Severe Thunderstorm Warning 12, NWS Green Bay, WI

Area Forecast Discussion
National Weather Service Green Bay WI
1212 PM CDT Thu May 12 2022

Updated aviation portion for 18Z TAF issuance

.SHORT TERM...Today...Tonight...and Friday
Issued at 426 AM CDT Thu May 12 2022

A convectively induced vorticity center that formed over West
Texas yesterday moved across Minnesota and northwest Wisconsin
last night and brought mostly non severe thunderstorms with wind
gusts to 35 mph and half inch hail. The activity was exiting the
lakeshore counties at 400 am.

The upper ridge across Wisconsin combined with southerly flow
bringing up very warm and humid air could result in record high
temperatures this afternoon. Highs in the middle 80s to low 90s
are likely away from the lake and bay. Those temperatures combined
with dewpoints of 65 to 70 will result in impressive instability
this afternoon and early evening, with CAPE values of 2000 to 3000
J/KG. There will likely be a temperature inversion to inhibit
convection, but a surface warm front moving north, or leftover
convective boundaries could produce additional thunderstorms today.
There is some severe potential for any thunderstorms that form.

Whatever storms do form this afternoon or evening should diminish
after sunset with warm and humid conditions expected overnight.
Friday will be warm and humid, but not as hot as today. A cold
front should produce thunderstorms as it moves across during the
afternoon and early evening. There should be sufficient instability
and upper support to produce some severe storms with damaging
winds and large hail.

.LONG TERM...Friday Night Through Wednesday
Issued at 426 AM CDT Thu May 12 2022

The 500mb ridge across the Great Lakes region will finally break
down and shift east this weekend. Meanwhile, a closed 500mb low
across the southern plains of Canada is expected to pivot across
southern Canada over the weekend with a cooler northwest flow
pattern expected early next week. Temperatures will start out
above normal Saturday, return closer to normal on Sunday and then
below normal for Monday and Tuesday before moderating closer to
normal by the middle of next week as the upper flow turns more
westerly.

A cold front will be lurking across northeast Wisconsin Friday
night. Strong or severe storms are possible Friday evening with
CAPE values of 1,500 to 2,500 J/KG. 0-6 km shear values are little
better tonight to support severe weather with bufkit soundings
indicating near 30 knots of shear. The storms should weaken by
late evening and overnight. The proximity of the frontal boundary
supports a chance of showers Saturday morning across eastern
Wisconsin.

For this weekend there are small chances of showers and a few
storms at times, however most of the time should be dry. High
temperatures Saturday will be above normal and closer to normal
Sunday. With the northwest flow pattern aloft, weak upper level
disturbances could bring a chance of shower on Monday and Tuesday.
A more substantial system passing to the south of the area will
bring a chance of showers on Wednesday. It will be fairly cool
Monday, where some locations across the far north could see highs
in the 50s. There is also the potential for frost Monday night
across the north with lows in the 30s.
&&

.AVIATION...for 18Z TAF Issuance
Issued at 1212 PM CDT Thu May 12 2022

VFR conditions are expected across much of the area this
afternoon, with some SCT-BKN cumulus clouds around 4-5k ft. Some
MVFR conditions are possible across north-central Wisconsin due to
the elevation difference. There may also be some haze in the air
this afternoon due to high moisture content. Isolated to
scattered thunderstorms are possible in the afternoon and
evening, mainly north of a AUW to GRB line.

VFR conditions are expected tonight, with low level wind shear
after dark as south winds increase to around 45 knots at 2000 ft
with surface winds around 10 knots.

VFR conditions are expected Friday morning, but then showers and
thunderstorms will bring lower conditions in the afternoon as a
cold front approaches.
&&

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

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

Hazardous Weather Outlook
National Weather Service Green Bay WI
400 AM CDT Thu May 12 2022

WIZ005-010>013-018>022-030-031-035>040-045-048>050-073-074-130900-
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-
400 AM CDT Thu May 12 2022

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

.DAY ONE...Today and Tonight

Scattered thunderstorms could produce wind gusts to 35 mph and small
hail as they exit northeast Wisconsin early this morning.

