textproduct: Green Bay

KEY MESSAGES

- Smoke from the Canadian wildfires may reach the surface at times today, which may impact air quality.

- An active weather pattern is expected for the end of the week and again early next week. Heavy rain and storms will be possible during this time. The probability of exceeding an inch of rain Thursday night and Friday is 30-56 percent.

DISCUSSION

Issued at 332 AM CDT Wed Jun 11 2025

Despite some restrictions to visibilities early this morning, the restrictions are due to some patchy fog not the Canadian wildfire smoke. As a frontal boundary develops to the south, temperatures will soar today under mostly sunny skies for much of the day until clouds develop later this afternoon and smoke filters in across the region. This smoke could reach the surface at times, which could affect air quality. Highs today are expected to range from the middle 70s across the north, with lower 80s across portions of central Wisconsin and the Fox Valley. Temperatures will then cool down for the rest of the week, with the next chance of 80 degree weather early next week.

The frontal boundary becomes more active tonight as a series of shortwaves track through the western Great Lakes region through Saturday. There will be a chance for showers and thunderstorms during this period until the main low pulls away from the area on Saturday. The best chance for widespread rain (60-90 percent) will be Thursday night into Friday as the warm front lifts north into Wisconsin and a shortwave tracks through the region. Outside of this window the best chances will be across central and east- central Wisconsin closer to the front locations near the Wisconsin and Illinois border. Thunderstorms across northern Wisconsin are not expected to be severe as the region will be north of the front and away from the best instability.

Dry weather is then expected for the second half of the weekend as a ridge of high pressure tracks across the Great Lakes region. The active weather will return on Monday and last through the middle of next week as a series of low pressure systems track through the western Great Lakes region. The evolution of these systems will bear watching as it is too early to determine how strong the storms will be due to the uncertainty of the timing and track of the low pressure systems.

AVIATION

for 06Z TAF Issuance Issued at 1027 PM CDT Tue Jun 10 2025

Main aviation concerns will be minor smoke impacts through Wednesday night, LLWS, and the arrival of showers and isolated storms in C/EC WI Wednesday evening.

Skies were mostly clear late this evening, but SCT-BKN mid-level clouds were seen upstream. Smoke has reduced vsbys to 5-7sm in eastern WI, and patchy fog was developing in NC WI. The smoke is expected to gradually shift NE of the region overnight, and any fog should mix out as strong boundary layer flow develops overnight, so not expecting a huge impact to vsbys. A few light sprinkles may fall from the mid-level clouds in the far north and south, but probably won't reach the ground in most areas.

Light surface winds will gradually increase overnight, then become W-NW and gusty as the cold front moves through on Wednesday. LLWS is expected to develop across C/EC WI overnight and into early Wednesday morning, as a low-level jet increases to 35-45 kts.

Another round of smoke is expected to develop over northern WI midday Wednesday, sag south during the afternoon, then gradually shift SW Wednesday night. This area of smoke could drop vsbys to MVFR (especially at AUW/CWA) during the afternoon/evening.

Showers and possibly a few storms will develop over C/EC WI Wednesday evening as frontogenetic forcing increases near a H8 warm front. Will likely only mention showers at the southern TAF sites for now.

GRB WATCHES/WARNINGS/ADVISORIES

None.