571
FXUS63 KGRB 052353
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
653 PM CDT Sat Oct 5 2024

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Gusty winds are expected on the Bay of Green Bay and Lake
  Michigan through Sunday evening. A Gale Warning is in effect
  through this evening, with Small Craft Advisories following
  Sunday and Sunday evening.

- Recent dry conditions, dry vegetation, and south winds gusting
  to 35 mph will lead to elevated fire weather conditions this
  evening. There is also potential for powerline fires due to
  the gusty winds.

- Showers and storms are expected to develop along a cold front
  this evening. A few strong to severe storms could produce
  damaging winds and small hail.

- Frost will be possible over north-central and northeast
  Wisconsin at times during the early morning hours from Monday
  through Thursday.

- Low afternoon relative humidity and dry conditions will be
  favorable for elevated fire weather conditions during the early
  to middle of next week.

&&

.DISCUSSION...
Issued at 237 PM CDT Sat Oct 5 2024

Short Term...Tonight and Sunday

A cold front will track across the region this evening. The
atmosphere is rather dry; however moisture convergence along the
front is expected to produce a broken line of showers and
thunderstorms coincident with a mid level PV anomaly tracking
through northern Wisconsin. Recent model runs show the best
chances will be across northern Wisconsin, where the best moisture
and dynamics will reside, with lesser chances further south. A
fairly strong wind field aloft will mean a few of the more
vigorous showers or storms could bring wind gusts to 50 knots to
the surface. The elevated nature of the storms and MUCAPE profiles
also indicate some large hail will also be possible. The front
will be fairly quick moving, with the activity out of the area by
midnight. Lows tonight are expected to range from the lower 40s
across the north, to the lower 50s across east-central Wisconsin.

Cooler temperatures are expected behind the cold front on Sunday,
with continued breezy conditions as a tight pressure gradient
remains across the western Great Lakes region. The gusty winds
could result in elevated fire potential; however, with cooler
temperatures and higher RH values the threat could be lower,
depending on how much rain falls this evening. Highs on Sunday are
expected to range from the lower 50s across the north, to the
lower 60s across east-central Wisconsin.

Long Term...Sunday Night Through Saturday

Upper-level troughing will exit our area to the east, but then
linger over the eastern Great Lakes and Northeast U.S. through
midweek. This will keep Northeast WI in a cooler pattern until a
broad upper-level ridge builds in from the west later in the
workweek. Low temperatures will drop into the 30s for most
locations on Monday night and warm only slightly for Tuesday and
Wednesday nights. Low-lying areas in north-central WI could see
lows around 30 Monday night. High temperatures across our region
will generally be in the 60s through Wednesday before returning to
the 70s on Thursday and Friday as the upper-level ridge arrives.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 653 PM CDT Sat Oct 5 2024

VFR conditions are expected this evening and tonight, with the
exception being some MVFR (and possibly short-lived IFR)
conditions as a broken line of showers and isolated storms quickly
spread west to east across the area this evening ahead of a cold
front. Best coverage and lowest conditions will be across northern
WI. Clearing is expected behind the front, with high-end MVFR
(RHI) and low-end VFR (GRB/ATW/GRB) clouds (mainly between
2000-5000 ft) pushing into/across the area on Sunday as colder air
arrives.

It will be breezy through much of the TAF period, but a lull is
expected as we lose the better mixing this evening into tonight.
Gusty south winds up to ~25 kts, will shift to the west late this
evening behind the cold front, gusting to ~20 kts through much of
the night. As winds shift to the west, a period of LLWS will be
possible, mainly across eastern WI, as winds at 2000 ft will
remain between 45-55 kts. LLWS will also be present tonight when
winds are not gusting at the surface. West-northwest winds will
gust to ~30 kts on Sunday.

&&

.MARINE...
Issued at 237 PM CDT Sat Oct 5 2024

Gale force southerly winds are expected ahead of an approaching
cold front late this afternoon. Gale force winds will continue
this evening as the cold front sweeps through Wisconsin, then ease
below gale force back to small craft conditions late tonight.
Small craft conditions will continue Sunday and Sunday evening
with gusty west to northwest winds behind the cold front.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

DISCUSSION.....Kurimski/ML
AVIATION.......Bersch
MARINE.........Kurimski