Frost Advisory 5, NWS Green Bay, WI

Area Forecast Discussion
National Weather Service Green Bay WI
254 PM CDT Sun Sep 25 2022

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Monday
Issued at 253 PM CDT Sun Sep 25 2022

Scattered showers and a few thunderstorms were moving across the
area this afternoon. Temperatures ranged from the upper 50s to
middle 60s.

For the rest of the afternoon into early this evening, an upper
level disturbance will drop southeast across the area and exit
eastern Wisconsin by mid to late evening. Latest analysis
indicated mixed layer CAPE values increasing to 200 to 400 J/KG
across central into north-central Wisconsin where the sun broke
out early this afternoon. Bufkit soundings also indicated wet
bulb zero heights around 6,000 feet to support storms with gusty
winds and hail. The latest Storm Prediction Center Day 1 Outlook
has central and portions of north-central and northeast Wisconsin
in the marginal risk of severe thunderstorms. The main risk at
this time would be hail and strong winds. Widespread severe
weather is not expected, but there could be a few reports of
large hail up to an inch in diameter and strong wind gusts,
especially in the marginal risk area.

Gusty northwest winds will be on the increase late this afternoon
and tonight. Wind gusts to around 40 mph are possible across Door
County with 20 to 35 mph are expected across the rest of the area.
Scattered showers will continue across the north as the cool air
flows over the warmer waters of Lake Superior. The cool cyclonic
flow aloft and northwest flow off Lake Superior combined with
daytime heating on Monday will result in additional shower
activity through the day. The highest chances of rain will be
across the north and far northeast. It will be cool with highs in
the 50s.

.LONG TERM...Monday Night Through Sunday
Issued at 253 PM CDT Sun Sep 25 2022

Main forecast concerns will be dealing with lingering lake effect
shower activity Monday night into Tuesday, frost/freeze potential
Mon/Tues/Wed nights and how Ian will impact the pattern for late
in the week. Temps will be below normal through mid-week, then
should be near normal or slightly above normal for the end of the
week and weekend.

Monday night into Tuesday...northwest/cyclonic flow will continue
over the western Great Lakes, as the upper level trough will
slowly work into the eastern Great Lakes. NNW/N flow over Lake
Superior and favorable delta Ts in the teens to low 20s will
continue to produce lake effect showers for mainly northern WI.
Best moisture will slowly shift east, with lingering activity
expected over far northeast WI and Door County on Tuesday.
Nighttime stability will keep winds down Monday night, but
should remain in the 10-20 mph range for much of the night. Winds
aloft start to diminish on Tuesday, with gusts to near 20-30 mph
expected for most of the area in the morning, a little higher
in/near Door County. CAA will bring in cooler temps for Monday
night, but lake effect clouds and winds in the boundary layer of
10-20 kts should keep frost more patchy in nature, mainly across
central WI. A chilly day is expected on Tuesday, with highs
ranging from the 40s across most of the Northwoods to the lower
and middle 50s farther south.

Rest of the long term...any lake effect activity will shut off
Tuesday evening as high pressure begins to build into the region,
bringing drier air and a northerly flow. The high will move
overhead on Wednesday then slowly shift east of the area on
Thursday, bringing dry and quiet weather. As we head into Friday
and Saturday, the battle will be on between an upper low pushing
to the Plains and the remnants of Hurricane Ian pushing north
from the Gulf States. Models still getting a handle of the
hurricane, so will need to see how the models trend. But it does
look like we will stay dry through at least Friday night. Tuesday
night is still looking like the coldest night as winds die down
and skies clear. Another freeze is expected for much of north
central WI with a frost as you work into the Fox Valley. Another
frosty night is likely on Wednesday night. Temps will slowly
moderate each day as we head into the weekend, as flow turns to
the south/southwest and heights/temps aloft climb.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1106 AM CDT Sun Sep 25 2022

Northwest winds will be on the increase this afternoon and tonight.
Gusts of 20 to 30 knots will be possible at times with locally
higher gusts. Scattered showers will continue this afternoon. A
few thunderstorms are possible from 19z Sunday to 03z Monday. Due
to the isolated nature of the storms, will leave them out of the
18z TAFs. If storms do form, small hail and gusty winds will be
the main risks. Scattered rain showers will linger overnight into
much of Monday across northern Wisconsin as gusty northwest winds
continue.
&&

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

SHORT TERM.....Eckberg
LONG TERM......Bersch
AVIATION.......Eckberg

Hazardous Weather Outlook
National Weather Service Green Bay WI
257 PM CDT Sun Sep 25 2022

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-262000-
Vilas-Oneida-Forest-Florence-Northern Marinette County-Lincoln-
Langlade-Menominee-Northern Oconto County-Door-Marathon-Shawano-
Wood-Portage-Waupaca-Outagamie-Brown-Kewaunee-Waushara-Winnebago-
Calumet-Manitowoc-Southern Marinette County-
Southern Oconto County-
257 PM CDT Sun Sep 25 2022

This Hazardous Weather Outlook is for north-central and northeast
Wisconsin.

.DAY ONE...Rest of the Afternoon and Tonight

Isolated to scattered thunderstorms will come to an end this
evening. A few of the storms could become strong and produce
gusty winds and hail up to an inch in diameter. Widespread
severe weather is not expected.

Northwest winds could gusts to around 40 mph over Door County
tonight into Monday morning.

.DAYS TWO THROUGH SEVEN...Monday through Sunday

Frost or a freeze is likely Tuesday night into Wednesday morning,
and again Wednesday night into Thursday morning, especially for
locations north and west of the Fox Valley.

.SPOTTER INFORMATION STATEMENT...

Spotters are requested to report hail a half inch in diameter or
greater to the National Weather Service in Green Bay.

LMZ521-522-541>543-262000-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
257 PM CDT Sun Sep 25 2022

This Hazardous Weather Outlook is for portions of northwest Lake
Michigan and the waters of Green Bay.

.DAY ONE...Rest of this Afternoon and Tonight

Thunderstorms are possible for the remainder of the afternoon
into early this evening. Some of the thunderstorms could produce
gusty winds and hail.

Increasing northwest winds will result in hazardous conditions
for small craft. A few gale force gusts will be possible at times
tonight, especially across the coastal waters of northern Door
County.

.DAYS TWO THROUGH SEVEN...Monday through Sunday

Persistent northwest winds will result in hazardous conditions
for small craft Monday through Tuesday evening, especially north
of Sturgeon Bay. A few gale force gusts will be possible at times
on Monday.

Eckberg/Bersch