Special Weather Statement, NWS Green Bay, WI

Area Forecast Discussion
National Weather Service Green Bay WI
631 PM CDT Mon Apr 5 2021

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Tuesday
Issued at 236 PM CDT Mon Apr 5 2021

Another warm and dry day across the area with temperatures in the
70s to lower 80s. Wausau, Marshfield and Wisconsin Rapids have
set record highs for the date with several other sites within a
degree or two of the record. The combination of the dry
vegetation, unseasonably warm temperatures, low humidity, and
gusty winds has led to another day of elevated fire weather
conditions. At least 6 fires have been noted today northwest of
the Fox Valley.

For tonight, a warm front will continue to lift northward across
northern Wisconsin. An area of low pressure along with a cold
front, and weak upper level disturbance across Minnesota will
head east into the state late tonight. For tonight, there is a
weak disturbance moving across the southern portion of the state.
This feature could trigger an isolated thunderstorm across
portions of central and east-central Wisconsin late this afternoon
into early this evening. Meanwhile, the main thunderstorm
activity is expected to develop across northern Minnesota late
this afternoon into this evening and then move eastward across
northern Wisconsin later this evening into the overnight hours.
Models indicating most unstable CAPE values of 1,000 to 1,500
J/KG, 0-6 km shear values of 30 to 35 knots and steep mid level
lapse rates support the potential for some strong or severe
thunderstorms across north-central Wisconsin later this evening
into early Tuesday morning. The SPC Day 1 Outlook has portions
of north-central Wisconsin in the Marginal Risk of severe weather.
Large hail and damaging winds will be the primary threat.

The first cluster of storms will exit the area late tonight into
early Tuesday morning. There will be a lull or break in the
activity until afternoon when activity fires up along the cold
front that will be sagging south during the day. Severe
thunderstorms are not expected on Tuesday. High temperatures
will range from around 60 north to the lower to middle 70s
south.

.LONG TERM...Tuesday Night Through Monday
Issued at 236 PM CDT Mon Apr 5 2021

A frontal boundary will remain across the western Great Lakes
region, which will bring several periods of showers and isolated
thunderstorms at times for the middle to late part of the week as
several low pressure systems track through the region. The main
low will approach the area as a closed off low Thursday and
Thursday night from the central Plains, lingering across the
region as another low approaches from the west by the weekend.
Although the track of the first low has come into better focus,
keeping the weather active for the middle to late part of the
week, the track of the second low is less certain. The uncertainty
of the track of this second low will be the difference between a
mainly dry weekend with a small chance for showers or a wetter
weekend. Given the lack of clarity will not stray from the NBM
POPs in this period. Yet another low pressure system is slated to
track through the area early next week, which could continue the
wet streak of weather across the western Great Lakes.

Temperatures during the extended portion of the forecast are
expected to 10 to 20 degrees above normal for this time of year.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 629 PM CDT Mon Apr 5 2021

VFR conditions are expected through the evening hours. Scattered
thunderstorms could form northwest of a AUW to IMT line later
tonight ahead of an approaching cold front. In addition, low
clouds and fog could from along the Lake Michigan shore later
tonight, but it is uncertain whether it would move inland to the
airports at MTW/SUE/2P2.

As the cold front moves slowly east across the area Tuesday, MVFR
ceilings are mostly expected with a chance of showers or thunderstorms.
It will be dry the majority of the time.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

SHORT TERM.....Eckberg
LONG TERM......Kurimski
AVIATION.......RDM

Hazardous Weather Outlook
National Weather Service Green Bay WI
820 PM CDT Mon Apr 5 2021

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-070130-
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-
820 PM CDT Mon Apr 5 2021

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

.DAY ONE...Tonight

There is a chance of thunderstorms tonight. There is a marginal
risk for severe weather tonight across portions of north-central
Wisconsin. The strongest storms could produce large hail.

.DAYS TWO THROUGH SEVEN...Tuesday through Monday

There is a chance for thunderstorms across the area Tuesday
afternoon and night, and again Wednesday afternoon and night.
These storms are not expected to be severe.

.SPOTTER INFORMATION STATEMENT...

Spotter activation should not be needed, but spotters are asked to
report any hail or gusty winds.

LMZ521-522-541>543-070130-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
820 PM CDT Mon Apr 5 2021

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

.DAY ONE...Tonight

There is a small chance of thunderstorms late tonight. Patchy
dense fog is also possible late tonight.

.DAYS TWO THROUGH SEVEN...Tuesday through Monday

Thunderstorms will be possible at times Tuesday through Wednesday
night. The storms are not expected to be severe. Patchy fog is
also possible at times.

RDM/Kallas

Special Weather Statement
National Weather Service Green Bay WI
913 PM CDT Mon Apr 5 2021

WIZ005-060315-
Vilas WI-
913 PM CDT Mon Apr 5 2021

...SPECIAL WEATHER STATEMENT...

At 913 PM CDT, Doppler radar was tracking strong thunderstorms 7
miles northeast of Butternut, or 8 miles west of Turtle Flambeau
Flowage, moving east at 15 mph.

Half inch hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Lac Du Flambeau, Boulder Junction, Winchester, Border Lakes Natural
Area, Rice Creek Natural Area, Arbor Vitae, Presque Isle, Manitowish
Waters, Van Vliet Hemlocks Natural Area and Trout Lake.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4624 8961 4591 8964 4590 9004 4598 9004
      4598 8993 4630 8993
TIME...MOT...LOC 0213Z 265DEG 14KT 4607 9037

RDM