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340
FXUS63 KMKX 271742
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
Issued by National Weather Service Chicago IL
1242 PM CDT Thu Jun 27 2024

.KEY MESSAGES...

-  Showers and scattered storms for Friday into early Saturday.
   There is a Marginal Risk for severe thunderstorms Friday
   night.

-  River flooding and high water levels will continue this week
   and into this weekend.

-  Moderate Swim Risk for Lake Michigan beaches this morning
   then possibly High Swim Risk for Friday afternoon and evening
   for Sheboygan and Ozaukee County beaches.

&&

.SHORT TERM...
-- Changed Discussion --
Issued 420 AM CDT Thu Jun 27 2024

Today through Saturday night:

High pressure over nrn MN will move to Lake MI for the afternoon
then to the Mid Atlantic States by 12Z Fri. Pleasant temps are
expected today and will range from the middle to upper 60s at
the Lake MI shoreline to the middle 70s over south central WI.
Clouds will then increase tnt via mid to upper level warm, moist
advection ahead of the n-s sfc trough moving across the Great
Plains.

A well organized upper trough will then track from the high
plains of MT to the Lake Superior region from Fri into Sat. A
sfc low will track ahead of it but the effective warm front will
stay well to the west and south for Fri. Nevertheless, there
will still be an influx of low to mid level warm, moist
advection and PWs of 1.5-1.8 inches for the afternoon. However
lapse rates are poor and any meaningful elevated or sfc based
CAPE does not arrive until late Fri evening and overnight. Will
still forecast showers likely in the afternoon but rainfall
amounts will be light.

The axis of the swly LLJ of 35-40 kts will then shift ewd across
srn WI Fri nt ahead of the approaching cold front that will pass
Sat AM. A narrow axis of MUCAPE around 1000 J/KG can be
expected along with PWs increasing to nearly 2 inches.
Convection that develops over MN and IA during the evening will
likely move across srn WI for the late evening and the
overnight but may weaken as it does so. Agree with SPC Day 2 of
only a Marginal Risk for this convection.

A weak cold frontal passage will then occur Sat AM but any
lingering convection will be spotty. Widespread rainfall amounts
of 0.25-0.50 inches are forecast with locally 1 inch possible
for the period of Fri-Sat AM. Nwly winds and cold advection to
then take hold late Sat and Sat nt but temps will first warm
into the 80s on Sat.

Gehring
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&&

.LONG TERM...
Issued 420 AM CDT Thu Jun 27 2024

Sunday through Wednesday:

Cold advection will weaken Sun AM with high pressure approaching
late in the day. A relatively cool and pleasant day is expected.
The high will shift east for Mon with sly winds developing and
warmer temps in the lower to middle 70s.

Another round of cyclogenesis will then occur across the nrn
Great Plains into Ontario for Mon nt-Tue with more warm frontal
pcpn expected over srn WI. A weak cold front will then pass Tue
nt with good chances of showers and storms continuing followed
by a drier, but still warm day on Wed.

Gehring

&&

.AVIATION...
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Issued 1242 PM CDT Thu Jun 27 2024

A few high level clouds are working their way into the area from MN.
VFR conditions will be maintained at all six TAF sites through the
end of the TAF period. Light easterly winds will continue through
the afternoon before becoming varriable overnight. Tomorrow
southerly winds will bring an increase in moisture to the area as
showers and storms form to the west in association with a shortwave.
All six TAF sites should remain dry through the morning hours,
although ceilings will be lowering. There is a chance that KMKE
could see some spotty showers through the afternoon period.

Carothers
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&&

.MARINE...
Issued 420 AM CDT Thu Jun 27 2024

High pressure around 30.1 inches over northern Minnesota early
this morning will move across Lake Michigan this afternoon.
Northerly winds will decrease through the day and actually back to
southwesterly over far northern Lake Michigan. Increasing
southeast to south winds are then forecast for Friday into Friday
night, becoming southwest to west on Saturday, as a cold front
moves through the region. Chances for showers and thunderstorms
increase during this period. Gusty northwest winds then should
occur Saturday night into Sunday, before high pressure around 30.2
inches moves into the region Sunday night.

3 to 4 foot waves early this morning over the nearshore waters
from Sheboygan to Winthrop Harbor will subside to 1 to 2 feet by
noon today. Increasing southeast to south winds and building waves
may reach Small Craft Advisory levels mainly north of Port
Washington from late Friday morning into Friday evening.

Gehring

&&

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

$$

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