-- Discussion containing changed information from previous version are highlighted. --
667
FXUS61 KCLE 121748
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
148 PM EDT Sat Jul 12 2025

.SYNOPSIS...
A cold front will approach the region late Saturday night as a
surface low pressure moves northeastward into the James Bay area.
The cold front will move through the region throughout the day
Sunday and exit by late Sunday night. High pressure will build in to
the south through Wednesday morning before periodic showers and
thunderstorms end the week.

&&

.NEAR TERM /THROUGH SUNDAY/...
9:40 AM Update:
Sent out an intermediate update, largely to update POPs this
afternoon and early evening. Satellite and surface observations
show a notable outflow boundary (with some gravity waves)
surging out of IN and towards western OH. Most CAMs attempt to
initiate convection from roughly Lorain to Mt Gilead early to
mid-afternoon, which is coincident with when this feature will
be passing through. The 12z ILN sounding already depicted 2000
J/KG of uncapped MLCAPE, and that airmass will be gradually
advecting into Northwest and North Central OH today. Given the
airmass, model signal, and obvious trigger, upped POPs to 30-40%
from Lorain-Mt Gilead points east for a time this afternoon.
Have POPs decreasing into Northwest PA. This may not be high
enough, though with weak forcing and warm/dry mid-levels there
is a question regarding coverage. Otherwise, can already make
out a bit more vertical cumulus along the cold front across
central IL, with a modest shortwave evident on satellite imagery
as well. This will likely trigger scattered to numerous storm
coverage to our west this afternoon that spreads towards
Northwest OH late afternoon or evening. The potential for severe
weather, mainly driven by favorable thermodynamics for wet
microbursts, remains evident with any stronger pulse cells or
loosely organized clusters this afternoon and early evening.

Gave hourly/max temperatures and hourly dew points a slight
adjustment based on current observations and latest trends. No
major changes resulted. Peak heat index values remain in the
97-100F range for 2-3 hours this afternoon from the Toledo area
east along and just inland from the lakeshore to Cleveland,
including around Sandusky and are generally 94-98 elsewhere.

Previous Discussion:
An upper level trough will continue to deepen just west of the Great
Lakes region and push eastward throughout the day on Saturday and
become negatively tilted. Below, the surface low will develop in
Southern Ontario and push northeastward. Ahead of the accompanying
cold front will be decent southwesterly flow bringing in warm, humid
air into the region. This will provide the potential for afternoon
and evening convection to form, mainly over Western Ohio. There`s
still uncertainty on when and where the convection will form as the
region will be fairly uncapped and can allow for any disturbance to
initiate convection. The SPC Convection Outlook has most of the
region in a marginal risk with areas from I-71 west in a slight risk
for severe weather. The environment will have some severe weather
potential, though will be capped by weak shear and weak mid-level
lapse rates. Strong low-level of over 8 C/km, MLCAPE of 1500-2500
J/kg, and DCAPE around 800-1200 J/kg will support downbursts and
damaging wind potential. There is also a marginal excessive rainfall
outlook for the same area as the slight for convection. There is a
low potential for flooding, but can`t rule out any localized impacts
with average storm motion of around 20 knots. There is less
confidence in severe potential for Erie Co, OH and points south and
east due to timing and the better environment will be to the west.

The other main point for Saturday will be the high temperatures and
heat index. Temperatures will be in the low 90s across the region
accompanied by dew points reaching into the high 60s/ low 70s and
heat indices will reach into the upper 90s. Due to convection and
showers throughout the day, it will be difficult to hit heat
advisory level criteria for a sustain period of time. Nonetheless,
it will still be a hot day and precautions will need to be taken if
spending time outside or if there is not access to air conditioning.
Temperatures Saturday night will still be warm in the low 70s as the
cold front will just starting entering the region.

