000
FXUS63 KMKX 230431
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1131 PM CDT Tue Aug 22 2017

.UPDATE...


&&

.AVIATION(06Z TAFS)...VFR conditions for Wed-Wed nt.
Sct-bkn040-050 cumulus for Wed afternoon.


&&

.PREV DISCUSSION... (Issued 925 PM CDT Tue Aug 22 2017)

UPDATE...

MARINE...Modest wnwly winds tonight becoming lighter on Tue and
shifting nely by middle to late afternoon via a lake breeze. Light
winds and low wave heights for the remainder of the week.

PREV DISCUSSION... (Issued 624 PM CDT Tue Aug 22 2017)

UPDATE...Nwly sfc flow and weak cold advection will continue
tonight into Wed morning, while high pressure over the Great
Plains will move to the Upper MS River Valley by late Wed.
Pleasant temps and comfortable humidity will continue.

AVIATION(00Z TAFS)...VFR conditions tonight into Wed eve.
Sct-bkn040-050 cumulus for Wed afternoon.

PREV DISCUSSION... (Issued 152 PM CDT Tue Aug 22 2017)

SHORT TERM...

Tonight and Wednesday...Forecast Confidence is high.

Cyclonic flow prevails tonight as a closed upper circulation
traverses the upper Great Lakes. Skies will clear this evening,
with good radiational cooling allowing temperatures to drop into
the 50s (perhaps even a few upper 40s in spots).

We`ll remain in northwest flow tomorrow with a shortwave trough
dropping through the western/upper Great Lakes. Cooler air will
ooze down from the north, with 925 mb temperatures falling into
the 10 to 12 degree range by Wednesday afternoon. Some cloud cover
is possible (especially in the east) in association with the
approaching upper wave. Otherwise look for cooler temperatures
with highs in the lower to mid 70s.

Wednesday night and Thursday...Forecast confidence is High.

A shortwave will push southeast into Wisconsin on the west side
of the Upper trough late Wednesday night, as a jet max pushes
southeast. Upper level divergence moves across southern Wisconsin
late Wednesday night, along with 700 mb upward motion, but it
weakens as it reaches the forecast area. Mid levels saturate, but
this occurs above 700 mb. as such light rain may evaporate with
mainly virga. A weak surface trough will drop south across the
large surface high across the upper and mid Mississippi Valley.

LONG TERM...

Thursday Night through Saturday...Forecast confidence is High.

The upper trough slowly reaches the northeast U.S. Thursday
night. The upper flow over Wisconsin then becomes more zonal
Friday. A weak shortwave moves into the Upper Mississippi Valley
Saturday.

High pressure and cooler air remains into Friday. The high is
expected to be over the eastern Great Lakes Saturday, with weak
warm advection on the back side of the high. The GFS brings light
showers into a few west areas Friday night and Saturday, but the
ECMWF is dry.

Sunday through Tuesday...Forecast confidence is High.

The upper shortwave drops into Wisconsin Sunday, but is fairly
weak. The shortwave remains through Tuesday on the ECMWF.

The ECMWF is a bit more aggressive in bringing some showers into
the east, with the GFS slower to push the ridge over the great
lakes off to the east.

AVIATION(18Z TAFS)...

SCT-BKN 040-060 cumulus will dissipate around sunset. SKC
thereafter. Gusty NW winds up to 25 knots will decrease this
evening. VFR conditions will continue into tomorrow.

MARINE...

Offshore winds will remain close to Small Craft Advisory levels
through early evening, with gusts occasionally reaching 25 knots.
The higher waves should be confined near the open waters given the
offshore flow. Small craft should exercise caution into early
evening. The gusty northwest winds will veer northerly and weaken
late tonight into Wednesday morning.

&&

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

$$

Update...Gehring
Tonight/Wednesday and Aviation/Marine...SPM
Wednesday Night through Tuesday...Hentz