Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 261432
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
932 AM CDT Wed Jul 26 2017

.MARINE...Main focus will be on any storms that swing through
later this afternoon into early this evening. At this time
expecting isolated strong storms. South winds remain below small
craft criteria today with lighter wind regime tonight with trough
passage. NE winds ramp up on Thursday which will lead to some
higher wave generation. these NE winds continue into Friday so a
Small Craft may be needed at some point during this NE wind
regime.

PC

&&

.PREV DISCUSSION... (Issued 755 AM CDT Wed Jul 26 2017)

UPDATE...

Latest HRRR still shows main thunderstorms with a line near the
advancing cold front this afternoon and this evening.

AVIATION(12Z TAFS)...

Middle to high clouds from upstream MCS`s will continue to affect
the area overnight into Wednesday. Isolated thunderstorms near
Sheboygan moving east. Ceilings will lower to around 4000 feet or
so with the showers and thunderstorms moving through the area
later afternoon into the evening ahead of a cold front. Ceilings
down to 2500 feet are possible later Wednesday night, along with
light fog.

Southwest winds today, gradually weakening during the day, with a
lake breeze near lake Michigan. Winds will shift to the north
behind the cold front later tonight.

PREV DISCUSSION... (Issued 221 AM CDT Wed Jul 26 2017)

SHORT TERM...

Today and Tonight...Forecast Confidence is medium...

A strong shortwave north of Lake Superior with a 120 knot 250 mb
jet as the base of the trough will move east, bringing the right
entrance region across central and southern Wisconsin this
afternoon and early evening. Moderate upper divergence and 700 mb
upward motion. The 700 mb wind max will be across northeast
Wisconsin this morning, with the 850 mb low level jet well to the
south moving across central Illinois. There is moderate
instability with 1500-2000 Joules/kg across southern Wisconsin.
However despite the cold front moving across low level forcing is
rather weak. SPC as pushes the slight risk back to just the far
southwest areas.

Precipitable water values do rise to 2 inches over the far south,
but then sag back south rather quickly. While some storms may
produce brief heavy rains, the threat of flash flooding is not
high enough for a watch.

LONG TERM...

Thursday...Forecast confidence is high:

Moisture and instability will continue to depart on Thursday from
north to south. Could see some lingering showers/storms though in
the morning, winding down early afternoon as the drier and more
stable airmass arrives.

Friday through Sunday...Forecast confidence is high:

High pressure will build in Friday, then hang around through the
weekend. Very pleasant weather is expected for this period, with
a good amount of sunshine to go along with near seasonable
temperatures and lower humidity.

Monday and Tuesday...Forecast confidence is medium:

Models are showing a weak low pressure system and associated front
moving through the region early next week. Not great agreement
among models with the details of this system, but it does look
like the best chance for some showers/storms would be on Monday.

Should see temperatures remain around normal values during this
period.

AVIATION(06Z TAFS)...

Middle to high clouds will continue to push through the area
overnight into Wednesday. Ceilings will lower to around 4000 feet
or so with the showers and thunderstorms moving through the area
later Wednesday afternoon into Wednesday night. Ceilings down to
2500 feet are possible later Wednesday night, along with light
fog.

South winds overnight will become west southwest on Wednesday,
gradually weakening during the day. Winds will shift to the north
behind the cold front later Wednesday night.

Scattered showers and thunderstorms will push through the area
later Wednesday afternoon into Wednesday evening. They should exit
later Wednesday night. Best chance for severe storms and locally
heavy rainfall will be southwest of Madison. Gusty winds and
hail remain possible elsewhere during this time.

MARINE...

South winds will linger at 10 to 15 knots across the nearshore
waters of Lake Michigan early this morning with waves of 2 to 3
feet, highest toward the Sheboygan area. Winds will gradually
weaken and become more west southwest this morning, with a
southeast lake breeze expected with lower waves.

Scattered thunderstorms should move through the area later
afternoon and evening with a weak cold front.

Gusty northeast winds Thursday into perhaps Friday will bring
building waves to the nearshore waters of Lake Michigan. These
waves may linger as late as Friday night. A Small Craft Advisory
may be needed for this period.

&&

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

$$
Today/Tonight and Aviation/Marine...Hentz
Thursday THROUGH Tuesday...DDV



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