960
FXUS63 KMKX 291954
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
254 PM CDT Wed May 29 2024

.KEY MESSAGES...

- Dry through Friday with cool nights in the 40s.

- Periodic shower and thunderstorm chances return Friday night
  through Saturday and Monday through mid week.

&&

.SHORT TERM...
Issued 254 PM CDT Wed May 29 2024

Tonight through Thursday night:

High pressure will drift overhead tonight. With clear skies, dry
air and calm wind, strong radiational cooling will allow
temperatures to drop into the lower 40s for inland areas. There
is a lot of model agreement on these lows and no chance of
getting lower than 39, per model guidance stats. The forecast
for tonight is around the 25th percentile. There are frost
concerns for northern Wisconsin.

Dewpoints for areas inland from Lake Michigan but east of
Madison should be in the mid 30s based on upstream obs in
northeast WI. This will keep fog chances out of the forecast
here. For areas west and northwest of Madison, the dewpoints
should be a little higher and closer to the temps. Fog in the
Wisconsin River Vally is likely, with some patchy fog possible
northwest of Madison, especially in the Dells area.

Plenty of sunshine is expected Thursday, with fewer clouds than
today. Light southeast winds will develop in the afternoon as
the high starts to depart. Highs Thursday should be a little
warmer for far inland areas than today with that return flow
around the high, so highs in the lower 70s.

Thursday night will be one more cooler night with inland lows
in the lower 40s. This forecast is on the lower side of
guidance (25th percentile), so temps may end up being a few
degrees warmer if the warm air advection kicks in a little
earlier than expected and can overcome the radiational cooling.

Cronce

&&

.LONG TERM...
Issued 254 PM CDT Wed May 29 2024

Friday through Wednesday:

The weather is expected to be dry Friday. Look for increasing
high clouds through the day as convection should be ongoing
toward the MN/WI border, especially in the afternoon. An
elongated, phased upper trough spanning from the Northern Plains
to Oklahoma will push an area of showers and thunderstorms
across the Plains tonight through Thursday. Strong ridging over
the Great Lakes will help to diffuse that upper level energy as
it juts out ahead of the parent upper low Friday, but remnant
boundaries and surface convergence should help keep showers and
storms developing in central MN and IA through the day. By
Friday afternoon, it looks like the southern stream upper low
will start to close off over Missouri and drifts east while the
northern stream one hangs back toward North Dakota.

So by Friday evening, there may be some remnant showers and/or
thunderstorms that make their way into southwest WI. Models are
leaning more toward a dry forecast for southern WI during this
time. For the overnight into Saturday morning, the forecast MCS
associated with the southern stream trough may try to sneak into
southern WI and this chance is depicted by both the 12z GFS and
ECMWF operational models. Chance for thunder during this time is
low due to decaying convection.

Saturday afternoon, the northern stream shortwave is expected to
swing across northern WI. Remnant moisture and convergence from
the departing system and the approaching trough may allow for
scattered showers and perhaps a few thunderstorms. Details for
this day are just not there yet so keep up with the forecast.
Subsidence and brief ridging should keep Sunday dry for southern
WI, although there is an outside chance for steep enough mid
level lapse rates west of Madison to allow for some diurnal
convection.

Models are picking up on an MCS developing upstream Sunday and
tracking through WI late Sunday night into Monday morning.
Again, not a lot of confidence in this scenario yet, but the
chance is there.

A more robust shortwave trough is expected to cross the
US/Canadian border near MN Tuesday evening. Thunderstorms with
this system may extend all the way down through Iowa and could
track into southern WI later Tuesday night or Wednesday morning.

Cronce

&&

.AVIATION...
Issued 254 PM CDT Wed May 29 2024

Diurnal cumulus clouds with bases around 4500 ft will diminish
as the sun sets this evening. Expect clear skies tonight with
patchy fog possible north and west of Madison, especially in the
Wisconsin River Valley. Fewer clouds than today are expected
Thursday. Look for increasing east- southeast winds and
increasing high clouds Thursday afternoon, but 10 kt or less.

Cronce

&&

.MARINE...
Issued 254 PM CDT Wed May 29 2024

Winds will weaken overnight into Thursday as high pressure works
its way across the Upper Great Lakes through Friday. Look for
increasing southerly winds later Friday into the weekend as a
low pressure trough approaches from the Northern Plains. Periods
of showers and thunderstorms are looking more likely Saturday
and Monday through Wednesday.

Cronce

&&

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

$$

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