-- Discussion containing changed information from previous version are highlighted. --
539
FXUS61 KCLE 141316
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
916 AM EDT Tue May 14 2024

.SYNOPSIS...
A near stationary boundary will linger across northwest Ohio
today before shifting east as a cold front late this evening
into tonight and then stalling again across central Ohio for
Wednesday as a low pressure system moves east across the Ohio
River Valley. High pressure returns on Thursday before a warm
front lifts north on Friday followed by a cold front Friday
night into Saturday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
-- Changed Discussion --
9:15 AM Update...
Biggest change with this update was to lower PoPs for this
evening through tonight, as best chance of rain remains to the
south and it looks to remain fairly scattered for our forecast
area.

Previous Discussion...
Currently, a quasi-stationary boundary associated with a low
pressure system near James Bay lingers to the northwest of the
area as another low pressure system over the central US
continues to develop. The associated upper level trough is
meandering east to eventually move across the Ohio River Valley
tonight, but with the continued slowing of this system in
models, have again delayed the chance of PoPs until late this
afternoon into the evening. Although moisture content will
continue to increase in the meantime, there is very little, if
any, mesoscale or synoptic forcing to allow for any widespread
development. Opted to keep chance PoPs this afternoon,
especially across the southern counties as marginal diurnal
instability may be enough to result in isolated showers. As the
overall system becomes more progressive late this afternoon into
the overnight hours, the low level and synoptic forcing becomes
better with an area of vorticity tracking east with weak
isentropic lifting. The best lift will be closer to the center
of the low (or across the southern counties of the CWA) which is
where there is highest confidence of showers tonight. Will have
to continue to monitor the progression of this system to see if
it slows anymore and possibly delays onset even later.

On Wednesday, the center of the low begins to shift closer to
the Mid-Atlantic Coast allowing for showers to gradually
diminish from west to east. Some hi-res models have suggested a
period on Wednesday afternoon with a notable increase in
instability across the eastern counties and suggest an
environment capable of a line of showers and thunderstorms to
move from near I71 east. Severe weather is not expected at this
time, but there remains quite a bit of uncertainty in this
forecast with how slow the system is moving.

Highs through the period will climb into the upper 60s to low
70s with overnight lows remaining mild and only dropping into
the mid to upper 50s.
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&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A weakening cold front should be south of the region by late
Wednesday evening with showers and thunderstorms shifting southward
with the boundary. A ridge of high pressure then pushes southward
into the region from Ontario as an upper level ridge also briefly
builds overhead. This upper level ridge should limit the coverage of
any convection on Thursday. However there may be just enough
convergence along a lake boundary to warrant a low chance mention of
showers or thunderstorms. As a warm front approaches the region from
the southwest Thursday night into Friday expect rain chances to
increase. These showers and thunderstorms should spread southwest to
northeast across the region Friday morning followed by additional
chances along a cold front that sweeps across the area Friday
evening into the overnight.

Highs through the short term period will be in the 70`s at most
locations. Cooler near the lakeshore on Thursday. Lows each night in
the 50`s to lower 60`s.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
Models continue to struggle with the timing of upper level ridging
over the southern Great Lakes over the weekend. The international
models are the most consistent with each other and have leaned that
direction for the forecast. So after some showers across the east on
Saturday it looks like the CWA may be dry until a cold front
approaches on Monday with an increased chance of thunderstorms.
Temperatures will continue to run above seasonal averages with highs
in the 70`s common. Lows mostly in the 50`s to near 60.

&&

.AVIATION /12Z Tuesday THROUGH Saturday/...
Widespread VFR conditions will persist through today and into
the first half of tonight as a quasi stationary boundary
meanders east into the area. The overall set up has resulted in
quite a bit of uncertainty as a low pressure and associated
upper level trough are expected to move east across the Ohio
River Valley and ultimately impact the progression of this front
to the north of it. Models are in agreement that once the system
becomes more progressive later today, better overall forcing for
showers will move over the area, although they will likely
remain scattered in nature. Due to this high uncertainty in the
timing and placement of showers, opted to maintain VCSH longer
than normal to account for the lack of confidence. The best
chance of thunder will be late afternoon into the early evening,
but again confidence in thunder development is low with the lack
of instability expected so handled that with VCTS. After
midnight tonight, showers should become more widespread and
ceilings will gradually begin to lower to MVFR for most
terminals from southwest to northeast. The only terminals opted
to drop to IFR with this update was KMFD, but will continue to
monitor in the coming hours for further expansion of IFR
conditions.

Southwest winds of 5-10 knots will persist through this
afternoon before gradually shifting to become east-northeast
tonight. Overnight winds will be light and variable.

Outlook...Non-VFR possible in showers and thunderstorms tonight
through Wednesday and again on Friday through Saturday.

&&

.MARINE...
Southerly winds of 5 to 10 knots are expected through early
afternoon but are expected to shift around to the north as a
weakening cold drifts southward across the lake through the night.
These northerly winds may increase to 10 -20 knots which will build
waves to 2 to 4 feet. THe stronger winds appear to be focuses from
Willowick to the Toledo Harbor. This will be the region to monitor
for a short lived small craft advisory late tonight into Wednesday
morning. High pressure then ridges southward  across the lake into
Thursday evening with a continue northeast wind. This may end up
producing choppy conditions from Fairport to The Islands. Winds
swing around to the south on Friday as a warm front moves across the
region. Low pressure moves eastward across the southern Great Lakes
by Friday night with a weakening cold front crossing the lake.

&&

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

&&

$$

SYNOPSIS...Campbell
NEAR TERM...Campbell/Saunders
SHORT TERM...MM
LONG TERM...MM
AVIATION...Campbell
MARINE...MM