358
FXUS61 KCLE 201756
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
156 PM EDT Thu Jun 20 2024

.SYNOPSIS...
An upper ridge over the eastern United States will retrograde
west through the end of the week. A low pressure system will
develop over the upper Midwest on Saturday and move through the
Great Lakes on Sunday, extending a cold front across the area.

&&

.NEAR TERM /THROUGH FRIDAY/...
9:50 AM Update...
Forecast remains on track this morning. Showers and
thunderstorms will once again develop this afternoon and evening
under a moist and unstable airmass characterized by dew points
in the upper 60s to lower 70s. Model soundings indicate the
potential for some strong to severe storms with DCAPE values in
the 1000-1200 J/kg range signaling the potential for damaging
wind gusts once again this afternoon and evening. Will continue
to monitor trends with latest hi-res guidance to better
understand timing and extent of any convection that arrives
later today. For now, the Storm Prediction Center has placed a
Marginal Risk (Level 1/5) for severe storms along much of the
Lake Erie lakeshore.

Previous Discussion...
An upper level high south and east of the forecast area will
continue to allow for similar weather conditions to the past
several days: above normal temperatures with hazardous heat
impacts and scattered showers and storms with some strong to
severe potential. Several days of repeated rounds of showers and
storms has allowed for plenty of clouds rolling throughout the
region which have helped keep overnight temperatures elevated,
but also have allowed each day start a bit slower with slightly
inhibited insolation keeping the temperature trends down a bit
before eventually reaching the 90s across the area. Will keep
this pattern going for the near term forecast with 90s achieved
on Thursday and Friday and dew points in the upper 60s to lower
70s allowing for heat index values near 100.

The best shower and storm chances appear to be in Northwest Ohio
and Northwest Pennsylvania this afternoon. For Northwest Ohio,
the best area of deep moist convergence will be into the I-75
corridor and this area has the best chance at meeting convective
temperatures, so will have up to a 50/50 PoP in this region. For
NW PA, there is a boundary from convection this morning that
will lace from western NY into interior NE OH. This could be a
source region for storms, especially if there is any form of a
lake breeze to enhance this area. The rest of northern Ohio is a
bit of a no man`s land for shower and storm development and it
would be impossible to get convection in this area, but the
chances are lower and are reflected with a PoP closer to 30%.
For tonight, the loss of diurnal heating should stabilize things
and keep rain chances very low and most folks should stay dry.
For Friday, it is tough to be too specific with rain chances but
the best region could end up being interior NE OH, depending on
how boundaries set up after today`s showers and storms. Any
storm could reach strong or severe limits given the instability
of this abnormally warm air mass - Wind would be the most common
threat.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
Have extended the Heat Advisory an additional day through Saturday
as temperatures rebound back into the mid to upper 90s ahead of an
approaching low pressure system across the Upper Great lakes. Mainly
isolated showers and thunderstorms will be possible once again
Saturday afternoon, although could see more "scattered" coverage
across the eastern half of the area. Modest SBCAPE of 1500 to 2000
J/kg will be present in addition to large theta-e differences. Will
be dealing with the potential for isolated downburst winds once
again with any stronger storms.

The better potential for more organized strong thunderstorms will
arrive on Sunday as an upper-level low moves east across the Upper
Great Lakes, extending a surface cold front through the area. The
better organized thunderstorm potential appears to be associated
just ahead of the front Sunday afternoon, on the tail of an exiting
mid-level jet, characterized by modest southwesterly flow of 30 to 35
knots. Damaging wind gusts will be the primary threat from any
stronger storms, although could see a low-end tornado risk as well
with 0-1 SRH around 100 m2/s2.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
Drier and more seasonable weather will arrive on Monday behind the
cold front, with temperatures in the low to mid-80s. Unfortunately,
the respite from the heat appears brief as another upper-level ridge
begins to build across the Central CONUS. Above-normal temperatures
will return on Tuesday with highs in the upper 80s to lower 90s,
albeit without the oppressive humidity. By Wednesday, models are
beginning to show the evolution of an upper-level trough traversing
east through the Great Lakes, extending a cold front south across
the area. Thunderstorms do appear likely at some point late Tuesday
night through Wednesday night, although confidence remains low on
timing and strength of the trough.

Behind the front, high pressure will build across the Great Lakes,
ushering in drier and more seasonable weather once again into the
area.

&&

.AVIATION /18Z Thursday THROUGH Tuesday/...
Scattered pop up thunderstorms are beginning to develop near the
lakeshore and across Northwest Ohio this afternoon. Highest
confidence in thunderstorms impacting terminals will be along
the lakeshore at TOL/CLE but can`t be ruled out to approach
FDY/MFD this afternoon. As will the last few days, thunderstorms
will diminish as we lose daytime heating this evening.

Light winds under 10 knots remain southerly this afternoon and
become light and variable overnight tonight. Can`t rule out
patchy fog developing again tonight across eastern terminals.
By Friday morning, winds turn northwesterly while remaining
below 10 knots.

Outlook...Isolated to scattered thunderstorms and non-VFR
conditions are possible again Friday afternoon. More organized
thunderstorms with non-VFR conditions possible Sunday afternoon.

&&

.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 through Sunday as daily isolated to scattered
thunderstorms could produce strong wind gusts. Thunderstorms may be
more widespread on Sunday ahead of an approaching cold front.

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 Thursday, June 19 to Sunday,
June 23 are listed below for our official climate sites.

Date   Toledo     Mansfield   Cleveland   Akron     Youngstown   Erie
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)
06-22  99(1988)    95(1988)   98(1988)    97(1988)   97(1933)    94(1988)
06-23  96(1911)    91(1964)   94(1948)    94(1923)   94(1943)    92(1964)

&&

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

&&

$$

SYNOPSIS...Sefcovic
NEAR TERM...Iverson/Sefcovic
SHORT TERM...Kahn
LONG TERM...Kahn
AVIATION...Iverson
MARINE...Kahn
CLIMATE...