240
FXUS63 KGRB 221943
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
243 PM CDT Sat Jun 22 2024

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- A complex of thunderstorms is expected to move across portions
   of central and east-central Wisconsin late this afternoon into
   this evening. Some of the storms could be strong and possibly
   severe with damaging winds.

 - The risk of heavy rain will continue into this evening as a
   complex of thunderstorms moves across the area. Rainfall totals
   of 1 to 4 inches have fallen where the Flood Watch is currently
   in effect. Have extended the Flood Watch until 10 pm until the
   storms moves out of the area.

 - Many rivers and streams will continue to rise into early next
   week due to runoff from todays rainfall.

 - Additional strong to severe thunderstorms are possible Monday
   night into Tuesday evening.

 - Another heavy rainfall threat may materialize late in the week
   (Friday into Friday night), as a cold front moves through the
   region.

&&

.DISCUSSION...
Issued at 242 PM CDT Sat Jun 22 2024

Short Term...Tonight and Sunday

Skies were cloudy across the area with scattered showers across
northeast Wisconsin. Temperatures were in the lower to middle 60s
across the north to the upper 70s from Waupaca to Appleton and
Oshkosh.

Rainfall totals of 1 to 4 inches has fallen where the Flood Watch
is currently in effect. Another complex of thunderstorms is
expected to move across the watch area late this afternoon into
this evening. I have decided to extend the Flood Watch until 10 pm
to account for another round of heavy rain. A few strong or severe
storms are possible south of Highway 10 as the complex moves
across the area, with strong or damaging winds the main risk.
Rainfall rates in the stronger cells will be in the 1 to 2 inch
range, which could result in urban street flooding and ponding of
water on area roads. Across the north, showers are expected at
times as an upper level disturbance swings across the north. The
showers and storms will taper off and end from west to east later
this evening and overnight.

On Sunday, another upper level disturbance combined with daytime
heating will trigger scattered and storms, especially from late
morning on. Bufkit soundings showing several hundred J/KG of CAPE
with strong shear of 40 to 50 knots. Some stronger storms are
possible with wind gusts to 45 mph and small hail. Could not rule
out an isolated severe storm. High temperatures should be in the
70s.

Long Term...Sunday Night Through Saturday

The main forecast concerns revolve around thunderstorm chances
Monday night through Tuesday evening, and again late in the week.

A short-wave moving through the region will keep a chance of
showers and isolated storms across east central WI Sunday evening.
Once the disturbance shifts east, the showers should quickly end.
Partial clearing and light winds should allow temperatures to
will allow temperatures to drop into the upper 40s and 50s.

Dry conditions persist through Monday, but a warm front will
bring a chance of storms back into the area Monday night.
Substantial instability will develop across the forecast area
later Monday night into Tuesday. Strong to potentially severe
elevated storms are possible Monday night, with additional storms
developing ahead of a cold front Tuesday into Tuesday evening.
Models are showing some support for an MCS moving through part of
the area late Monday night/early Tuesday, and perhaps less
convection along the cold front on Tuesday, so there are some
issues that still need to be resolved here.

High pressure will bring dry conditions to the region from late
Tuesday night through Thursday.

A frontal system is forecast to move through the region sometime
during the Thursday night to Saturday period, with the most likely
timing occurring Friday into Friday night. This system should have
have a nice surge of Gulf of Mexico moisture, with PWATs possibly
surpassing 2 inches. Heavy rainfall may once again become a
concern.

Aside from a very warm and humid day on Tuesday, most of the
extended period should average just a little above normal for
temperatures.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1231 PM CDT Sat Jun 22 2024

Poor flying conditions expected to continue through Sunday morning
due to showers/storms/low clouds this afternoon into this evening,
then low cloud through Sunday morning. CIGS at times will run at
or below IFR conditions. The showers and storms should come to an
end this evening. Some stronger storms with gusty winds and
blinding rain are possible across central and east-central
Wisconsin late this afternoon into early this evening. On
Sunday afternoon, scattered showers and isolated thunderstorms are
possible, especially during the afternoon into the early evening
hours. Some of these storms could contain gusty winds to around
40 mph and small hail.

&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 10 PM CDT this evening for WIZ030-031-035>040-
045-048>050.
&&

$$

DISCUSSION.....Eckberg/Kieckbusch
AVIATION.......Eckberg