851
FXUS61 KCLE 051754
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
154 PM EDT Fri Jul 5 2024

.SYNOPSIS...
Low pressure entering the Great Lakes region will extend a cold
front across the area tonight. The low will depart northeast
into eastern Canada for Saturday and high pressure will enter
behind the system for Saturday night. High pressure will remain
influential across the region through Monday.

&&

.NEAR TERM /THROUGH SATURDAY/...
130 PM...
Widespread light rain continues to spread northeast across the
area early this afternoon, associated with the remnants of an
upstream convective complex overnight. For the most part, it
appears the thunderstorm threat is very limited through the rest
of today with the exception of far NE OH and NW PA where some
more robust cu ahead of the rain could develop into an isolated
thunderstorm or two, particularly near the lake breeze. Starting
to see some redevelopment along the cold front across portions
of IN, although instability will be waning as the front reaches
our area near sunset.

Previous Discussion...
The forecast for today and tonight is a fairly low confidence
convective forecast with the overall trend being a lower chance
for overall shower and storm coverage and, in turn, a fairly
minor threat for strong to severe storms.

Clouds and fog remain across the region this morning in the
wake of generally widespread rain on Thursday and Thursday
night. Some clearing in Northwest Ohio has allowed temperatures
to fall a bit from the rest of the region into the low-to-mid
60s. Across the area, dew points remain high in the mid-to-upper
60s, except in cooler Northwest Ohio. Looking elsewhere, a line
of storms near the cold front over northern Illinois and
southern Wisconsin will curl up into Michigan. South of there, a
storm complex marches across eastern Missouri into southern
Illinois. This feature should continue east for today, generally
along and south of the Ohio River into the central/southern
Appalachians. This complex will be key for our area today as the
convective debris clouds advecting northeast toward the area
will limit temperatures and the system could rob the area of
just enough moisture to keep things more tame. By mid-to-late
morning, expecting mid-level clouds to be the main feature in
the forecast area. Some drier air will advect from the northeast
and dew points could actually drop into the mid 60s. The cold
front will be near the Ohio/Indiana border by mid-afternoon and
the question will be how much will the air mass destabilize
ahead of this feature. If temperatures are sub-85 F and dew
points are sub-70 F, it is going to be fairly difficult to get
good storm coverage going well ahead of the front and there
could just be some storms immediately with the front. Therefore,
have largely capped PoPs at a 50/50 chance but have lowered
some areas to just 30 or 40% at best later today. With the area
in a favorable location of the upper level jets, there is ample
wind shear for storms to organize, if they can get going, and
there would be a damaging wind threat. The Day 1 Marginal from
SPC remains for the the entire area. The overall window for
storms would start in Northwest Ohio around 2 PM and exit east
of the forecast area around Midnight with the cold front.
Clearing conditions will enter behind the front tonight and
temperatures will cool again into the 60s.

Surface low pressure remains near the forecast area in southern
Ontario on Saturday morning with its supporting upper trough
over the Great Lakes region. The surface cold front will be well
east of the area by daybreak on Saturday and drier air will be
entering the region with dew points trending down toward the
lower 60s. While the air mass is a touch drier than
today/tonight, the lift across the region should be enough to
generate some isolated shower activity and have some 20 PoPs for
much of northern Ohio and NW PA. Temperatures will be cooler
than normal near 80 degrees.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
Broad mid/upper troughing will stretch from the northern Rockies
through the northern and central Great Lakes this weekend through
early next week while an extension of the Bermuda ridge extends into
the SE CONUS and Mid Atlantic region. This will keep seasonably warm
and humid conditions in place, but the worst of the summer heat will
stay well to the south. Weak surface ridging centered over the
central and southern Great Lakes Saturday night and Sunday will
shift into the eastern Great Lakes Monday as a shortwave deepens the
broad mid/upper troughing over the northern Plains. This will allow
temperatures to warm several degrees Monday compared to Sunday as
return southerly flow sets up, but the influence of the gradually
departing surface ridging will keep conditions dry from Saturday
night all the way through Monday. By Monday night, chances for
showers and thunderstorms will gradually increase from west to east
as the aforementioned shortwave progresses across the Midwest and
the associated surface low lifts into the western Great Lakes. Most
of the precip will hold off until the trailing cold front arrives
Tuesday, but with moist SW flow deepening ahead of the system, there
will be at least spotty shower and thunderstorm activity in NW and
north central Ohio Monday night, so chance PoPs look reasonable.

Highs in the low/mid 80s Sunday will warm into the upper 80s/low 90s
Monday. Lows Saturday night and Sunday night will range from the
low/mid 60s, with upper 60s/low 70s Monday night.

&&

.LONG TERM /TUESDAY THROUGH THURSDAY/...
Tuesday will be the best chance for rainfall over the next week as
the aforementioned mid/upper shortwave progresses through the Great
Lakes, with the surface low reaching near Quebec by Tuesday night.
This will drag the cold front across the region during the day
Tuesday. Timing will likely change slightly between now and then,
but synoptic forcing from the right entrance of a 70-90 knot H3 jet
streak combined with daytime heating should generate widespread
showers and thunderstorms ahead of the front, so kept likely PoPs
from the model blend. Too early to pinpoint any severe weather
threat, but given the forcing and jet dynamics, there could be
strong to severe storms and locally heavy rainfall depending on
timing of the front and the amount of instability. This will be
monitored as we get closer.

Longwave mid/upper troughing will deepen across the Great Lakes and
NE CONUS in the wake of the front Tuesday night through Thursday.
This will support cooler, less humid conditions along with mainly
dry weather, although isolated showers and thunderstorms are
possible in the afternoons in response to daytime heating beneath
cooler air aloft. Highs in the mid/upper 80s Tuesday will cool into
the upper 70s to mid 80s Wednesday and Thursday.

&&

.AVIATION /18Z Friday THROUGH Wednesday/...
VFR across the TAF sites early this afternoon with primarily VFR
to persist through the TAF period. In this update, replaced all
mention of vcts with vcsh as the thunderstorm threat continues
to decrease. Much of the current radar returns are relatively
light and are not posing any impact to vsbys. There could be
some redevelopment behind this cloud/rain shield later this
afternoon into the early evening, though confidence is low.
There could be some isolated non-VFR conditions associated with
low cigs and/or vsbys from patchy fog tonight, particularly
inland, though confidence was too low to include in this
update.

Winds are generally out of the south to southwest early this
afternoon, 5 to 10 knots, with the exception of CLE/ERI where a
lake breeze has shifted winds out of the northwest, 5 to 10
knots. South to southwest winds will gradually favor a more
southwest to west direction through tonight into Saturday,
increasing to 10 to 15 knots with gusts around 20 knots by early
Saturday afternoon.

Outlook...Non-VFR possible in showers and thunderstorms Tuesday
into Tuesday night.

&&

.MARINE...
Quiet conditions are expected on the lake through the next 5 days
with a weak pressure gradient keeping winds fairly light, resulting
in waves staying below 2 feet most days. Light and variable winds
today will turn WSW and increase to 10-15 knots tonight and
Saturday. This will build wave heights to 2 to 3 feet in the central
and eastern basins, which will be the highest waves of the forecast
period. Winds turn W and decrease to 5-10 knots Saturday night
before becoming N at 5-10 knots late Sunday and E Sunday night, then
swinging around to SE Monday with 5-10 knot speeds continuing. S to
SW winds increasing to 10-15 knots are expected Monday night and
Tuesday ahead of a cold front.

&&

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

&&

$$

SYNOPSIS...Sefcovic
NEAR TERM...Kahn/Sefcovic
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...Kahn
MARINE...Garuckas