CLE issues Area Forecast Discussion (AFD) at Aug 12, 2:02 PM EDT851
FXUS61 KCLE 121802
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
202 PM EDT Tue Aug 12 2025
.SYNOPSIS...
A trough will move into the Great Lakes Region today pushing a weak
cold front south across the area on Wednesday. High pressure will
build south out of Canada on Thursday and influence the region
through Saturday.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
8:20 AM:
Weak lift ahead of a small vort max is combining with a moist
and unstable environment to spark a few convective showers (and
possibly a rumble of thunder) in the vicinity of Erie, PA early
this morning. Added some POPs through 11 AM to account for this.
The rest of the forecast is on track.
Previous Discussion:
The local area resides on the western periphery of high pressure
along the East Coast while an upper level trough approaches the
Great Lakes region from the northwest. One more hot day is expected
today before the heat decreases with a cold front on Wednesday.
Highs will be near 90 again today and portions of Northwest and
North Central Ohio will experience heat index values in the upper
90s.
The forecast challenge through the near term resides around timing
of showers and thunderstorms as a slow moving cold front moves
southeast across the area through Wednesday. Starting off today, the
atmosphere remains dry this morning aside from some low and mid-
level moisture seen crossing Lake Erie on satellite imagery. Some of
this residual moisture is expected to linger across far NE Ohio and
NW Pennsylvania and may be sufficient for a few showers and
thunderstorms to develop along the lake breeze early to mid
afternoon. HRRR soundings near the lake breeze interface suggest ML
CAPE values around 1200 J/kg while areas south of the lake breeze
are likely to remain capped. Lowered pops for inland areas and also
decreased the coverage slightly. Moisture is expected to increase
from the southwest late today but models disagree on the
timing. The NAM favors a faster arrival while the RAP/GFS are
closer to 00Z or later before we see enough moisture for
thunderstorms to increase in coverage across northwest Ohio. For
this reason will have slight chance to low chance pops through
the afternoon before moisture moving up the Mid-Mississippi
Valley arrives this evening and coverage increases. Shortwave
energy moving into western Ohio ahead of the deepening trough
will provide support for showers and thunderstorms into this
evening. A pre-frontal trough reaches NW Ohio this evening while
the actual cold front is still back near Chicago. A push of low
and mid-level theta-e advection is likely to sustain showers
and scattered thunderstorms overnight into NE Ohio. PW values
will be near 2 inches and rainfall is expected to be efficient.
By Wednesday morning, the cold front will be near Toledo with much
of the area still in the warm sector ahead of the front. Showers
from overnight may still be ongoing in the south and east before
dissipating in the morning. Good coverage of showers and
thunderstorms should re-develop along the front and move southeast
through the afternoon with ML CAPE values of 1500-2000 J/kg. While
most areas will see a quarter to a half inch of rain through
Wednesday, pockets of 1-2 inches are possible where thunderstorms
occur. A few thunderstorms could produce wind gusts of 40-50 mph
with wet microbursts but overall the severe weather threat is
expected to be low.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
A broad trough will be over eastern Canada at the start of the
short term with one more shortwave moving through the northwest
flow aloft. Will hold onto a low slight chance pop on Thursday
before high pressure strengthens north of the area. Highs on
Thursday settle back into the low 80s with more comfortable
humidity with dewpoints in the low 60s. Thursday night will be
the coolest of the week with lows in the upper 50s to low 60s.
Models are starting to suggest a fairly strong shortwave will
cross Lake Erie but with surface high pressure still expecting a
mostly dry day. Temperatures on Friday start to creep back up a
couple degrees.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
Upper level ridge amplifies north up the Mississippi Valley towards
Chicago over the weekend. Saturday is expected to be a dry day
with temperatures trending back above normal. After that we will
need to monitor the placement of the ridge and when a shortwave
moving through the northwest flow around the ridge could push a
frontal boundary south into the area. This could be as early as
Sunday or Monday providing the next opportunity for thunderstorms
but confidence is below normal with respect to timing. Hot
conditions are likely to persist until a front pushes south
into the area.
&&
.AVIATION /18Z Tuesday THROUGH Sunday/...
Primarily VFR conditions are expected to persist through the
TAF window with two windows for showers and thunderstorms that
may reduce cigs/vis to MVFR at times. The first window will be
diurnally driven showers and storms that have begun to develop
along a lake breeze this afternoon. Expect for these
showers/storms to continue through late this afternoon/early
evening (~22Z). Highest confidence in TSRA impacting a terminal
will be at KERI where a TEMPO group for TS impacts is in place
from 18-22Z.
The next window will be overnight tonight as a cold front
approaches the local area from the west. Some uncertainty with
the coverage of showers but went ahead and added -SHRA around
05Z at western TAF sites (KTOL/KFDY) before showers move east
towards KERI around 09Z. Kept out any TS mention for now given
lower confidence, but future TAF packages/amendments may be
needed to introduce TS.
Generally southerly to southwesterly winds 5-10 knots across
inland terminals. Meanwhile, a lake breeze has allowed for
westerly to northwesterly winds 8-10 knots to develop a KCLE and
KERI. Winds turn light and variable after 00Z tonight before
turning generally westerly Wednesday morning.
Outlook...Isolated to scattered showers and thunderstorms with
non-VFR conditions are forecast through Wednesday evening.
&&
.MARINE...
Generally quiet marine conditions will continue through this
week as southerly to southwesterly winds 5-10 knots persist over
the lake. Winds will become northerly at 8-12 knots behind the
cold front Wednesday night/early Thursday. High pressure builds
over the lake late this week which will allow for winds to
return light and variable. Lake breezes will likely occur again
on Friday and Saturday afternoon. There will be favorable
conditions for waterspouts as the cold front approaches the lake
from the west tonight and Wednesday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...10
NEAR TERM...10/Sullivan
SHORT TERM...10
LONG TERM...10
AVIATION...13
MARINE...13
Source:
CLE issues Area Forecast Discussion (AFD) at Aug 12, 2:02 PM EDT---------------
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