008
FXUS63 KGRB 080855
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
355 AM CDT Tue Jul 8 2025

Forecast discussion for routine morning forecast issuance

.KEY MESSAGES...

- A few showers and thunderstorms are possible across the area
  today, with the best window for any convection in the afternoon.

- Additional shower and thunderstorm chances possible late Friday
  into Saturday. Heavy rainfall possible with this second system.

&&

.DISCUSSION...
Issued at 355 AM CDT Tue Jul 8 2025

Precipitation Trends Today...
Overnight shower activity has largely missed our corner of
Wisconsin for the late overnight period. The more organized
clusters to our north have largely tracked along the upper
shortwave and 700mb moisture axis, while the more scattered shower
activity to our south remains oriented along the weak WAA and
mositure influx to our south. Lowered the pops through the mid to
late morning as a result, as virga and satellite do show lingering
potential for a stray shower, but not as widespread as previously
forecast. As moisture and warm air aloft continue to push into the
region through the morning, would expect some spotty showers and
storms to develop over the region by the late morning and early
afternoon. An uptick in any convection is then anticipated for the
mid to late afternoon as the tail end of weak shortwave trough
crosses into the region. Daytime instability remains modest due
to cloud cover, around 800-1200 J/kg,and shear remains relatively
weak so the threat for severe weather remains low. Some brief
heavy rainfall will be possible and storms will be relatively slow
moving, but limited thunderstorm coverage should help mitigate
hydro concerns. Probabilistic guidance keeps the probability of
exceeding half an inch of rain to around 20-30%, with only far
north-central getting to around 40%.

End of the Week System...
The next shot of active weather in the region will be around the
end of the week as a negatively tilted trough crosses into the
region Friday afternoon and evening. A surge of warmth and
moisture ahead of the trough will push PWATs above 2 inches, which
will certainly allow for another heavy rain threat. Initial looks
at severe potential for our area are unimpressive, with most model
soundings showing a lack of instability, likely due to an earlier
arrival of both rain and clouds which will limit reaching better
surface convective temperatures. How long the rain lasts into
Saturday is uncertain at this point, as the trough is expected to
promote the development of a low pressure system that then slides
off to our northeast. How far this gets during the ovenright
period will dictate how much wrap around moisture we see as the
CAA follows on Saturday. Retained the pops from the previous
forecast cycle for now.

Temperature-wise we will run fairly close to normal through the
week, with a weak warming trend into Friday that could bring us
into the middle 80s.

&&

.AVIATION...for 06Z TAF Issuance
Issued at 946 PM CDT Mon Jul 7 2025

VFR conditions will continue this late evening, then isolated to
scattered showers and isolated storms with VFR/MVFR (possibly
briefly IFR at times) ceilings/vsby are forecast to arrive from
west to east after midnight. Continued the TEMPO groups for storms
across central and north central WI, where thunder chances are
highest, but storm coverage looks to be rather small. Went with
PROB30 for locations over the east. After the initial area of
showers and isolated storms moves through, isolated showers or
storms will be possible the rest of the afternoon and evening on
Tuesday with MVFR/VFR ceilings. Included PROB30s for this threat.

Winds will remain light out of the south/southeast overnight.
Winds will shift to the west/northwest on Tuesday, but remain
mainly under 10 kts.

&&

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

&&

$$

DISCUSSION.....Uhlmann
AVIATION.......Bersch