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720
FXUS61 KCLE 201802
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
202 PM EDT Sun Aug 20 2017

.SYNOPSIS...
High pressure will build across the Ohio Valley and eastern
Great Lakes today. The high will move east of the area on
Monday. The next low will move northeast across the Great Lakes
Tuesday and take a cold front across the region Tuesday night.

&&

.NEAR TERM /THROUGH MONDAY/...
No major changes to the forecast with the midday update. Models
still indicating the potential for isolated convection to fire
across west central Ohio late this afternoon and move into the
area as a mid level disturbance approaches the area from the
west. While low level moisture has increased a bit resulting in
an expansive cumulus field across the area of interest, not
confident enough to include isolated shower/storm chances at
this point. Will continue to monitor convective trends through
the afternoon forecast issuance and may add pops then.

Original discussion...

High pressure will be in control of the region today. However as
it slides eastward through the day it will allow some moisture
at 850 mb to advect back into the area from the Central
Highlands southward into Central Ohio. A couple of the higher
resolution models are trying to generate some showers/thunder
within this area of moisture. While we do expect the increase in
moisture it is difficult to believe there will be enough lift
to produce any rain. So at this point we will keep a dry
forecast for today. The dry conditions will continue through
tonight but the low level moisture will continue to increase
into Monday. This increase in moisture should lead to more cloud
cover across the region. Thunderstorm chances will increase on
Monday with a couple areas to monitor. One area being some
convergence along a lake breeze boundary from east of Cleveland
into NW PA. The other area would approach NW Ohio from the west
with a weak piece of jet energy approaching along with increased
warm advection. The chances of seeing scattered convection
develop over Indiana and drift toward NW Ohio Monday
afternoon/evening seems like a decent possibility.

Temperatures today and Monday will be above seasonal averages.
Monday will be the warmest day of the near term with highs mid
80s to around 90. Becoming more humid tonight with lows in the
lower to mid 60s for most locations.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
With the warm and moist air continuing to flow into the area, have
bled the chance for precip into the northwest half of the area
Monday night. But the main focus will be on Tuesday/Tuesday evening
as a trough digs southeast across the Great Lakes and brings a
potentially well timed cold front to northern OH/nw PA.
Strong/severe storms a possibility.

Wednesday will begin a multi-day stretch of below normal
temperatures as another shortwave amplifies the trough and delays its
exit. Will go with highs in the lower and mid 70s. Somewhat
concerned with the cold air and trough aloft that there may be a few
showers. At this point will hold it with a silent 20 PoP.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
Will still be in the midst of the cool trough and in fact there is
indication that another lobe of energy will rotate through the base
of the trough. There is some timing differences between the
GFS/ECMWF, but again this could be enough to spark a few rouge
showers across the area. While waiting on better timing
consensus and moisture availability, will again hold with a
silent 20 PoP for most. Highs will be a little closer to 70
Thursday.

Will moderate temperatures and keep the forecast dry going into the
weekend with high pressure across the region.

&&

.AVIATION /18Z Sunday THROUGH Friday/...
High pressure will continue to slide east across the region. An
increase in low level moisture will result in some scattered cu,
with some models indicating potential for TSRA/SHRA from KMFD to
KCAK. However, will continue to hold off on mention in TAF and
monitor radar for development. Some MVFR BR possible at sites
around daybreak as winds go light. TSRA chances return late in
the period, but confidence is low this far out.

OUTLOOK...Non-VFR likely in scattered showers/tstms on Tuesday
and Tuesday night.

&&

.MARINE...
High pressure across the upper Ohio Valley today and Monday will
provide for lighter winds on the lake with an afternoon shift to
onshore flow each day. Tuesday though an active cold front will
be approaching from the northwest. Southwest flow will increase
and the lake will be choppy. Waves will build enough by late
afternoon to be in need of a small craft advisory for at least
areas east of Avon Point. With the passage of the cold front
Tuesday evening, a good push of cold air advection takes place
and the choppy conditions will likely persist through the night.
The far east end may again be in need of a small craft advisory
Wednesday with the northwest flow. High pressure will then move
southeast across the Great Lakes Thursday with winds on Lake
Erie shifting around to the northeast.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.

&&

$$
SYNOPSIS...Mullen
NEAR TERM...Greenawalt/Mullen
SHORT TERM...Oudeman
LONG TERM...Oudeman
AVIATION...Greenawalt
MARINE...Oudeman