724
FXUS61 KCLE 030857
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
442 AM EDT Wed Jul 3 2024

.SYNOPSIS...
A ridge continues to exit eastward from our region this morning as a
warm front sweeps northeastward through northern Ohio and northwest
Pennsylvania. A weak cold front is still poised to sweep generally
southeastward through our area this evening through the predawn
hours of Thursday morning. Behind the cold front, a weak ridge
builds from the western Great Lakes through the balance of Thursday
as the aforementioned front settles in vicinity of the upper and
middle portions of the Ohio River.

&&

.NEAR TERM /THROUGH THURSDAY/...
A ridge at the surface and aloft exits E`ward this morning as a
warm front sweeps NE`ward through our CWA and ushers-in a warmer
and more humid air mass originating over the Gulf of Mexico and
southern Gulf Stream. Behind the ridge and warm front, W`erly
flow aloft and embedded shortwave disturbances affect our region
through tonight. A weak cold front is still poised to sweep
generally SE`ward through our region this evening through the
predawn hours of tomorrow morning.

Fair weather is expected to persist through midday today as
the strongest frontogenesis/moist isentropic ascent along the
upper-reaches of the warm front and associated elevated
convection remain north of our CWA. Stronger low-level
warm/moist air advection behind the surface warm front and
daytime heating amidst peeks of sunshine are expected to allow
highs to reach mainly the mid 80`s to lower 90`s late this
afternoon as warm/moist sector boundary layer CAPE grows to weak
to moderate magnitudes amidst moderate effective bulk shear and
PWAT values rise to near 2.0". These projected PWAT values are
near the record-high values for 00Z/July 4th at the four upper-
air stations closest to our CWA. Periods of scattered multicell
showers/thunderstorms with torrential rainfall and frequent
lightning are expected this afternoon through sunset as low-
level convergence/ascent along the cold front and pre-front
surface trough axes accompanying shortwave disturbances
encounter the aforementioned thermodynamic and kinematic
environment. Some thunderstorms are expected to be severe with
damaging convective wind gusts since daytime heating will allow
convective mixing of the boundary layer to yield steep low-level
lapse rates and about 500 to 1000 J/kg of DCAPE. W`erly mean
mid-level flow is expected to have a large component
perpendicular to the cold front and pre-front surface trough
axes. Therefore the potential for training convection appears
limited. However, isolated flash flooding is possible in low-
lying and/or poor drainage areas impacted by multiple rounds of
showers/storms. Severe hail is not expected since melting levels
will easily exceed 10.5 kft AGL in the warm/moist sector.
Tornadoes are not expected due to a lack of significant
strengthening/veering of low-level winds with height.

Shower/thunderstorm coverage along/ahead of the cold front is
expected to become isolated later this evening and especially
after midnight as the warm/moist sector boundary layer
stabilizes slightly via nocturnal cooling. However, boundary
layer CAPE is expected to remain weak to moderate and effective
bulk shear will remain moderate, which will allow convection to
remain organized (i.e. multicellular) and continue to produce
periods of heavy rainfall and frequent lightning. The potential
for severe thunderstorms is expected to end by midnight as
nocturnal cooling causes low-level lapse rates and DCAPE to
weaken, respectively. Lows are expected to reach the upper 60`s
to lower 70`s around daybreak Thursday morning as a surface
ridge associated with a slightly-cooler and less humid air mass
builds from the western Great Lakes, behind the cold front.

On Independence Day, W`erly flow aloft and embedded/subtle
shortwave disturbances continue to affect our region as the
aforementioned cold front settles near the upper and middle
portions of the OH River. Peeks of sunshine and daytime heating
are expected to allow late afternoon highs to reach the upper
70`s to mid 80`s. Sufficient daytime heating of land surrounding
~72F Lake Erie and a weak synoptic MSLP gradient accompanying
the building surface ridge will allow a lake breeze to occur
during the late morning through early evening and penetrate up
to about five miles inland. Thus, the coolest highs on
Independence Day are expected over and within several miles of
Lake Erie. Surface dew points in the 65F to 70F range and
diurnal convective mixing of the boundary layer will yield weak
to moderate boundary layer CAPE and DCAPE, respectively, as
PWAT values remain near the 75th percentile in the "cool" sector
and effective bulk shear remains moderate. This thermodynamic
and kinematic environment is expected to support additional
multicell showers and thunderstorms capable of producing
torrential rainfall, strong convective wind gusts, and frequent
lightning. Odds favor primarily fair weather north of the U.S.
Route 30 corridor as the building ridge is accompanied by
stabilizing subsidence. However, weak low-level convergence/ascent
along the Lake Erie lake breeze front may trigger isolated
showers/storms during the afternoon through early evening.
Roughly along and south of U.S. Route 30, isolated showers
and thunderstorms remain possible, especially during the afternoon
through early evening, due to residual outflow boundaries and the
area`s closer proximity to the aforementioned front. However,
Independence Day is not expected to be a complete washout anywhere
in our CWA.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
With the surface frontal boundary still stalled well south toward
the Ohio River, will continue chipping down PoPs a little bit for
Thursday night with a range of 20% near Lake Erie to 45% near Mount
Vernon. The front will be preventing a better moisture to lift north
and return to the region, which will limit shower/storm coverage. A
mid-level wave moving through the region will be the lifting source
for any convection on Thursday and should allow for some showers and
storms and will not remove PoPs at this time.

