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Area forecast discussion 
National Weather Service Cleveland Ohio
727 am EDT Sat Jul 30 2016

Synopsis...
an area of low pressure will slowly move east across Ohio over the
weekend along a stalled frontal boundary. The low will depart to
the east on Monday with high pressure building overhead for the
first half of next week. A warming trend will get underway by
mid-week as the upper level ridge builds overhead.

&&

Near term /until 6 PM this evening/...
broad upper level trough that has been located upstream of the
region will shift eastward today. Meanwhile the area of surface low
pressure starting off this morning across Indiana will shift into
Ohio and provide a focus for showers and thunderstorms. Numerous
showers and thunderstorms early this morning along the northeast
Lakeshore and into Pennsylvania have brought over an inch of rain
to many areas based on radar estimates.

Still some uncertainty on how exactly convection will unfold
today. A fairly pronounced dry-slot has spread over the area with
activity firing to the north in Michigan. The parallel hrrr is
handling this activity pretty well and shows it expanding into
Northwest Ohio. The lack of mid-level cloud beneath the dry-slot should
enable better daytime heating and an increase in instability. Ml
cape values should reach or exceed 1500 j/kg and scattered to
numerous thunderstorms are expected to develop across Northern
Ohio. Convection will fill in to the north of the low where there
is an area of convergence from the surface to 850mb. Expect this
boundary to be a row of counties or more south of the Lakeshore
and tried to focus highest pops in that area. Storms will only be
moving at 10-15 mph and heavy rain will be possible. Some
locations received 2 inches or more of rain yesterday and will
need to be monitored today for localized flooding. Quantitative precipitation forecast will range
from little or none in some areas to 2+ inches in others.
Temperatures will be warmer in the west where breaks are more
likely in the clouds with highs in the lower 80s, tapering to the
upper 70s in northwest Pennsylvania.

&&

Short term /6 PM this evening through Tuesday night/...
diurnal trend expected with the convection decreasing in coverage
through the evening. With that said, will hold onto at least a
chance of thunderstorms for all areas given the moist airmass and
trough overhead. Scattered thunderstorms will develop again on
Sunday but better coverage should be in the east where better
moisture remains.

Upper level trough axis shifts east of the area by Monday with the
airmass drying out as surface high pressure expands overhead.
Dewpoints will drop back into the lower 60s on Monday and near 60 on
Tuesday resulting in lower humidity. Temperatures will gradually
warm with mostly sunny skies and a ridge building aloft. Highs will
be back into the mid 80s by Tuesday.

&&

Long term /Wednesday through Friday/...
an upper level ridge is progged to move east toward the forecast
area Wednesday through Friday. This will surely send another surge
of warm air back to the forecast area. Albeit temperatures are not
expected to be quite as warm as we saw with the last round of hot
weather but it will climb up into the upper 80s.

As the upper level ridge builds east, the models are hinting at a
possible potent little positive vorticity maximum that is expected
to move southeast over the top of the ridge and affect the western
portions of the forecast area. This feature is progged to have a
bit of deep moisture associated with it and may bring a round of
showers and thunderstorms to the area. Will add a mention of at
least a chance for showers and thunderstorms in the western half of
the area Wednesday.

High pressure will then become the dominant weather feature until
Friday morning when a cold front is progged to move east toward the
area. The timing of the cold front pegs it on arrival in the
forecast area in the late afternoon. I suspect with this timing
there is the potential for severe thunderstorms Friday afternoon
into the evening with the cold front.

Otherwise, warmth continues through the forecast period as return
southerly flow develops ahead of the cold front.

&&

Aviation /12z Saturday through Wednesday/...
once again, really tough forecast to deal with today as low
pressure moves northeast through the area. Scattered pop up
showers and thunderstorms continue to develop along the lake and
over the lake and over eastern portions of the forecast area.
Expecting more activity to develop later this afternoon as an
upper level disturbance moves east into the region and supports
the convective activity. Low clouds and visibilities at this time
should improve this morning and expecting more low clouds and
visibilities tonight as moisture lingers across the area. Winds
generally light and variable.

Outlook...non-VFR possible Sunday. Areas of morning fog possible
each morning.

&&

Marine...
after a 10 to 15 knot wind today from the northeast on the lake,
winds diminish to light and variable through the rest of the
forecast period. Conditions for will be ideal for recreational
boaters during this time period. Scattered thunderstorms could be a
threat on the lake today through Sunday morning.

&&

Cle watches/warnings/advisories...
Ohio...none.
PA...none.
Marine...none.

&&

$$
Synopsis...kec
near term...kec
short term...kec
long term...Lombardy
aviation...Lombardy
marine...Lombardy

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