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000
FXUS63 KMKX 231957
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
257 PM CDT Tue Apr 23 2024

.KEY MESSAGES...

- Conditional frost/freeze risk late tonight and again Wednesday
  night with temperatures around or just below freezing.

- Active pattern Friday through this weekend. Multiple rounds of
  showers/storms will result in locally heavy rainfall. The
  severe storm risk is more uncertain, but bears monitoring.

&&

.SHORT TERM...
Issued 300 PM CDT Tue Apr 23 2024

Tonight through Wednesday night:

Following the initial front coming through this afternoon, as
the surface low slides southeast a secondary backdoor cold front
will slide down the lake with northwest winds turning north
behind the front. Associated with the front there may (30-40%)
be enough forcing despite the fairly dry air to bring a few
showers and maybe even a few rumbles of thunder with a fairly
sharp temperature shift behind the front with temperatures
falling around 15 degrees in just a few hours.

Clouds are then expected to clear out behind the front as more
stable air moves in with higher pressure pushing south into the
northern Great Lakes region overnight. However winds will remain
breezy overnight from the north given the fairly strong pressure
gradient over the region. Temperatures tonight are expected to
reach around freezing and while that would typically signal some
front the winds will likely (80%) keep frost largely at bay
with the exception of the far northwestern part of the CWA that
could see some frost develop toward the early morning hours
Wednesday morning.

High pressure will dominate the region Wednesday with weak
large scale ridging overhead. The dry air will allow for clear
skies throughout the day into tonight. As the pressure gradient
weakens we should expect to see much lighter winds with largely
light northeast winds expected. Overnight there will be a risk
(60-70%) for a freeze with widespread frost given light winds
and temperatures falling to around 30 degrees for parts of the
CWA, with potential for temperatures to fall even further. We
are holding off on a Freeze Watch for now but there may be a
need as we fine tune our temperatures this evening.

Kuroski

&&

.LONG TERM...
Issued 300 PM CDT Tue Apr 23 2024

Thursday through Tuesday...

Persistent long wave trough pattern will set up over the western
states starting Thursday. Initially our region will be under
ridging aloft, which will result in a quiet weather Thursday into
early Friday. After a chilly start Thursday temperatures will
respond to southerly winds and warm advection with highs away from
the lakes returning to the 60s (50s by the lake).

The region will beneath southeast flow aloft from Friday through
Monday, flattening out toward the middle of next week. This will
send a series of shortwaves our way, with periods of rain and
embedded storms. Warm advection rain will enter from the southwest
through the day Friday and persist into early Saturday. ENS/GEFS
probabilities place the best opportunity for greater than 0.5" of
rain across western and southwestern portions of the state.

Depending upon timing and clearing, a portion of Saturday may
remain dry with scattered convection possible during the afternoon
and evening. If enough clearing is observed, we will need to
monitor for a few strong/severe storms during the afternoon given
the potential for MUCAPE in excess of 1500 J/kg and sufficient
deep shear.

The next best opportunity for widespread rain moves in from the
southwest Saturday night and lasts into Sunday night. A bit more
uncertainty from the guidance with this wave as there are
indications that the parent wave will be filling/weakening as it
moves into the area. That said, jet dynamics and a moist
atmosphere will support another decent round of rainfall. The ENS
focuses the best chances for greater than 0.5" of rain across the
western portions of the state, while the GEFS is focused more on
the southern portion of the state. This is largely due to the
differences in wave depth, speed and location. Will need to keep
an eye on the potential for severe on Sunday, but our area seems
to be (at best) on the north edge of any risk.

Overall, Friday to Monday looks active with multiple rounds of
rain. This will not be a complete washout of a weekend as the
ensembles point toward a dry period between the two main waves
Friday and Sunday. There are some concerns for a few severe storms
Saturday and once again Sunday, however these risk will be driven
by the mesoscale evolution each day. Temperatures will be
at/above average.

Gagan

&&

.AVIATION...
Issued 300 PM CDT Tue Apr 23 2024

In addition to the front coming through this afternoon we will
be monitoring another backdoor cold front from the north, which
will bring enough moisture to bring additional showers and maybe
a few rumbles of thunder this evening.

With a dry airmass in place, cloud development will be in the
VFR category (at or above 5000 ft). The front quickly surges
through the area by late this evening with some clearing. Will
need to monitor for MVFR cigs for a few hours near the lakefront
overnight associated with moisture off the lake.

High pressure builds into the region for Wednesday with quiet
weather conditions expected with largely clear skies. North
winds will start gusty, but gradually decrease through the day.

Kuroski

&&

.MARINE...
Issued 300 PM CDT Tue Apr 23 2024

Expect winds to turn north early this evening, from north to
south across Lake Michigan behind a backdoor cold front coming
down across the lake as the surface low finishes its sweep
through the western Great Lakes region. A period of north gales
are expected tonight behind the cold front, and a Gale Warning
has been issued. Building waves are expected as well tonight.
Winds and waves will gradually lighten up Wednesday into
Thursday, as high pressure moves southeast across the region.
Small Craft remains in effect through Wednesday for waves and
winds.

South winds will then increase again Friday and remain gusty into
the upcoming weekend, as multiple low pressure systems move
northeast through the region. There will be additional chances for
gales Saturday with much of the extended seeing potential for
Small Craft conditions in the nearshore.

Kuroski

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Gale Warning...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
     LMZ567-LMZ868...7 PM Tuesday to 4 AM Wednesday.

     Gale Warning...LMZ080-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-
     LMZ779-LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...10 PM Tuesday
     to 7 AM Wednesday.

     Small Craft Advisory...LMZ643-LMZ644-LMZ645-LMZ646 until 10 PM
     Wednesday.

&&

$$

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