764
FXUS63 KMKX 160352
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1052 PM CDT Thu Aug 15 2024

.KEY MESSAGES...

- An isolated thunderstorm or two may occur from now into the
  early morning hours. The severe threat overall has lower, but
  a stronger storm may occur in Sauk County and along the
  Wisconsin River Valley.

- Gusty southeast winds and building waves on Lake Michigan will
  create hazardous conditions to small crafts and beachgoers
  this afternoon and tonight. Thus both a Small Craft Advisory
  and Beach Hazard Statement is in effect.

- Another round of showers and thunderstorms will move across S
  WI Fri afternoon and early evening. There is a Marginal Risk
  for severe thunderstorms with damaging winds and large hail.

&&

.UPDATE...
Issued 1023 AM CDT Thu Aug 15 2024

The overall severe threat has lowered this evening as the
environment has been marred by subsidence, capping, and the late
arrival of more favorable forcing aloft. There is a lone
thunderstorm over Richland County that is hanging on at this
time, utilizing the remaining 1000 to 1500 J/kg of MLCAPE that`s
left in the environment. The expectation is that this storm
should remain steady-state or weaken as it tracks east into Sauk
County and the Wisconsin River Valley, as instability becomes
less favorable with time. Currently the storm has an SPS issued
on it for 30mph gusts and half inch hail in Richland County, and
its generally expected that the storm shouldn`t produce a
higher threat than that.

Elsewhere, an isolated storm or two may occur as the wave moves
in aloft and forcing for ascent spreads over southern WI, but
coverage will be far lower than previously forecast.

CMiller

&&

.SHORT TERM...
Issued 300 PM CDT Thu Aug 15 2024

Tonight through Sunday:

The lgt-mdt rainfall is coming to an end over ern WI, as the
low to mid level warm, moist advection and shortwave trough move
ewd. At the sfc, the warm front will follow the pcpn but stall
over far srn WI this evening.

For tnt a couple areas of more widespread development will
focus to the north and south. A shortwave trough coming out of
NE will move into west central IL by 06Z with deep convection
expected in nrn IL that could clip far srn WI. The upper low
over ne ND will gradually drift sewd with its PVA and better low
level convergence focusing over west central WI moving ewd.
Thus only expect sct showers and storm development tnt with more
of a focus from 03Z-09Z with the weak passage of a sfc trough.
MLCAPE of 1000-1500 J/kg can be expected with decreasing wind
shear, thus the SVR threat is very low.

For Fri-Fri nt the upper low and sfc low will move across Lake
Superior and nrn WI with a shortwave trough rotating around it
through srn WI. MLCAPE around 1500 J/KG will develop ahead of
this feature and CAMs and larger scale models all agree on
fairly widespread showers and storms for Fri afternoon,
lingering into the evening. PWs will rise above 1.5 inches once
again with heavy rainfall rates expected but storm motion of
25-30 kts should limit the urban and small stream flooding
threat. Weak to mdt deep layer shear is forecast so the SPC Day
Two Marginal Risk looks good.

The low pressure area will be slow to move away on Sat reaching
Lake Huron by 00Z Sun. Its cold front and another vorticity
maximum will move through srn WI. 50-60 percent chances for
showers and storms are forecast for ern WI with lesser chances
to the west. 500 mb heights will then be rising Sat nt-Sun
bringing a return of some sunshine for Sun, but still a slight
chance for a shower over ern WI.

Gehring

&&

.LONG TERM...
Issued 300 PM CDT Thu Aug 15 2024

Monday through Thursday:

An upper ridge will prevail over the central and srn Rockies and
the high plains through the week. Sfc high pressure will remain
in the vicinity of WI during this period. Pleasant and dry
summer weather is expected.

Gehring

&&

.AVIATION...
Issued 1049 PM CDT Thu Aug 15 2024

Overall IFR conditions will linger into tonight amid high low
level moisture and areas of fog may form overnight as a result.
Clouds should remain mostly BKN to OVC, but may scatter west of
Madison near dawn. Winds will be light and southerly overnight.
An isolated thunderstorm can`t be ruled out but forecast
coverage has come down considerably with time this evening given
a lack of cohesion between thunderstorm ingredients.

Tomorrow, clouds should lift to VFR and scatter with time during
the late morning, then increase in the afternoon as showers and
thunderstorms reform tomorrow afternoon. Winds tomorrow should
be breezy and southwesterly.

CMiller

&&

.MARINE...
Issued 300 PM CDT Thu Aug 15 2024

Low pressure around 29.7 inches over northwest Minnesota will
slowly move across northern WI Friday afternoon and to Lake Huron
by late Saturday. Breezy south winds tonight will weaken for
Friday, then becoming westerly Friday night for the south half
and northerly for the north half. The winds will then transition
to breezy north to northwest winds for the weekend. The winds will
gradually weaken early next week as high pressure arrives over the
lake by Tuesday. A Small Craft Advisory remains in effect into
tnt from Sheboygan to Winthrop Harbor due to breezy sely winds
and high waves.

Gehring

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...Beach Hazards Statement...WIZ052-WIZ060 until 7 AM Friday.

     Beach Hazards Statement...WIZ066-WIZ071-WIZ072 until 1 AM
     Friday.

LM...Small Craft Advisory...LMZ643-LMZ644 until 7 AM Friday.

     Small Craft Advisory...LMZ645-LMZ646 until 1 AM Friday.

&&

$$

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