308
FXUS61 KCLE 040609
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
209 AM EDT Sat May 4 2024

.SYNOPSIS...
An active pattern continues as a cold front moves east across
the area tonight. Another warm front will lift north on Saturday
followed by a cold front on Sunday as the parent low moves
northeast into Quebec. High pressure will push in briefly
Monday.

&&

.NEAR TERM /THROUGH TONIGHT/...
10 PM Update
Continued to downtrend pops this evening as shower activity
diminishes across the area. Kept pops in the chance or lower
range with a downtrend from west to east through the overnight.
With diurnal stabilization and recent radar trends, opted to
remove thunder mention from the forecast for the rest of the
night. An isolated rumble isn`t out of the question but
probabilities are too low for forecast mention at this point.
Main forecast challenge overnight will be low end fog potential
across the area. Expecting extensive mid/high cloud cover so
despite moist boundary layer and lighter winds, radiational
cooling should be inadequate for widespread fog development.
Some patches cannot be ruled out, especially where rainfall
persisted this evening, but again, not confident enough for
explicit forecast mention at this time.

Original discussion...An active weather pattern will continue
through the near term period as multiple boundaries enhanced by
upper level shortwaves move across the area. Setting up the big
picture, there is a broad upper level trough across the northern
contiguous US with an associated low pressure at the surface
centered over the north-central US. A cold front associated with
this system will move east across the area tonight, bringing
another chance of precipitation. Much of the support for shower
development is coming from upper level embedded shortwaves which
are advecting vorticity across the area. This support coupled
with an area of low level convergence should allow for more
widespread showers to become established along and east of I71
this evening into the overnight hours. Overall mesoscale
conditions, including instability and shear, remain very minimal
this afternoon so getting any thunder may be hard but cannot
rule out a few rumbles. Primary concern would be heavy rainfall
in the strongest showers which may result in nuisance flooding.

By Saturday morning, a nose of high pressure pushes over the
area and allows for a very brief, although cloudy, period of no
precipitation. By Saturday afternoon, another warm front will
move north across the area, allowing the chance of showers and
isolated thunderstorms to return. These should gradually begin
to taper from west to east early Sunday as another cold front
approaches, but maintained slight chance for this period.

Highs tomorrow will reach into the 70s across western counties,
but will remain in the 60s for far NE OH and NW PA. Overnight
lows both nights will be in the upper 50s to low 60s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A cold front will likely be approaching Toledo early Sunday and will
slowly cross the area from west to east by Sunday evening. A slug of
deeper moisture and associated showers may still be impacting far
eastern OH into northwestern PA early Sunday, though farther west
should start the day fairly dry. Additional showers & thunder are
expected to develop along the cold front by late morning or early
afternoon is it drifts east out of northwestern Ohio and into north
central Ohio and then continue east through the afternoon and early
evening. Overall, Sunday will feature more clouds than sun with
showers and thunder around at times, though a washout type steady
rain is unlikely. Not seeing much of a severe weather threat on
Sunday, as forcing and shear will be weak. Thermodynamics may
support a few stronger storms east/southeast of a Mount Gilead -
Parma - Chardon - Edinboro line during the later afternoon hours,
with small to perhaps near-severe hail and locally strong winds the
main concern if any storms briefly pulse stronger before collapsing
due to the lack of stronger shear. Storm motion won`t be all that
fast so can`t rule out a gully-washer or two, though am not
expecting enough organization for much of a flooding threat either.

High pressure briefly noses in from the north Sunday night into
Monday behind the cold front, which should allow us to dry out. As
the front begins returning as a warm front late Monday into Monday
night rain chances may begin returning from the southwest. Gut
feeling is that Monday and Monday night may end up drier than
currently forecasted, though given enough model spread and a need to
be collaborated, only made modest reductions to the NBM POPs.

Highs on Sunday will hinge on how long we can break into some
sunshine behind showers exiting to the east in the morning and
activity developing and spreading across the area along the cold
front during the midday and afternoon timeframe. For now, generally
have most of the area in the 70s. Highs generally range from the mid
60s along the lake to the low to mid 70s well-inland on Monday. Lows
Sunday and Monday nights will generally settle into the 50s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The long term will begin with a trough over the northern Plains and
a ridge centered over the Southeast, with broad southwest flow in
between. The trough will begin shifting towards the Midwest and
Great Lakes by Friday. A warm front is expected to lift through on
Tuesday, with a cold front expected to cross Thursday into Friday.
There will be relatively higher chances for showers and thunder both
with the warm frontal passage Tuesday into Tuesday evening, and
again Thursday into Friday as the cold approaches and crosses. While
we`ll be in the open warm sector on Wednesday, activity may develop
upstream and spread in later in the day or at night. Severe weather
and flooding potential are uncertain, as we will be on the fringes
of a moist and unstable with enough flow aloft for organized
convection. However, many solutions develop organized clusters of
convection well upstream across the Mississippi and Ohio Valleys
most days, which would tend to track just to our south and also act
to overturn the greater instability before it can advect in. We are
not currently "outlooked" for severe weather by the SPC which seems
reasonable given the uncertainty and potential limiting factors
mentioned above, though experimental machine learning severe weather
guidance from Colorado State University does suggest severe
potential may bleed into our area (with greater risk just to our
southwest) if upstream convection is not too expansive. Temperatures
will lean warmer than normal until the cold front crosses.

&&

.AVIATION /06Z Saturday THROUGH Wednesday/...
A few pockets of light showers are ongoing at the start of the
period. Nearly anywhere could get a light shower overnight but
coverage will be limited and most won`t. Only included a tempo
for a light shower at MFD which seemed most likely over the next
couple hours. Otherwise ceilings are VFR but expect to see some
MVFR cloud fill in through the overnight period. On Saturday
there is a little better forcing to see scattered showers with a
few thunderstorms develop across Central Ohio and spread north
through the afternoon. Coverage will be focused more towards
Northeast Ohio and Northwest Pennsylvania through the evening.
Tried to time some tempos in for showers where appropriate. Did
not include thunderstorms at this time but a few thunderstorms
will be possible and may need to add as confidence increases.
Otherwise ceilings will tend to be MVFR for much of the day with
reduced visibilities in showers and IFR possible in
thunderstorms. Ceilings are expected to lower on Saturday night
as a slow moving trough approaches from the west.

Winds will tend to be 10 knots or less through the period. Light
and variable winds through 14Z will become south to
southeasterly for most inland terminals. Lakeshore areas will
hold onto an east or northeast wind for longer, but also
eventually expected to shift around to the south/southeast. Erie
is the one site that may see gusts to around 20-25 knots
tomorrow afternoon/evening.

Outlook...Non-VFR likely with periodic showers and thunderstorms
through Tuesday.

&&

.MARINE...
No marine headlines are expected for the foreseeable future.
Southeast winds may briefly become gusty in the nearshore waters off
of Pennsylvania late Saturday night into early Sunday morning,
though sustained winds likely remain below Small Craft Advisory
criteria. A cold front will cross on Sunday. A warm front lifts
across the lake Tuesday into Tuesday night, followed by a cold front
next Thursday or Friday. A few thunderstorms are possible over the
lake Saturday afternoon through Sunday afternoon ahead of an
approaching cold front, though greater potential will likely be
inland. Additional thunderstorms are possible at times over the lake
Tuesday through Friday next week.

&&

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

&&

$$

SYNOPSIS...Campbell
NEAR TERM...Campbell/Greenawalt
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...KEC
MARINE...Sullivan