textproduct: Milwaukee/Sullivan

KEY MESSAGES

- Fog is likley tonight. There is the potential for freezing fog and dense fog mainly inland from Lake Michigan. - Above normal temps expected Wednesday through Thursday.

- Another round of rain (70-90%) expected Thursday afternoon into early Friday morning and cannot rule out wintry mix on the backside.

- Keeping an eye Friday night into Saturday for the next chance (40-60%) of accumulating snow for portions of southern WI, but exact amounts and track of this system still remain in question.

UPDATE

Issued 953 PM CST Tue Jan 6 2026

The potential for freezing fog and dense fog has increased tonight as short range guidance has suggesting most of southern WI inland from Lake Michigan will see vis between 1/4 to 2 miles around daybreak on Wednesday. Freezing fog will be most likely where fog becomes dense (vis down to 1/4 mile). A dense fog advisory, freezing fog advisory, or some combination of the two depending upon overnight temperatures, may be needed. Trends will be monitored overnight and advisories may be issued pending the appropriate conditions.

In areas were freezing fog occurs, some slick spots may form on untreated surfaces. Cautious travel is advised for the morning commute.

CMiller

SHORT TERM

Issued 230 PM CST Tue Jan 6 2026

Tonight through Wednesday night:

Rain continues across our northern half of the CWA this afternoon with lower visibilities. Outside of the lingering rain, southern portions of the CWA will see foggy conditions and mist/drizzle through the remainder of the evening. Will see the upper-level trough and any lingering rain kick east tonight, but foggy conditions linger overnight, while an upper-level ridge gradually builds into the Midwest through Wednesday with high pressure skirting up the Ohio River Valley tonight. Looking at overnight only lows dipping into the upper 20s to low 30s as clouds are progged to linger through the night, which are keeping temps slightly milder side.

Wednesday will see southerly flow and low-level WAA return to southern WI on the backside of the high pressure sitting to our southeast. Temps are expected to warm into the 40s through the afternoon and would not be surprised to see a few locations a bit warmer especially with any peaks of sun in southwest and far southern WI with NBM hinting at 30-50% chance of exceeding 45F. However, on the flip side 12z HREF along with models sounding suggest the inversion just above the surface may trap enough moisture to hold onto some clouds a bit longer, thus limiting the full potential of the warming. So will trend a bit more conservative on the temps given this potential, but nevertheless, temps will run above normal for this time of year. Overnight lows wednesday will also follow this warming trend with lows forecast above freezing as southerly flow/WAA persists as the upper-level ridge builds across the region.

Wagner

LONG TERM

Issued 230 PM CST Tue Jan 6 2026

Thursday through Tuesday:

Thursday is looking to warmest day of the week where the upper- level ridge axis treks overhead of the Upper Midwest while a warm front lifts into southern WI. Overall trend continues to support above normals temps for Thursday, but questions on how far north the warmest of these temps will make it remain in question as the surface low is progged to track from KS into our neck of the woods. Some models such as the GFS have it a bit further north over/along southern WI border while ECMWF and NAM have the low center staying just to the south moving across northern IL. Given the associated mid-level shortwave trough lifting from the Plains showing signs of phasing with another shortwave trough to the north lends way to the overall uncertainty in temps along with track of this system. Nevertheless, there continues to be favorable dynamics, synoptic forcing, and moisture stream from the Gulf accompanying this system to bring increased precip chances regardless of the the track. Latest trends and above freezing temps support mostly rain across southern WI through the later half of the day Thursday. However, as the low lifts to the northeast Thursday night and lingering moisture on the backside along with the 850mb 0C line sliding south, could see some wintry mix of rain/snow or snow on the backside of this departing system Thursday night lingering into Friday morning. Currently not expecting much in the way of accumulation given the airmass drying out and borderline freezing temps, but the potential will be there.

Friday will see a cooler, Canadian airmass filter in behind the departing system through the day, but prevailing southerly flow aloft ahead of the incoming trough may overall limit the coldest air from moving into the region. So Friday is still expected to trend above normal with temps, but not as warm as the previous days.

Otherwise, will be keeping an eye on deeper aforementioned upper- level trough stretch across the central CONUS as it tracks into the Upper Midwest later Friday into Saturday. While still several days out, global models and ensembles have the main surface low track from the lower Mississippi River Valley up to the east of southern WI ranging from over lower MI to the eastern Great Lakes. This will bring another round precip to southern WI later Friday night into Saturday. While the initial onset of precip overnight Friday may start off as rain, especially in southeastern WI, the easterly trend of the low track while undergoing cyclogenesis will more likely support wintry precip, mainly snow given our location on the backside/cold side of the deepening system. Thus, there continues to be increased potential to see accumulating snow for Saturday across southern WI. Overall specific details on low track, precip/snow amounts, and impacts remain up in the air this far out.

Then the pattern calms down for Sunday as high pressure builds in behind the Saturday system. However, long range model trends in a more active pattern through the start of next week with a series of mid-level shortwave trough passage through middle of next week.

Wagner

AVIATION

Issued 1001 PM CST Tue Jan 6 2026

Low ceilings and fog will persist overnight, with potentially becoming dense inland from Lake Michigan close to 12Z Wed. With freezing temperatures possible, freezing fog will be possible where dense overlaps with the appropriate temperatures. Given the light winds and overall sfc high pressure working into the area, fog is likely to persist past dawn, gradually clearing by Wednesday afternoon.

Models then suggest ceilings should rapidly rise and scatter out Wednesday afternoon.

CMiller

MARINE

Issued 230 PM CST Tue Jan 6 2026

Low pressure over lower MI will continue to lift eastward up the St. Lawrence River Valley tonight. Winds will remain breezy and out of the northwest this evening accompanied by some rain and fog, where we cannot rule out seeing some pockets of dense marine fog at times given the warm air moving in overnight. Winds will also weaken and turn westerly into early Wednesday morning before turning southwesterly as high pressure treks up the Ohio River Valley through the day Wednesday. Will see breezy south-southwesterly winds continue into Thursday before another low pressure tracks up from the Central Plains and across the southern tip of Lake Michigan Thursday night. Behind this low pressure expected winds to increase and turn more northerly for Friday before gradually easing Friday afternoon and turning more easterly ahead of another developing low pressure. This system is progged to lift from southern Plains up into the eastern Great Lakes for Saturday bringing a return of stronger northerly winds with the next potential to see small craft conditions for southern WI nearshore waters and gales over the open waters of Lake Michigan through Saturday night.

Wagner

MKX WATCHES/WARNINGS/ADVISORIES

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