Area Forecast Discussion
Issued by NWS Milwaukee/Sullivan, WI

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FXUS63 KMKX 110449
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
1149 PM CDT Thu Aug 10 2017

.UPDATE...


&&

.AVIATION(06Z TAFS)...

scattered clouds around 4 thsd ft with patchy IFR fog.

MVFR ceilings are likely late tonight into Friday, with some IFR
CIGS possible around sunrise.

Could see a shower Friday afternoon with a mid level trough over
the Upper Great Lakes.

&&

.PREV DISCUSSION... (Issued 903 PM CDT Thu Aug 10 2017)

UPDATE...

Mid/upper level trough axis has moved east ending the thunderstorm
chances. Next concern will be stratocumulus shield moving in late
tonight and Friday morning.

AVIATION(03Z TAFS)...

Dry weather is expected overnight. Could see a shower Friday
afternoon with a mid level trough over the Upper Great Lakes.

MVFR ceilings are likely late tonight into Friday, with some IFR
CIGS possible around sunrise.

MARINE...

Winds and waves are expected to stay below Small Craft Advisory
through Friday morning. however a north flow late friday
afternoon and Friday night may result in winds near small craft
advisory levels.

PREV DISCUSSION... (Issued 235 PM CDT THU AUG10 2017)

TONIGHT AND FRIDAY - Forecast Confidence...High.

Showers and storms are beginning to fire this afternoon as expected.
Storms will be likely into early evening, with some of the storms
possibly reaching severe levels. Large hail and damaging winds are
the main threats.

After storms exit the southeast this evening, dry weather is
expected overnight. Could see a shower or sprinkle tomorrow as the
cooler air aloft moves through, but most places will remain dry.

Below normal temps are likely on Friday, with mostly cloudy skies
lingering much of the day and the cooler airmass aloft moving
through.

FRIDAY NIGHT THROUGH SUNDAY - Forecast Confidence...Medium to
High.

A mainly dry and comfortable period is expected.  Lingering low to
mid level cyclonic curvature on Saturday will fight against a very
dry atmosphere, so only expecting few-sct cumulus redevelopment.
Hence expecting a mostly sunny day with 925H temps resulting in
daytime temps warming to slightly below seasonal normal. Weak warm
air advection ahead of a slowly moving upper level wave in the
northern Plains may clip far southwest Wisconsin with a few showers
or storms Sunday afternoon.  Otherwise, a bit more cloudiness can be
expected on Sunday due to the proximity of the upstream short wave.
Temperatures on Sunday will be similar to Saturday.

EXTENDED PERIOD...

SUNDAY NIGHT THROUGH THURSDAY - Forecast Confidence...Medium to
High.

Most of this period is looking dry and seasonal for mid-August.
Persistent down-stream low pressure troffing over eastern Canada
into the eastern Great Lakes will result in dry NNW steering flow
across the western Great Lakes.  Upstream, short wave high pressure
ridging will gradually expand in coverage and intensity and spread
into the western Great Lakes early next week.  925H temps look
seasonal with readings in the 15-18 degree range and resultant
daytime temperatures warming into the 70s to around 80.

Protective ridge should keep southern WI dry at least through
Wednesday.  Medium range guidance in reasonable agreement showing
ridge flattening out due to strong short wave moving ENE through the
northern plains into the western Great Lakes around mid-week. GFS
Ensembles show some variation in the timing of the short wave trof
with several perturbations holding onto lingering ridging.  GFS
increase precipitable water rapidly to around 2 inches Wednesday
night into early Thursday. For now wl include chance pops Wednesday
night into Thursday.

AVIATION(18Z TAFS)...Thunderstorms are likely this afternoon into
early evening. The main focus will be across the southeast half of
the forecast area. A few of the storms could reach severe levels,
with damaging winds and large hail the main threats.

After storms exit the southeast this evening, dry weather is
expected overnight. Could see a shower or sprinkle tomorrow, but
most places will remain dry.

Lower ceilings are likely later tonight into Friday as cooler air
aloft moves into the area.

MARINE...Waves could approach 4 feet through late afternoon north
of Port Washington under breezy south winds. Otherwise, winds and
waves are expected to stay below Small Craft Advisory levels the
next several days.

&&

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

$$

Update...Hentz
Tonight/Friday and Aviation/Marine...MBK
Friday Night through Thursday...DDV



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