826
FXUS63 KGRB 280351
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1051 PM CDT Mon May 27 2024

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- There will be additional chances for showers and thunderstorms
  through Tuesday. Severe weather is not anticipated.

- Due to recent rainfall, a few rivers are expected to remain at
  bankfull but below flood stage.

- Areas of patchy frost are possible late Wednesday night into
  Thursday morning across far northern Wisconsin.

&&

.DISCUSSION...
Issued at 255 PM CDT Mon May 27 2024

Short Term...Tonight and Tuesday

Scattered showers and isolated thunderstorms should diminish this
evening as an upper level disturbance moves across southwest
Wisconsin. A couple storms could produce wind gusts to 35 mph and
pea size hail. Skies will remain mostly cloudy tonight with
cyclonic upper flow. Low temperatures will be close to normal.

Another shortwave will move across the region Tuesday, and produce
additional showers and thunderstorms. A few storms could produce
small hail and wind gusts to 35 mph in the afternoon. The clouds
and scattered showers will hold high temperatures around five
degrees below average.

Long Term...Tuesday Night Through Monday

Beginning of the extended sees lingering chances for light rain
and storms across the forecast area before a brief reprieve from
precip. A high amplitude blocking pattern will settle in across
the central CONUS mid-week, keeping most of the Midwest high and
dry into the weekend. Next chances for rain will then arrive late
Friday into early Saturday as return flow from departing high
pressure tracks a plume of Gulf moisture across the Mississippi
Valley. High temperatures will plateau in the mid to upper 70s
Saturday and Sunday following a gradual incline throughout the
week.

Tuesday evening through Friday... No significant changes to the
forecast regarding rain chances Tuesday afternoon and evening.
Light rain is expected to be ongoing Tuesday evening as a mid-
level shortwave continues to dig south across Wisconsin before
exiting to the south and east. Synoptic support remains
unimpressive due to the absence of any surface features, thus mid-
level forcing associated with the shortwave will be the main
driver for rain/storm chances. Some short-lived thunderstorms will
be possible during peak heating as a swath of marginal
instability and decent lapse rates extend into central Wisconsin.
The remainder of the work week then looks to be mostly dry as an
omega block builds into the central CONUS. Prevailing
south/southwesterly flow will hence act to advect warmer air up
from the south, resulting in a gradual increase in temperatures
into the weekend. This being said, areas of patchy frost across
the far north continue to be a concern late Wednesday night into
Thursday morning as light winds and windows for clearing may allow
for temperatures to drop down into the low to mid 30s.

Weekend rain chances... Models continue to disagree about timing
of precip arrival into the weekend. At a first glance, several
questions remain regarding rain amounts and convective potential,
including how quickly the profile can saturate due to the
influence of lingering dry air to the east. How progressive the
parent shortwave and attendant cold front are would also be a
determining factor in how long precip will linger into Sunday.
Will continue to monitor as we get closer to the event and
medium-range models come into play.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1045 PM CDT Mon May 27 2024

Scattered showers will taper off early in the TAF period as a
short-wave trough departs the region. Another weak disturbance
will bring light showers into NC WI by around daybreak, but a
stronger system will arrive for the afternoon and early evening.
This third short-wave will bring NMRS showers and scattered
thunderstorms to much of the region, with the best chance of
storms occurring over the southwest half in the afternoon and
early evening. Have opted to add a TEMPO group for storms at
AUW/CWA/ATW/GRB. VFR conditions will prevail through most of the
TAF period, though there may be a brief period in the late morning
and early afternoon, when the bases of a developing cumulus cloud
deck will be MVFR. In addition, MVFR conditions may accompany any
storms that develop. The showers and storms should taper off
Tuesday evening.

&&

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

&&

$$

DISCUSSION.....RDM/Goodin
AVIATION.......Kieckbusch