945
FXUS63 KGRB 290307
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1007 PM CDT Tue May 28 2024

Updated aviation portion for 06Z TAF issuance

.KEY MESSAGES...

- Due to recent rainfall, a few rivers are expected to remain at
  bankfull but below minor flood stage through late this week.

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

&&

.DISCUSSION...
Issued at 414 PM CDT Tue May 28 2024

Short Term...Tonight and Wednesday

Main concern in this forecast period is the evolution of the
scattered showers and thunderstorms through late this evening,
especially in east-central WI.

This evening through tonight...The last of the embedded shortwaves
within a mid-level trough over Ontario will continue to slowly move
over the central Great Lakes region during this forecast period. The
mid-level support from this shortwave, in combination with several
land boundaries colliding in an area with around 800 J/kg of CAPE,
caused thunderstorms to quickly pop-up in east-central WI. With
little deep-layer shear of 20-25 kts in this area, the storms have
and will struggle to maintain an updraft, resulting in locally heavy
rainfall and small hail. Meanwhile, rain over central and north-
central WI will shift eastward and combine with the scattered
showers and storms in east-central WI. This will keep chances for
showers and storms in east-central WI through late this evening.
Additionally, radar is picking up on isolated showers and storms in
western WI this afternoon, that may drop into central and north-
central WI this evening. However, these showers are diurnally
driven, so anticipate these showers and storms to decrease as the
sun sets. The remainder of the night will be dry with some clearing
in central and north-central WI, as high pressure sneaks into the
region.

Wednesday...High pressure will continue to build over the area
allowing for the return of dry weather. Plenty of sunshine is
expected for Wednesday, however, forecast soundings indicate a cu
field developing in the afternoon. High temperatures will remain a
few degrees below normal with values ranging from low to middle 60s
along the lakeshore, to the middle 60s to low 70s elsewhere.

Long Term...Wednesday Night Through Tuesday

Dry weather is anticipated for the first portion of this forecast
period before the pattern becomes unsettled starting Friday.

Wednesday night through Friday...High pressure is expected to
remain over the area for Wednesday night into Thursday and keep
conditions dry. However, with the high pressure overhead into
Thursday morning, chilly temperatures are expected with lows
ranging from the low 30s to low 40s. Anticipate frost to develop
for some locations, especially across the Northwoods, where
temperatures will be coldest. The high pressure will gradually
exit on Thursday and Thursday night, allowing winds to turn
southwesterly and lift warmer, moist air into the region for
Friday. Depending on how quickly or slowly this high pressure and
associated upper-level ridge exits to the east on Friday, the
forecast area may see the next chance for precip from the trailing
embedded shortwave. Models indicate much of the forecast area
should remain dry on Friday, with the exception in far north-
central WI, where rain may develop later on Friday.

Rest of the extended...Models are struggling with the evolution of
the upper-level pattern and how the embedded shortwaves will
interact beyond Friday. However, there does appear to be multiple
chances for showers and thunderstorms at times throughout the
weekend and into early next week.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 1000 PM CDT Tue May 28 2024

Isolated showers should end by the beginning of the new TAF
period, as a short-wave trough departs. Clearing has already
occurred over the western part of the forecast area, and should
spread into eastern WI later tonight into early Wednesday. Expect
VFR conditions to prevail, except in NC WI, where patchy ground
fog will drop vsbys to IFR overnight into early Wednesday. Cannot
rule out the potential for fog in east central WI, where heavy
rainfall fell earlier today, but winds should provide enough
mixing to prevent it in most areas. Winds will be from the north
tonight, then gradually veer NE-E on Wednesday.

&&

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

&&

$$

DISCUSSION.....Kruk/Kruk
AVIATION.......Kieckbusch