Milwaukee/Sullivan forecast discussion

Update

Issued 709 PM CDT Thu Oct 22 2026

Low clouds and areas of fog have moved onshore from Milwaukee northward over the last couple hours. Most locations aren't seeing much in the way of fog, though there has been a persistent patch of dense fog in the Milwaukee area the last hour or so. Given upstream webcams and observations, still expecting some improvement in visibility in Milwaukee over the next hour or two. Will hold off on a dense fog advisory for now given the local nature of the dense fog and expectation of a fairly short duration.

The low clouds and patchy fog will gradually expand south and west this evening into the overnight hours, likely not reaching as far as Madison. Otherwise, quiet weather is expected tonight, with temps a few degrees milder than last night.

DDV

Short Term

Issued 233 PM CDT Thu Oct 22 2026

Tonight through Friday night:

The main issue will be the low stratus and fog deck that may shift south southwest into eastern portions of the area into tonight and Friday morning. The current low stratus deck with some light fog is lingering over portions of northern Lake Michigan into northeast Wisconsin, and hugging the shoreline southward at Sheboygan and Port Washington. This area has mixed out somewhat with daytime heating over far northern Lake Michigan and eastern Lake Michigan. This may continue through later this afternoon with peak heating.

However, think that the more solid area of low stratus and light fog over northeast Wisconsin into the western portions of Lake Michigan probably will hold on into tonight and Friday morning. Short term models are showing this area shifting south southwest into eastern portions of the area, especially near Lake Michigan, into this evening and lingering into Friday morning. Given that high pressure well to the east will continue to bring light southeast winds, moisture off of the lake may help to solidify this area of low stratus and fog.

Dense fog is possible as well into Friday morning, given the light winds and low stratus clouds possibly sinking toward the ground under the inversion. For now, will continue to bring in these low stratus clouds and fog into eastern parts of the area into this evening and linger into Friday morning. Later shifts will need to monitor the progress of the low stratus deck and visibility drops in case any Dense Fog Advisories are needed.

Once the low clouds and fog mix out later Friday morning, another mild and dry day is expected for Friday, with middle to high clouds gradually moving into the area Friday night. Lows tonight and Friday night should be in the upper 40s southeast to lower 50s northwest. Highs Friday should reach the lower to middle 70s inland, with upper 60s closer to the lake with onshore flow.

Wood

Long Term

Issued 233 PM CDT Thu Oct 22 2026

Saturday through Thursday:

500 mb cluster analysis continues to show an anomalous ridge axis over the Great Lakes region Saturday gradually shifting eastward Sunday into Monday, with flow becoming more zonal across the region. At the surface, south to southwest winds should continue to maintain dry conditions and warm temperatures Saturday into Sunday. Highs should continue to be in the upper 60s to lower 70s each day, with a southeast lake breeze possible Saturday afternoon near the lake. Ensemble members are supportive of these values and the ensemble spreads are very small, indicating higher confidence.

Models then show a cold front slowly shifting southeast toward or through the area Sunday night or Monday, with winds shifting to the northeast behind the front later Monday into Monday night. The front may not have much moisture to work with, so any shower chances look minimal (under 15 percent) at this time. There should be some clouds that occur during this time. Temperatures should cool off Monday with the northeast winds, with highs more seasonable values in the upper 50s to middle 60s.

Ensemble members are rather mixed for shower chances through next week, as there is disagreement with the timing and placement of low pressure moving through the region. Kept NBM precipitation chances for now (20 to 30 percent) for Wednesday into Thursday, until more clarity can be found. Temperatures look to be a little above seasonal normal values.

Wood

Aviation

Issued 709 PM CDT Thu Oct 22 2026

Low clouds and areas of fog have moved onshore from Milwaukee northward over the last couple hours. Most locations aren't seeing much in the way of fog, though there has been a persistent patch of dense fog in the Milwaukee area the last hour or so. Given upstream webcams and observations, still expecting some improvement in visibility in Milwaukee over the next hour or two.

The low clouds and patchy fog will gradually expand south and west this evening into the overnight hours, likely not reaching as far as Madison. Otherwise, quiet weather is expected tonight through Friday under high pressure, with a return to VFR conditions likely in the east by late tomorrow morning or early afternoon. Light and variable winds tonight will pick up a little out of the south/southeast during the day tomorrow.

DDV

Marine

Issued 233 PM CDT Thu Oct 22 2026

A Dense Fog Advisory is in effect until 10 PM CDT this evening for the nearshore waters north of Port Washington, for a low cloud and fog deck. It may move slowly southward into this evening, so expansion of the fog and Dense Fog Advisory southward may occur.

The fog has become a low cloud deck over the northern portions of the lake this afternoon. This area may become more fog once again into this evening, with some dense fog possible. It may also spread southward and linger into Friday morning. Fog may develop in southern portions of the lake as well tonight into Friday morning, with patchy dense fog possible.

High pressure around 30.3 inches will gradually shift eastward through Friday, while strengthening to around 30.5 inches over southern Quebec. Light winds will continue into tonight, increasing a bit out of the south on Friday behind the strengthening high. South to southwest winds will then persist through the weekend, between the high to the east and a cold front to the northwest. Winds will shift to the north and northeast behind the cold front on Monday.

Winds and waves may reach Small Craft Advisory levels Saturday for areas north of Port Washington, and for all of the nearshore waters later Monday into Tuesday, as winds turn onshore.

Wood

Mkx Watches/Warnings/Advisories

WI...None. LM...Dense Fog Advisory...LMZ643 until 10 PM Thursday.

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