CLE issues Area Forecast Discussion (AFD) at Aug 20, 1:41 AM EDT726
FXUS61 KCLE 200541
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
141 AM EDT Wed Aug 20 2025
.SYNOPSIS...
Low pressure will cross Lake Erie and northern Ohio this evening,
dragging a cold front across the region tonight. The front will slow
over the Appalachians Wednesday into Wednesday night before Canadian
high pressure builds in from the north by Thursday and Friday.
Another cold front will move through Saturday.
&&
.NEAR TERM /THROUGH TODAY/...
Showers and thunderstorms this evening have been efficient rain producers.
Activity is waning in intensity as it pushes east away from the
reservoir of better instability which remains focused across
western Ohio. Storm strength has been hampered by weak mid
level lapse rates and peak gusts this evening have been around
35 knots. While additional thunderstorms may continue to develop
along the cold front which extends from near Sandusky to
Findlay, potential for any severe thunderstorms has decreased.
Previous discussion...The focus for this afternoon and evening
will be on scattered convection developing ahead of the cold
front, bringing the potential for localized strong winds and
heavy rainfall. The first wave of showers and embedded thunder,
which was driven by warm air advection and isentropic ascent E
and NE of the retreating warm front, has weakened over NE Ohio
and NW PA. The airmass is recovering in the wake of this earlier
round, where breaks of sunshine have allowed surface
temperatures to warm into the mid 80s in much of NW and north
central Ohio. This combined with dew points that rapidly
increased into the upper 60s/low 70s in the warm sector has
allowed MLCAPE values to reach 500-1000 J/KG in NW and north
central Ohio. There is no capping in place, so as low-level
convergence and frontogenetic forcing continue to increase aided
by the right entrance of a 50-65 knot H3 jet streak crossing
central Michigan, convection will continue to expand in coverage
ahead of the front through the evening. HREF ensembles and
individual CAM members have struggled all day with the timing,
evolution, and placement of the convection, but the latest runs
seem to be initializing slightly better based on current radar
trends. Expect the broken line of showers and thunderstorms
developing from western Lake Erie to Wyandot County to continue
to fill in somewhat as it moves east this evening, and this
should be the main show. The marginal CAPE mentioned above
combined with effective bulk shear of around 30 knots near the
front will support the SWODY1 Marginal Risk for severe weather,
but this threat will be very isolated, with wind being the main
threat. Given the surface low and associated enhanced vorticity
passing overhead, cannot entirely rule out an isolated, brief
spin up tornado either, but this is lower confidence compared to
the gusty winds. Locally heavy rainfall will accompany any
convection given PWATs in the 1.75 to 2.00 inch range.
The bulk of the convection will be east and southeast of the
region by 00Z, but periodic showers will hang back over the
area, mainly along and east of I-77, much of the night as the
cold frontal progression slows over the Appalachians combined
with continued upper jet support as the mid/upper trough axis
crosses the southern Great Lakes, so increased POPs over eastern
areas tonight. The best mid/upper forcing departs Wednesday,
but the cold front will become quasi- stationary over the
Appalachians through Wednesday night in response to Hurricane
Erin lifting north offshore of the NC Outer Banks. This will
cause an inverted surface trough and low-level moisture to drift
westward into our eastern CWA Wednesday and Wednesday night, so
kept POPs slightly higher than raw NBM. Most areas will not see
much rain Wednesday and Wednesday night (certainly no washouts),
but elevated cloud cover and scattered off and on showers will
be around, slightly delaying the transition to the beautiful
upcoming weather.
