475
FXUS61 KCLE 131859
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
259 PM EDT Thu Jun 13 2024

.SYNOPSIS...
A ridge exits generally eastward before a cold front sweeps
southeastward through our region during the predawn through
mid-morning hours of Friday. Behind the front, a ridge builds
from the Upper Midwest through Saturday before it begins to
exit slowly toward New England on Sunday.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
Aloft, W`erly flow and embedded shortwave disturbances affect
our region through Friday afternoon. Flow veers to NW`erly
Friday evening with the passage of a stronger shortwave
disturbance and as a subsequent ridge builds from the central
U.S. and vicinity. At the surface, a ridge exits generally
E`ward before a cold front sweeps generally SE`ward through our
region during the predawn through mid-morning hours of Friday.
Behind the front, a ridge builds from the Upper Midwest and
vicinity through daybreak Saturday. Tonight`s lows are expected
to reach the 60`s around daybreak Friday. On Friday, low-level
CAA behind the front will contribute to cooler late afternoon
highs. Readings are expected to reach the lower to mid 70`s in
NW PA and mainly the mid 70`s to mid 80`s in northern OH. The
warmest highs are expected in our I-75 corridor counties. Friday
night`s lows are forecast to reach mainly the 50`s around
daybreak as continued low-level cold/dry air advection and
considerable clearing accompanying the building ridge contribute
to efficient radiational cooling.

Primarily fair weather is expected during the near-term period
due to stabilizing subsidence accompanying the pre-front and
post-front ridging. However, upstream showers/thunderstorms
initiating along a pre-front surface trough may overspread our
I-75 corridor counties, Lake Erie, and vicinity this evening,
especially after sunset. Additional isolated showers and
thunderstorms are expected along the surface cold front and
along the upper-reaches of the front. The frontal convection
should exit gradually E`ward or SE`ward between roughly daybreak
and early evening on Friday. However, a few showers/thunderstorms
associated with low-level convergence/moist ascent along the
prominent shortwave trough`s attendant surface trough axis may
enter NW OH from the northwest Friday evening before dissipating
around sunset as the boundary layer stabilizes via nocturnal
cooling. Showers/thunderstorms are expected to be organized
given the expectation of weak to moderate instability, including
elevated CAPE, amidst moderate to strong deep layer bulk shear.
Weak mid-level lapse rates and development/growth of DCIN
associated with nocturnal cooling-related boundary layer
stabilization should contribute to very limited potential for
severe thunderstorms through Friday morning. However, during
Friday afternoon through early evening, a few thunderstorms may
become severe with damaging convective wind gusts, especially
roughly along/south of the U.S. 30 corridor, where greater low-
level moisture should yield greater MUCAPE and sufficient
diurnal convective mixing of the boundary layer should yield
moderate to strong DCAPE and weak or no DCIN amidst steep low-level
lapse rates.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A dominant upper level ridge will begin to push east across the
region on Saturday. This will produce a large area of subsidence
over the region, allowing for dry conditions to persist. The bigger
story over the weekend and into next week will be the rising
temperatures. Behind the departing cold front from Friday night,
temperatures on Saturday will only climb into the mid 70s along and
east of I71 and possible touch 80 west of I71. With dewpoints
lingering in the mid 40s to low 50s, the weather will feel pleasant.
Saturday night will cool into the mid to upper 50s. On Sunday, as
WAA increasing, temperatures will climb into the mid 80s to low 90s,
but again with dewpoints in the low 50s the apparent temperature
will feel close to the actual temperature. Overnight lows will be
warmer Sunday night, only falling into the mid to upper 60s,
possibly not dropping below 70 in some locations.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
On Monday, a shortwave trough is expected to move along the northern
edge of the ridge becoming established over the eastern US. With
south-southwesterly flow expected to establish both WAA and
increased moisture advection across the area, cannot rule out a few
afternoon thunderstorms developing when instability is at its
greatest, especially across the northern counties. Confidence in
this is low, especially if the vort max shifts further north and
limits upper level support. For the remainder of the period, there
is a non-zero chance of isolated afternoon thunderstorms, but given
the non-favorable synoptic pattern, not expecting anything
widespread.

The biggest story through the long term period will be the rising
temperatures to well above normal for this time of year. Monday
temperatures will start in the low to mid 90s everywhere and will
persist through Thursday. With dewpoints expected to linger in the
60s, possibly reaching into the 70s at times, the conditions outside
will be quite muggy and the apparent temperature values will
approach 100 degrees, especially across western counties. Important
to note that the forecast reflects a bit warmer of a trend than some
long range models to try and account for the very dry antecedent
conditions at the surface and the impacts that will have on overall
temperatures. As a result of these conditions, the NWS HeatRisk tool
has ranked the impact from these temperatures as major to extreme,
noting that people will be affected without effective cooling and/or
adequate hydration and that there will be little relief overnight as
temperatures linger in the 70s. The greatest impacts will be felt in
some health systems, heat-sensitive industries,and infrastructure.
Please remain updated with the latest forecast and prepare for the
hot conditions in advance.

&&

.AVIATION /18Z Thursday THROUGH Tuesday/...
W`erly flow aloft and embedded disturbances affect northern OH
and NW PA through 18Z/Fri. At the surface, a cold front is
poised to sweep SE`ward through our area between ~07Z and
~13Z/Fri. Otherwise ridging affects our region. Widespread low
clouds resulting in VFR/MVFR ceilings are expected along/behind
the surface cold front. Regional surface winds trend SW`erly
around 5 to 15 knots ahead of the front. These winds will gust
up to 15 to 25 knots through ~00Z/Fri. Behind the front, our
regional surface winds will be around 5 to 10 knots, veer to
NW`erly, and eventually veer further toward NE`erly during
Fri afternoon, especially roughly along/west of I-71.

Primarily VFR are expected ahead of the front. However,
isolated pre-front showers/thunderstorms may overspread Lake
Erie, our I-75 corridor counties, and vicinity from the west
this evening. Otherwise, isolated showers/thunderstorms are
expected to accompany the passage of the surface front. Behind
the surface front passage, additional isolated showers/thunderstorms
accompanying the upper-reaches of the front are expected to
begin to exit generally SE`ward after 11Z/Fri. Fair weather is
expected roughly along and northwest of a KFDY to KERI line by
18Z/Fri. Brief MVFR and erratic surface gusts up to 40 knots
may accompany showers/storms, especially this evening.

Outlook...Non-VFR possible with isolated showers/thunderstorms
through early Friday evening. Otherwise odds favor VFR through
this Tuesday.

&&

.MARINE...
Low pressure currently centered over Lake Superior will drag a cold
front east across Lake Erie tonight. Showers and thunderstorms are
possible along and ahead of the boundary. In addition, winds ahead
of the cold front will remain from the southwest at 10-15 knots
before shifting to north-northwest flow by Friday morning and
weakening to 5-10 knots. This shift to northerly flow will result in
waves up to 2 feet along the coast of Lake Erie. As a dominant upper
level ridge and associated high pressure shift over the region,
winds will shift out of the east-northeast at 5-10 knots for
Saturday and Sunday. Offshore flow of 5-10 knots becomes established
Sunday night and looks to persist for much of next week as the
aforementioned ridge remains in place.

&&

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

&&

$$

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