Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 191449 AAA
AFDMKX

Area Forecast Discussion...UPDATED
National Weather Service Milwaukee/Sullivan WI
949 AM CDT Sat Aug 19 2017

.UPDATE...

Fog and low clouds continue to dissipate this morning, with plenty
of sunshine expected for the remainder of the day under high
pressure.

&&

.MARINE...

Quiet conditions are expected this weekend under high pressure.

&&

.PREV DISCUSSION... (Issued 553 AM CDT Sat Aug 19 2017)

AVIATION(12Z TAFS)...

Clear skies have lead to early morning fog and low stratus across
parts of the area. It isn`t widespread, so it should be quick to
burn off after sunrise this morning. Until then, look for some IFR
CIGS/VSBYS through mid morning with VFR conditions into the
evening. Another clear night will lead to more fog late tonight.

PREV DISCUSSION... (Issued 154 AM CDT Sat Aug 19 2017)

SHORT TERM...

Today and tonight...Forecast confidence is high.

As a sharp mid level wave exits to the east early this morning,
high pressure will take charge, providing a quiet day with plenty
of sunshine and warm temperatures. Winds will be light out of the
west, except along Lake Michigan where winds will turn east to
southeast later this morning and afternoon due to the lake breeze
circulation. Early morning fog in some of the river valleys will
burn off quickly this morning, only to repeat process later
tonight.

LONG TERM...

Sunday...Forecast confidence is medium.

A low amplitude shortwave trough will ride quasi-zonal flow aloft
through the Upper Midwest and western Great Lakes. Mid to upper
moisture associated with the wave will reach southern Wisconsin
during the afternoon with a corresponding increase in cloud cover.
High pressure over the lower Great Lakes will hold sway in the lower
levels, but its position to our east will allow for return flow with
low-level thermal and moisture advection later in the day. The
high`s residual influence combined with low-level capping and the
lack of a clear trigger support maintaining a dry forecast despite
the arriving wave aloft. It should feel warm and muggy, with highs
topping out in the 80s and dewpoints climbing well into the 60s.

Sunday night through Tuesday...Forecast confidence is medium.

The upper pattern amplifies slightly in response to slow moving
troughing across south central Canada. Several low amplitude
perturbations are evident within the mean flow while progressing
from the Great Plains into the western Great Lakes. The low-level
baroclinic zone associated with a quasi-stationary front should
near southern Wisconsin late Monday into Tuesday morning, before
sinking south as a cold front later on Tuesday. Periods of showers
and thunderstorms are possible, with the greatest odds in the
Sunday night/early Monday and Monday night/Tuesday morning
periods. Some heavy rainfall and strong storm potential is there
as well, but predictability for which areas are most likely to see
this is low. Keep up with the forecast. Muggy conditions will
persist into at least Tuesday morning, before a push of slightly
drier and cooler air arrives behind the cold front. Unfortunately,
it still appears that cloud cover will affect the Eclipse viewing
in southern Wisconsin on Monday.

Wednesday through Saturday...Forecast confidence is high.

A meridional flow pattern will prevail across the CONUS, featuring a
closed upper cyclone over Quebec and upper ridging across the Great
Plains. These features will gradually shift east in response to a
wave breaking along the Pacific Northwest coast on Thursday into
Friday. Locally, cyclonic flow will prevail for Wednesday into early
Thursday, with blustery conditions and some residual cloud cover
possible. Thereafter, mid-level heights will rise later Thursday
into Friday allowing surface high pressure to take hold across the
Great Lakes. This should be a cooler period, as 850 mb temperatures
drop into the 8 to 10 degree range. Mean temperatures are likely to
be a bit below seasonal normals for much, if not all, of this period.

AVIATION(06Z TAFS)...

There will be some IFR/MVFR VSBYS due to fog through about 13z
this morning...mainly away from Lake Michigan and in the usual
river valleys and low lying areas. A similar setup is expected
tonight. Otherwise VFR conditions can be expected with light
westerly winds today. The lake breeze will cause winds to turn
east to southeast along Lake Michigan later this morning and
afternoon.

MARINE...

Winds and waves will remain below small craft advisory levels
through at least the early part of next week. Look for light
westerly winds early this morning, then turning southeast later
this morning and afternoon as a lake breeze kicks in. Winds will
be south to southeast on Sunday at 10kts or less.

&&

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

$$

Update...DDV
Today/Tonight and Aviation/Marine...Davis
Sunday THROUGH Friday...SPM



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