NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 070040
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
740 PM CDT Wed May 6 2026

.KEY MESSAGES...

- Widespread frost across southern WI tonight/Thursday morning
  with additional frost chances Thursday night/Friday morning
  for inland WI.

- Chances (20-50%) for showers and thunderstorms each day
  Thursday through Saturday, but rainfall is expected to be
  light with this activity.

- Warmer temps Friday and Saturday with highs in the 60s-70s.

&&

.UPDATE...
Issued 730 PM CDT Wed May 6 2026

With the current temperature observations remaining on track
with the forecast, the Frost Advisory remains in effect tonight
into Thursday morning (1 AM to 8 AM Thu) for the entire region.
The only lingering piece of uncertainty with regards to the
frost is how quickly the existing ~6,000 ft stratocumulus
clouds (mainly north towards central WI) will continue to erode,
and how soon a second batch of clouds will arrive from the west
Thursday morning (around dawn or ~1 hour predawn). Short range
model consensus suggests we've got plenty of time for
radiational cooling overnight, with low temps in the low 30s.

Sheppard

&&

.SHORT TERM...
Issued 150 PM CDT Wed May 6 2026

Tonight through Thursday night:

Upper-level low continues to sit over the Hudson Bay region
bringing northwesterly flow pattern across the region into the
weekend. Will continue to see cooler temps tonight with this
pattern tonight into Thursday as northwest to westerly low-level
winds prevail ahead of the surface high working its way across
the Central Plains. Thus looking at another night of frosty
conditions across inland portions of southern WI with lows in
the lower 30s. While some concerns with the cloud cover limited
the spread of frost development, given the trends still think it
will drop cold enough especially with any breaks in the clouds.
Thus issued a Frost Advisory for much of inland southern WI
counties.

High pressure over the Plains extending into the region will
gradually slide south-southeastward for Thursday. Winds are
looking more westerly to southwesterly component. Thus looking
at a bit warmer temps with the beginnings of low-level WAA and
temps climbing into the upper 50s and back into the 60s.

However, looking at a mid-level ripple of vorticity to work
across the area during the afternoon. This with the low-level
look to be enough to spur a scattered showers development
through the afternoon. Cloud cover may limit temps a bit with
this activity, but still a bulk of the 12z HREF members ping
enough SBCAPE (50-200 J/kg) to add mentions for isolated
thunderstorms from the afternoon shower activity.

Thursday night will be slightly warmer with lows in the mid 30s
to around 40F as WAA and southerly flow increases across the
area, but still looks to be areas of frost northwest of HWY-151
with patchy coverage further south and east. So may need another
frost headline.

Wagner

&&

.LONG TERM...
Issued 150 PM CDT Wed May 6 2026

Friday through Wednesday:

Continue to see temps gradually warm up for Friday and Saturday
with the persisting low-level WAA over the region. However
accompanying the the warmth will also be a few chances for
showers and maybe a few isolated thunderstorms. Friday chances
main driver will be another shortwave trough rounding the base
of the upper-level trough along with low-level WAA. While the
better forcing and chances continue to trend south of the WI/IL
border, still looks to be enough of the forcing and moisture to
creep north into our neck of the woods with 15-30% chance. While
thunderstorm are looking less likely cannot rule of a few
rumbles of thunder as well.

Saturday is looking to be the warmest day of the weekend with
highs creeping into the upper 60s and lower 70s. This warmer
setup and increased slug of Pacific moisture ahead of another,
stronger mid- level shortwave trough will bring better shower
and thunderstorm chances to the area later in the day. The
associated surface low is progged to trek across eastern Ontario
and in to Quebec dragging a west to northeast orientated cold
front southward down across the region. Moisture parted with a
meager amount of instability may be enough to trigger a few
thunderstorms with this round of showers.

Then things cool down behind the frontal passage for Sunday
lingering into the start of next week as high pressure is
progged to build into the region. Then the pattern looks to
warm back up toward the middle of next week as the pattern
becomes more progressive as the upper- level trough finally
kicks eastward allowing additional trough to dig across the
region through the middle of the week.

Wagner

&&

.AVIATION...
Issued 730 PM CDT Wed May 6 2026

The west-northwest breeze and broken stratocumulus cloud cover
are both expected to erode through this evening over southern
WI, leaving dry weather, VFR conditions, and nearly calm winds
overnight.

The breeze resumes out of the southwest Thursday morning,
veering due west. Sustained winds around 10 kts expected, with a
few gusts to ~20 kts in the afternoon. A southeasterly lake
breeze will attempt to push against these prevailing winds
early/mid afternoon (and might reach shoreline terminals); it
should make more inland progress as both wind fields subside
late Thursday afternoon / Thursday evening. A 20-40% chance for
rain is forecast through the daytime hours Thursday (mainly
between 10 AM and 6 PM CDT), and would be popcorn style /
scattered showery activity. A stray rumble of thunder cannot be
completely ruled out, but has been left out of the PROB30 groups
of TAFs for now.

Sheppard

&&

.MARINE...
Issued 150 PM CDT Wed May 6 2026

High pressure over the Plains continues to track south and east
turning west winds to south-southwest while remaining lighter
across Lake Michigan through the end of the week. Friday night
into Saturday looks at the southerly winds to pick up ahead of
an incoming cold front along with increased shower/thunderstorm
chances. Expect this southward moving cold front to turn winds
more northerly behind it later Saturday into Sunday as high
pressure builds across the region for the start of next week.

Wagner

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Frost Advisory...WIZ046-WIZ047-WIZ051-WIZ052-WIZ056-WIZ057-
     WIZ058-WIZ059-WIZ060-WIZ062-WIZ063-WIZ064-WIZ065-WIZ066-
     WIZ067-WIZ068-WIZ069-WIZ070-WIZ071-WIZ072...1 AM Thursday
     to 8 AM Thursday.

LM...None.
&&

$$

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