785
FXUS63 KGRB 112350
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
650 PM CDT Tue Aug 11 2026

Updated aviation portion for 00Z TAF issuance

.KEY MESSAGES...

- Generally small (20-40%) chances for a shower/storm at times
  through Thursday with next more organized rain potential
  (50-70% chance) around Saturday. Severe weather chances
  appear low at this time.

-  Locally dense fog possible late tonight into Wednesday
   morning region-wide.

-  Near average temperatures will trend cooler for the weekend.

&&

.DISCUSSION...
Issued at 1240 PM CDT Tue Aug 11 2026

Overall, a fairly low impact weather regime will persist through
late week. Seasonably strong northwest flow aloft will continue
through Thursday although the stronger instability and greater
moisture will remain south of the local area. Some small (20-40%)
chances for showers/storms continue through Thursday, but synoptic
forcing and low-level convergence are weak. The stronger flow aloft
will result in elongated hodographs, so an isolated strong storm
cannot be ruled out through Wednesday, particularly south of
highway 29, where instability is generally higher.

Rain chances decrease further towards the end of the work week as
mid-level heights build across the Upper Midwest. However, showers
and storm chances (50-70%) will return to start the weekend as
a progressive shortwave trough moves across the region.
Precipitable water values increase above the 95th percentile
ahead of this system, but seasonably cool temperatures and
relatively weak instability look to limit the severe weather
risk, with little signal currently indicated in the machine
learning guidance. Generally drier and seasonable weather is
forecast behind the weekend system.

Otherwise, some fog development may occur tonight with light flow
and a moist boundary layer. At least locally dense fog may occur,
especially given the favorable time of year with nights becoming
longer, but will have to watch cloud trends overnight.

&&

.AVIATION...for 00Z TAF Issuance
Issued at 650 PM CDT Tue Aug 11 2026

Fog will be again be the main focus for the aviation forecast
tonight. Initial fog may again come in off of Lake Michigan which
will impact MTW, but expect relatively clear skies to allow for
some patchy fog to develop across most of the area. Therefore
included some fog mentions across all TAF sites overnight. Any fog
will likely bring categorical changes down towards MVFR and IFR at
times overnight, with the lowest visibility and ceiling expected
for areas near the shoreline of Lake Michigan.

Wednesday is expected to be predominantly dry for most of the
region, but a few isolated showers are possible in the late
afternoon and evening. Confidence on timing and placement remains
low at this time, so kept them out of the TAF for the time being,
but may see a bigger empathizes on active weather in later TAF
updates.

Winds will stay light through the period.

&&

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

&&

$$

DISCUSSION.....JM
AVIATION.......Uhlmann

NWS GRB Office Area Forecast Discussion