Patchy fog may occur tonight, with dense fog possible in a few areas.

- Gradual warming trend expected through the Saturday.

- Next chances for precipitation primarily across central Wisconsin (15 to 30 percent) Saturday night into Sunday.

UPDATE

Issued 729 PM CDT Thu Mar 19 2026

Middle to high clouds should gradually push southeastward into the area tonight. Light winds should also gradually veer to the south and southwest later tonight, with weak warm air advection occurring. This should help dew points slowly rise overnight into early Friday morning.

This may help lower dew point depressions enough with the light winds to bring patchy fog, especially over south central Wisconsin. There could be dense fog in some areas, mainly in low lying areas where winds decouple and temperatures meet dew points. The cloud cover may limit fog potential, so will have to watch trends into this evening and see how things develop. The frontal boundary pushing southeast through the area Friday morning should mix out any lingering fog.

Some middle to high clouds may linger Friday morning, before an area of low stratus clouds pushes southward into the area Friday afternoon. This is despite high pressure over the region keeping winds fairly light. This low cloud deck may linger into Friday night. Temperatures Friday will depend on how soon the low clouds move in. For now, have highs in the lower to middle 60s in areas west of Madison, with middle 40s toward Fond du Lac and Sheboygan and 50s elsewhere. More low clouds may limit how warm temperatures get Friday.

Wood

SHORT TERM

Issued 135 PM CDT Thu Mar 19 2026

Tonight through Saturday:

Temperatures have quickly risen to 50 degrees away from Lake Michigan, with temperatures in the 40s across central Wisconsin (more snowpack) and near Lake Michigan (light lake breeze). Expecting mostly sunny skies to prevail, with highs a few degrees above current temperatures as spring sunshine continues for the next few hours.

Tonight, temperatures will fall into the mid to upper 30s. This will be near dewpoints with very light winds under high pressure. This may lead to patchy fog tonight. However, a northern Wisconsin low pressure system will bring increasing southwesterly winds during the late overnight hours into Friday morning, scrubbing out fog and allowing for a period of low stratus. Winds shift to become northwesterly Friday morning, bringing additional low clouds in.

Friday afternoon, clouds will scatter out across southwestern to far southern Wisconsin as winds diminish, allowing for temperatures to rise into the upper 50s to near 60 degrees. Elsewhere, where cloud cover lingers, expect highs in the upper 40s to low 50s.

Additional shortwaves traverse southern Canada and the northern Great Lakes region Friday night and Saturday, keeping winds southerly and temperatures warm. Expect Friday night lows in the upper 30s and Saturday highs in the 50s near Lake Michigan and central Wisconsin, the 60s in the majority of southern Wisconsin, and even the low 70s possible in far southwestern Wisconsin.

MH

LONG TERM

Issued 135 PM CDT Thu Mar 19 2026

Saturday night through Thursday:

Ensemble and deterministic model guidance suggests several clipper systems will progress west to east across the region through this time period, though with much of the QPF (precipitation) passing well north of the region. The first could pass anytime from Saturday night through the daytime hours Sunday, likely only lasting a small fraction of that window. Our forecast calls for 15-25% precip chances with it (highest towards east-central WI), and based off the antecedent warmth, this would be all rain. On the back side of this system (depending on it's track, which is widely disputed amongst ensembles), we wouldn't be surprised to see a trace of flurries / freezing drizzle in the cold conveyor, though the odds of any measurable / impactful precip are 15% or less at this time. North to northeasterly flow on Sunday will advect some cooler air into the region (particularly along the Lake MI shoreline), there's a wide spread in the exact temperature values (with ~50 degree inland highs as the median), but the main story will be 'much cooler than Saturday'. As CAA continues into Sunday night, ensemble temperature IQRs for minimum temperature fall to the mid to upper 20s.

The rest of the clipper systems through this period pass north of our region, allowing temperatures to gradually moderate upwards. Predominantly dry weather expected through the period, with the majority of model QPF missing us to the north once again. Generally, the earliest we could see a more organized low pressure system (with higher precip chances) would be late next week (Thursday and onwards) based on ensemble guidance.

Sheppard

AVIATION

Issued 729 PM CDT Thu Mar 19 2026

Middle to high clouds should gradually push southeastward into the area tonight. Light winds should also gradually veer to the south and southwest later tonight. Patchy fog may occur, especially over south central Wisconsin including Madison and Janesville. There could be dense fog in some areas, mainly in low lying areas where winds become calm. The cloud cover may limit fog potential, so will have to watch trends into this evening and see how things develop.

Low level wind shear conditions are also expected overnight into early Friday morning across the area, with southwest to west southwest winds around 40 knots at 2000 feet AGL.

The frontal boundary pushing southeast through the area Friday morning should mix out any lingering fog. Winds will shift to the northwest to north behind the front Friday morning.

Some middle to high clouds may linger Friday morning, before an area of low ceilings around 1000 to 1500 feet AGL pushes southward into the area Friday afternoon. This is despite high pressure over the region keeping winds fairly light. This low cloud deck may linger into Friday night.

Wood

MARINE

Issued 135 PM CDT Thu Mar 19 2026

High pressure of 30.2 inches will keep winds light and variable through this evening, with southeasterly winds developing late tonight as low pressure around 29.7 inches progresses east into Lake Superior. Winds will shift to northwesterly as low pressure exits eastward Friday morning. Winds shift northeasterly as high pressure of 30.2 inches builds into Ontario Friday night. Low pressure then develops in the lee of the Wyoming Rockies Saturday morning, shifting winds to southeasterly and allowing them to increase as low pressure progresses eastward Saturday night. Low pressure crosses northern Illinois into southern Lower Michigan as it deepens to 29.4 inches, leading to northerly winds backing to northwesterly Sunday into Sunday night. Gales are possible during this timeframe. High pressure with lighter winds then dominate on Monday.

MH

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...None.