507
FXUS63 KGRB 162003
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
303 PM CDT Tue Jun 16 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Showers and storms end by evening. Most storms will produce
  small hail and gusty winds. An isolated storm could produce
  quarter sized hail over eastern WI.

- Another round of showers and storms are expected for Wednesday
  (80-100% chance). A few strong storms with small hail and gusty
  winds may occur. Moderate to heavy rainfall will have a 60-80%
  chance of exceeding 1 inch of rain.

- Below average temperatures in the 60s and 70s through the week.

&&

.DISCUSSION...
Issued at 303 PM CDT Tue Jun 16 2026

Active weather continues through late this week. Temperatures will
remain below normal.

Into this evening...Compact, tightly wrapped up shortwave trough
crosses the region. Instability has built sufficiently to result
in strong to severe storms early this afternoon with 0.5 inch to
1.0 inch hail, especially with such low freezing levels. Lack of
shear well under 20 kts means main storm mode will be pulse type.
Showers and storms will exit eastern WI after 6-7p.

Wednesday...
Another, stronger shortwave drops towards the region on Wednesday,
bringing another round of showers and storms. The track of the
accompanying surface low is expected to remain over southern
Wisconsin which should keep warm front and more unstable air south
of the area, and greatly limit the overall severe potential. That
said, some overrunning moisture from the surface warm front
combined with some surface heating and sufficient shear will
still support at least embedded storms. Best potential for any
stronger storms will be from central to east-central Wisconsin,
mainly south of highway 10. Heavy rainfall will also be possible
with any convection. There is a Marginal Risk of Excessive
Rainfall stretching across central to east-central Wisconsin and
southwards as well.

Rest of the forecast period...Another brief round of scattered
(20-30% chance) showers will be possible on Thursday, driven
primarily by strong surface heating. Convective support will be
relatively minimal, so expect impacts from any scattered showers
to be minimal. After this, the only chance for more widespread
active weather would be Saturday night into Sunday, when another
larger system enters western Great Lakes. Greatest risk for rain
appears to be setting up for Sunday instead of Saturday.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1232 PM CDT Tue Jun 16 2026

Numerous showers with scattered thunderstorms will prevail through
the afternoon as sfc low crosses WI. Greatest instability is over
east-central WI and this is where hail the size of quarters and
wind gusts over 30 kts could occur this afternoon. Mainly VFR cigs
are expected, though pockets of MVFR are possible, especially over
central WI. Showers end by this evening, with the next round of
showers and possible thunder arriving late Wednesday morning.

&&

.MARINE...
Issued at 303 PM CDT Tue Jun 16 2026

S to SE winds increase Wednesday afternoon before shifting to NE
as sfc low passes by to the south. Waves build sufficiently enough
that a Small Craft Advisory and Beach Hazards Statements will
eventually be needed. The higher waves will linger into Thursday
morning, before winds shift offshore to the NW.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......JLA
MARINE.........JLA

NWS GRB Office Area Forecast Discussion