textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Rain is likely (about 60 to 80 percent chances) area wide tonight across all of southern Wisconsin.

- Temperatures continue to trend well above normal through the end of the week.

SHORT TERM

Issued 357 AM CST Thu Dec 25 2025

Today through Friday night:

The fog that developed around midnight into the early morning hours is decreasing as winds pick up. This trend of diminishing fog will likely continue as the north to northeast winds continue to increase and become breezy. With visibilities improving Santa and Rudolph should have an easier time traversing southern Wisconsin.

A strong high pressure system in central Manitoba early this morning will move southeast into Ontario before swinging into Quebec tonight. Meanwhile a shortwave and sfc low from the northern plains will push eastward into the Ohio River Valley tonight into Friday afternoon. As this low progresses east toward the state, strong WAA, the LLJ and lift from the shortwave will bring widespread precipitation. This will largely be rain as there will be no cloud ice due to the dry air in the upper levels and temps will be above freezing for the longest period of time. The only concern for a different precip type will be this evening where the northwestern corner of our CWA (Sauk, Columbia, Marquette and Green Lake Co)could get some light freezing rain/drizzle. This will be entirely dependent on when the precipitation starts and when the WAA kicks in. From forecast soundings and CAMs its 15% chance or less that any freezing drizzle develops and moves into southern Wisconsin. Temperatures will be right at freezing during the evening hours from roughly 9 to midnight which is the best timing window as well. Given everything, if freezing rain/drizzle does occur a glaze or less of accums will be possible on untreated surfaces. Once temperatures rise above freezing and rain begins to fall any icing that did accumulate will melt over time. Therefore the only concerns for travelers will be those leaving late Christmas Day. Be mindful that those heading north will be moving into a more favorable environment for freezing drizzle/rain and sleet so plan travel accordingly. For those hunkering down for an early night after waking up early to open presents, the rain will continue through the overnight hours into Friday morning. With the mild temperatures, rain and the last of the melting snow, can't rule out some fog developing prior to sunrise, but breezy winds should prevent it from becoming dense. Rain should clear the entire area from west to east by early Friday afternoon.

High pressure will move in behind the exiting low Friday leading to dry conditions and mild temperatures through the rest of the day.

Patterson

LONG TERM

Issued 357 AM CST Thu Dec 25 2025

Saturday through Wednesday:

Saturday brings the next approaching low pressure system and chances for precip Saturday night through Sunday. This all starts with an upper level low swinging down from Canada into the northern Plains and then progresses eastward toward Ontario. While this primary trough moves through the northern CONUS, a shortwave from the Pacific northwest will swing through toward the northern Ozarks. Guidance tends to treat this shortwave one of two ways, by either having good phasing between the systems as they progress east or bad phasing with the shortwave lagging just a bit behind. Guidance does favor these two features eventually phasing together Sunday night into Monday. What this all means for southern Wisconsin is that the mild temperatures and southerly winds will continue through Saturday night. Low chances for rain (10-25%) Saturday night into Sunday morning as the lift moves in. Precip chances increase to around (30 to 50%) for Sunday afternoon. Winds will begin to turn to the northwest Sunday afternoon and polar air will come with the wind change. This will bring a chance for a wintry mix of rain/snow that could become all snow as the precipitation ends Sunday evening.

Winds will increase and become brisk Sunday evening leading to quickly dropping temperatures. Below zero wind chills are expected Sunday night into Monday morning. Will have to keep an eye on the winds during this time period as the could be a potential for a Wind Advisory, but confidence is low on that at this time.

With the colder temperatures setting in for early next week, the next chance (<20%) for snow looks to be Tuesday night into Wednesday. Guidance suggests a low pressure system will advect from Saskatchewan into southeastern Ontario and drag a cold front across Wisconsin. There is some uncertainty on if we will have enough moisture for any good measurable snow, but will have to wait and see what shakes out.

Patterson

AVIATION

Issued 357 AM CST Thu Dec 25 2025

Predominately VFR to MVFR ceilings early this morning. The low level stratus clouds around 1-3 kft are very slowly eroding from the north to the south. This will lead to a period of VFR conditions for much of the morning and afternoon with only high level clouds streaming in from the northwest. Late this afternoon into this evening MVFR to IFR conditions are expected to return to the area ahead of our next chance for rain/drizzle. There is a small potential that terminals in southwestern Wisconsin have a very small window of improved ceilings (maybe an hr or two) prior to the next system coming in. Visibilites are expected to drop to around 2-4 SM with the rain/drizzle. When the rain and drizzle ends early Friday morning there will be a potential for fog which will keep visibilites low through the end of the period.

Northeast winds this morning will turn to easterly by early this afternoon and become gusty. The gusty east winds will remain breezy and become southeasterly tonight into Friday morning.

Patterson

MARINE

Issued 357 AM CST Thu Dec 25 2025

North winds have developed early this morning as high pressure of 30.5 inches noses into the region from the north. Winds will then turn easterly this afternoon as the high moves east then southeasterly tonight as low pressure of 29.7 inches moves across central Illinois.

Stronger low pressure will affect the region late in the weekend into Monday, moving from the central Plains into the eastern Great Lakes. This will initially result in increasing southeast winds Saturday night and early Sunday, followed by a good chance for gales Sunday night and Monday as a strong cold front sweeps across Lake Michigan. Much colder air will also pose a risk for freezing spray.

Patterson

MKX WATCHES/WARNINGS/ADVISORIES

WI...None. LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...9 AM Thursday to 2 PM Friday.