FXUS63 KGRB 160230 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 930 PM CDT Thu Oct 15 2026 Forecast discussion for routine evening forecast issuance .KEY MESSAGES... - Widespread rain continues tonight, becoming scattered into Friday morning. Most locations should see an additional 0.25 to 0.5" of rainfall. - Northwest winds increase on Friday, with gusts between 30 and 40 mph expected. Locally higher gusts to 45 mph will be possible along the lakeshore counties. Gale force gusts are expected across marine zones. - A Freeze Watch remains in effect for Friday night as low temperatures fall into the upper 20s to low 30s for areas inland of Lake Michigan. && .DISCUSSION... Issued at 900 PM CDT Thu Oct 15 2026 Rain chances through Friday... Radar and surface obs show widespread stratiform rain ongoing late this evening as cold front infringes on northwest Wisconsin and phased upper trough approaches the Great Lakes. Expect rain to become more scattered in coverage overnight into Friday morning with the loss of moisture advection and upper jet support, though most locations should still pick up an addition 0.25 to 0.5" of QPF. Probabilities for receiving 0.5" of rain through tonight sit at around 30 to 60%, highest over far northeast Wisconsin where modest mid-level FGEN resides in proximity to the surface low. Rain then tapers off from west to east late Friday morning, though wrap around moisture may keep showers or drizzle around over east-central Wisconsin through the afternoon. Winds... Gradient winds ramp up Friday morning as a surge of CAA accompanies northwesterly wind shift and building high pressure over the Plains. Deep daytime mixing will tap into 40 to 45 knot winds at 850 mb Friday afternoon, resulting in a high confidence (60 to 90%) setup for widespread surface gusts between 30 and 40 mph. Only caveat will be Door County, where locally higher gusts will be bumping up against advisory criteria. HREF currently shows a 20 to 40% chance for gusts exceeding 44 mph over northern Door, with sustained winds also coming within a mph or two of criteria. Current thinking would be to hold off on an advisory for the time being due to low confidence, though CAM trends will have to be monitored on subsequent shifts. Temperatures... Intrusion of arctic high paired with stout northwesterly flow will result in a brief spell of well below normal temperatures Friday and Friday night. Highs will struggle to meet 50 degrees for many locations, with lows then plummeting into the mid 20s to low 30s. Setup still looking favorable (50 to 70%) for a hard freeze Friday night, so have retained the Freeze Watch. A rapid pattern shift to more seasonable temperatures then occurs over the weekend as return flow sets up and upper flow de- amplifies. As such, highs are progged to read mainly in the mid to upper 60s through at least mid-week, with several shots at seeing 70 degrees. Extended... High pressure looks to be the main driver of the synoptic pattern through at least the middle of next week, with no organized systems on the horizon. More active pattern then looks to set up toward the end of next week as upper flow re-amplifies, though details are few this far out. && .AVIATION...for 00Z TAF Issuance Issued at 600 PM CDT Thu Oct 15 2026 Expect IFR cigs to persist through at least 06Z, though brief improvements to MVFR will be possible. Otherwise, main impacts to aviation will revolve around ongoing periods of light to moderate rain that are forecast to continue through Friday morning. Have thus gone prevailing SHRA with reduced vsbys at all TAF sites. Rain coverage then becomes more SCT late tonight into Friday morning, which should signal an improvement to more widespread MVFR cigs. Potential for cigs lifting to VFR then exists after 18Z. Northwesterly winds ramp up late Friday morning as rain comes to an end from west to east. Surface gusts between 30 and 40 mph are forecast for all terminals, peaking early Friday afternoon. A brief period of LLWS will be possible over RHI, AUW, and CWA early Friday morning as 850 mb winds increase. && .MARINE... Issued at 900 PM CDT Thu Oct 15 2026 Gale Warning remains on track for the Bay and Lake as northerly winds ramp up following cold FROPA later this evening. HREF probabilistic guidance is currently showing a 65 to 95% signal for 10-meter wind gusts exceeding 39 mph, which should translate pretty well to gale force gusts over our marine zones. Waves will build 4 to 7 ft on the Bay and 6 to 10 ft on the Lake during this time. Have opted to throw out a wind down Small Craft Advisory along the Lake Michigan nearshore waters on this shift, as waves remain elevated through around 08Z Saturday as winds shift to more westerly. && .GRB WATCHES/WARNINGS/ADVISORIES... Freeze Watch from late Friday night through Saturday morning for WIZ020-030-031-035>040-045-048>050-073-074. && $$ DISCUSSION.....Goodin AVIATION.......Goodin MARINE.........Goodin