NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 200038
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
738 PM CDT Sun Jul 19 2026

.KEY MESSAGES...

- The Wisconsin DNR has issued an Air Quality Advisory for all
  of Wisconsin that remains in effect until Noon CDT Monday.
  Lingering wildfire smoke will lead to unhealthy air quality.

- Severe storms are possible late Monday afternoon through
  Monday evening. All severe hazards are possible, with an
  Enhanced (level 3 out of 5) threat level. There is some
  uncertainty regarding the placement and coverage of these
  storms.

- There is a High Swim Risk for area beaches in Ozaukee and
  Sheboygan County beaches Monday afternoon. Life threatening
  waves and currents are expected in High Swim Risk areas. Stay
  out of the water, and away from dangerous areas like piers,
  breakwalls and river outlets.

&&

.UPDATE...
Issued 730 PM CDT Sun Jul 19 2026

Forecast details remain on track this evening.

CMiller

&&

.SHORT TERM...
Issued 250 PM CDT Sun Jul 19 2026

Tonight through Monday night:

Dry weather continues today and tonight beneath 1015mb high
pressure. Wildfire smoke lingers in place. DNR / EPA Air Quality
Monitoring Stations indicate predominantly "Unhealthy" (Red)
AQI values from PM2.5 (smoke) across southern Wisconsin (as of
250 PM CDT), with some improvement to 1 category lower
("Unhealthy for Sensitive Groups") over far southeastern
Wisconsin with what appears to be some dilution / mixing-out of
the smoke. HRRR smoke concentration forecasts resolve this
dilution over southeastern WI as well, and even allow it to
slowly continue this evening. Some of the more persistent smoke
appears to be towards southwest and central WI, where little to
no improvement is expected over the next several hours. A light
southwest breeze begins to slowly remove the concentrated smoke
overnight, with the majority of the air-quality impacts wrapping
up by midday Monday. Note that the Air Quality Advisory issued
by the WI-DNR remains in effect for the entire region through
Noon CDT Monday. Trace amounts of smoke may then linger into
Monday afternoon, though the latest guidance suggests it'll be
below Advisory limits.

3 triggering mechanisms / time windows for convection will need
to be monitored on Monday. The first involves the nose of the
500mb jet streak / shortwave trough approaching from the
northwest. QG ascent could fire off isolated to scattered
convection over southwestern WI as seen in the 18z run of the
HRRR. A decaying storm complex (or freshly initiated one) could
reach areas west of Madison late Monday morning thru early
Monday afternoon, with practically zero model runs depicting
activity east of there.

Next, we have the strengthening Surface-850mb moisture
transport and WAA mid to late Monday afternoon. A few CAMs
(including, once again, the 18z HRRR) allow isolated to
scattered convection to fire, this time with even better
dynamics (from the shortwave aloft) and thermodynamics (CAPE
building to 1,000-2,000 joules, locally higher northwest of
Madison). The increasing hodograph curvature from the WAA allows
for supercellular development and an all-hazards severe threat.

Third, we have the synoptic cold front which arrives Monday
night. Some models allow for convective cold pools to reinforce
/ accelerate the front, allowing it to arrive in time to
increase convective coverage over our region into the evening.
Other models leave it well behind the storms and bring it
through with dry weather (this is the favored solution). In
either case, the environment is favorable for storms to cold-
pool and grow upscale Monday evening, which could result in an
MCS crossing or clipping the region.

Long story short, we face a level 3 out of 5 severe threat
Monday afternoon into Monday evening, with higher confidence in
storms for the evening. Coverage and placement of storms remains
highly uncertain.

Sheppard

&&

.LONG TERM...
Issued 250 PM CDT Sun Jul 19 2026

Tuesday through Sunday:

~30% chances for showers and thundestorms forecast Tuesday
afternoon in far eastern WI along the lake breeze front. Other
than that, predominantly dry and quiet weather expected through
the rest of the work week. A noticeably cooler and drier
airmass (highs in the 70s, dewpoints around 50 degrees) passes
through with a high pressure system on Wednesday. A gradual
increase in temps / humidity is then expected through the
upcoming weekend.

Sheppard

&&

.AVIATION...
Issued 737 PM CDT Sun Jul 19 2026

a mixture of VFR and MVFR conditions are in place this evening
as wildfire smoke coninues to cause vis restrictions in spots.
Smoke should linger through tonight as high pressure exits east
with smoke gradually clearing as southwest winds kick in Monday.

Clouds will increase overnight and thunderstorms are expected at
times tomorrow. Their is greater confidence in an afternoon and
evening round of storms tomorrow than a morning round. The later
round will feature severe weather.

Southwest winds will be breezy with gusts from 20 to 25 knots
Monday afternoon.

CMiller

&&

.MARINE...
Issued 250 PM CDT Sun Jul 19 2026

Wildfire smoke currently overspreads Lake Michigan, with areas of
denser smoke reducing visibility to around 1 nautical mile at
times. A Marine Dense Smoke Advisory is in effect across Lake
Michigan into early Monday morning.

Relatively light and variable winds expected to continue today
underneath high pressure around 30.0 inches. High pressure exits
southeastward tonight, with 29.4 inch low pressure tracking
southeastward across Manitoba and Ontario Canada tonight into
Monday. South to southwest winds build across the lake tonight,
becoming gusty into Monday. A few gusts to gale force will be
possible Monday afternoon and evening over the northern half of
the lake. Strong to severe thunderstorms will also be possible
Monday afternoon through Monday night across the lake.

A cold front crosses the lake Monday night into Tuesday morning.
Winds veer northwest and become gusty again as it passes. Winds
veer due north later Tuesday into Tuesday night with a few gusts
to gale force possible.

Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060...1 PM Monday to 7 AM
     Tuesday.

LM...Small Craft Advisory...LMZ643-LMZ644...1 PM Monday to 7 AM
     Tuesday.

     Small Craft Advisory...LMZ645...1 PM Monday to 1 AM Tuesday.

&&

$$

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