textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Areas of very light snow or flurries this afternoon and evening with the passage of an arctic front.

- An Arctic airmass settles in this weekend with wind chills ranging from -10F to -30F late Friday night through Sunday night. A Cold Weather Advisory is in effect from Madison to Milwaukee and north toward central WI from late tonight through Saturday morning. Another advisory will likely be needed Sat nt-Sun AM for all of Srn WI. - Next week temps return to near normal with daytime temps around or above freezing by midweek.

SHORT TERM

Issued 450 AM CST Fri Dec 12 2025

Today through Saturday:

The upper trough over Manitoba will amplify as it moves sewd into Ontario today and tonight. Cyclogenesis will ensue north of Lake Superior this afternoon and continue ewd as well. This will drive the arctic front, currently over wrn MN, through srn WI this evening. Areas of very light snow or flurries can be expected with the frontal passage. Brisk nwly winds and very cold temps will drop the wind chill temps to -20 to -25F for Sat AM from Madison to Milwaukee and northward. Thus a Cold Wx Advisory is now in effect.

During the day on Sat, a frontogenetic band of light snow will move across IA and IL, but it could clip far srn WI. 20-40% chances of light snow are forecast near the IL border. High temps only in the single digits above zero are forecast. An upper trough axis will then swing sewd from Canada Sat nt, thereby reinforcing the arctic air. Low temps well below zero for well inland locations are forecast along with wind chill temps of -20 to -29F over all of srn WI. The arctic high around 1045 mb will reach IA by 12Z Sun then move ewd into the Ohio Valley by Sun nt. Swly winds and warm advection will then begin Sun nt but still with cold temps and wind chills hanging on.

Gehring

LONG TERM

Issued 450 AM CST Fri Dec 12 2025

Saturday night through Thursday:

The arctic high pressure weakens and pushes southeast of the region Monday, continuing into the Atlantic Ocean through mid week. Breezy southwest winds (strong WAA) are expected through the first half of next week, likely boosting daytime highs around or slightly above the freezing mark Tuesday, then towards 40 degrees for Wednesday. Strong low pressure tracking eastward across Canada will allow the WAA to continue the pace even as the arctic high dissipates and merges into the Atlantic mid week. Dry weather is looking likely through the first half of the week.

Predictability drops from mid next week onwards, but models do hint at a passing low pressure system, which could be anything from a small clipper system (00z-GFS) to a more dominant synoptic low pressure system (00z-ECMWF). We've left precip chances (30-40%) in the forecast from Wednesday evening onwards to compensate.

Sheppard

AVIATION

Issued 450 AM CST Fri Dec 12 2025

Patchy light freezing fog through 14Z. Otherwise VFR conditions until MVFR Cigs develop ahead of the arctic front this afternoon with MVFR Cigs continuing in the evening with flurries. The stratus clouds will then dissipate by late tnt.

Gehring

MARINE

Issued 450 AM CST Fri Dec 12 2025

Light and variable winds this morning will give way to breezy southwest winds this afternoon as low pressure around 29.7 inches develops north of Lake Superior and moves east through the weekend. The low will sweep an arctic front across Lake Michigan tonight, with a prolonged period of brisk northwest winds and heavy freezing spray for much of the weekend.

High pressure around 30.8 inches will move southeast from the northern Plains and through the western Great Lakes late Sunday. Winds ease later Sunday as the high approaches, but gusty winds may return early next week as the high exits into the Ohio River valley.

Brisk nwly winds has resulted in a Small Craft Advisory from Sheboygan to Winthrop Harbor for this evening through Sun A>

Gehring

MKX WATCHES/WARNINGS/ADVISORIES

WI...Cold Weather Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056- WIZ057-WIZ058-WIZ059-WIZ060-WIZ063-WIZ064-WIZ065- WIZ066...midnight Saturday to noon Saturday.

LM...Heavy Freezing Spray Warning...LMZ080-LMZ261-LMZ362-LMZ364- LMZ366-LMZ563-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ675- LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876- LMZ878...midnight Saturday to 9 AM Sunday.

Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...9 PM Friday to noon Sunday.