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000
FXUS63 KMKX 170924
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
424 AM CDT Wed Apr 17 2024

.KEY MESSAGES...

- A line of showers and thunderstorms will track through
  southern WI this morning. May see gusty winds and small hail
  along with ponding and minor flooding for low- lying areas
  from heavier rainfall.

- Gusty west winds this afternoon and again Friday

- Light rain most of the day on Thursday

&&

.SHORT TERM...
Issued 422 AM CDT Wed Apr 17 2024

Today and Tonight:

The occluded front made it to our western county warning area
and is slowly making it way across southern WI this morning.
Cells are tracking north and the line is moving east. Occluded
fronts are notorious for severe surprises so we are watching the
radar closely for any brief spinning cells. There is a lot of
low level shear and helicity, as well as decent CAPE up to 1000
j/kg, but there is also CIN present. Gusty winds and small hail
are the main threats, but can`t rule out a weak tornado.

The line of showers and storms should clear east central WI by
14z/9AM. After that, a few showers may still rotate through the
area as the occluded low tracks across the center of the state.
Look for westerly winds to ramp up this afternoon with gusts up
to 35 mph possible into the early evening hours.

Cronce

&&

.LONG TERM...
Issued 422 AM CDT Wed Apr 17 2024

Thursday through Tuesday:

A shortwave trough digging through the Central Plains from NE to
IL tonight into Thursday will be the focus for our next chance
of rain across southern WI. A narrow area of 600-700mb
frontogenesis is expected to slide across southern WI Thursday
afternoon. This should be enough to saturate the mid levels and
then in turn the low levels, and light rain showers are
expected for much of the day.

Models have been fairly consistent with this signal of light
QPF, and precip amounts should be less than 0.25 inch. It seems
like the mid level baroclinic zone has shifted a little farther
north and there is better interaction between the system over
the Ohio River Valley and the shortwave that will be passing
over us. This gives higher confidence in measurable rain,
especially toward the IL border (>90%).

We will enter into a lengthy period of fairly dry northwest flow
from Friday through Thursday. Temperatures will be at or below
normal for most of the period, with normal highs in the upper 50s
to around 60 for mid to late April. Lows will be in the 30s Friday
night and through Sunday night. Saturday night looks the coldest
with below freezing temps possible.

Gusty westerly winds are expected Friday as broad low pressure
over Ontario exits the region. Deep mixing is the main reason
for those gusty winds, with gusts up to 40 mph possible.

A shortwave trough crossing the Central Plains Monday and Monday
night will help us warm briefly. There is a chance of rain with
this feature, although there are model differences in the track of
this associated low and therefore the precip. It looks like the
pattern will change back to warm and unsettled beyond Day 7.

Cronce

&&

.AVIATION...
Issued 422 AM CDT Wed Apr 17 2024

MVFR ceilings with bases between 1500 and 2500 ft AGL snuck into
southern WI behind the main line of storms that exited late in
the evening, and ahead of the next line of storms that are
associated with the occluded front. Small hail and gusty winds
are possible with this morning line of storms. The MVFR ceilings
may clear out briefly in the wake of the storms, but expect them
to fill back in for much of the day. Additional light rain
showers are possible through early afternoon.

Winds are a little gusty out of the southeast ahead of the
occluded front this morning. Gusty southwest winds will arrive
behind the front, and then westerly winds will take over for the
afternoon. Drier air mixing in will help raise the ceilings as
the day goes on, but confidence is low on the timing of when VFR
conditions return.

Cronce

&&

.MARINE...
Issued 422 AM CDT Wed Apr 17 2024

Low pressure of 29.4 inches over southeast Minnesota will track
through central Wisconsin today and across northern Lake Michigan
this evening while weakening to 29.6 inches. Strong easterly
winds will continue across all but the southern third of the lake
until around 7 AM CDT. While winds will diminish across most of
the lake today, the far northern areas should see frequent gale
force gusts through late afternoon. No change to the gale
headlines.

Gusty westerly winds will develop today and gradually diminish
tonight into Thursday as the low departs the area. A Small Craft
Advisory is in effect for the southerly winds this morning and
then westerly winds this afternoon and early evening.

Weakening low pressure around 29.8 inches over Ontario Thursday
night will track into Ontario through Friday night. Westerly
winds will be gusty on Friday near the lakeshore, but not as
much over the lake. Another Small Craft Advisory will be needed.

Cronce

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Gale Warning...LMZ364-LMZ366-LMZ563-LMZ565-LMZ567-LMZ643-
     LMZ669-LMZ671-LMZ868-LMZ870-LMZ872 until 7 AM Wednesday.

     Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646...7 AM
     Wednesday to 9 PM Wednesday.

     Gale Warning...LMZ261-LMZ362 until 7 PM Wednesday.

&&

$$

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