175
FXUS61 KCLE 171802
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
202 PM EDT Wed Jul 17 2024

.SYNOPSIS...
A weak cold front drifts southeastward across the area today.
Behind the front, high pressure builds into the Great Lakes
region by Thursday, lingering overhead through the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
2:00 PM EDT Update...
Most of the forecast remains valid per latest trends in obs and
model guidance. A surface cold front, augmented by convective
outflow extends from near Youngstown to near Columbus and
continues to move SE`ward. This front is expected to exit the
rest of our CWA by this late afternoon. Filtered
sunshine/daytime heating have led to weak to moderate
destabilization of the warm/moist sector boundary layer.
Isolated to scattered showers/thunderstorms will accompany the
surface portion of the front and roughly 925-850 mb portion of
the front, along which moist isentropic ascent will continue to
release weak to moderate and elevated instability. Given the
projected evolution of the front at the surface and aloft, these
showers/storms are expected to exit our area by this early
evening. Made minor adjustments to POP/QPF/sensible WX grids
through this early evening to account for latest trends in obs
and model guidance. Please see discussion below for further
details.

Previous Discussion...
Isolated to scattered rain showers are observed on radar, a few
moving into the I-75 corridor and then more around the Greater
Cleveland area. The showers in the Cleveland area have developed
along the outflow boundary of a storm that died over Lake Erie.
The true cold front looks to be located across lower Michigan
and just on the other side of Lake Erie. Should continue to see
isolated to scattered coverage of showers across the area
through much of the morning. It`s possible there is an isolated
thunderstorm but it`s unlikely. An uptick in coverage is
expected early this afternoon, with scattered showers and
storms, especially east of I-71.

The cold front should cross the region by 00Z this evening with
a cooler airmass advecting in. The main upper-level trough
builds in with northwest flow advecting in cold air aloft, cold
enough for very minor lake-induced light rain showers and mostly
cloudy skies downwind of Lake Erie mainly in Northeast Ohio late
tonight and during the day Thursday. The colder airmass will
result in highs down into the low to mid 70s (about 6-12 degrees
below normal).

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
A refreshing period of mid-summer weather is in store with high
pressure on the backside of an eastern Canada/New England trough in
control of this portion of the forecast. Expect mainly clear/sunny
skies with no rain chances and light winds. Highs will range from
the mid to upper 70s in PA to the upper 70s to near 80 on Friday,
warming into the low to mid 80s Saturday. Overnight lows will be on
the cool side of average, especially Thursday and Friday nights when
most areas away from the lake and the denser urban area near
Cleveland will get into the 50s. Can`t rule out a few rural
locations in northeast OH and northwest PA threatening the upper
40s, especially Friday night. Lows begin trending slightly milder
Saturday night but still will range from the mid 50s to mid 60s.
Went a bit cooler than blended model guidance for lows away from the
lake and east of ~I-71 Thursday, Friday, and Saturday nights.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
Troughing over eastern Canada and New England will slowly lift out
this period as a modest trough digs over the central U.S., resulting
in gradual moisture return. Still expecting dry weather through
Sunday night. Monday will be mainly dry but clouds will likely begin
increasing, with a few afternoon showers or storms not ruled out
especially across our western and southern counties. By later Monday
night and Tuesday more solid chance POPs (30-50%) begin returning to
the forecast. While there aren`t any big systems to key on, the
global models and ensembles generally suggest we`ll get into a
relatively unsettled south-southwest flow with gradually increasing
moisture and occasional small shortwaves moving through. This should
lead to at least occasional potential for scattered showers and
storms returning to the forecast by Tuesday, though the pattern
doesn`t look too concerning for a severe wx or heavy rain concern at
this distance. Highs will generally be in the low-mid 80s with lows
in the 60s for this period with gradually increasing humidity.

&&

.AVIATION /18Z Wednesday THROUGH Monday/...
A cold front extends from roughly KYNG to KCMH. The front
continues moving southeastward and is expected to exit our
region by 20Z/Wed. A ridge builds behind the front and from the
north-central U.S. Isolated to scattered showers/thunderstorms
are expected along and near the front, especially across the
southern-half of our region. Conditions continue to vary between
VFR and MVFR, with brief windows of IFR possible in moderate to
heavy rainfall. Showers/thunderstorms are expected to end from
northwest to southeast through this early evening.

Regional surface winds are expected to veer from westerly to
northwesterly through the TAF period and range from around 5 to
10 knots. A brief/slight increase in wind speeds is possible as
the cold front passes. Low/mid-level ceilings are expected to
scatter-out from northwest to southeast through this early
evening. However, scattered to broken lake-effect clouds with
bases near 3kft AGL are expected over and generally southeast of
Lake Erie late this evening through the mid-morning hours of
Thursday. Lake-effect clouds may produce very light rain.

Outlook...VFR expected Thursday afternoon through Monday.

&&

.MARINE...
A cold front is crossing the lake early this morning and will bring
winds around to a north-northwesterly direction into the day today.
A secondary trough axis will cross the lake from west to east this
evening, shifting winds to a more northerly direction. A third and
final trough looks to swing across the lake Thursday afternoon,
shifting winds to a north-northeast direction. Winds will mainly be
in the 5 to 15 knot range through Thursday evening, though a brief
push to near or slightly greater than 15 knots is likely behind the
trough passage this evening into tonight and perhaps again late
Thursday afternoon. Waves will generally range from 1 to 3 feet with
the modest onshore flow through Thursday evening, though if we do
see a couple of periods of winds slightly greater than 15 knots we
could see some brief 2-4 footers close to the southern shoreline
between the Islands and Conneaut, OH. Overall we look to remain
below Small Craft Advisory criteria though conditions may be rough
enough to make recreational boating less than pleasant and generate
a moderate risk for rip currents along the Ohio shoreline east of
the Islands.

Generally tranquil marine conditions are expected later Thursday
night through early next week with high pressure in control through
the weekend and then no major systems in store early next week. In
terms of convective hazards, the risk for thunderstorms over the
lake is minimal for the next several days with low potential
potentially returning by Monday or more likely Tuesday next week. It
will become marginally unstable over the lake late tonight through
Thursday morning as cooler than average air moves over the warm mid-
July waters. The amount and depth of instability appears marginal
for waterspouts, and while we can see them without a land breeze in
these shorter fetch set-ups, the lack of a land breeze is another
strike against the potential. Ultimately, refrained from a forecast
or HWO mention as confidence is low given the very marginal
setup.

&&

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

&&

$$

SYNOPSIS...Saunders
NEAR TERM...Jaszka/Saunders
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Leonard
MARINE...Sullivan