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233
FXUS61 KCLE 190125
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
925 PM EDT Fri Aug 18 2017

.SYNOPSIS...
Weak high pressure will slide across the Ohio Valley this
this evening and early tonight. Towards morning, weak low
pressure associated with a disturbance aloft will drop across
the lower Great Lakes and Ohio Valley on Saturday. High pressure
will build across the Great Lakes Sunday, then move east of the
area on Monday.

&&

.NEAR TERM /THROUGH SATURDAY NIGHT/...
As expected most of the diurnal clouds have dissipated. Some
clouds continue to impact the immediate lakeshore areas east of
CLE. These too should lift to the north leaving a period of
mostly clear to partly cloudy skies. Mid level clouds will begin
to arrive from the west later tonight. Much of the new guidance
coming in including the latest HRRR and SREF suggest that our
precip forecast may be overdone for Saturday. Have gone ahead
and lowered pops into the chance category and have removed all
likely wording. This seems reasonable as coverage should be no
more than scattered in coverage with chances at any given
location limited to just a few hours. Best chances remain at the
southeast end of the area during the afternoon. No changes to
temps as dewpoints at the surface continue to slowly come down.

Previous...Satellite shows clouds thinning across northern Ohio
and nwrn PA as weak high pressure and drier air move in and the
low north of the area continues to pull northeast. Expecting
this trend to continue into the evening with clearing for late
evening and the early overnight. Towards morning however models
show another weak low moving in from the west supported by a
developing upper level trough. Models differ graphically on
cloud cover and associated moisture but both the NAM and GFS do
print out likely pops for the event which seems reasonable given
the upper support. Will not however be an all day rain...
Believe the best chance for the western half of the area is from
dawn through 16z or so shifting east in the afternoon as drier
air again moves into the west. Saturday night should be dry
outside of a possible lingering shower for an hour or so in the
evening. Will have only a 20 pop for that possibility. Night
temps near normal. Saturday temps near to a couple degrees below
normal.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
High pressure will be over the area providing dry wx Sun thru
Mon before moving off to the east for Tue to allow a cold front
to drop SE into the area by Tue evening. Moisture is limited
with this front so will keep pops in chc category. Near normal
temps on Sun will warm above normal for Mon and Tue.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Broad troughiness will move east across the eastern half of Canada
by mid week causing a fairly strong area of low pressure to move
east northeast across the central and eastern Canada as well.  A
strong cold front will push east across the area Tuesday night
ushering in some colder air to the local area from the north.  The
front will bring showers and thunderstorms to the area Tuesday night
and push east of the area Wednesday morning.  There the is the
possibility for some lake effect rain showers following the frontal
passage Wednesday into Thursday.  Strong cold air advection will
likely cause waterspouts to develop provided winds are not too
strong to shear them apart.  Strong high pressure at the surface
will build east across the Great Lakes region through the latter
half of the week even though upper level troughiness will persist
through this period.  Cold air advection will begin to wane by the
end of the forecast period as the high pressure begins to move east
of the area.

&&

.AVIATION /00Z Saturday THROUGH Wednesday/...
Things remain quiet with lot`s of diurnal looking cumulus
floating about. These clouds should go away for a few hours
before mid level clouds begin to spread back east across the
local area overnight. Precip chances will hold off till around
12z in the west and till late in the morning or even early
afternoon across the eastern end of the area. The new guidance
coming in is backing off on precip coverage from earlier models
runs. So will back off on thunder chances in the new TAFs. Most
locations will have a 3 or 4 hour of window for precip during
the period with it dry otherwise. Winds have started to come
down and the gustiness should end after sunset. The flow will be
mainly west or southwest under 10 knots.

OUTLOOK...Non-VFR possible in scattered showers/tstms on
Tuesday.

&&

.MARINE...
High pressure ridging moving into the lake will cause the winds to
diminish some tonight and allow the SCA conditions to end. A trough
will push east across the lake Sat into early Sat night causing the
winds to waver from SW to West. High pressure moves over the lake
for Sun thru Mon to produce light mostly south to southwest winds.

A cold front is expected to push SE across the lake Tue night
causing SW winds to increase to 10 to 20 knots on Tue ahead of the
front, veering to NW by the end of the night and continuing Wed.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement until 4 AM EDT Saturday for OHZ011-012-
     089.
PA...Beach Hazards Statement until 4 AM EDT Saturday for PAZ001.
MARINE...Small Craft Advisory until 4 AM EDT Saturday for LEZ146>149.

&&

$$
SYNOPSIS...TK
NEAR TERM...TK/Kubina
SHORT TERM...Adams
LONG TERM...Adams/Oudeman
AVIATION...Kubina
MARINE...Adams