793
FXUS63 KGRB 051143
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
643 AM CDT Sun Jul 5 2026

Updated aviation portion for 12Z TAF issuance

.KEY MESSAGES...

- Dry conditions are expected through at least early Tuesday, with
  the exception of a stray shower this afternoon and evening in
  central and northern WI. Widespread shower and thunderstorm
  chances return midweek.

- Seasonal summer temperatures are expected for the remainder of
  the holiday weekend, rising slightly above normal for the start
  of the work week.

&&

.DISCUSSION...
Issued at 259 AM CDT Sun Jul 5 2026

This Morning through Monday Night...Despite a weak mid-level
shortwave/trough residing over the area today, a lack in instability
and prevailing northeast winds ushering in drier air should keep the
area dry today. The only exception would be a diurnally driven
isolated shower or a couple of sprinkles across central or far
northern WI during peak heating, but overall impacts would be very
low. High pressure and upper-level ridging will then build over the
area Sunday night into Monday night, keeping the area dry under
mostly sunny skies.

Rest of the Forecast...A weak shortwave riding the ridge looks to
move over the Upper Mississippi Valley on Tuesday, which will mainly
bring showers and storms to northwest WI, but may expand into north-
central WI Tuesday afternoon. However, it will be competing with dry
air in the mid-levels. The better chances for widespread showers and
storms moves through the area sometime midweek with the arrival of a
stronger shortwave/trough supported by the RRQ of the upper-jet.
Models are indicating PWATS of 1.50 to 2.00 inches during the peak
of the precipitation, leading to the potential for heavy rainfall
and potential flooding. While there is still uncertainty in the
exact timing and placement of the shortwave and axis of heaviest
rainfall, agree with WPC`s Excessive Rainfall Outlook that includes
the majority of the area in a Slight Risk (level 2 of 4). As for
severe potential, instability typical of early July is anticipated
during this time making stronger storms possible; however, there is
still no signal of a higher end severe event within the statistical
suite of guidance.

Temperatures...Seasonable temperatures are expected for today with
high temperatures ranging from the upper 70s to low 80s. Dew points
will lower today, making for a pleasant summer day. Temperatures
look to be in to upper 70s and 80s for most of the week, with
dew points rising midweek.

&&

.AVIATION...for 12Z TAF Issuance
Issued at 642 AM CDT Sun Jul 5 2026

Mid and high clouds prevailed across most of the region this
morning. However, low-end VFR/MVFR cigs with cloud bases of 1300
to 3500 ft AGL were observed in central WI and along the
lakeshore, lowest cigs along the lakeshore. With prevailing
north/northeasterly winds, anticipate these low-end clouds to
move into the GRB and ATW TAF sites within the next few hours. The
low-end cigs should become SCT by mid-morning across all impacted
TAF sites, but cloud bases will only lift slightly with afternoon
cu expected to develop. Clouds will clear late this evening and
remain clear through the TAF period.

The north/northeast winds will become east/northeast by midday
around 5 to 10 kts. A few gusts to around 15 kts are possible at
the MTW TAF site late this afternoon into early this evening.
Winds will become light and variable this evening through the
remainder of the TAF period.

&&

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

&&

$$

DISCUSSION.....Kruk
AVIATION.......Kruk

NWS GRB Office Area Forecast Discussion