571
FXUS63 KGRB 172134
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
434 PM CDT Sun Aug 17 2025

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Periods of showers and thunderstorms are expected early Monday
  through Monday night. A few strong or severe storms are possible
  Monday afternoon and evening. Rainfall may be heavy at times. By
  Monday night, portions of central and east-central Wisconsin
  could see rainfall amounts above one inch (probabilities of
  between 40-70%).

- Dry weather is expected from Tuesday through much of the work
  week.

&&

.DISCUSSION...
Issued at 434 PM CDT Sun Aug 17 2025

This evening through Monday...This afternoon`s satellite and radar
imagery showed a few showers developing along an 850mb warm front in
west-central WI ahead of an approaching mid-level shortwave. These
showers may reach central WI this evening, but given lower dew
points in central WI compared to west-central WI, anticipate these
showers will struggle to expand eastward. As the mid-level shortwave
shifts more eastward late this evening/tonight, some CAMs indicate
convection developing along the 850mb warm front before the main
area of convection associated with the shortwave expands/shifts into
the area Monday morning. Any shower activity that may develop ahead
of the main area of convection would be isolated and brief.

The main area of showers and storms looks to move across the region
from west to east sometime from Monday morning through early Monday
afternoon, with additional rounds of showers and storms potentially
developing Monday afternoon and perhaps Monday evening. Any
thunderstorm activity in the morning would not be severe. However,
if enough destabilization can occur after the morning activity,
portions of central and east-central WI could see a few strong or
severe storms during the Monday afternoon/evening time frame. If
these storms develop, damaging winds, small hail, and heavy
downpours would be the main threats. By Monday night, rainfall
amounts 0.50 to 1.00 inches are forecast. But, with PWATs of 1.5 to
2.25 inches, cannot rule out the potential for total rainfall
amounts around 2 inches, especially if storms move over the same
locations. Additionally, low-lying and urban areas in portions of
central WI would be more susceptible to flooding, due to recent
rainfall from Saturday.

Rest of the forecast...Following Monday`s shortwave and associated
convection, surface high pressure will slide into the region from
the northwest as upper-level ridging builds over the area as well.
This pattern, bringing dry conditions and near normal temps, will
prevail through at least early Friday before the next chance of
showers and storms may arrive with a cold frontal passage sometime
Friday or Saturday.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 104 PM CDT Sun Aug 17 2025

Northeast winds have brought a BKN low stratus deck inland from
Lake Michigan early this afternoon, resulting in periods of MVFR
cigs to the east-central WI TAF sites. Meanwhile, high clouds
spread eastward over the central WI TAF sites early this
afternoon, with some lingering lower clouds mainly between
4000-7000 ft AGL. Anticipate the low clouds off of Lake Michigan
will dissipate/erode by late this afternoon as the high clouds
continue to spread eastward.

Cloud cover will increase through late this evening and overnight
as the next chance for showers and storms arrives from the west.
The exact onset of the showers and storms is still uncertain as
some short-range models indicate a leading line of showers and
storms may move over the TAF sites from west to east roughly
between 07z to 14z before the main line of showers and storms
moves over the area from west to east roughly between 12z to 18z.
Have accounted for the potential leading convection with PROB30
groups at all TAF sites, with TEMPO groups for the main line. Any
storms will likely be accompanied by at least MVFR cigs and
vsbys.

Breezy east to southeast winds will prevail throughout this TAF
period with gusts potentially reaching 20 kts at times.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement through Monday morning for WIZ022.

Beach Hazards Statement through Monday afternoon for WIZ040-050.
&&

$$

DISCUSSION.....Kruk
AVIATION.......Kruk