NWS-Milwaukee/Sullivan Forecast Discussion

						FXUS63 KMKX 262007
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
307 PM CDT Tue Sep 26 2023

.SHORT TERM...
(Issued 307 PM CDT Tue Sep 26 2023)

Tonight through Wednesday night:

The forecast in a nut shell has scattered rain and thunderstorms
chances continuing across southern Wisconsin through Wednesday
night. Then warm and dry weather will be in store Thursday
through early next week.

A low pressure system is very slowly moving across eastern Iowa
toward northern Illinois. This low pressure system will continue
to weaken as it moves across far southern Lake Michigan into
Indiana Wednesday evening. As this system moves eastward, we can
expect a continuation of the conditions we have seen over the last
24 hours. Bands of showers and a few embedded thunderstorms will
line up across much of Wisconsin and Illinois. This will result in
on again off again rainfall. This pattern is expected to continue
through much of the day Wednesday. By Wednesday night, the better
moisture and lift will be moving east out of the state bringing
an end to our rain chances.

Heavy rainfall rates will be possible through tonight. There is a
large warm cloud depth and high PWATs across southern Wisconsin
which brings concern for 1-2 inch per hour rainfall rates. This
could lead to some localized flooding tonight, especially for
areas that have already received 2-4 inches of rainfall today.
Urban areas and places with poor drainage will potentially have
issues under those higher rainfall rates as well.

Strong to severe storm potential is very low through tonight as
there is very limited CAPE to work with and the little in the way
of helicity/shear. Granted this is a similar risk to the previous
day. So the best chances overall are along our southern tier of
counties (the WI/IL border). The main risk with any storm that
does get stronger would be a potential funnel or even a brief
tornado.

Lastly winds are expected to become gustier tonight with gusts up
to 25 knots expected. This will cause waves to build across our
nearshore waters resulting in a High Swim Risk and Small Craft
Advisory this evening through Wednesday evening.

Patterson

&&

.LONG TERM...
(Issued 307 PM CDT Tue Sep 26 2023)

Thursday through Tuesday:

With the cut off low pressure continuing its journey east,
weakening along the way. High pressure will begin to take over of
much of the central and eastern CONUS. This large area of high
pressure looks to dominate through the weekend and into next week.
Low pressure is expected to sit over the Rockies during much of
this time, which will result in persistent southerly winds and
some WAA. The WAA will give southern Wisconsin another weekend of
summer like weather with warm, dry days. Day time highs are
expected to climb into the mid to upper 70s. Its not out of the
question for a few areas to even hit 80. Confidence is high on
this ridge building and expanding across the region. It is
unlikely that there will be any ridge running disturbances that
would be able to bring any precipitation to southern Wisconsin
during this time.

Patterson

&&

.AVIATION...
(Issued 307 PM CDT Tue Sep 26 2023)

Largely MVFR to IFR conditions across southern Wisconsin through
this evening. Tonight, there will be a chance for some LIFR
ceilings to develop, with the greatest chance for some LIFR
conditions across western Wisconsin. Rain and storm coverage has
become scattered this afternoon. Rainfall coverage is expected to
increase again this evening and overnight. The chances for
thunder and lightning will be low across the area with the best
chances along the Wisconsin and Illinois border. With the moderate
to heavy rainfall, visibilites are expected to range from 2-5 SM.
Any prolonged breaks in rainfall will result in higher
visibility.

Winds will be out of the east through the period with gusts of
15-20 kts possible. Any brief modifications of the wind field may
be induced by the heavier showers/storms as they pass by.

Patterson

&&

.MARINE...
(Issued 307 PM CDT Tue Sep 26 2023)

High pressure of 30.6 inches over the Hudson Bay will slowly
weaken and drift south through Wednesday, while weak low pressure
around 29.8 inches over eastern Iowa will shift east across
northern Illinois. Moderate east winds will continue through
Wednesday between these two systems, with rounds of showers,
especially across the southern half of the lake. A Small Craft
Advisory is in effect from this evening into Wednesday evening
due to the easterly winds gusting near 25 kts and waves increases
to between 4-6 feet.

Thursday onward will see the return of dry weather. Light
southeast to east winds will prevail across the lake into early
next week.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060-WIZ066-WIZ071-
     WIZ072...10 PM Tuesday to 10 PM Wednesday.

LM...Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...10 PM
     Tuesday to 10 PM Wednesday.

&&

$$

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