Isolated showers and thunderstorms will weaken and move eastward
overnight into Sunday morning along a surface pre-frontal trough.
Thunderstorms will reinitiate with diurnal heating from Erie Co, PA
points south and east through Knox Co, OH. There will be less
favorable environmental conditions in this area as it will still be
early in the day when the storms fire off and there will be
contamination from overnight showers and thunderstorms. Similar
story regarding the rainfall from Saturday, not ideal conditions for
flooding, but can`t rule out localized heavy rain in urban and flood
prone areas due to slow moving storms and the slow moving front.
Temperatures Sunday will be cooler with highs in the mid 80s.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
The surface cold front will slowly exit the region to the east with
a little help from an upper level short wave. There may be a few
lingering showers across the far eastern counties overnight Sunday
due to the slow moving front. Dry weather is expected through the
short term as an upper level ridge builds in to the south-southeast
of the region. Temperatures will start to be back on the climb as
southwesterly flow takes hold. This will also allow dew points to
start to climb back into the mid to upper 60s especially on Tuesday.
Highs for the Monday will be in the mid 80s with a slight rise for
Tuesday into the upper 80s and touching 90s in a few locations out
west. Overnight lows will be pleasant with lows in the mid to upper
60s each night.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
PoPs return Wednesday as a low pressure system deepens across the
Upper Mississippi Valley and moves northeast into the Great Lakes. A
warm front will push north throughout the day Wednesday bringing
showers and thunderstorms. The best chance for PoPs will be Thursday
afternoon with the cold front, though it`s uncertain how quickly it
will exit the region overnight Thursday into Friday. Given this,
there will be some lingering PoPs across the area through most of
Friday but with low confidence at this time. Temperatures will be at
their warmest on Wednesday during the long term with high in the
upper 80s/low 90s before the front and precipitation moves in
Thursday. Highs Thursday and Friday will drop into the low to mid
80s with overnight lows in the 60s.

&&

.AVIATION /18Z Saturday THROUGH Thursday/...
-- Changed Discussion --
Mixed-bag of mainly VFR and IFR/LIFR this afternoon and evening,
with non-VFR associated with lower vsbys from thunderstorms. A
line of showers and thunderstorms across Northwest Ohio is
expected to gradually push east through this afternoon, with its
outflow potentially interacting with another area of developing
showers and storms along the I-71 corridor. Thus, brief windows
of tsra tempos are included at most sites except CAK/YNG/ERI
where drier mid-level air and weaker dynamics should preclude
any coverage higher than isolated. Gusty winds of 30 to 40 knots
are possible with any storms impacting TAF sites through this
evening.

Otherwise, coverage of thunderstorms should diminish later this
evening, though can`t rule out some stray showers overnight. A
cold front will move south through the area Sunday morning and
afternoon, though think any shower/storm development should
occur after 18Z, particularly across the southeast portion of
the area.

Winds are generally out of the south to southwest this
afternoon, 10 to 15 knots with periodic gusts of 20 to 25 knots.
Winds will weaken to less than 10 knots overnight, and gradually
shift towards the west to northwest behind a cold front on
Sunday, around 10 knots.


Outlook...Non-VFR with patchy fog or low ceilings will be
possible Sunday night and Monday night, especially for inland
areas away from Lake Erie. Scattered showers and thunderstorms
are once again expected Wednesday afternoon.
-- End Changed Discussion --

&&

.MARINE...
Southerly flow averaging around 10 knots expected today,
becoming southwesterly tonight following the passage of a pre-
frontal trough. Winds speeds should be in the 10-15 knot range
tonight, though there are a few models that have winds briefly
approaching 20 knots at times. Wind speeds improve on Sunday,
becoming northwest on Sunday night after a cold front moves
southeast across Lake Erie. High pressure builds in on Monday
and Tuesday, with light and variable winds expected (aside from
a weak lake breeze each afternoon).

&&

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

&&

$$

SYNOPSIS...23
NEAR TERM...23/Sullivan
SHORT TERM...23
LONG TERM...23
AVIATION...Kahn
MARINE...Saunders