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938
FXUS63 KMKX 051502
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1002 AM CDT Sun May 5 2024

.KEY MESSAGES...

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- Showers and thunderstorms are expected at times Tuesday
  through Thursday. Some storms could be strong on Tuesday.
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&&

.UPDATE...
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Issued 950 AM CDT Sun May 5 2024

Mostly clear skies and light winds are expected today. No
changes to the forecast.

Marquardt
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&&

.SHORT TERM...
Issued 318 AM CDT Sun May 5 2024

Today through Monday:

Some fog remains possible this morning in patchy spots owing the
wetting rains from yesterday evening, building subsidence, and
light winds. The Wisconsin River Valley will be the most favored
region for fog development.

Otherwise today, high pressure will continue to shift east and
settle over the Upper Great Lakes by tonight. Clear skies and
full solar insolation should lead to a well mixed boundary layer
and fairly low dew points in the upper 30s to low 40s. Winds
will be light out of the north, becoming more light and variable
this afternoon. Highs should reach the upper 60s to near 70,
generally west of Waukesha, Washington, Racine, and Kenosha
counties, as the weak pressure gradient will allow a lake
breeze to start fairly early in the afternoon and push inland,
keeping highs in the mid 60s closer to the lakeshore.

Temperatures will cool into the 40s tonight under mostly clear
skies and continuing subsidence. Another round of fog in the
Wisconsin River Valley may occur.

Monday will be another beautiful day, with slightly warmer
daytime highs inland in the low to mid 70s as ridging aloft
amplifies. Prevailing winds will be off of the lake from the
east as high pressure moves toward Lake Huron, keeping
conditions cooler again in lakeshore counties and their westward
neighbors.

CMiller

&&

.LONG TERM...
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Issued 428 AM CDT Sun May 5 2024

Monday night through Saturday:

WAA and an occluded front are expected to approach Wisconsin
Monday night as a low deepens over Eastern Montana/Western
North Dakota. Showers and thunderstorms are expected to spread
southwest to northeast into the state early Tuesday morning
into the post dawn hours. There are two camps of solutions for
Tuesday and Wednesday as the NAM and 00z ECMWF favor
precipitation coming through as a solid line along the occluded
front through the daytime hours on Tuesday, while the GFS favors
a dying line in the morning with more redevelopment in the
afternoon. This in turn then influences the storm potential on
Wednesday.

If the ECMWF/NAM solution verifies, much of Tuesday
afternoon could be dry following the passage of the occluded
front and its precipitation by the early afternoon. Without a
blow- up of precipitation Tuesday afternoon, favorable dew
points may be pushed into central IL, then return north on
Wednesday behind a warm front as a surface low deepens over the
middle Mississippi Valley. EPS ensembles show a strong wave
aloft and more favorable flow on Wednesay, and the ECMWF shows
convection blowing up along the warm front just south of the
WI/IL border Wednesday afternoon.

The GFS has the precipitation lifting north Tuesday
morning/afternoon with redevelopment during the mid to late
afternoon over southern WI. Shear looks like it would be
marginal, but the GFS supports steep mid level lapse rates,
hinting toward a severe hail threat, provided a storm
establishes itself. This convection Tuesday afternoon would then
give a reinforcing push to dew points southward down to the
Ohio River Valley. The GFS then also forms a low Wednesday, but
the warm front only rises as far north as central Illinois, and
Wednesday storm chances stay well south.

With all of these confounding factors, it remains too early to
put a definitive label on the storm threat for Tuesday and
Wednesday, but trends will be monitored for better confidence
with each successive model run.

A weak sfc trough may then linger for Thursday providing
additional rain chances. Beyond, slight chances for rain linger
into the weekend as a weak upper trough passes over the Upper
Great Lakes.

CMiller
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&&

.AVIATION...
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Issued 950 AM CDT Sun May 5 2024

VFR conditions are expected through Monday. East winds will be
10 knots or less. A lake breeze will move inland during the day.
Mostly clear skies are expected.

Marquardt
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&&

.MARINE...
Issued 324 AM CDT Sun May 5 2024

High pressure will spread into the Upper Great Lakes Region and
linger through Monday. This high pressure will bring light
northerlies to the lake this morning, with winds growing light
and variable over the lake this afternoon into tonight. Monday,
winds look to become easterly at times, but lack of a strong
pressure gradient over the area will mean that the east winds
will be interspersed with boughts of light and variable
conditions.

Monday night, winds will grow southeasterly and breezy to 20 knots
over the southern half of Lake Michigan by Tuesday morning. Winds
then come around to westerly after a front lifts north over the
area Tuesday night into early Wednesday morning. A brief period
of Small Craft Advisory criteria waves may occur Tuesday
morning.

CMiller

&&

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

$$

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