Special Weather Statement, NWS Green Bay, WI

Area Forecast Discussion
National Weather Service Green Bay WI
255 PM CDT Mon May 31 2021

Forecast discussion for routine afternoon forecast issuance

.SHORT TERM...Tonight and Tuesday
Issued at 255 PM CDT Mon May 31 2021

For this afternoon/evening, isolated to scattered showers and
storms will continue across northern WI, then spread south/east
through the area during the late afternoon and early evening.
Activity having a hard time getting organized due to weak bulk
shear (weakening from west to east as the shortwave over Lake
Superior tracks east) and weak/weakening convergence away from
any lake breeze boundary. Starting to see some agitated cumulus
along the boundary, but not robust yet. MUCAPEs have climbed to
between 700-1200 J/kg over parts of central and north central WI,
with much lower values in the Fox Valley and lake shore due to the
lower dewpoints. Steep low level lapse rates were noted with
modest mid-level lapse rates of around 6.5-7 C/km. The low wet
bulb heights of 6000-7000 feet will continue to favor hail
producing storms, with the strongest possibly producing some
severe hail. Some gusty winds will be possible too, but
diminishing wind fields will limit the damaging wind potential.
Locally heavy rainfall is expected where the storms train over the
same location. The activity will encounter less instability and
less moisture as it heads east, especially near/after sunset, so
much of the activity looks to wane by 03-04z.

For late evening/overnight, skies will at least partially clear
out as the trough and front exit the area. Light winds, recent
rainfall and mostly clear skies will lead to some fog development,
especially where the heavier rain falls. Lows look to fall into
the middle 40s to lower 50s for most spots.

For Tuesday, look for any fog to burn off in the early morning
hours, with partly to mostly sunny skies expected to start the
day. A few more clouds will develop through the day. Weak high
pressure looks to keep things dry, along with limited moisture,
but can't rule out a stray shower along the remnant outflow
boundary and/or lake breeze. A couple models showing some fog on
Lake Michigan during the day, but not sure if dewpoints will be
high enough to generate fog over the water. Will wait to see how
dewpoints respond after the rainfall and the system passes before
adding any lake fog. Temps will be very spring-like and will
return to a little above normal readings, with most spots seeing
highs in the 70s, except cooler near the shores of Lake Michigan.

.LONG TERM...Tuesday Night Through Monday
Issued at 255 PM CDT Mon May 31 2021

A weak upper trough will cross the region Wednesday into Thursday,
but most of the energy will pass south of GRB CWA. Despite the
lack of significant forcing, there may be enough afternoon
instability to support isolated/scattered showers and thunderstorms.

An upper level ridge will build over the western Great Lakes
region late in the week, and this will help to suppress convective
development. The ridge is expected to shift east by Sunday and
Monday, resulting in the development of deep southerly flow,
increasing moisture (PWATs exceeding 1.5 inches), and a renewed
chance of thunderstorms.

Temperatures are expected to gradually rise through the week,
reaching well into the 80s by the weekend.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1243 PM CDT Mon May 31 2021

Look for isolated to scattered shower and storms to push across
the area this afternoon and early evening as an upper level trough
and weak cold front swing across the region, ending northwest to
southeast by around 03z. The strongest storms could produce hail
and surface wind gusts over 40 knots. Outside of the convection,
VFR conditions are expected into the evening.

Skies will at least partially clear out behind the trough/front,
with some ground fog expected to develop in the late evening and
overnight hours. Decided to go with some prevailing groups for
IFR/MVFR VSBYs, but some LIFR/VLIFR maybe be needed in the 08-12z
timeframe. The fog will burn off early Tuesday morning. Then,
good flying weather are expected the rest of Tuesday with only
some late morning and afternoon cumulus clouds. A stray shower
cannot be ruled out over central or eastern WI in the afternoon
along a lake breeze and remnant outflow boundary but VFR
conditions are expected to prevail. Winds will be southwest
today, with a few gusts of 10-20 kts, then winds become light and
variable tonight into Tuesday morning.
&&

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

SHORT TERM.....Bersch
LONG TERM......Kieckbusch
AVIATION.......Bersch

Hazardous Weather Outlook
National Weather Service Green Bay WI
241 PM CDT Mon May 31 2021

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-011945-
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-
241 PM CDT Mon May 31 2021

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

.DAY ONE...Tonight

Isolated to scattered thunderstorms are expected through early
evening, especially across central and northern Wisconsin. There
is a marginal risk of severe storms with large hail and gusty
winds.

.DAYS TWO THROUGH SEVEN...Tuesday through Monday

There is a small chance of thunderstorms Wednesday into Thursday,
and again Sunday into Monday. It is too early to determine the
severe weather threat.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed through this evening.

LMZ521-522-541>543-011945-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
241 PM CDT Mon May 31 2021

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

.DAY ONE...Tonight

Thunderstorms may pose a hazard to mariners through this evening,
especially north of Sturgeon Bay. A few of the stronger storms
could contain hail and gusty winds.

.DAYS TWO THROUGH SEVEN...Tuesday through Monday

There is a small chance of thunderstorms Wednesday into Thursday,
and again next Monday. Any storms that develop will pose a hazard
to mariners.

Bersch/Kieckbusch

Special Weather Statement
National Weather Service Green Bay WI
522 PM CDT Mon May 31 2021

WIZ073-312300-
Southern Marinette County WI-
522 PM CDT Mon May 31 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN MARINETTE COUNTY UNTIL
600 PM CDT...

At 521 PM CDT, Doppler radar was tracking a strong thunderstorm near
Pound, or 19 miles west of Menominee, moving southeast at 30 mph.

