012
FXUS63 KGRB 061131
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
631 AM CDT Sun Oct 6 2024

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- A colder airmass will move into the region today with afternoon
  highs 10 to 20 degrees colder. Areas of frost are forecast late
  tonight to the north and west of the Fox Valley.

- Conditions hazardous to small craft will continue through this evening
  due to gusty west-northwest winds and high waves. A Small Craft
  Advisory is in effect for the Bay of Green Bay and Lake
  Michigan.

- Areas of frost will be possible, mainly north of Highway 29,
  during the early morning hours from Tuesday through Thursday.

- Low afternoon relative humidity and dry conditions will be
  favorable for elevated fire weather conditions on each day from
  Monday through Friday.

&&

.DISCUSSION...
Issued at 341 AM CDT Sun Oct 6 2024

Short Term...Today...Tonight...and Monday

Cyclonic upper flow around an upper low moving towards
James Bay will bring much cooler air into the area today and Monday
on gusty west winds. While it will be much cooler than the last
several weeks, temperatures will be close to normal for this time
of the year.

Winds should diminish tonight and skies should clear. This may allow
for some frost to form in central and northcentral Wisconsin. A light
breeze and dry air will probably prevent significant frost formation.

Long Term...Monday Night Through Saturday

Between upper level troughs over the Gulf of Alaska and the east
coast of North America, a relatively potent ridge will gradually
move east from the Rockies to the Great Lakes this week. This slow
moving pattern will generally lead to quiet weather. The ridge
will flatten by next weekend as shortwave energy digs into the
western Great Lakes, which will provide the next chance of
rainfall. Until then, focus of the forecast generally revolves
around fire weather and frost potential.

Fire Weather:  Northwest flow aloft and high pressure at the surface
will promote a dry airmass across the region on Tuesday and
Wednesday.  The minimum humidity each afternoon will fall between 25
to 40 percent across the region.  Fortunately, winds will be light
and not exacerbate the dry conditions.  The low humidity will lead
to elevated fire weather conditions.

Then a warming trend takes place from Thursday through Saturday. The
warming temps will counteract the increasing moisture and continue
to lead to low humidity between 30 to 40 percent each afternoon.
Elevated fire weather conditions will be possible on each day.

Frost potential:  The dry airmass, light winds, and clear skies will
be favorable for good radiational cooling conditions each night from
Monday night through Wednesday night.  Lows are forecast to fall
into the low to middle 30s each night which could lead to
frost/freeze conditions.  Will continue to highlight in the HWO.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 630 AM CDT Sun Oct 6 2024

CLouds will increase across the region from northwest
to southeast today. MVFR ceilings are possible north of a TKV to
IMT line with VFR ceilings to the south. West northwest winds will
gust to around 30 knots in most places.

Skies should clear this evening, and surface winds will diminish.
Low level wind shear is possible in most areas after dark, with
northwest winds around 10 knots at the surface and northwest winds
at 40 knots at 2000 ft.

VFR conditions are likely Monday, with some scattered to broken
clouds in the afternoon.

&&

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

&&

$$

DISCUSSION.....RDM/MPC
AVIATION.......RDM