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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCLE 031359
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
959 AM EDT Mon Aug 3 2020

.SYNOPSIS...
Weak high pressure this morning will drift east as a cold front
approaches from the central Great Lakes. A weak low will move
into southern Ontario this afternoon then reach western New York
Tuesday morning. A cold front is expected to move across the
region from west to east through Tuesday morning. High pressure
will build across the region midweek into the weekend.

&&

.NEAR TERM /THROUGH TUESDAY/...
Minor adjustments to pops with the mid morning update. Hi-res
guidance indicating some shower and possible thunderstorms
developing from southwest to northeast across the area beginning
early this afternoon, mainly along and east of the I-71 corridor.
Ongoing forecast was a little quicker with development vs. the
latest model trends, so slowed down the arrival of chance/low
likely pops a few hours. Otherwise, the forecast is generally on
track.

Original discussion...
Showers will gradually increase ahead of a cold front today as
an upper level trough cools the atmosphere aloft. The cooling
aloft may result in scattered thunderstorms but do not think the
thunder will be widespread. Cloud cover will keep temperatures
slightly below seasonal averages with highs ranging from the
upper 70`s to around 80.

Cold front continues its move across the region tonight with a
continuation of showers and thunderstorms through the evening.
Think the thunder will dissipate after sunset but expect
scattered showers to persist through the night. Cold front will
reach the eastern CWA by sunrise on Tuesday. Lows tonight in the
60`s.

Upper level trough will trail the surface cold front that should
be east of the region by Tuesday afternoon. Still enough cool
air aloft in the wake of the front for some high based showers
through sunset. These will mainly be across NE OH/NW PA. Cooler
in the wake of the front on Tuesday with highs mostly in the mid
to upper 70`s.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
Upper level trough will remain persistent across the Great Lakes
region Tuesday night and then quickly shift off to the east
Wednesday. Broad cyclonic flow will be present Wednesday followed by
a shortwave trough that will shift east over the area Thursday.
Surface high pressure will build northeast across the area through
Thursday night and will bring a return to fair weather to the
region. Large area of upper level negative vorticity advection and
fairly dry air will also be a dominant feature across the area. As
the surface high slides east into the region, some cold air
advection will take place keeping temperatures relatively cool
through the period.  Highs Wednesday will be in the middle 70s and
Thursday will see highs in the upper 70s to lower 80s. Otherwise,
lows will be in the lower to middle 50s.

&&

.LONG TERM /FRIDAY THROUGH SUNDAY/...
An upper level shortwave trough will race east across the area
Friday with a vigorous positive vorticity advection taking place.
Ridging will move east over the area Saturday resulting in the
stalling of the surface high pressure over the northern Appalachians
to New York state by Sunday morning.  A series of fast moving
shortwave troughs will move into the area Sunday and Sunday night
with some associated moisture.  Can`t rule out a threat for showers
and thunderstorms possibly late Saturday night or Sunday into Sunday
night.  As surface high pressure shifts east, a return to a warm air
advection pattern will result in temperatures gradually warming from
the lower 80s Friday to the middle and upper 80s by Sunday.  Lows
will be in the middle to upper  60s across the area through the
period except upper 50s Friday night in the extreme east.

&&

.AVIATION /12Z Monday THROUGH Friday/...
Low level warm advection across the east may bring MVFR/IFR
conditions to eastern OH into NW PA through mid morning. This
will mainly impact KYNG into inland NW PA. Some patchy MVFR/IFR
ground fog will be possible around sunrise but will likely miss
most TAF sites. Showers and scattered thunderstorms will
increase in coverage into the afternoon ahead of a cold front
that will move into NW OH by 18Z. MVFR and brief IFR conditions
will be associated with the heaviest showers/thunderstorms.

Wind will be light through sunrise then increase to around 10
knots from the southwest this afternoon. Winds will shift to the
NW and N after 06Z as a cold front moves from west to east
overnight.

Outlook...Non-VFR in scattered showers and thunderstorms that
move west to east across the area on Tuesday.

&&

.MARINE...
Winds on the lake will be gradually diminishing today through
Tuesday morning as the low pressure system that affected the area
yesterday continues to move northeast of  the area. Another weak
wave of low pressure will move through the region today.  There is
the possibility with the showers and thunderstorms today through
Tuesday morning for waterspouts and cooler air over the lake
increases instability.  Winds will be diminishing to light and
variable through the day Wednesday into Wednesday night. This
overall trend will continue into Friday.

&&

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

&&

$$
SYNOPSIS...MM
NEAR TERM...Greenawalt/MM
SHORT TERM...Lombardy
LONG TERM...Lombardy
AVIATION...MM
MARINE...Lombardy