244
FXUS63 KMKX 270239
AFDMKX

Area Forecast Discussion
National Weather Service Milwaukee/Sullivan WI
939 PM CDT Mon Jun 26 2017

.UPDATE...

Showers have dissipated. Expect some ground fog mainly in river
valleys during the early morning.

&&

.MARINE...

High pressure will be centered over the Upper Ohio Valley Tuesday
afternoon. The light west winds may give way to a Lake Breeze with
southeast winds Tuesday afternoon.

After lighter winds Tuesday, Small craft advisory conditions are
likely to return Wednesday under gusty southerly winds, along with
likely thunderstorms.

&&

.PREV DISCUSSION... (Issued 738 PM CDT Mon Jun 26 2017)

UPDATE...

AVIATION(00Z TAFS)...

Clearing skies are expected this evening, with mostly sunny skies
Tuesday morning giving way to sct afternoon cumulus. Will have to
watch for the possibility of a lake breeze forming mid to late
Tuesday afternoon.

Aside from IFR/LIFR fog in the Wisconsin River valley late
tonight into early Tue morning, VFR conditions will prevail
through Tuesday.

PREV DISCUSSION... (Issued 326 PM CDT Mon Jun 26 2017)

SHORT TERM...

Tonight and Tuesday...Forecast confidence is high:

Scattered showers will wind down late this afternoon and early
evening as daytime heating is lost. Clearing skies are then
expected this evening and overnight.

The showery and cool pattern will finally break Tuesday, with
plenty of sunshine expected under high pressure. Additionally, low
level flow will head toward a southerly direction during the day,
allowing a return of milder temperatures. Highs will still be a
bit below normal, but mid-70s will be a nice improvement. Lighter
winds will be an added bonus to the pleasant day tomorrow. Could
see a lake breeze form due to the milder temps and lighter winds,
but it would likely hold off from moving inland until mid to late
afternoon. So, lakeshore areas should get in on the milder temps
too.

Tuesday night through Thursday...Forecast confidence medium.

Sly flow and warm advection will be ongoing Tue nt but will
increase on Wed when a strong sly LLJ to the west veers to swly
at 50-60 kts as it shifts ewd across srn WI. A shortwave trough
will pass during this time providing upper support. So overall,
moderate to strong warm advection and Q-vector convergence
expected for Wed and lingering into Wed eve. The CAPE will not
become appreciable until late Wed aft-eve although sfc based
convection is questionable due to clouds and cooler temps during
the daytime hours. Thus the best chances for strong or severe
storms will be the evening as warm, moist advection continues via
a veering LLJ. If sfc based convection does occur then all severe
threats including tornadoes would be possible. Some concern for
training convection Wed eve due to the veering LLJ becoming more
aligned with the upper flow, so at least a minor flash flood
threat will be possible. A cold front will gradually pass late Wed
nt-Thu AM with the focus for convection remaining over IL/IA for
Thu and Thu eve.


LONG TERM...Friday through Monday...Forecast confidence low to medium.

It appears a shortwave trough and wave of low pressure may track
farther nwd and bring widespread showers and tstorms to srn WI for
Fri. The severe threat will likely stay south where higher CAPE
values will be present. For Sat, a shortwave trough and wave of
low pressure will move ewd across the nrn Great Lakes with a
trailing cold front, thus chances for showers and storms will
continue. If CAPE can build to appreciable levels, a severe threat
could be possible. A weak high pressure area will follow for Sun
followed by another wave of low pressure and showers and tstorms
for Mon although it could stay south. Temps and humidity during
this period will be near normal.

AVIATION(18Z TAFS)...

Isolated to scattered showers are still expected this afternoon
into early evening as a shortwave moves through. A rumble of
thunder is possible.

Clearing skies are expected this evening, with mostly sunny skies
Tuesday morning giving way to few/sct afternoon cumulus. Will have
to watch for the possibility of a lake breeze forming mid to late
Tuesday afternoon.

Aside from more fog possible in the Wisconsin River valley later
tonight into early Tue morning, VFR conditions will prevail
through Tuesday.

MARINE...

Gusty winds will continue into early evening, so left the timing
of the Small Craft Advisory as is.

After lighter winds Tuesday, advisory conditions are likely to
return Wednesday under gusty southerly winds.

&&

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

$$

Update...Hentz
Tonight/Tuesday and Aviation/Marine...DDV
Tuesday Night through Monday...Gehring