Additional scattered thunderstorms are expected across the area this
afternoon and evening. There is a marginal threat of severe storms
with large hail and damaging winds mainly west of highway 41.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

There is a chance of thunderstorms Friday afternoon and Friday
night. Some of the storms could become strong or severe with
damaging winds and large hail.

There are small chances of thunderstorms at times this weekend. These
storms are not expected to be severe.

.SPOTTER INFORMATION STATEMENT...

Spotter activation could be needed across northern Wisconsin this
afternoon and evening, and again Friday afternoon and evening across
much of the area.

LMZ521-522-541>543-130900-
The Bay of Green Bay south of a line from Cedar River MI to Rock
Island Passage-Lake Michigan from Washington Island to Sheboygan-
400 AM CDT Thu May 12 2022

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

.DAY ONE...Today and Tonight

Scattered thunderstorms are expected early this morning. They
could produce wind gusts to 30 knots and small hail. In addition,
fog may reduce visibilities at times today and tonight.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

There is a chance of thunderstorms Friday afternoon and Friday night
that may produce strong winds and large hail. Isolated thunderstorms
are possible at times this weekend that could pose a hazard to
mariners.

Areas of dense marine fog are possible at times through Saturday
afternoon. High waves could create conditions hazardous to small
craft Friday on Lake Michigan.

RDM/Eckberg

Special Weather Statement
National Weather Service Green Bay WI
1157 AM CDT Thu May 12 2022

WIZ030-031-035>039-045-048-049-122100-
Marathon-Shawano-Wood-Portage-Waupaca-Outagamie-Brown-Waushara-
Winnebago-Calumet-
1157 AM CDT Thu May 12 2022

...HIGH HEAT INDEX VALUES EXPECTED THIS AFTERNOON...

Record breaking temperatures combined with high relative
humidities will result in heat indices of 95 to 100 degrees
across central Wisconsin east to the Fox Valley this afternoon.

If you are spending an extensive amount of time outside this
afternoon or if you are vulnerable to heat illness, be sure to
stay hydrated and take breaks out of the sun.

Kurimski

Special Weather Statement
National Weather Service Green Bay WI
149 PM CDT Thu May 12 2022

WIZ010>013-018>021-030-031-035>037-073-074-122015-
Waupaca WI-Southern Marinette County WI-Langlade WI-Wood WI-
Marathon WI-Portage WI-Oneida WI-Northern Marinette County WI-
Lincoln WI-Southern Oconto County WI-Shawano WI-Florence WI-
Northern Oconto County WI-Menominee WI-Forest WI-
149 PM CDT Thu May 12 2022

...Scattered strong thunderstorms will impact portions of Wood,
southeastern Lincoln, Marathon, southeastern Oneida, Shawano,
Portage, Forest, Florence, Marinette, Menominee, northwestern
Waupaca, northern Oconto and Langlade Counties through 315 PM CDT...

At 148 PM CDT, Doppler radar was tracking scattered strong
thunderstorms, moving northeast at 30 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Wausau, Stevens Point, Wisconsin Rapids, Shawano, Antigo, Crandon,
Marshfield, Weston, Merrill and Rib Mountain.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4481 9032 4602 8870 4598 8864 4602 8853
      4595 8819 4592 8810 4587 8807 4582 8814
      4578 8809 4579 8799 4571 8781 4556 8783
      4550 8779 4535 8789 4535 8775 4539 8769
      4534 8765 4531 8767 4424 8957 4425 9032
TIME...MOT...LOC 1848Z 228DEG 27KT 4500 8915

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

Hykin

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
217 PM CDT THU MAY 12 2022

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

0210 PM     HAIL             MOSINEE                 44.78N 89.69W
05/12/2022  M0.88 INCH       MARATHON           WI   TRAINED SPOTTER

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREEN BAY WI
222 PM CDT THU MAY 12 2022

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

0214 PM     HAIL             ANTIGO                  45.15N 89.15W
05/12/2022  M0.25 INCH       LANGLADE           WI   TRAINED SPOTTER

            PEA SIZED HAIL. LASTED A COUPLE MINUTES.

&&

KJ