-- Discussion containing changed information from previous version are highlighted. --
622
FXUS63 KMKX 080356
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1056 PM CDT Tue May 7 2024

.KEY MESSAGES...

-- Changed Discussion --
- Just a few lingering showers into the early morning hours.

- More rain Wednesday night and Thursday with chances for
  thunderstorms as well.
-- End Changed Discussion --

&&

.UPDATE...
-- Changed Discussion --
Issued 1055 PM CDT Tue May 7 2024

Just a few lingering showers are expected over the next 2-3
hours. Otherwise low pressure will continue to weaken over the
northern Great Lakes tnt-Wed while shortwave ridging is expected
aloft. A nice and warm day is expected for Wed with cooling near
the lake.


Gehring
-- End Changed Discussion --

&&

.SHORT TERM...
Issued 314 PM CDT Tue May 7 2024

Tonight through Wednesday night:

Periods of rain and thunderstorms will continue across southern
Wisconsin through this evening. The window for severe
thunderstorms will be over the next couple or hours with the
best chances across southeastern Wisconsin. The warm front is
currently snaking across far southern Wisconsin. This is the
area that highlights the best threat for strong to severe
storms. Far southeast Wisconsin is also right along the better
CAPE and effective bulk shear gradient which will give those
areas the best chance for any type of supercellular
development. Storms that ride along the warm front will have the
best potential for any brief tornadoes over the next couple
hours. The warm front will provide the surge of winds and just
enough of a change in direction to be able to actualize any
brief spin ups. Steep mid level lapse rates, upper level
synoptic support, and the warm/moisture air advection across our
forecast area make hail the primary threat. Can`t rule out some
isolated damaging winds especially with any thunderstorms
quickly collapses.

Additional showers and thunderstorms are expected to develop
later this afternoon and evening. As the environment becomes
more worked over due to the ongoing rain/storms the chances for
any strong to severe thunderstorms will decrease. The rain
chances will persist until the warm/occluded front moves out
over Lake Michigan late this evening. Overnight tonight, dry
weather is expected. The dry conditions will be short lived as
additional rain and storms are expected Wednesday afternoon and
evening.

For rain and storms Wednesday, the potential for strong to
severe storms is very low. This will largely be in part to the
easterly winds and the mid level lift/support remaining south of
the state. An upper level trough will swing through the region
providing some lift and there will be some decent moisture.
Overall looking more like a stratiform type of set up with
southern Wisconsin remaining on the northern side of the mid and
sfc level troughing. The easterly winds look to undercut any
potential for warmer air to move in near the surface as well
which will keep any rain/storm elevated. So while there will be
rain and a few claps of thunder, severe weather is not
anticipated. Rain is likely to linger into the overnight hours
Wednesday.

Patterson

&&

.LONG TERM...
Issued 314 PM CDT Tue May 7 2024

Thursday through Tuesday:

Rain is expected to continue through Thursday afternoon (50-60%)
as mid-level cyclonic flow associated a shortwave trough and
surface low pressure across Indiana and Ohio propagate eastward.
Mid- level lapse rates of 5-6 C/km and mid-level CAPE values
upwards of 100 J/kg combined with the synoptic scale influences
across southern Wisconsin may give rise to a few rumbles of
thunder on Thursday mainly along the Wisconsin/Illinois border,
but primarily rain is expected especially into the afternoon.

Heading into the weekend and early next week, a fairly unsettled
pattern develops across the upper midwest with multiple mid-level
shortwave troughs and ridges propagating across Wisconsin. Brief 500hPa
ridging and warm air advection on Friday is expected across the
state throughout the morning and early afternoon, allowing for
quiet weather conditions Friday morning. A 500hPa shortwave
trough and cold air advection will quickly follow this ridge
providing synoptic scale ascent and steepening lapse rates such
that showers and thunderstorms develop across southern Wisconsin
Friday afternoon into Saturday morning (30-40%). A surface low is
expected to develop across southern Ontario in response to the
upper-level wave and sink southward across Lake Michigan providing
for additional shower and thunderstorm development Saturday
afternoon. Another brief 500hPa ridge then builds across Wisconsin
again on Sunday.

Model guidance begins to diverge in their solutions on
Monday as another mid-level shortwave trough traverses the upper
midwest through early next week.

Falkinham

&&

.AVIATION...
-- Changed Discussion --
Issued 1055 PM CDT Tue May 7 2024

Areas of ground fog may form tnt due to the rainfall, but it
should remain rather limited in coverage and intensity due to
very dry air just above the surface. Otherwise VFR conditions
through Wed. MVFR Cigs and Vsbys will then develop as rain
arrives Wed evening into the overnight. Cigs may fall below 1
kft for the overnight hours.


Gehring
-- End Changed Discussion --

&&

.MARINE...
Issued 314 PM CDT Tue May 7 2024

Breezy east to southeast winds will prevail through much of
Wednesday as a low around 29.1 inches lingers over the northern
Great Plains. Periods of showers ans thunderstorms will continue
through this evening. A few storms occlude be strong with gusty
winds and hail, particularly this afternoon and early this
evening. Best chance for strong to severe storms will be across
the southern third of the Lake. Fog has begun to develop across
the central third of the lake as warm moist air surges
northward. The best chances for fog development will be for open
water zones north of the warm front through this evening. Winds
will shift to northeast over the lake Wednesday afternoon and
evening as a second area of low pressure around 29.5 inches pass
south of Lake Michigan. Additional periods of showers and
thunderstorms are possible from Wednesday evening through
Thursday, with conditions drying out Thursday night. Northerly
winds will persist through Friday morning, prior to turning out
of the southwest on Friday afternoon as a 29.7 inch low pressure
moves across Ontario. Gales are not anticipated through the
duration of the period.

Patterson

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
WI...None.
LM...None.
-- End Changed Discussion --
&&

$$

Visit us at weather.gov/milwaukee

Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/NWSMilwaukee
www.twitter.com/NWSMilwaukee
www.youtube.com/NWSMilwaukee