NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 151514
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1014 AM CDT Sat Aug 15 2026

.KEY MESSAGES...

- Dry conditions for most into early afternoon. Hit & miss
  showers & thunder possible late afternoon & evening.

- Additional shower and storm potential overnight
  into Sunday, but plenty of dry time for the rest of the
  weekend.

- High Swim Risk today for Lake Michigan beaches in Milwaukee,
  Ozaukee, and Sheboygan counties.

- Dry and seasonal for the start of the week with storm chances
  returning midweek.

&&

.UPDATE...
Issued 1015 AM CDT Sat Aug 15 2026

Have pulled back mentionable precip probabilities through early
afternoon across the majority of southern Wisconsin.

A remnant MCV is pivoting toward the Illinois-Indiana border
late this morning. Lift from the feature, combined with a
surface warm front attempting to lift toward the Wisconsin-
Illinois border, has triggered areas of shower development over
primarily over north-central and northeastern Illinois. Tied to
surface high pressure along the Ontario-Quebec border, a surface
ridge & attendant low level dry air has suppressed much of the
precip in southern Wisconsin. Given the aforementioned trends &
loss of lift from the eastward-progressing MCV, have thus pulled
mentionable precip probabilities out of the forecast through
early afternoon across the majority of the area. Did maintain
some isolated shower mentions through the lunch hour in far
southeast Wisconsin, with dry conditions thereafter.

Attention turns south and west moving into this afternoon and
evening. Surface analysis shows the aforementioned warm front
swinging northwest toward an area of low pressure near Grand
Forks, ND. Continued eastward progression of the surface low,
along with an advancing upper shortwave currently over the
Sioux Falls, SD vicinity, will allow the warm front to advance
northeastward into this afternoon/evening. Borne out in current
radar trends near the Twin Cities, will need to monitor for
widely scattered development of elevated showers/thundershowers
within the increasing wing of warm advection as the warm front
attempts to encroach. Not anticipating severe weather hazards in
any activity. Expect that some scattered shower & thunderstorm
potential will extend into the evening & overnight hours
tonight. Will offer additional details regarding this potential
in the early afternoon update.

Quigley

&&

.SHORT TERM...
Issued 100 AM CDT Sat Aug 15 2026

Today through Sunday:

The latest model guidance and satellite / radar trends affirm that
the vast majority of convection this morning will continue to
roll south of WI, predominantly impacting IL. A few stray cells
may lift and decay into southern WI, or even develop overhead
with the northern-most edge of the WAA, but coverage should
remain scattered to isolated. With MUCAPE 500 joules or less,
storms will be weak for our area. PWAT of 2" or greater could
make these showers efficient rain-makers, but the expected
sparse coverage and short lifecycle ought to limit
accumulations.

Some of the 00z CAM guidance depicts widely scattered showers
wrapping around the back side of the departed convective complex
this afternoon, yielding some continued slight rain chances for
southern WI this afternoon. Other guidance that doesn't show this
activity allows some gaps in the clouds to form this afternoon,
with a potential evening round of showers or even weak storms then
possible. In either case, should be minimally impactful unless
instability exceeds the current expectations (ex. the clouds part
early and additional sunshine makes it through).

A cold front crosses the region late tonight into early Sunday
morning, yielding widespread 25-45% chances for showers and
thunderstorms. By the time it arrives, MUCAPE should be generally
1500 joules or less (HREF mean is below 1,000 joules predawn),
which is plenty for some thunder, but with 0-6km bulk shear
generally 20kt or less predawn, the odds of strong to severe
storms are looking very low at this time. Chances decline
rapidly past daybreak Sunday, leaving predominantly dry weather
through the rest of Sunday. The initial wind shift + front will
leave the humid air (70 degree dewpoints) in place for Sunday,
and will allow some sunshine to make it through the clouds,
potentially allowing the southeast half of the CWA to briefly
reach 2,000 joules SBCAPE into midday Sunday, but by then the
surface front is far gone, along with the 500mb trough. Keeping
chances low (roughly 20% or less) for afternoon redevelopment.

Sheppard

&&

.LONG TERM...
Issued 100 AM CDT Sat Aug 15 2026

Sunday night through Friday:

A surface ridge of high pressure passes overhead early next
week, leading to dry and slightly less humid conditions.
Temperatures hold close to seasonal norms, dewpoints fall to the
low / mid 60s.

Chances for showers and thunderstorms return midweek as a cold
front / surface pressure trough sweeps eastward across the
midwest. High pressure builds into the midwest late in the work
week, yielding predominantly dry weather.

Sheppard

&&

.AVIATION...
Issued 640 AM CDT Sat Aug 15 2026

Shower chances continue through the morning for terminals closer
to the WI/IL border, while areas north of I-94 are likely to
stay predominately dry through the day. Cannot completely rule
out an isolated storm or two, but chances remain very low.
Additionally, lower MVFR ceilings are looking to spread into
southern WI through the morning and continue through a good
chunk of the day ahead of the approaching system. Winds will
gradually pick up and shift more southeasterly as well. May see
a brief period of improvement in ceiling heights later this
afternoon/evening, but additional scattered shower and storm
chances return tonight into Sunday as a cold front pushes
through the region.

Wagner

&&

.MARINE...
Issued 100 AM CDT Sat Aug 15 2026

Synopsis:
Periods of showers and storms continue over the southern half of
Lake Michigan today and tonight as a front remains stalled south
over Illinois and Indiana. Low pressure of 29.8 inches over Kansas
will track to the northeast this morning, then due east toward
southern Lake Michigan this evening. This low should help to bump
up winds and waves across the southern two thirds of Lake Michigan
through the daytime hours today, decelerating tonight as it closes
in. A cold front will then sweep across the lake late tonight into
Sunday morning, with chances for showers and weak storms. A light
northwest breeze arrives with the front into Sunday.

Beyond this system, a broad ridge of high pressure of 30.1 inches
will push into the Great Lakes early next week before another
potential front moves through the region midweek.

Nearshore Zones:
A Small Craft Advisory is in effect for zones north of North Point
Lighthouse from 8 AM to 7 PM CDT today due to breezy southeast
winds and high waves. Waves are expected to approach the 3 to 6 ft
mark. Winds are less certain, but should be between 10 and 20 kt
sustained with gusts up to 25 kt. Highest confidence in these
gusts is towards central Lake MI, adjacent to Sheboygan.

Sheppard

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066 until 7 PM
     Saturday.

LM...Small Craft Advisory...LMZ643-LMZ644 until 7 PM Saturday.

&&

$$

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