264 FXUS63 KGRB 111218 AFDGRBArea Forecast Discussion National Weather Service Green Bay WI 718 AM CDT Sat Oct 11 2025
Updated aviation portion for 12Z TAF issuance
.KEY MESSAGES...
- Above normal temperatures into early next week, slightly cooler mid-week before warmer readings return late next week.
- A few showers/sprinkles possible near Lake Michigan today, but otherwise dry this weekend. Chance for light rain Sunday night into Monday and again late next week.
&&
.DISCUSSION... Issued at 323 AM CDT Sat Oct 11 2025
Today into Sunday:
Temps were a little slow to fall across parts of central WI overnight, but many spots have or should drop into the mid-upper 30s in the pre-dawn hours, so will not make any changes to the Frost Advisory. Patchy ground fog is also possible across parts of central and north-central WI through shortly after sunrise.
Dry conditions are expected for most of the weekend as mid and upper level ridging move across the Great Lakes. The exception will be near Lake Michigan, where delta Ts in the low teens combined with moist/cyclonic flow behind a departing low pressure system will bring some shower/sprinkles chances. Activity should be pretty isolated and light (only a hundredth or two possible), so will keep PoPs in the 10-24% range. Clouds will increase over eastern WI this morning as well due to the north/northeast flow, but look for more sunshine as you move west. As flow turns southeast and temps aloft climb, look for any lake effect showers to diminish late today, but moist/upslope flow will lead to additional clouds over land, especially across central and northern WI. Some fog will also be possible.
Highs this weekend will be above normal, mainly in the 60s, with a couple spots possibly hitting 70 on Sunday in/west of the Fox Valley. Lows tonight will be warmer than previous nights, with most spots in the 40s to around 50. A few upper 30s will be possible in the typical cold spots of central and north-central WI.
Sunday Night into Next Week:
Next chance for area-wide rain will arrive west to east after dark Sunday into Monday morning as a frontal boundary moves across the region. LREF showing highest probabilities over north-central WI, so will carry likely (60-70%) PoPs there, with 25-50% PoPs elsewhere. As with the last front, the precip looks to be on the light side, with LREF showing only a 30% chance of more than a quarter of an inch of rain over north-central WI, with lower chances to the south. Very low threat of a rumble of thunder as little to no instability will accompany the front (only up to ~200 MUCAPE), so will not carry any thunder. Mainly dry conditions are expected Tuesday into Wednesday, and possibly into Thursday or Friday, as upper ridging builds into the western Great Lakes. However, models vary on the timing/strength of the ridge, which will determine just how long we can hold off the next chance for rain. It does appear that rain (storm?) chances increase towards/ into next weekend as a deep trough approaches from the west. Temps will remain above normal into Monday, especially across eastern WI where we could touch 70 degrees. Then a return to near normal temps is forecast mid-week with a gradual warming trend towards next weekend.
&&
.AVIATION...for 12Z TAF Issuance Issued at 718 AM CDT Sat Oct 11 2025
Patchy ground fog across north-central WI will lift early this morning. Otherwise, look for an area of MVFR clouds to slowly shift west/south across parts of northeast WI. The cloud deck should stay east of AUW/CWA, but may get to RHI for a time. This cloud deck will scatter out/retreat this afternoon, but increase again later this evening and overnight.
Light winds will become east and southeast through the day, remaining under 10 kts.
&&
.GRB WATCHES/WARNINGS/ADVISORIES... Frost Advisory until 8 AM CDT this morning for WIZ030-035-036- 045. &&
$$
DISCUSSION.....Bersch AVIATION.......Bersch
NWS GRB Office Area Forecast Discussion