518
FXUS61 KCLE 141328
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
928 AM EDT Wed Aug 14 2024

.SYNOPSIS...
High pressure will remain over the southern Great Lakes today
before gradually moving east tonight and Thursday to allow low
pressure to move into the Great Lakes by Friday. This low will
lift a warm front across the region Thursday night and Friday
followed by a cold front Saturday. The low will continue to
meander across the Great Lakes through Sunday.

&&

.NEAR TERM /THROUGH THURSDAY/...
9:30 AM Update...
Slight adjustments were made to temperatures to reflect slightly
warmer conditions being observed, but aside from that there were
no other changes needed with this update.

6:30 AM Update...

The forecast remains on track this morning with no changes
needed.

Original Discussion...

Very quiet weather will continue through the near term as a
large area of strong surface high pressure remains in control.

Skies are clear early this morning with water vapor loops
showing abundant amounts of dry air across the region owing to
the surface high and broad mid/upper troughing across the Great
Lakes and Northeast U.S. This pattern will move very little
through the day today as the surface high remains centered over
southern Ontario, so expect mostly sunny skies and pleasant
temperatures and humidity levels under light N to NE winds. By
tonight and Thursday, the mid/upper trough axis will slowly
shift into New England with the surface high drifting east to be
elongated from the eastern Great Lakes to the Mid Atlantic by
late Thursday. This is in response to a mid/upper shortwave
trough crossing the northern and central Plains and closing off
as it becomes stacked with the associated surface low by the
time is reaches the Upper Midwest late Thursday. Clouds will
increase from west to east Thursday afternoon as warm/moist
advection and isentropic ascent develops in the mid-levels
ahead of the warm front. This could support a few showers in NW
Ohio Thursday evening, but low-level moisture will be slow to
increase given the very dry air at the onset (dew points mostly
stay in the 50s Thursday), so most areas will stay dry until
Thursday night.

Highs today will range from the upper 70s/low 80s in NE Ohio and
NW PA to the low 80s in NW and north central Ohio, warming into
the low/mid 80s areawide Thursday. Parts of NE Ohio could see
upper 80s Thursday given more sunshine expected, but again, dew
points will remain tolerable. Lows tonight will fall into the
upper 50s/low 60s, with some mid 50s in interior NW PA.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
The quiet weather pattern will come to an end Thursday night with
unsettled weather continuing into the weekend as a low pressure
system deepens over the Upper Midwest/northern Great Lakes and
meanders east through the long term period. The low will lift a warm
front northeast towards the CWA Thursday night into Friday with a
cold front slowly crossing the area Friday night into Saturday.
Precipitation chances increase from the west ahead of the warm front
Thursday night into Friday with widespread showers and expected
during the day Friday.

The air mass will be quite humid with dew points climbing into the
upper 60s to lower 70s and PWAT values approaching 1.5 to 2 inches
within the warm sector Friday afternoon and evening. Storm motion
will likely be progressive, but moist antecedent conditions in
conjunction with the potential for heavy rainfall rates will result
in a flooding risk areawide. A Marginal Risk for excessive rainfall
(issued by WPC) remains in place early Friday morning (prior to 12Z)
through Friday.

There`s less confidence in the potential for strong to severe
weather Friday. There`s still a bit of uncertainty in the timing of
precipitation early Friday and placement of the warm front during
peak diurnal heating Friday, as well as timing for the best upper
level forcing. There will likely be widespread showers and
thunderstorms Friday morning which could stabilize the atmosphere
and prevent stronger storms from developing Friday afternoon and
evening. If the atmosphere does manage to recover/destabilize, there
could be enough moisture/buoyancy and shear for isolated strong to
severe thunderstorms with damaging wind gusts and hail being the
primary threats.

Showers and thunderstorms will progress east into NE OH and NW PA
Friday night into Saturday as the system`s upper low/trough drift
into the region and the surface cold front sweeps across the CWA.
There should be a brief period of lower precipitation chances behind
the front with only a chance (30-50%) of showers across NE OH and NW
PA Saturday night.

Highs will be in the upper 70s to mid 80s Friday before temps cool a
few degrees for the daytime hours Saturday. Overnight lows will be
in the 60s each night.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
Weakening surface low with a trough aloft will crawl east across the
eastern Great Lakes for the majority of the long term period,
allowing several shortwaves to pivot across the CWA Sunday through
early next week. Scattered and periodic shower and afternoon
thunderstorm chances continue during this time with the highest PoPs
confined to peak diurnal heating. 850mb moisture may begin to
dwindle Monday into Tuesday, so generally expect a downward trend in
precipitation coverage and chances as the period progresses,
especially in NW OH where the forecast may end up being dry Monday
and Tuesday. Temperatures will be several degrees below normal in NE
OH/NW PA, although locations in NW OH may experience warmer (but
still slightly below normal) temperatures.

&&

.AVIATION /12Z Wednesday THROUGH Sunday/...
VFR is expected to continue through the TAF cycle as high
pressure remains overhead today and gradually shifts east
tonight.

Light and variable winds early this morning will become N to NE
at 3 to 7 knots this afternoon before turning light S to SE
tonight.

Outlook...Periods of isolated to scattered showers/thunderstorms
with non-VFR are possible Thursday afternoon through Sunday.

&&

.MARINE...
Light and variable winds are expected today, although there may be a
period of onshore winds to about 10 knots behind the lake breeze
this afternoon. Southeast winds under 10 knots develop tonight into
Thursday before winds gradually increase to 10 to 20 knots ahead of
an approaching warm front late Thursday into Friday. Southwest winds
10 to 20 knots are anticipated Friday night through Saturday which
may require marine/beach hazard headlines if forecast winds and
waves trend higher. Winds shift to the northwest behind a cold front
and diminish (slightly) to 10 to 15 knots Saturday night and
Sunday.

&&

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

&&

$$

SYNOPSIS...Garuckas
NEAR TERM...Campbell/Garuckas
SHORT TERM...Maines
LONG TERM...Maines
AVIATION...Garuckas
MARINE...Maines