256
FXUS61 KCLE 191037
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
637 AM EDT Wed Jun 19 2024

.SYNOPSIS...
Upper level ridge providing heat for the area remains in place
through the end of the week with isolated to scattered shower
and storms each day. A weak cold front drops southward into
northern Ohio and northwestern Pennsylvania Thursday lifting
back northward as a warm front Friday.

&&

.NEAR TERM /THROUGH THURSDAY/...
635 AM Update...
Minor temperature edits. No other significant changes. Not as
hot for most today, but dewpoints climb higher.

Previous Discussion...
Dome of high pressure aloft remains anchored over the mid Atlantic
coast, so no major changes to the overall airmass in place. Two
changes to some of the specifics going into today, however. First is
the plume of high level moisture streaming up from the Gulf of
Mexico into the southern Great Lakes. This will result in a decrease
in the insolation factor today, and will knock a couple degrees off
the forecast high temperatures compared to the first two days of the
work week. This could also lead to a slight inhibition of convective
development with a slightly less diurnal heating factor. That said,
with the instability remaining in place, still expecting isolated to
scattered convection today, and will peak during the prime heating
hours of the day despite the cloud cover. The second part of the
forecast that is a bit of a change is that the dewpoints today will
increase and have lower 70s dominating the CWA as opposed to upper
60s dominating. So even though the temperatures may not be quite as
high, heat indices in the upper 90s to 100 will continue with the
higher dewpoints. Will leave the Heat Advisory in place although it
is probably a bit of a more marginal call today. For Thursday, a
weak cold front drops into the area, with perhaps yet a little more
relief to the heat for the far northern zones and could become a
focus for convective initiation.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
The heat wave and headlines will continue through at least Friday
with extensions into Saturday possibly needed in future
updates. Daily afternoon heat indices in the mid to upper 90s to
near 100 will remain likely. Not much relief is expected during the
overnight periods either with low temperatures in the 70s.

Isolated strong thunderstorms are possible in the afternoon
and early evening on Friday as moderate to strong instability
persists across the southern Great Lakes, aided by a stream of steep
mid-level lapse rates and moist low-levels. A very weak cold front
may stall in the vicinity of northern OH which could also be the
basis for convective initiation. Weak shear less than 20 knots is
expected, so anticipate any thunderstorms that do develop will be
poorly organized and generally short-lived. These storms will
primarily carry a damaging wind risk given steep low-level
lapse rates and large theta-e differences. Locally heavy rain is
also possible.

Storm chances appear to be trending downwards for Saturday afternoon
as deeper mixing into mid-level dry air is possible, evident by
dew points dropping into the 60s. However, this would also favor
less cloud cover and thus higher temperatures reaching into the mid
to upper 90s. Future shifts may need to evaluate the Heat Advisory
extension into Saturday.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
The better potential for more organized strong thunderstorms will
arrive on Sunday as a well-defined upper-level low moves east across
the Upper Great Lakes, extending a surface cold front through the
area. Moderate instability appears to remain in place combined with
30 to 35 knots of southwesterly mid-level flow. This system will
bring an end to the extreme heat wave as behind the front, cooler
and more seasonable weather will arrive, with temperatures in
the low to mid-80s on Monday. Anticipate dry weather conditions as a
surface high briefly builds in across the Great Lakes.

However, the respite from the heat appears brief as another upper-
level ridge begins to build across the Central CONUS by Tuesday.
Above-normal temperatures will return on Tuesday with highs in the
upper 80s to lower 90s, albeit without the oppressive humidity.

&&

.AVIATION /12Z Wednesday THROUGH Sunday/...
The TEMPO TSRA groups and timing are on the lower confidence
side as there is not much consensus on initiation timing which
could vary by a few hours for different terminals. AMDs probably
needed to account for this, but expect cumulus congestus and
towering cumulus once again for the whole area today, especially
during peak heating in the afternoon hours. Wind gusts to 30kts
possible in TSRA. Outside of thunderstorms, winds SSW less than
10kts.

Outlook...Primarily VFR expected through Friday. Isolated to
scattered thunderstorms and non-VFR conditions are possible
again Thursday and Friday afternoons.

&&

.MARINE...
A generally quiet marine forecast is in store for Lake Erie as a
large upper-level ridge remains across the Eastern CONUS, resulting
in limited surface flow. Only concern will be in the afternoon and
early evening hours this week as daily isolated to scattered
thunderstorms could produce strong wind gusts.

Will need to monitor wind and wave trends towards the end of the
weekend and into early next week as a cold front moves east across
the area on Sunday. Ahead of the front, southwest winds of 15 to 20
knots are possible, shifting towards the northwest behind the front
on Monday, 10 to 15 knots.

&&

.CLIMATE...
A prolonged stretch of hot weather is expected this week.
Temperatures are forecast to approach or exceed record highs on
several days. The records for Tuesday, June 18 to Friday, June
21 are listed below for our official climate sites.

Date   Toledo     Mansfield   Cleveland   Akron     Youngstown   Erie
06-19  98(1995)    94(1994)   92(1995)    94(1994)   94(1994)    92(1931)
06-20  98(1953)    94(1988)   96(1988)    95(1933)   95(1933)    92(2016)
06-21  100(2022)   96(1988)   95(2022)    97(1933)   98(1933)    95(1933)

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Heat Advisory until 8 PM EDT Friday for OHZ003-006>014-017>023-
     027>033-036>038-047-089.
PA...Heat Advisory until 8 PM EDT Friday for PAZ001>003.
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...26
NEAR TERM...Campbell/26
SHORT TERM...Kahn
LONG TERM...Kahn
AVIATION...26
MARINE...Kahn
CLIMATE...