FXUS63 KGRB 191745
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1245 PM CDT Tue May 19 2026

Updated aviation portion for 18Z TAF 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 18Z TAF Issuance
Issued at 1123 AM CDT Tue May 19 2026

MVFR stratus deck has persisted over most of the forecast area
this afternoon as the cold front continues to progress to the
east. Downsloping northwest winds may help scatter out some of the
lower clouds later this afternoon and evening, with GRB, ATW, and
MTW expected to lift to VFR within the next few hours. BKN MVFR 
cigs will likely stick around in/near RHI for the majority of the
TAF period, though windows for improvement to VFR will be 
possible.

Winds have already shifted to the west/northwest as of this 
afternoon, with the east-central sites expected to shift within 
the next hour or two. Gusts between 20 and 25 knots will be 
possible through this afternoon, before winds subside this evening
and overnight with the loss of daytime mixing.

&&

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

&&

$$

DISCUSSION.....GK
AVIATION.......Goodin