Highs will cool into the mid/upper 70s Wednesday, but it will
still be rather muggy. Lows tonight will stay in the mid 60s to
around 70, but cooler and drier air will start to move in
Wednesday night thanks to Canadian high pressure over the
northern Great Lakes finally starting to build south, so expect
lows to fall into the low/mid 60s Wednesday night.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
The aforementioned large surface ridge of Canadian high
pressure will slowly build from the northern Great Lakes through
the central and southern Great Lakes Thursday through Friday
night. This will finally push the old frontal boundary farther
south, so a few lingering showers in eastern Ohio and western PA
Thursday morning should end by afternoon as the drier air and
subsidence work into the region. The Canadian high combined
with mid/upper troughing over the eastern Great Lakes and New
England will bring refreshingly cooler and less humid air to the
region, with highs in the mid/upper 70s Thursday and upper
70s/low 80s Friday. Lows both Thursday and Friday nights will
fall into the upper 50s/low 60s, with some mid 50s in interior
NE Ohio and NW PA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
The cooler and less humid pattern will turn even cooler for the
extended range as a deep mid/upper trough digs from the northern
Plains and Upper Midwest Saturday through the Great Lakes
Sunday. This trough will carve out across the entire eastern
CONUS early to mid next week (and likely beyond) bringing the
coolest airmass since this past Spring. Scattered showers and
thunderstorms will accompany the strong cold frontal passage
Saturday into Saturday night before transitioning to lake-
effect rain showers over the "snowbelt" of NE Ohio and NW PA
Sunday into early next week given lake surface temps in the
upper 70s F and 850 mb temps falling to 5 to 7 C and what looks
to be well- aligned W to NW flow. It is getting to be that time
of year!
Highs will warm into the low/mid 80s ahead of the front Saturday
before cooling into the mid/upper 70s Sunday and only low 70s
Monday and Tuesday.
&&
.AVIATION /06Z Wednesday THROUGH Sunday/...
Low pressure is still working its way its across Lake Erie, and
as it does show, should see ceilings quickly drop to IFR at most
TAF sites over the next couple hours. IFR ceilings should last
through the rest of the overnight before quickly improving to
MVFR shortly after sunrise, with MVFR ceilings lasting through
the day Wednesday and into Wednesday night. IFR conditions may
last longer at KERI, where it's possible ceilings remain at or
lower than IFR through the day today. The bulk of rain and
thunderstorms are exiting the forecast area, though there may
be isolated to scattered rain showers at times through the dad
today.
Light and variable winds over the next few hours will become
northerly, with speeds in the 6-12 knots range. The stronger
winds in this range will occur closer to Lake Erie where wind
gusts of 20-25 knots are possible.
Outlook...Non-VFR may continue through Thursday with isolated
rain showers and low ceilings, primarily across northeastern
Ohio and northwestern Pennsylvania. Additional non-VFR possible
in scattered showers and thunderstorms Saturday through Sunday,
mainly east of I-77.
&&
.MARINE...
Low pressure will cross the lake this evening into Wednesday
before departing to the east Wednesday night. Winds will be
variable at around 10 knots or less through tonight before
becoming north/northeast and increasing to 10 to 15 knots during
the day Wednesday and 15 to 25 knots Wednesday night through
much of Thursday. Small Craft Advisories and Beach Hazards
Statements have been issued from Reno Beach OH east from 00Z/8
PM Wednesday night through Thursday evening. Winds/waves may be
lower in the far western basin given the shorter fetch so have
held off on headlines for this area; may need to add Maumee Bay
to Reno Beach in a future update if winds/waves trend higher.
Waterspouts are possible with the low/cold front passage tonight
into early Wednesday with chances continuing through Wednesday
night as a trough lingers over the region.
Northeast winds will diminish to 10 to 15 knots late Thursday
night with east/northeast winds to 5 to 10 knots anticipated
Friday. Winds will then shift to the southwest as a cold front
approaches from the west on Saturday morning before becoming
northwesterly and increasing to 10 to 15 knots behind the front
Saturday night. West flow will continue through Sunday. As of
now, marine conditions are forecast to remain below Small Craft
Advisory limits, but will need to keep an eye on wind/wave
trends as the weekend approaches.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement from this evening through Thursday
evening for OHZ007-009>012-089.
PA...Beach Hazards Statement from this evening through Thursday
evening for PAZ001.
MARINE...Small Craft Advisory from 8 PM this evening to 11 PM EDT
Thursday for LEZ143>148.
Small Craft Advisory from 8 PM this evening to 8 PM EDT
Thursday for LEZ149.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...Saunders
MARINE...15
Source:
CLE issues Area Forecast Discussion (AFD) at Aug 20, 1:41 AM EDT---------------
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