NWS-Green Bay Forecast Discussion

						FXUS63 KGRB 091706
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
1206 PM CDT Thu Jul 9 2026

Updated aviation portion for 18Z TAF issuance

.KEY MESSAGES...

- Scattered showers and a few thunderstorms will come to
  an end late this afternoon. Severe storms are not expected.

- Will need to watch precipitation trends this weekend. A few
  storms are possible Saturday and Sunday.

- Trends continue to be monitored for the excessive heat potential
  early next week with highs in the 90s at some locations.

&&

.DISCUSSION...
Issued at 145 AM CDT Thu Jul 9 2026

Scattered showers continued early this morning near Rhinelander
and Merrill eastward into northern Door County ahead of a weak
cold front that is expected to sag southward today. As the front
sags southward, rain chances return to central and east-central WI
this morning which will continue into the afternoon. Bufkit
soundings indicated 500 to 800 J/KG of CAPE and shear values
around 20 knots, thus not expecting severe weather today. The
showers and storms will end from north to south this afternoon.

Tranquil conditions are expected on Friday. A new wrinkle to the
forecast for the weekend. High pressure is expected to set up
across the state. Return flow/850mb warm advection sets up Friday
night, which should result in scattered thunderstorms developing
across Minnesota and western WI. Some of the activity may spill
into far north-central WI towards 12z Saturday. The combination of
daytime heating and possibly an outflow boundary from the
overnight convection is expected to bring a chance of showers and
storms across the north Saturday afternoon. Confidence is low on a
dry forecast for Sunday as the Canadian/ECMWF are bringing a weak
impulse across the area at 500mb. The ECMWF is more bullish than
the Canadian model on the QPF output for Sunday. Will continue to
monitor to see if rain will need to be added for this period.

500mb ridge builds early next week, resulting increasing heat and
humidity later this weekend through the middle of next week.
850mb temperatures are pretty toasty off the ECMWF/Canadian/GFS
that would support highs in the lower to middle 90s at our typical
hot spots. Current forecast is a little bit lower that what the
max values would be each day. None the less, it will be hot.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1205 PM CDT Thu Jul 9 2026

A weak cold front is dropping south from roughly Wisconsin Rapids
(ISW) to Appleton (ATW) late this morning. A mix of ceilings
ranging from IFR to VFR exist along the front and across much of
central, east-central, and far northeast WI. Skies are clearing
across far northern WI as a drier airmass moves in the low
levels.

Widely scattered showers and isolated storms will be possible
along and ahead of the boundary through 00Z. The IFR/MVFR ceilings
are expected to gradually rise, but MVFR ceilings could persist
through 20-22Z along the front. Brief downpours could drop
visibilities to IFR in the heaviest shower activity.

Skies are anticipated to clear tonight which will set up a
favorable ground fog scenario. The most favored area for ground
fog will be across central WI and parts of the Fox Valley where
dewpoints will struggle to mix out this afternoon. LIFR/IFR flight
conditions will be possible in the ground fog from 08-13Z Fri.

Fair weather clouds are expected to build after the fog burns off
later Fri morning.

Light winds are expected over the TAF period.

&&

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

&&

$$

DISCUSSION.....Eckberg
AVIATION.......MPC