textproduct: Milwaukee/Sullivan

KEY MESSAGES

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

- Chances (about 60 to 80 percent) for light rain or drizzle in southeast Wisconsin late this afternoon/evening, with rain/heavy drizzle likely (about 60 to 80 percent chances) area wide Christmas night.

SHORT TERM

Issued 230 PM CST Wed Dec 24 2025

Tonight through Friday:

The first of 2 systems over the next 48 hours pushes in later today through the evening. This is a very weak system overall dominated in large part by low level moisture and WAA with some shortwave energy aloft perhaps playing a very minor role. Soundings are suggestive of widespread moisture in the low levels sliding through this evening. Some near surface dry air may prevent precip from reaching the surface at first but will moisten up enough for most of the area. Models are suggestive of better WAA and omega further south in the CWA leading to likely chances (60-80%) but decreasing toward central WI where forcing is limited and may not moisten quickly enough to allow for some precip. With this being a shallow event with no ice crystal participation given the strong WAA this is largely expected to be a drizzle event. There is a very slight chance (<5%) for some of this to be freezing drizzle in central WI if that area can even manage to squeeze out some precip while being a bit cooler.

By midnight precip should be entirely out of the region with high pressure moving across the northern Great Lakes largely keeping us dry. However, cooler temps toward central WI will fall below freezing and any water still on roads may freeze but this too seems very unlikely to be of concern. Quiet conditions largely expected Christmas day. As move into Christmas night and into Friday morning we will see the next chance for precip. This too looks likely a mostly rain event. This is associated with some better forcing with a weak surface low pushing through that will bring a LLJ with strong WAA, and a decent shortwave aloft as well. Precip is largely expected late Christmas evening through mid Friday morning. There is some concern for freezing rain to mix in toward central WI with this event but models really limit potential given the extremely small window as rain pushes in because temps are expected to warm overnight given the strong WAA. This event may too lack ice so much of precip may end up as drizzle but the strong WAA may allow for a bit more collision and coalescence in the cloud layer making for some larger drops or perhaps heavier drizzle.

Late Friday morning precip will push out as the low pushes out and weak high pressure pushes in with large scale ridging overhead. Thus dry conditions are expected for the remainder of the day Friday.

Kuroski

LONG TERM

Issued 230 PM CST Wed Dec 24 2025

Friday night through Wednesday:

A weak sfc ridge will pass Fri nt, but stratus clouds underneath a strong subsidence inversion will persist and maintain relatively mild low temps.

Sly winds and warm advection will ensue for Sat as low pressure moves from the Dakotas to nrn MN and adjacent Ontario. This is in response to a larger scale upper trough over srn Saskatchewan. A shortwave trough extends from the aforementioned trough over ID during this time. The larger scale trough moves to Ontario for Sunday while the fast moving shortwave trough moves to the Middle MO River Valley. These two troughs may initially support two centers of low pressure with one over Ontario and another over nrn IL for Sun AM via the ECMWF Ens. However, the GEFS MSLP forecast favors the nrn IL low as dominant. Either way, cyclogenesis will ensue over srn Ontario and the lower Great Lakes with one dominant low becoming established by Sun nt. Mild temps are forecast into Sun AM over srn WI along with 20-40% chances of light rain and snow into Sun evening. Intensifying nwly winds and cold advection will begin Sun afternoon or evening with a return of polar air for early next week. The brisk nwly winds and polar air will support below zero wind chills for Sun nt-Mon AM, and will be watching the wind speeds for potential Wind Advisories.

A shortwave trough in nwly flow aloft and the accompanied PVA and warm advection will then support 20 percent chances for light snow Tue nt-Wed. For late Wed and beyond there is much uncertainty pertaining to another surge of arctic air, but weaker sfc flow and cold advection is more favored.

Gehring

AVIATION

Issued 230 PM CST Wed Dec 24 2025

Lower CIGS from the morning have finally pushed out leaving largely high clouds remaining for now. We will see our next weak system roll in late this afternoon and through the evening bringing drizzle to much of southern WI for at least a few hours at any given location. This will bring with it some MVFR/IFR CIGS and perhaps some reduced VSBYS as well. This will blow out fairly quickly overnight. A brief return to VFR CIGS as this system pushes out with some lingering MVFR CIGS toward the IL/WI border. Toward daybreak northeast winds off the lake will develop another period eastern WI MVFR/IFR CIGS as they did this morning as another strong inversion will keep moisture in the lowest levels trapped. The extent and time of this is a bit uncertain but the eastern half of WI through Christmas morning will have concern for this. A return to VFR CIGS expected later in the day.

Attention then turns to Christmas night into Friday as another system pulls through likely bringing additional chances for low CIGS and even lower VSBYS as precip could be a bit heavier, perhaps heavy drizzle.

Kuroski

MARINE

Issued 230 PM CST Wed Dec 24 2025

A weak low pressure trough will cross Lake Michigan this evening, and then another high pressure system will bring a push of northerly winds down the lake early Thursday morning. Winds shifting from southerly to northerly and becoming breezy from the north to northeast Thursday. Small Craft conditions expected Thursday into Friday with high waves and winds. Weak low pressure will cross Illinois and Indiana on Friday. There is a high chance for gales Sunday through Monday as low deepens as it moves across eastern Canada. Nearshore will at least need a Small Craft but the nearshore may very well see gales as well.

Kuroski

MKX WATCHES/WARNINGS/ADVISORIES

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