205
FXUS63 KGRB 190638
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
138 AM CDT Tue May 19 2026

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- Isolated strong winds gusts are possible early this morning as
  scattered thunderstorms move across the area.

- Frost or freeze headlines may be needed Tuesday night and
  Wednesday night.

- Warming back up this weekend with returning chances for showers
  and storms.

&&

.DISCUSSION...
Issued at 138 AM CDT Tue May 19 2026

Scattered thunderstorms will continue to move northeast across east-
central and northeast WI early this morning in association with a
passing mid-level short-wave and strengthening LLJ. The risk for
severe thunderstorms is very low given weak instability, however, any
storm may be capable of producing brief wind gusts of 40-50 mph and
small hail. On the western back edge of these storms surface obs
from SE MN and western WI are showing 40-50 mph wind gusts out of
the southeast, indicative of a wake low. As the precipitation erodes
to the east expect these stronger wake low winds to make it into
central WI over the next few hours.

Another round of showers and storms is likely later this mornings as
a cold front, currently snaking from far NW WI back toward south-
central MN, sweeps across the region. CAMs do show some weak
instability (100-300 J/kg) building ahead of the front which could
support an isolated stronger thunderstorm, however, the risk for any
storms reaching severe limits is low. Behind the front steep low-
level lapse rates associated with the CAA regime may spur on isolated
showers through this afternoon. Any lingering showers should wane
this evening as high pressure starts to build back into the region.
The area should remain under the influence of high pressure for the
remainder of the week leading to dry conditions.

With the high overhead Wednesday night and a dry air mass in place
(PWATs ~0.3") lows are forecast to fall near freezing across
northern WI which may prompt the need for frost/freeze headlines.

The next chance (30-50%) for showers and thunderstorms arrives this
weekend as southerly return flow delivers warmer and more moist air
back to the region. Global ensembles and long range ML products are
not highlighting much of severe storm with this system at this
point.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1251 AM CDT Tue May 19 2026

Ongoing line of rain and thunderstorms is moving east across
central and into northeast WI as of 0530Z. The main line has
exited KAUW, KCWA, and KRHI, but a small thunder threat remains
for the next couple hours from additional development to the south.

Main hazard along and east of the main line over the next 3 to 4
hours will be strong wind gusts to 40 knots and heavy rain. There
remains a small potential for isolated severe wind gusts to 50
knots, but expect this potential to diminish as the storms move
east.

Widely scattered showers remain throughout Tuesday morning, with
conditions area-wide drying out after ~18Z. Most location are
still VFR, but expect cigs to drop to IFR/MVFR overnight, with
improvements to MVFR/VFR this afternoon. Additionally, fog off
Lake Michigan will drop vsby at KMTW at times through Tuesday
morning.

South winds veer southwest overnight, and then veer to the west-
northwest Tuesday behind the cold front, along with wind gusts to
25 kts.

&&

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

&&

$$

DISCUSSION.....GK
AVIATION.......KLJ

NWS GRB Office Area Forecast Discussion