NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 271042 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
542 AM CDT Thu Aug 27 2026

.KEY MESSAGES...

- Areas of fog in the WI River Valley and other low lying areas
  of south central WI for early this AM and early Fri AM.

- Trending active this weekend into early next week, with
  multiple periods of showers and storms forecast.

- Small Craft Advisory-criteria conditions return to the
  nearshore waters Saturday afternoon through Sunday. A Beach
  Hazard Statement may also be needed this weekend.

&&

.UPDATE...
Issued 542 AM CDT Thu Aug 27 2026

Southern WI is still in cyclonic flow this morning due to a
500mb low sitting over Hudson Bay in Canada. This pattern
remains favorable for diurnal cumulus clouds, and the weak
shortwave tracking through southern WI today will give them a
boost around midday. The overall moisture and forcing is too low
for showers, but a few darker/thicker clouds (and a few
sprinkles) may develop in southeast WI along the lake breeze
this afternoon.

Today's lake breeze will be a little stronger than the
lake breezes over the past few days. It is due to the pressure
gradient between the exiting surface trough and high pressure
building into WI.

Cronce

&&

.SHORT TERM...
Issued 1118 PM CDT Wed Aug 26 2026

Today through Friday:

Light nnwly sfc winds will prevail tnt, but decouple at times
especially in low lying areas. Fog will likely develop in the WI
River Valley of sw WI.

A weak shortwave trough within nwly flow aloft will then pass
Thu AM into the early afternoon and will aid fair weather cumulus
development. Another summer day with highs near 80F is forecast
along with a westward moving lake breeze over ern WI.

For Thu nt, high pressure will expand from Lake Superior across
the nrn Great Lakes. Light and variable winds and good
radiational cooling conditions are expected over srn WI with a
little more fog over south central WI for early Fri AM. The high
will then move into the lower Great Lakes on Fri. 500 mb height
rises will begin over the wrn Great Lakes but with only lgt
ssely winds expected. High temperatures may warm just a tad in
the lower 80s with another lake breeze expected for far ern WI.

Gehring

&&

.LONG TERM...
Issued 1118 PM CDT Wed Aug 26 2026

Friday night through Wednesday:

A broad, but low amplitude upper ridge, will move into the
central and srn USA this weekend and continue into next week.
Well organized low to mid level warm, moist advection that will
bring the ridge into the central USA will affect srn WI Sat
afternoon into Sunday. PWATs will rise above 1.5 inches with
conditional unstable conditions developing. Showers and
thunderstorms are likely Sat nt when the main tropospheric
baroclinic zone will move across the region. However, the
baroclinic zone will stall early in the week with continued
chances for showers and storms each day. Heavy rainfall may
become a concern this weekend into early next week. The
stationary front should gradually shift more south by Tue or
Wed.

Gehring

&&

.AVIATION...
Issued 542 AM CDT Thu Aug 27 2026

Expect diurnal cumulus clouds with bases around 5000 ft to
develop by late morning once again. They may become BKN for a
time this afternoon, especially in southeast WI along the a
fairly stout lake breeze. Expect clear skies once again tonight
with a little better chance for fog outside of the Wisconsin
River Valley.

Cronce

&&

.MARINE...
Issued 542 AM CDT Thu Aug 27 2026

Modest northerly winds will continue today as the low pressure
trough exits Michigan and the Upper Great Lakes. Winds then
become light and variable tonight and Friday as high pressure
moves from the northern Great Lakes to the lower Great Lakes.

High pressure then pulls east Saturday and low pressure slowly
approaches from the Great Plains. Breezy southerly winds will
develop for the weekend, but gusts are expected to remain below
gale force.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...None.
&&

$$

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