The front will be lifted back north as a warm front on Friday, as
low pressure will move through the Great Lakes region on Friday and
Saturday. Have likely PoPs across the entire area at some point on
Friday or Friday evening, as the combination of the warm front,
surface low, and upper trough will allow for good coverage of
showers and storms. There could be some concerns for strong to
severe storms and heavy rain with a flood threat on Friday with good
instability expected across the region, dew points trying to reach
70 degrees, and a 30 kt 850 mb jet ahead of the cold front. There is
a Day 3 Marginal Risk for severe weather for portions of the
forecast area.

The cold front will sweep across the region by Saturday afternoon
and PoPs will be on a downward trend to completely dry for the first
half of the day. Low pressure will be north of the area still on
Saturday and will allow for somewhat breezy southwest winds to
remain in the region. High pressure will build from the southwest by
the end of the period and allow for fully dry and cooling conditions
on Saturday night.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
High pressure across the region on Sunday with an upper ridge
overhead should allow for a dry start to next week. The surface high
will move east and the upper ridge will give away to an upper trough
for Monday into Tuesday and rain chances will start to trickle in
for the first couple of weekdays, as a cold front will approach and
cross the area. Temperatures early next week appear seasonable for
early July with 80s for highs.

&&

.AVIATION /06Z Wednesday THROUGH Sunday/...
A ridge at the surface and aloft exits E`ward through ~14Z/Wed
and is followed by W`erly flow aloft, embedded disturbances, and
surface troughing. A surface warm front continues to sweep
N`ward through our region through ~14Z/Wed. In addition, a weak
cold front is expected to drift ESE`ward into our region after
23Z/Wed and near a KPCW to KFDY line by 06Z/Thurs. SE`erly winds
around 5 to 10 knots veer to S`erly and increase to 10 to 15
knots with the passage of the warm front. The S`erly to SW`erly
winds are expected to gust up to 20 to 25 knots between ~15Z and
~23Z/Wed. The cold front passage will cause SW`erly winds around
5 to 15 knots to veer to W`erly.

Primarily VFR are expected through the TAF period. Periodic
upper-level ceilings early this morning are expected to lower
to mid-level ceilings and then low-level ceilings near 5kft AGL
in a somewhat sporadic fashion from WSW to ENE between ~12Z and
~16Z/Wed. Scattered showers and thunderstorms are expected
along/ahead of the cold front, especially after 19Z/Wed.
Showers/storms are expected to move generally E`ward across our
region. Brief/erratic surface wind gusts up to 30 to 50 knots
and brief MVFR/IFR are expected with showers and especially
storms.

Outlook...Non-VFR expected with periodic/scattered
showers/thunderstorms Wednesday night through Saturday.

&&

.MARINE...
Southerly flow will increase across the lake today as a cold front
approaches the region. Believe winds will stay below 20 kt and will
not issue a Small Craft Advisory this morning, but strong offshore
flow will likely make recreational boating unpleasant for a chunk of
today. The front will cross the lake tonight and light westerly flow
will take over. The front settles along the Ohio River for Thursday
and the lake will be a no man`s land for flow and variable wind
direction will be on the lake for the holiday, but light flow
overall. The front will lift back north as a warm front on Friday
and southeast flow will be favored. A surface low will move north of
the lake Friday night into Saturday and enhanced southwest flow will
develop across the lake and a Small Craft Advisory headline will be
possible. The low will depart the region on Saturday night and high
pressure will build from the southwest, reducing the southwest flow
on the lake through Sunday.

&&

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

&&

$$

SYNOPSIS...Jaszka
NEAR TERM...Jaszka
SHORT TERM...Sefcovic
LONG TERM...Sefcovic
AVIATION...Jaszka
MARINE...Sefcovic