Nickel size hail and wind gusts up to 50 mph will be possible with
this storm.

Locations impacted include...
Marinette, Menominee, Crivitz, Pound, Peshtigo, Porterfield, Beaver,
Middle Inlet, Coleman and Harmony.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in Green Bay.

&&

LAT...LON 4494 8759 4494 8766 4497 8776 4499 8776
      4499 8785 4502 8795 4506 8812 4511 8812
      4511 8817 4528 8806 4534 8768 4531 8767
      4529 8769 4520 8774 4517 8774 4514 8768
      4511 8766 4510 8761 4497 8758
TIME...MOT...LOC 2221Z 298DEG 27KT 4517 8803

Kieckbusch

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
529 PM CDT MON MAY 31 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0513 PM     HAIL             1 NNW LAC DU FLAMBEAU   45.97N 89.89W
05/31/2021  U0.50 INCH       VILAS              WI   PUBLIC

            REPORT FROM MPING: HALF-INCH (0.50 IN.).

&&

Special Weather Statement
National Weather Service Green Bay WI
535 PM CDT Mon May 31 2021

WIZ022-073-312330-
Southern Marinette County WI-Door WI-
535 PM CDT Mon May 31 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL DOOR COUNTY UNTIL 630 PM
CDT...

At 534 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 8 miles northwest of Ephraim to near Marinette.
Movement was east at 20 mph.

Half inch hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Marinette, Menominee, Jacksonport, Ephraim, Egg Harbor, Newport State
Park, Baileys Harbor, Sister Bay, Peninsula Center and Fish Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4516 8697 4511 8695 4490 8722 4495 8780
      4496 8777 4496 8776 4499 8776 4499 8780
      4513 8756 4506 8752 4496 8758 4493 8747
      4493 8746 4507 8736 4517 8744 4521 8742
      4525 8734 4522 8721 4531 8712 4535 8681
TIME...MOT...LOC 2234Z 267DEG 13KT 4527 8725 4502 8769

Kieckbusch

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
540 PM CDT MON MAY 31 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0532 PM     HAIL             8 N TOMAHAWK            45.58N 89.73W
05/31/2021  M0.25 INCH       ONEIDA             WI   TRAINED SPOTTER

            FEW MINUTES OF SMALL HAIL

&&

TIMMU

Special Weather Statement
National Weather Service Green Bay WI
542 PM CDT Mon May 31 2021

WIZ010-018-019-312345-
Langlade WI-Oneida WI-Lincoln WI-
542 PM CDT Mon May 31 2021

...SIGNIFICANT WEATHER ADVISORY FOR LINCOLN...SOUTHEASTERN ONEIDA AND
NORTHWESTERN LANGLADE COUNTIES UNTIL 645 PM CDT...

At 541 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Parrish to 8 miles south of Harrison to 6
miles north of Dutch Corners. Movement was southeast at 20 mph.

Nickel size hail and winds in excess of 30 mph will be possible with
these storms.

Locations impacted include...
Merrill, Tomahawk, Harrison, Parrish, Gilbert, Dutch Corners, Birch
Trails Girl Scout Camp, New Wood Wildlife Area, Veterans Memorial
County Park and Bradley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

If on or near a lake, get out of the water and move indoors or
inside a vehicle. Remember, lightning can strike out to 10 miles
from the parent thunderstorm. If you can hear thunder, you are close
enough to be struck by lightning. Move to safe shelter now! Do not
be caught on the water in a thunderstorm.

Persons in campgrounds should consider seeking sturdy shelter until
these storms pass.

&&

LAT...LON 4554 8993 4554 8935 4548 8905 4547 8904
      4546 8893 4533 8906 4514 8940 4524 9005
      4531 9005
TIME...MOT...LOC 2241Z 307DEG 16KT 4543 8942 4536 8947 4532 8959

Bersch

Special Weather Statement
National Weather Service Green Bay WI
558 PM CDT Mon May 31 2021

WIZ019>022-030-031-036>040-073-074-010000-
Waupaca WI-Southern Marinette County WI-Langlade WI-Outagamie WI-
Marathon WI-Portage WI-Brown WI-Southern Oconto County WI-Shawano WI-
Kewaunee WI-Northern Oconto County WI-Door WI-Menominee WI-
558 PM CDT Mon May 31 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN BROWN...NORTHERN
PORTAGE...SOUTHEASTERN MARATHON...KEWAUNEE...SOUTHERN MARINETTE...
DOOR...MENOMINEE...NORTHERN WAUPACA...SOUTHERN OCONTO...NORTHERN
OUTAGAMIE...SOUTH CENTRAL LANGLADE AND SHAWANO COUNTIES UNTIL 700 PM
CDT...

At 555 PM CDT, Doppler radar was tracking strong thunderstorms
extending from eastern Marathon and western Shawano counties
eastward into southern Oconto and southern Marinette counties. The
storms will continue to sag farther south into the northern Fox
Valley by 7 pm.

Half inch hail and winds in excess of 40 mph will be possible with
the stronger storms.

Locations impacted include...
Green Bay, Stevens Point, Shawano, Sturgeon Bay, Antigo, Kewaunee,
Bay Shore Park, Clintonville, Oconto and Pulaski.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4498 8715 4447 8748 4454 8971 4512 8922
      4501 8755 4494 8759 4493 8771 4490 8777
      4486 8777 4471 8792 4463 8793 4469 8780
      4487 8765 4493 8746 4500 8741
TIME...MOT...LOC 2255Z 270DEG 23KT 4496 8903

Kieckbusch