419
FXUS63 KGRB 182051
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
351 PM CDT Mon Aug 18 2025

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Areas of rain, with a few rumbles of thunder, will continue
  through late this evening. The rain may be heavy at times,
  mainly across central and east-central Wisconsin. Localized
  flooding in low-lying and urban areas is possible in these
  areas.

- Isolated showers are possible on Tuesday, with much of the week
  remaining dry. Friday will bring the next chance for area-wide
  showers and storms.

&&

.DISCUSSION...
Issued at 351 PM CDT Mon Aug 18 2025

This evening/Tonight...This afternoon`s water vapor and radar
imagery showed areas of rain moving northeast across the region
associated with a 500mb vort max from a nearby shortwave. Additional
shower activity was also developing in portions of central and east-
central WI, where a weak LLJ was located. The rain and shower
activity is expected to continue through late this evening, ending
from west to east. Still cannot rule out a few rumbles of thunder in
central and east-central WI, where the greater instability (CAPE of
500-1000 J/kg) is located. However, any heavier shower or
thunderstorm will generate heavy rainfall with high rainfall rates
(0.5 to 1"/hr) in central and east-central WI, as PWATs of 2-2.25
inches will prevail through the evening. Localized flooding remains
possible, mainly in low-lying and urban areas.

As the precip comes to an end, the recent rainfall and light winds
will cause fog to develop late this evening through early Tuesday
morning. Models indicate the potential for locally dense fog, mainly
in central and north-central WI, but fog will be possible area-wide.
A Dense Fog Advisory may be needed.

Tuesday...In the wake of the shortwave, northwest winds, CAA, and
lingering low-level moisture will prevail across the region. Some
models indicate isolated showers, with a few rumbles of thunder,
developing in spots during the afternoon and evening, but impacts
will be low.

Rest of the forecast...Surface high pressure will slide into the
region from the northwest as upper-level ridging builds over the
area. This pattern, bringing dry conditions and near normal temps,
will prevail through at least early Friday before the next chance of
showers and storms returns with a cold frontal passage sometime
Friday into Saturday.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1259 PM CDT Mon Aug 18 2025

Areas of rain and IFR/MVFR conditions prevailed across the region
early this afternoon, with a few thunderstorms near ATW and
approaching MTW. The scattered rain showers will continue through
this afternoon and end from west to east this evening. Cannot rule
out the potential for a few rumbles of thunder at the east-central
WI TAF sites during the late afternoon, so have included PROB30
groups. Any heavy shower or storm would also produce lower vsbys.

Following the departure of the precip, fog is expected to develop
due to the recent rainfall and calming winds. Cigs of IFR/LIFR are
likely to occur, potentially dropping to VLIFR at times at the
central and north-central WI TAF sites. Reduced vsbys are also
expected with the fog, with dense fog developing at times.
Conditions will slowly improve towards the end of this TAF period
and throughout Tuesday afternoon.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement until 6 PM CDT this evening for WIZ040-
050.
&&

$$

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