319
FXUS63 KGRB 022014
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
314 PM CDT Thu Jul 2 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- Chance (20-40%) for thunderstorms across central WI and east-
  central WI this evening into tonight. Risk for severe storms is
  low, but strong wind gusts, frequent lightning, and periods of
  heavy rain are possible with any storms across east-central WI.

- Periodic chances for showers and thunderstorms continue through
  the holiday weekend.

&&

.DISCUSSION...
Issued at 314 PM CDT Thu Jul 2 2026

Thunderstorm Chances rest of Today/Tonight... The risk for severe
thunderstorms has generally decreases for the forecast area for the
rest of today. Current satellite imagery shows the remnant outflow
boundary from this mornings storms is stating to retreat back north
into southern WI but with the lack of a stronger mid-level short-
wave to drive mass response think this boundary will remain over
southern WI, generally along the I-94 corridor. There is a complex
of storms ongoing across far eastern IA at this time that will track
along this boundary across southern WI this afternoon and evening.
CAMs do show some development on the northern periphery of this
complex over the Fox Valley after 01Z. However, with the boundary
expected to be well south of the region, subtle height rises, and a
lack of upper-level support think this will be more pulse type
convection with the main hazards being lightning and periods of
moderate to heavy rainfall. CAMs also show some storms developing
over northeast MN and northwest WI in response to a complex of
thunderstorms developing over the Dakotas this evening. These storms
may track toward Vilas/Oneida counties early Friday morning,
however, confidence in these storms impacting northern WI is low.

Rounds of Showers and Storms Friday and Saturday...A mid-level short-
wave is progged to deepen over the northern Rockies and track east
arriving into the forecast area Friday morning. This short-wave may
be accompanied by a remnant MCV from a decaying MCS over MN. As
these features move into central WI Friday morning they may drive
some pulse type thunderstorms along a northward lifting boundary,
however, it`s unclear how much instability there will be at this
time. Another short-wave is progged to pass through the western
Great lakes later in the day Friday as well which could bring
additional rounds of thunderstorms to the area, however, the timing and
intensity of any thunderstorms is uncertain as these details will be
influenced by preceding rounds of convection across upper Midwest.
One more round of thunderstorms is expected Saturday as another
trough moves across the region, however, global ensembles do differ
with the strength of the upper jet associated with this feature. This
would impact now organized any thunderstorms may become.

Drier trend Sunday into next week...Global ensembles favor an upper
ridge building over the western Great Lakes late into the weekend
and early next week. This brings a drier continental air mass to the
region resulting in largely dry weather to start next week. There are
some model differences regrading the passage of a few subtle short-
waves that may kick off isolated to scattered showers Tuesday and
Wednesday, however, the probability of seeing rain at any given
location those day is ~20%.

Temperatures Trends...Friday will continue to be seasonally warm with
highs in the middle 80s across much of the region and heat indices
climbing near 90 degrees across eastern WI. Temperatures will
moderate this weekend as the real humid airmass slides to the east.
Highs Saturday and Sunday are forecast to reach the upper 70s to low
80s.

&&

.AVIATION...for 18Z TAF Issuance
Issued at 1254 PM CDT Thu Jul 2 2026

Widespread MVFR status continues to linger over much of the forecast
area, way from Lake Michigan early this afternoon. An area of light
showers also continues to move east across the Fox Valley. There have
been a few lightning strikes reported by satellite over the past hour
so included PROB30 groups at ATW and MTW with -TSRA. Cigs will begin
to scatter out this afternoon with most terminals returning to VFR
through the afternoon. There is another chance (20-40%) for
thunderstorms south of a MFI to GRB line this evening, beginning
after 01Z and continuing through much of the night. Main concerns
with any storms will be damaging wind gusts and heavy rain.

Otherwise, there are low chances (20-40%) for patchy low stratus or
fog development (MVFR to IFR) late tonight, mainly over central into
north-central Wisconsin. Confidence was not high enough to include
in the TAFs for this update.

&&

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

&&

$$

DISCUSSION.....GK
AVIATION.......GK

NWS GRB Office Area Forecast Discussion