000
FXUS63 KMKX 151708
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1208 PM CDT Mon Apr 15 2024

.KEY MESSAGES...

- Above normal temps, sunny skies, and very low afternoon
  relative humidity continues today.


- Showers and storms will likely (60-85%) bring over an inch of
  rain Tuesday afternoon through Wednesday afternoon.

- There is a conditional severe threat for far south central WI
  Tuesday afternoon and evening.


&&

.UPDATE...
Issued 1208 PM CDT Mon Apr 15 2024

A sfc ridge will slowly shift ewd this afternoon with winds
becoming ely by the end of the day. The dewpoints are beginning
to mix out over some areas of srn WI and expect this to
continue. Minimum RHs values will drop to 20-25 percent for some
areas, but elevated fire wx conditions are not expected due to
lgt winds. Otherwise high temps in the lower 70s away from the
lake looks good.

For tnt and Tue AM, strong low pressure will move from the
central high plains and across NE. Ely winds and clouds will
increase with only 20-30 percent chances of showers and storms
over sw WI through noon. Afterward, strong low to mid level thetae
advection is expected ahead of the occluded low and negative
tilt upper wave. An ATM river with PWs of 1.2-1.4 inches will
arrive with the warm front reaching far sw WI around early
evening, although some of the strongest convection may go
through beforehand. Thus much of srn WI will see elevated
showers and storms but with mdt effective shear and MUCAPE of
1000-1500 J/KG especially toward sw WI where the frontal
inversion won`t be as deep. Thus the highest SVR potential for
large hail and damaging winds will be along and west of a line
from WI Dells to Madison to Janesville with lesser chances to
the east.


Gehring

&&

.SHORT TERM...
Issued 447 AM CDT Mon Apr 15 2024

Today and Tonight:

High pressure overhead will allow for lighter northerly winds
today. A lake breeze will develop this afternoon. High
temperatures will be warm, but not as warm as yesterday, topping
out in the lower 70s inland from Lake Michigan. With plenty of
sunshine, there is a chance we could reach higher temps than
forecast (again). We are in a very dry air mass which helps
this.

Cronce

&&

.LONG TERM...
Issued 447 AM CDT Mon Apr 15 2024

Tuesday through Sunday:

A closed low pressure system approaching from the Central
Plains will bring a round of showers and thunderstorms to
southern WI Tuesday afternoon through Wednesday afternoon. The
arrival time of the precip is later than previous forecasts. The
severe potential is very conditional late Tuesday afternoon and
evening. The weakening low over Iowa will push the surface warm
front into northern IL and maybe into a small area of south
central/southwest WI. Wind shear will be very high along this
front, so it will just be a matter if the instability can make
it this far north to produce severe storms. With that much
shear, it would not take much to produce organized, low-top
storms. SPC has a sliver of our area in a Slight Risk for severe
storms and this seems reasonable, but very conditional.

Total rainfall from Tuesday afternoon through Wednesday
afternoon should be around an inch in southeast WI to around 1.5
inches near Wisconsin Dells. The MKX-WPC QPF Probs have a 60%
chance of greater than 1 inch in Milwaukee and an 85% chance
just west of Madison. There is not a lot of spread between the
ensemble model total precip solutions, so that provides a
littler higher confidence in our forecast amounts.

Winds may also be of concern Tuesday afternoon and night, but we
took the tempered approach with wind speeds and gusts for now.
There are a few outlier model solutions that are driving the NBM
on the high side. It will still be breezy, but easterly gusts
should remain under 35 mph. Gusty west to northwest winds up to
30 mph are possible Wednesday afternoon and night as the
weakening low exits to the east.

A broad upper low will slowly move across the western and
central Canadian provinces Thursday through Friday. Showers are
possible across southern WI as weak ripples in the flow track
along a front that is well to our south. The chance for showers
is decreasing. Thursday high should still be in the 60s, but
colder air will start to seep into our area Friday night as that
Canadian low exits the area. Temperatures will be at or below
normal from Saturday through early next week.

Cronce

&&

.AVIATION...
Issued 1208 PM CDT Mon Apr 15 2024

VFR conditions today, tonight, into Tue afternoon but with
breezy ely winds developing on Tue. Widespread showers and
storms will then move into sw WI and south central WI late
Tue afternoon or early evening with MVFR Cigs developing, along
with significant reductions in Vsbys and Cigs within the
storms.


Gehring

&&

.MARINE...
Issued 447 AM CDT Mon Apr 15 2024

Light northerly winds will become easterly this evening and
increase through the night as low pressure of 29.2 inches
approaches from the Central Plains. The low will reach central
Lake Michigan Wednesday evening with a central pressure around
29.5 inches. There is uncertainty about quickly the low will
weaken by the time it reaches Lake Michigan and shortly
thereafter.

Stronger easterly winds are expected Tuesday afternoon and
night, with the potential for gale force gusts up to 35 kt in
the central and northern parts of the lake. Some models have
higher winds so there is lower confidence in gales. We are
holding off issuing a gale watch for now. Winds will become
westerly with gusts up to 30 kt Wednesday night into Thursday
behind the departing low.

Cronce

&&

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

$$

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