792
FXUS63 KGRB 172354
AFDGRB

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

Updated aviation portion for 00Z TAF 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 00Z TAF Issuance
Issued at 642 PM CDT Sun Aug 17 2025

NE winds were bringing drier air into the region, causing low
clouds to eride from NE to SW early this evening. Doubt that the
clearing will make it into our far southwest counties, as some
showers have formed there in association with a weak MCV. These
showers were tracking east, and should tend to weaken as they
encounter drier air toward the Fox Valley.

More widespread showers and a few embedded thunderstorms will
form across C/NC WI late tonight, then spread northeast across
the rest of the forecast area through Monday morning. These
showers will be associated with an 850 mb warm front and another
weak short-wave trough. Have put TEMPO groups at each TAF site to
depict the most likely 4-hour period of rain. Ceilings are
expected to lower to MVFR/IFR as the steadier rains taper off
late tonight into Monday morning. Persistent low stratus and even
some light fog is expected across the Northwoods through the day.
A warm front will approach C/EC WI late Monday afternoon, and
this may trigger scattered thunderstorms. Have only added Prob30
groups for these, given the expected scattered coverage.

&&

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

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

$$

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