NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 111841
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
141 PM CDT Tue Aug 11 2026

.KEY MESSAGES...

- Additional chances for showers and thunderstorms along the
  WI/IL border tonight and into Wednesday, but severe weather is
  not expected at this time.

- Fog is expected tonight, with patchy dense fog possible in low
  lying areas and along Lake Michigan.

- An active pattern returns Thursday into the weekend, with
  multiple rounds of thunderstorms expected. Currently not
  expecting severe activity.

- Near normal to below normal temperatures expected through the
  end of the week and through the weekend.

&&

.SHORT TERM...
Issued 141 PM CDT Tue Aug 11 2026

Tonight through Wednesday night:

Isolated to scattered thunderstorms possible this afternoon
through tonight across far southern Wisconsin as a weak
stationary front remains draped along the WI/IL border.
Generally zonal flow in the jet stream level will allow for
fast-moving shortwaves along the frontal boundary to produce
locally enhanced thunderstorm activity. Due to the diffuse
nature of the forcing, not expecting any widespread strong
thunderstorms. However, can't rule out an isolated stronger
storm right along the frontal boundary with MUCAPE around 2500
J/kg along and south of the I-94 corridor. Westerly bulk shear
around 45-50 kt will continue across the region through
Wednesday as well, giving sustenance to storms that do tap into
the higher MUCAPE and develop.

A stronger shortwave ejecting from the Canadian High Plains
phases with the stationary front across the central Plains
overnight Wednesday. This serves as a focal point for the
strongest-forced storms of the next few days, with PoPs
increasing into Thursday morning as the shortwave approaches.
Plenty of moisture (PWATs ~1.5 inches) combined with the
stronger shortwave indicates more confidence in widespread
thunderstorm coverage going into Thursday morning.

Outside of precipitation chances, expecting temperatures to
remain in the normal to below normal range (highs in the low
80s, lows in the low to mid 60s) throughout the short term
forecast window as the stationary front keeps the warmest
conditions just south of the border. Overnight, with lingering
high dewpoints near the frontal boundary and calming winds,
expect widespread fog development. Patchy dense fog is possible
in low-lying areas and near Lake Michigan.

MH

&&

.LONG TERM...
Issued 141 PM CDT Tue Aug 11 2026

Thursday through Tuesday:

Low pressure deepens over the central Plains on Thursday, with a
remnant baroclinic / frontal zone oriented NW to SE across the
midwest. Precip chances range from 20-70% across the CWA Thursday
(highest towards the southwest corner of Wisconsin), with at least 1
minor shortwave providing some potential triggering for convection.
Thunderstorms would likely be weak if applicable, given the lack of
return flow ahead of the low. The true warm sector appears to remain
well south into Illinois.

Predominantly dry weather expected into Friday as high pressure
builds into the Great Lakes region. As weak low pressure tracks
eastward across the midwest, showers and thunderstorms are looking
likely at times from Friday night through Saturday night, with
lingering 20-30% chances into Sunday as the associated cold front
swings through. Passing high pressure may then lead to predominantly
dry weather into Monday.

Temperatures should remain mild through the entire forecast period,
lingering around seasonal norms or even slightly cooler.

Sheppard

&&

.AVIATION...
Issued 141 PM CDT Tue Aug 11 2026

VFR conditions will continue through this evening, with isolated
thunderstorms along the WI/IL border. These thunderstorms would
be brief with gusty conditions directly beneath them. Overnight,
isolated thunderstorms may linger, but become less intense with
no gusty winds expected. Outside of thunderstorms, expect light
and variable winds. Winds calm overnight, with widespread fog
around 2 SM visibilities developing. Patchy dense fog (1/4 SM or
less) is possible in low-lying areas and along Lake Michigan.
Fog will burn off by the mid-morning hours on Wednesday, with
VFR conditions and light and variable winds expected
thereafter.

MH

&&

.MARINE...
Issued 141 PM CDT Tue Aug 11 2026

Predominantly light and variable winds are expected to continue
today through Thursday, with periodic chances for showers and
thunderstorms for the southern third of the lake (near a stalled
frontal boundary). Patchy fog is also possible along and south
of the frontal boundary.

High pressure around 30.3 inches builds into the Great Lakes region
Thursday night, resulting in a 10 to 20 kt northeast breeze across
Lake Michigan and pushing the frontal boundary south of the lake.
These winds will continue into Friday, with dry weather expected.

Winds veer southeast and accelerate into Saturday as high pressure
shifts over the lower Great Lakes and low pressure lifts northeast
from the central Plains. This system will bring chances for showers
and thunderstorms at times Saturday morning through Sunday morning.
Decelerating northwest winds expected into early next week behind
the associated cold front.

Sheppard

&&

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

$$

Visit us at weather.gov/milwaukee

Follow us on Facebook, X, and YouTube at:
www.facebook.com/NWSMilwaukee
www.x.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee