590
FXUS63 KGRB 061813
AFDGRB

Area Forecast Discussion
National Weather Service Green Bay WI
113 PM CDT Thu Aug 6 2026

Forecast discussion for routine afternoon forecast issuance

.KEY MESSAGES...

- There is a marginal (1/5) risk for severe weather Friday
  afternoon through Friday evening.

- Several rounds of showers and storms are expected this weekend
  through early next week, though confidence in storm timing and
  severity remains low.

- Near normal high temperatures in the low to mid 80s through
  most of next week.

&&

.DISCUSSION...
Issued at 112 PM CDT Thu Aug 6 2026

Near term through Friday morning...High pressure will result in
mostly clear skies and light winds. Patchy fog may occur again
tonight, but it will not be as dense and widespread as it was this
morning.

Rain/storm chances...Leading chance of storms Friday afternoon
into Friday evening appears to carry the highest risk for severe
this weekend. Tail of very sharp shortwave seen over Saskatchewan
today swings across MN to Lake Superior Friday afternoon. Cold
front reaches western Lake Superior to northwest WI during peak
heating of the day, with MLCAPEs increasing to 1500-2000J/kg just
ahead of the front. Strongest effective shear is closer to
shortwave, near 40 kts, with 30+ knots from northern WI to central
WI by late afternoon. Shear tails off to less than 20 kts farther
east. A few strong storms with gusty winds the primary hazard are
expected over north-central and central WI, shifting east while
weakening through late evening until around midnight.

Beyond Friday, general idea remains on track. NW flow will bring
several weaker shortwaves across the area, but primary area of
higher instability and shear remains west and southwest of
northeast WI, Iowa into northern Illinois. Decent agreement that
after the front passes later Friday night, Saturday will be dry,
with another round of smaller pops late Saturday night. As low
pressure forms over the central Plains late in the weekend, front
will return north and bring the highest chances for showers and
storms Sunday night into Monday. Some time frame during this
broader window will feature widespread showers and embedded
storms as the low-level jet and elevated instability will be
aimed toward at least our southern forecast area. This is also
when ECMWF EFI still shows the closest approach of greater signal
for higher CAPE/shear, so this will have to be watched especially
given the front will be nearby. Given the front straddling the
area and PWATs over 1.5 (80-90th percentile), there is a marginal
risk (level 1 of 5) for excessive rainfall/flooding especially if
there are training storms.

Front settles south of WI next Tuesday, but weaker waves in
northwest flow could still allow for a few showers or storms
Tuesday into Wednesday. Pops for this time remain low, at 15-30%.

Temperatures/smoke...Temperatures will continue to be around normal
in the low to mid 80s through the weekend as upper flow flattens
out and weakens. Humidity levels will be comfortable, with
dewpoints reading in the upper 50s to mid 60s. There will be an
increase in dewpoints into the mid and upper 60s on Friday ahead
of the front. A plume of elevated wildfire smokes works its way
into Wisconsin through Friday. Another push of smoke occurs late
in the weekend into early next week. No significant impacts to
visibility or air quality are expected with the smoke.

&&

.AVIATION.../18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1125 AM CDT Thu Aug 6 2026

VFR conditions will prevail this afternoon with light winds.
Although flow off the surface will increase somewhat tonight,
light boundary layer flow will support at least patchy fog
overnight into early Friday, especially across eastern
Wisconsin, with confidence in fog development decreasing with
westward extent across central Wisconsin. South to southwest
winds will develop Friday morning ahead of a cold front with
thunderstorm potential increasing from west to east beyond this
TAF period Friday afternoon/evening.

&&

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

&&

$$

DISCUSSION.....JLA
AVIATION.......JM

NWS GRB Office Area Forecast Discussion