578
FXUS63 KGRB 111120
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
620 AM CDT Wed Sep 11 2024

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Isolated showers early today, then dry through Friday. Chances
  for showers and storms return Saturday night through early next
  week.

- Summer-like temperatures continue with highs mainly in the 80s
  through early next week.

&&

.DISCUSSION...
Issued at 317 AM CDT Wed Sep 11 2024

Short Term...Today...Tonight...and Thursday

Shortwave trough and modest low-level jet will spur on last batch
of showers that move through this morning. Sfc obs show bases of
clouds causing the showers remain high, thus rain amounts will be
mainly under 0.10 inch. Mesoanalysis shows MUCAPE has vanished,
so have removed any thunder from here on out. Once the showers
exit, dry weather takes hold for the rest of the week. Expect
elevated wildfire smoke through Thursday, leading to more of a
milky sky both days. This smoke will hold down temps slightly
today, but with H85 temps nearing 20c, afternoon temps will still
reach the mid 80s.

Weakening pressure gradient tonight will allow for lighter winds
and temps to drop into the upper 40s to lower 50s, coolest over
northern WI. Cooling temps and moistening low-level inversion will
result in patchy fog overnight central to northern and northeast
WI. Temps back well into the 80s again on Thursday, though chances
of seeing any 90 degree readings have lowered. Winds becoming
southeast will keep conditions slightly cooler near Lake Michigan.

Long Term...Thursday Night Through Tuesday

Precipitation trends are the main focus from this forecast period.
Otherwise, above normal temperatures are expected to continue
through at least early next week with highs mainly in the upper 70s
to low 80s.

Precipitation...An upper-level ridge of high pressure will reside
over the region Thursday night into Friday, keeping conditions dry.
Meanwhile, the remnants of Hurricane Francine will be lifting north
along the Mississippi River Valley and weakening as it runs into the
dry air from the high. Models are in agreement for Francine`s
remnants to make it as far north as the confluence of the
Mississippi and Ohio rivers by Friday night, before gradually moving
east over the Tennessee Valley for the weekend. Although models
agree the forecast area will not see direct impacts from Francine,
moisture from the tropical system will transport into the Upper
Mississippi Valley via southerly flow on the backside of the
ridge/high pressure. This will result in sporadic showers and storms
over the forecast area from late Saturday through early next week.
Despite weak forcing during this time, a couple hundred J/kg of CAPE
and PWATs of 1.25 to 1.50 inches may result in some brief heavy
downpours within any thunderstorm.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 619 AM CDT Wed Sep 11 2024

VFR conditions today. Isolated showers will impact MTW early.
Elevated wildfire smoke will persist across the region, but no
reduction in surface visibility is expected. LLWS has ended, but
southwest winds may still gust up to 20 knots this afternoon.

Tonight some late night fog is possible, especially at RHI where
IFR visibility could occur. Otherwise, VFR conditions will continue
with elevated smoke persisting.

&&

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

&&

$$

DISCUSSION.....JLA/Kruk
AVIATION.......JLA