675
FXUS61 KCLE 151952
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
352 PM EDT Wed Jul 15 2026

.WHAT HAS CHANGED...
The potential for thick wildfire smoke continues to increase
tonight and Thursday, and there is growing potential for it to
linger through at least Friday. Chances for showers and
thunderstorms continue to increase late Friday and Saturday, but
Sunday has trended dry.

&&

.KEY MESSAGES...
1) Hot conditions will continue through Saturday, but the
humidity will temporarily drop for Thursday and Friday leading
to lower heat indices in the upper 80s to low 90s.

2) Wildfire smoke to affect the region tonight and Thursday
leading to poor air quality, which could linger through Friday.

3) Periodic showers and thunderstorms are expected Friday
through mid next week. The greatest potential for organized
storms is late Friday and Saturday.

&&

.DISCUSSION...
KEY MESSAGE 1...
The center of the anomalous 600 DAM H5 ridge has shifted to a
position from the corn belt through the Ohio Valley this
afternoon, with satellite and water vapor loops showing a band
of moisture associated with convection dropping southeastward
through the northern and central Great Lakes on the northern
edge of this ridge. This band of clouds and scattered
showers/thunderstorms will continue to sag toward the area this
evening and tonight as a weak cold frontal boundary sags across
Lake Erie and NW PA and eventually through northern Ohio by
Thursday morning. Strong mid-level capping is in place beneath
the ridge this afternoon characterized by 700 mb temps of 12 to
14 C and a defined EML, so despite strong instability (MUCAPE
over 4000 J/Kg on the latest Mesoanalysis), not sure that the
weak approaching front can sufficiently breach the cap to get
any convection into our area. The 12Z runs of the HREF and RRFS
backed off on the thought of isolated convection early tonight,
but given the instability, kept slight chance POPS in the 00
through 06Z timeframe for an isolated cell or two dropping
across the lake.

Otherwise, the main impact of the weak cold frontal passage
tonight will be a 5 to 10 degree drop in dew points. Air
temperatures will remain hot Thursday and Friday (mid 80s to low
90s), but the brief influence of surface high pressure building
into the northern and eastern Great Lakes will advect drier
low-level air into the area, keeping dew points in the upper 50s
to mid 60s. This will limit heat indices to the upper 80s/low
90s Thursday and Friday.

A strong mid/upper shortwave progressing from the northern
Plains into the Great Lakes late Friday and Saturday will lift
the frontal boundary back northward as a warm front, and this
will bring the sticky air (dew points over 70 F) back into the
region for Saturday to go along with one more hot day. More on
that system in key message 3 below.

KEY MESSAGE 2...
The most unique element of this forecast is growing concern for
thick wildfire smoke tonight and Thursday, possibly lingering
through Friday. Wildfires continue to burn in northern Minnesota
and central Ontario Province, and visible satellite loops today
have been showing the smoke plume funneling east/southeast
across the northern and central Great Lakes and New England in
the NW flow on the northern edge of the mid/upper ridge. The
frontal boundary is helping to converge and bring this plume to
the surface, and surface observations and webcams in northern
Lower Michigan have shown very poor visibilities today. As the
frontal boundary sags into the area tonight and Thursday, the
smoke plume is expected to sag in as well. The 12Z HRRR and RRFS
were more aggressive with smoke density and visibilities late
tonight through Thursday night, so smoke coverage has been
increased in the forecast during that time. This may support
visibilities as low as 1 to 3 miles at times, as well as very
poor air quality. People are encouraged to limit time outdoors
Thursday. At least patchy smoke could linger Friday given a
continuation of NW flow aloft, but confidence is lower beyond
the time range of the HRRR and RRFS, so kept it out of the
forecast Friday for now.

KEY MESSAGE 3...
As mentioned above, a strong mid/upper shortwave trough will
progress from the northern Plains through the Great Lakes late
Friday and Saturday. This system will finally shunt the large
mid/upper ridge southwest into the southern Plains and Rockies,
with a strong cold frontal passage Saturday evening or Saturday
night. The old frontal boundary will lift back north as a warm
front Friday night and early Saturday in response to the
approaching shortwave and associated surface low. As this front
lifts back north, a 30+ knot low-level jet and associated strong
theta e advection could trigger an MCS across the central Great
Lakes Friday night. Depending on the evolution and track of
this complex, some showers and thunderstorms could spill into
the region Friday night and early Saturday. The more likely
timeframe for organized convection will be along and ahead of
the cold front Saturday evening. Moderate to strong instability
is expected in the warm sector, and given what looks like a
dynamic shortwave trough for mid summer (moderate to strong mid
level flow), severe weather and heavy rainfall is possible. The
amount of instability will be influenced by how much debris
cloudiness and showers get into the area Saturday morning from
the prior MCS. Given the set up, would anticipate our CWA to be
included in a future severe weather outlook from the SPC for
Saturday.

Canadian high pressure will bring cooler, drier, and less humid
conditions Sunday and Monday, but chances for showers and storms
will return late Monday and Tuesday as another cold front drops
through the area. Mid/upper troughing deepening across the
eastern CONUS through the middle of next week will allow
progressively cooler air to build in, and temperatures will be
below normal for a change.

&&

.AVIATION /18Z Wednesday THROUGH Monday/...
Widespread VFR conditions persist this afternoon as high
pressure continues to influence the weather in the area. As the
evening progress, hazy conditions will become more widespread as
smoke from Canadian wildfires begins to sink south across the
area. As an inversion develops tonight, between 03-06Z on
Thursday, some of the smoke will become trapped near the
surface, likely reducing visibilities to at least 5-6SM, but
could be lower at the northern terminals. Conditions will not
improve much on Thursday with the smoke stream situated right
over the area. Some hi-res models do suggest IFR visibilities
possible by Thursday afternoon due to the density of smoke, but
with low confidence opted to cap at MVFR visibilities and not
lower. Will have to monitor upstream observations in the coming
hours.

west-northwest winds of 5-10 knots this afternoon, periodically
gusting up to 20 knots near the lakeshore, will weaken near
sunset and becoming light overnight with overall flow shifting
to be from the north. These northerly winds will increase to
5-10 knots by mid to late Thursday morning.

Outlook...Non-VFR visibility possible tonight through Thursday
night due to wildfire smoke. Non-VFR likely Friday night
through Saturday night in showers and thunderstorms.

&&

.MARINE...
Southwest winds across Lake Erie of 5-10 knots this afternoon
will diminish to 5 knots or less this evening in to the
overnight hours as a weak cold front sags south across the lake.
Behind this boundary, winds will become northerly at 5 to 10
knots into Thursday night, resulting in waves across the
nearshore to build to 2 feet or less. A warm front will lift
north late Friday into early Saturday, allowing for south-
southwest winds of 10-15 knots to develop. A cold front will
quickly follow late Saturday into Sunday with winds sustained at
10-15 knots but shifting to become more northerly. During this
period, waves across the central basin will build to 2-4 feet,
possibly needing a Small Craft Advisory for part of Sunday. An
active weather pattern continues into next week, resulting in
numerous wind shifts and periods of waves between 2 and 4 feet.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Heat Advisory until 8 PM EDT this evening for OHZ003-006>011-
     017>023-027>033-036>038-047.
PA...None.
MARINE...None.

&&

$$

DISCUSSION...Garuckas
AVIATION...04
MARINE...04