Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 111752 AAB
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
1252 PM CDT Wed Oct 11 2017

.UPDATE...


&&

.AVIATION(18Z TAFS)...

Low stratus clouds ranging from 600 to 1200 feet or so are
expected this afternoon, tonight and Thursday across the area.
They should be the lowest later tonight into early Thursday
morning. There should be light drizzle at times, especially later
tonight into early Thursday morning.

Light fog is expected as well toinght into Thursday morning.
Visibility values may get down to around 1 mile later tonight into
early Thursday morning in parts of south central Wisconsin. Gusty
northeast winds will veer east later this afternoon and weaken
into tonight. They will veer southeast on Thursday.

Wood

&&

.PREV DISCUSSION... (Issued 1107 AM CDT Wed Oct 11 2017)

UPDATE...

Showers have ended across the area, as the main 500 mb shortwave
trough moves further to the east of the region. Low stratus clouds
are expected to linger into Thursday across the area, trapped
under the low level inversion.

Gusty northeast winds will become east and gradually weaken by
later this afternoon, as the surface low moves further east of the
region. These winds will become southeast tonight into Thursday.

Looks like there will be some drizzle that will affect the area
at times tonight into Thursday, with the light winds and saturated
low levels. Not much of a diurnal temperature range is expected
into Thursday.

Wood

MARINE...

Small Craft Advisory remains in effect until 7 PM CDT this
evening north of Port Washington, and until 5 AM CDT Thursday
morning south of there. Gusty northeast winds of 15 to 25 knots,
with gusts to 30 knots, should linger into this afternoon. The
weakening pressure gradient will allow winds to weaken later this
afternoon into this evening from north to south across the
nearshore waters.

Subsequent waves in the 5 to 8 foot range early this afternoon
should gradually subside from north to south as well into tonight.
3 to 6 foot waves will remain into tonight south of Port
Washington.

Wood

PREV DISCUSSION... (Issued 546 AM CDT Wed Oct 11 2017)

AVIATION(12Z TAFS)...
Not much change to the previous aviation discussion...we are
going to see an extended period of IFR/MVFR CIGS/VSBYS across
southern Wisconsin that will probably stretch through Thursday
night. Low pressure will pull away from the region today bringing
a gradual end to the widespread rainfall this morning. But, the
overall flow will remain weak with deep moisture trapped across
the region, likely resulting in some drizzle at times. We should
see improvement to MVFR levels today, but then drop back down to
IFR as things cool tonight.

PREV DISCUSSION... (Issued 312 AM CDT Wed Oct 11 2017)

SHORT TERM...

Today and tonight...Forecast confidence is high.

The rain will gradually come to an end early this morning as the
mid level short wave pulls off to the east. But, southern
Wisconsin will remain in a very weak flow beneath a COL in the
overall weather pattern through tonight. Deep moisture should
be trapped within a low level inversion or at least an isothermal
profile into Thursday. So, the potential for drizzle in the wake
of the exiting main rain area looks decent into the afternoon and
possibly through tonight. The brisk northeast winds will slowly
subside, but given the cloud cover, temps will be on the cool
side.

Thursday... Forecast confidence is high.

Low level warm air advection will keep the low clouds intact over
southern WI on Thursday. Most of the models are painting light qpf
over the area, but the moisture will be shallow and forcing will
be quite weak. This spells drizzle, light fog and low clouds for
us. Max temps will struggle to reach 60 under these conditions
with light easterly winds.

LONG TERM...

Friday through Sunday... Forecast confidence is high.

Southern WI will be in the warm sector of the approaching low from
the Plains and associated inverted trough extending up through
northern WI on Friday. Southerly winds will help temps rise into
the lower 70s before the rain gets here.

Friday night, that inverted trough/cold front will slide southward
through southern WI and bring a swath of light rain accumulating
to around a quarter inch. Forcing for the front will wane toward
Sat morning, so expect a diminishing trend in precip as it
reaches southeast WI.

The right entrance region of the upper jet will slide into
southern WI on Sat as a mid level trough digs through the central
Rockies. The resultant surface low will slide northeast through
southern WI and bring rain Sat afternoon and evening. There is
fairly good agreement between the models about timing and
placement of this low pressure system. This more dynamic system
could bring a few thunderstorms to southern WI Saturday
afternoon/evening. This one will have higher precip totals with an
inch or more possible. Showers should linger through Sunday until
the system departs.

Monday through Wednesday... Forecast confidence is medium.

Colder air behind this system looks like it will be very brief.
The pattern becomes more zonal for the middle of next week which
means more above normal temperatures and fairly dry weather.

AVIATION(06Z TAFS)...

We are likely to see an extended period of IFR/MVFR CIGS/VSBYS
across southern Wisconsin that will probably stretch through
Thursday night. Low pressure will pull away from the region today
bringing an end to the widespread rainfall. But, the overall flow
will remain weak with deep moisture trapped across the region,
likely resulting in some drizzle at times. We should see
improvement to MVFR levels today, but then drop back down to IFR
as things cool tonight.

MARINE...

The northeast winds will remain gusty through the morning, then
diminish through the afternoon. The small craft advisory has been
extended for a large part of the area through 4am tonight since
it will take some time for the waves to drop below small craft
advisory levels.

Small craft advisory conditions are expected at times this weekend
as low pressure moves through the region.

&&

.MKX WATCHES/WARNINGS/ADVISORIES...
WI...None.
LM...Small Craft Advisory until 5 AM CDT Thursday for LMZ644>646.

     Small Craft Advisory until 7 PM CDT this evening for LMZ643.

&&

$$

Update...Wood
Today/Tonight and Aviation/Marine...Davis
Thursday THROUGH Tuesday...Cronce



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