Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 112010
AFDMKX

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

.DISCUSSION...

Tonight And Thursday...Forecast Confidence Is High.

Models are showing good agreement with a surface col moving into
the area tonight, sliding to the east on Thursday. Winds will
weaken into tonight with this feature, gradually veering to the
east, then to the southeast on Thursday. The low stratus clouds
are expected to linger into Thursday across the area, trapped
under the low level inversion.

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. The best shot will be later tonight into early
Thursday morning, so kept that mention in the forecast. Not much
of a diurnal temperature range is expected into Thursday.

Friday and Friday night - Confidence...Medium
Tightening 850 millibar baroclinicity along with better
isentropic forcing will result in increasing rain chances. This
forcing focuses along and northwest of surface cold front with
highest chances increasing into the northwest cwa during the
afternoon. With strong upper jet max to our north there will be
divergence aiding in the forcing as the better baroclinicity
slides into southern WI on Friday night. No shortwave of note but
enough jet enhances forcing and lower level lift to keep the rain
chance going through Friday night.

Saturday and Saturday night - Confidence...Medium to High
Looks like a very unsettled period with low pressure proggd to
move through central or southern WI Saturday night. An abundance
of moisture will be in place with some favorable dynamics both in
the low levels and upper levels. Strong upper divergence with
right rear quad of upper jet along with left front quad of
impinging LLJ suggests column lift will be on the high side. For
now the GFS soundings are showing an inversion around 800-825
millibars that keeps CAPE more on the elevated side. There is more
than ample 0-6km and 0-1km shear at play. Should more surface
based CAPE be realized things could get a little feisty. As we`ve
seen in the recent past enough shear/low LCL`s can compensate for
a lack of CAPE. For now will certainly keep the thunder going but
will have to monitor how the lower level warm sector evolves into
the CWA as this low pulls through the state.

Sunday through Wednesday - Confidence...Medium
Cold advection arrives in the wake of the low with northwest winds
ushering in 850 temps down to near zero C. This low level thermal
trough lingers into Monday morning. This cool pocket then gets
whisked away pretty quick later Monday and all the way into
Wednesday. In fact 925 temps rise to 10-13C into for Tuesday and
Wednesday so the cooldown will be short lived.

&&

.AVIATION(18Z TAFS)...Low stratus clouds ranging from 600 to 1200
feet or so are expected into 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 by early this evening, and weaken
into tonight. They will veer southeast on Thursday.

&&

.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.

The weakening pressure gradient will allow these winds to weaken
into this evening from north to south across the nearshore waters.
The winds will veer to the east this evening, and southeast on
Thursday.

Subsequent waves in the 4 to 8 foot range will gradually subside
from north to south as well into tonight. 3 to 6 foot waves will
remain into tonight south of Port Washington.

&&

.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.

&&

$$
Tonight/Thursday and Aviation/Marine...Wood
Thursday Night through Wednesday...Collar



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