700 FXUS63 KGRB 100247 AFDGRBArea Forecast Discussion National Weather Service Green Bay WI 947 PM CDT Thu Oct 9 2025
Updated aviation portion for 06Z TAF issuance
.KEY MESSAGES...
- Showers and a few thunderstorms late tonight into Friday, along with increasing winds.
- Above normal temperatures through next Monday, then a return to near normal conditions during the next work week.
- Additional rain chances occur Sunday night into Monday, and Wednesday night into Thursday.
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.DISCUSSION... Issued at 241 PM CDT Thu Oct 9 2025
Canadian high pressure continued to shift east through the Great Lakes this afternoon, with southerly flow developing over the forecast area. Mostly sunny skies prevailed over the forecast area, except near Lake Michigan, where cloud cover was locally enhanced by a lake breeze.
Precipitation...Dry conditions prevail through this evening, but a clipper system will bring precipitation chances late tonight into Friday. This system is quite dynamic, with a 30 to 40 knot low-level jet late tonight into early Friday, a cold frontal passage on Friday, and a potent short-wave/upper low tracking through NE WI Friday afternoon. Have increased pops with this system, mainly with the pre-frontal showers associated with the low-level jet and WAA. Will also maintain a slight chance of thunderstorms (due to strong dynamics/weak instability) until the front shifts east of the region mid-day. Winds will be on the increase, with gusty S-SW winds in association with the low-level jet ahead of the front, then gusty NW winds in the CAA in the wake of the cold front Friday afternoon and night. A Small Craft Advisory is in effect for all of our nearshore zones (including the bay) from late this evening through Friday night.
Dry conditions are anticipated for the end of the weekend, but shower chances return Sunday night into Monday, and again Wednesday night into Thursday.
Temperatures...An extended period of mild temperatures is expected through Monday, with lows in the 40s and lower 50s, and highs in the 60s. A return to near normal readings occurs for the rest of the next work week.
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.AVIATION...for 06Z TAF Issuance Issued at 946 PM CDT Thu Oct 9 2025
A cold front will bring showers overnight into Friday morning. Expect a transition from VFR to MVFR with showers and gusty winds as the front moves through the area. Thunderstorm coverage is expanding over western WI, and will add a tempo to AUW/CWA at the start of the taf period.
Showers will develop across central and north-central WI (KRHI, KCWA, KAUW) between 05-07Z, spreading to the east (KGRB, KATW, KMTW) by 10-12Z. A period of MVFR ceilings (020-030 AGL) remains possible over north-central and central WI on Friday morning. Gusty S-SW winds ahead of the front will shift to gusty NW (20-25 kts) Friday afternoon in the wake of the front. Another round of MVFR ceilings is expected to develop Friday evening over northeast Wisconsin.
Outlook: Lingering MVFR ceilings and gusty north to northeast winds may continue into Saturday morning.
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.GRB WATCHES/WARNINGS/ADVISORIES... None.
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DISCUSSION.....Kieckbusch AVIATION.......MPC
NWS GRB Office Area Forecast Discussion