NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 211922
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
222 PM CDT Thu May 21 2026

.KEY MESSAGES...

- A Beach Hazard Statement is in effect through Saturday
  afternoon for a High Swim Risk at beaches in Milwaukee,
  Racine, and Kenosha Counties. The beaches in Sheboygan and
  Ozaukee Counties have a high swim risk beginning Friday
  afternoon.

- Expect a gradual warming trend through the Memorial Day weekend.

- Rain chances (20-40%) return Friday night into Saturday
  morning, mainly in southeast WI, with lower chances (20-30%)
  at times through the holiday weekend.

&&

.SHORT TERM...
Issued 222 PM CDT Thu May 21 2026

This afternoon through Saturday:

Mid level clouds are streaming across southern WI this
afternoon. With very dry air below 10,000 ft, any precip falling
from aloft would be sprinkles by the time it hits the ground, so
falling as virga. The onshore winds with the cooler lake and
just a little added moisture from the virga is causing some low
clouds over southeast WI.

A broad low pressure trough setting up over the Plains and the
gradually departing Great Lakes high will allow for an
increasing pressure gradient over southern WI Friday. The
persistent easterly winds will cause high waves of 3 to 5 feet
along the lakeshore most of the period between now and Saturday
afternoon. Therefore, the current Beach Hazards Statement for a
High Swim Risk for Milwaukee, Racine and Kenosha Counties was
extended until 4 PM Saturday. The northern two counties
(Sheboygan and Ozaukee) were added into the headline starting at
4 PM Friday.

That broad upper trough will develop into two distinct surface
lows on Friday; one over SD and one over far southern IL.
The IL low is trending farther south and east in the latest
model runs, thus we have a lower chance (25 to 40%) of light
rain spreading across southeast WI late Friday night into
Saturday morning.

That upper trough will push into northern WI by mid-late
Saturday morning which will end our precip chance. However,
there may be some lingering precip from an additional upper
trough that could track into south central WI during the day
Sat, but this would be light and short-lived.

Cronce

&&

.LONG TERM...
Issued 222 PM CDT Thu May 21 2026

Saturday night through Thursday:

An upper trough will slowly drift across the Upper Great Lakes
Saturday night through Sunday night. A weak shortwave ripple in
the mid level flow may be enough to trigger a few showers. Right
now, it looks like that ripple may cross southern WI late
Saturday night into Sunday morning. With this being unfavorable
timing for any added instability due to daytime heating, the
chance for precip is low (15-30%) and lightning would not be a
risk. If this timing shifts into Sunday afternoon, a few storms
would be possible.

The upper low will depart Sunday night, and a weak mid level
shortwave trough is expected to slide through WI on northwest
flow Monday afternoon/evening (Memorial Day). This could kick
off some scattered showers and perhaps a few thunderstorms.
Again, no all-day washout for any outdoor holiday plans, but
have a plan to get indoors if any storms approach.

Temperatures near the lake will be cooler all weekend due to the
onshore wind through Saturday and then a lake breeze Sunday and
Monday. Inland areas will see mid 60s Friday, around 70 on
Saturday, and mid 70s-upper Sunday. Monday looks like the
warmest day with highs around 80, but that could be cooler if
showers/clouds arrive earlier in the day.

Southern WI will remain warm and fairly humid Tue-Thu, although
shower/storm chances return for this period, mainly inland from
Lake Michigan.

Cronce

&&

.AVIATION...
Issued 222 PM CDT Thu May 21 2026

Mid level clouds are streaming across southern WI this
afternoon. With very dry air below 10,000 ft, any precip falling
from aloft would be sprinkles by the time it hits the ground, so
falling as virga. Northeast to east winds will diminish a bit
this evening but then increase by mid Friday morning. The
onshore winds with the cooler lake and just a little added
moisture from the virga is causing some MVFR clouds with bases
around 2500 ft right along the lakeshore. This is affecting
southeast terminals of MKE, RAC, ENW, and BUU. They could
briefly appear at MWC and UES this afternoon.

Cronce

&&

.MARINE...
Issued 222 PM CDT Thu May 21 2026

High pressure centered over Lake Superior will will gradually
shift eastward through the end of the week. Persistent east to
northeast winds of 10 to 20 knots are expected through Friday,
with winds becoming northerly on Saturday as low pressure over
Illinois lifts northeast into southern Michigan. Winds could
increase a bit Friday night into Saturday, depending on the
exact track and strength of the low, though winds are likely to
stay below gale force. Southerly winds are then expected to
develop early next week.

A Small Craft Advisory is in effect for nearshore zones south of
the North Point Light until Saturday afternoon due to persistent
east-northeast winds and waves of 3 to 5 feet. By Friday
morning, the Port Washington zone is added to the S.C.A. and the
Sheboygan zone goes into effect late Friday afternoon.
the period of highest waves will be late Friday afternoon
through mid Saturday morning. It looks like the waves should
diminish below criteria by late Saturday afternoon.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ066-WIZ071-WIZ072 until 4 PM
     Saturday.

     Beach Hazards Statement...WIZ052-WIZ060...4 PM Friday to 4 PM
     Saturday.

LM...Small Craft Advisory...LMZ643...4 PM Friday to 4 PM Saturday.

     Small Craft Advisory...LMZ644...7 AM Friday to 4 PM Saturday.

     Small Craft Advisory...LMZ645-LMZ646 until 4 PM Saturday.

&&

$$

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