CLE issues Area Forecast Discussion (AFD) at Sep 6, 3:35 PM EDT929
FXUS61 KCLE 061935
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
335 PM EDT Sat Sep 6 2025
.SYNOPSIS...
A deep trough of low pressure will persist across the Great
Lakes through Sunday before a large dome of Canadian high
pressure builds in Sunday night and Monday. This high will
remain in control through midweek while gradually shifting
offshore of the New England coast.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
Mid afternoon visible satellite and water vapor loops nicely
highlight an unseasonably deep mid/upper longwave trough across
central and eastern North America downstream of a strong
mid/upper ridge west of the Rockies extending well north through
British Columbia. This highly amplified pattern will maintain
well below average temperatures and breezy conditions the
remainder of the weekend, as well as periods of lake-effect rain
showers given the strong cold air advection and well-aligned
moist, cyclonic flow across the roughly 70 F lake waters.
In terms of the lake-effect, drier air and subsidence behind an
upper jet max and associated surface trough that moved through
this morning has slowed the development of lake-effect rain
bands. Regional radar as of mid afternoon shows lake-effect
showers and instability showers filling in upstream across
northern and central Lower Michigan, and these are tied to the
colder pool of air beneath the main mid/upper trough axis that
will swing through the southern Great Lakes tonight. As this
trough axis approaches this evening, deepening synoptic moisture
and better aligned WSW boundary layer flow combined with
deepening instability and resultant lake induced equilibrium
levels will allow a single, dominant band to develop over the
lake and affect western NY and perhaps northeast parts of Erie
County, PA. As the mid/upper trough axis swings eastward through
the night, an associated surface trough will slowly press
across the lake, and this combined with boundary layer flow
veering W and eventually WNW will slowly push the band inland
across the primary snowbelt of eastern Cuyahoga, Lake, Geauga,
Ashtabula, and Erie and Crawford Counties in PA. The increasing
south shore convergence as the surface trough moves through
combined with equilibrium levels rising to around 15,000 feet
and lake induced CAPE reaching about 750 J/kg late tonight will
support periods of heavy rain within the main band, as well as
some thunder and lightning. Utilized a blend of RGEM and WRF-ARW
for POPS and QPF tonight and Sunday morning to try and best
capture the movement and placement of the main band. After 12Z
Sunday, an establishing 290-300 degree boundary layer flow may
push the band as far SW as northern Lorain, southern Cuyahoga,
northern Medina, Summit, and Portage Counties before weakening
and giving way to more scattered lake-effect showers by late
morning through the afternoon as drier air and increasing
subsidence gradually build in. Most areas of NE Ohio and NW PA
should see under 0.25 inches of QPF, but localized amounts of
0.50 to 1 inch cannot be ruled out where the band persists which
appears to be most likely from the east suburbs of Cleveland
into Geauga County in the roughly 09-13Z timeframe Sunday
morning. A large surface high over the Upper Midwest will build
in Sunday night, gradually shutting down the remaining lake-
effect showers, but kept the trend of hanging onto at least
slight chance POPS in far NE Ohio and NW PA longer.
Highs Sunday will be limited to the mid/upper 60s, with low/mid
60s in NE Ohio and NW PA. Lows tonight will fall into the
low/mid 40s, except low 50s near the lakeshore. As the high
builds in Sunday night, low 40s will be widespread inland from
the lake, with a few upper 30s possible along the U.S. 30
corridor and in interior NE Ohio and NW PA, but expect
temperatures to remain a few degrees above frost thresholds at
this time.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The chilly pattern will gradually relax early in the week as the
big Canadian high centered over the southern Great Lakes Monday shifts
off the New England coast by Tuesday night, with mid-level
heights also rebounding in response to the west coast ridge
breaking down and an upper low progressing onshore of Oregon and
California. This will set up spectacular early Fall weather,
with plenty of sunshine and highs in the upper 60s/low 70s
Monday warming into the mid/upper 70s Tuesday. Lows will also be
moderating, with generally low/mid 40s Monday night (50s near
the lake) increasing to upper 40s/mid 50s Tuesday night.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
Quiet weather will continue in the extended, but temperatures
will cool a few degrees after the mid week warmth behind a cold
front and associated mid/upper trough that progresses through
the Great Lakes Wednesday night and Thursday. This trough will
not be nearly as strong, but guidance suggests troughing and
associated NW flow to continue across the Great Lakes and NE
CONUS through next weekend along with another Canadian high
settling into the region, so slightly cooler and mainly dry
conditions will persist. Used NBM POPS at this point, which are
completely dry Wednesday through Saturday, but will need to
evaluate for possible showers with the front Wednesday
night/Thursday depending on the degree of forcing and moisture.
Highs in the upper 70s/low 80s Wednesday will cool into the mid
70s to near 80 Thursday and generally low/mid 70s Friday and
Saturday.
&&
.AVIATION /18Z Saturday THROUGH Thursday/...
Cool northwest flow across the Great Lakes region has allowed
for mid-level cloud cover to develop this afternoon mainly
across Lower Michigan and along the Lake Erie lakeshore.
Ceilings remain VFR with SCT/BKN cloud deck between 4-6 kft.
Expect for any afternoon cloud cover to erode later this
evening. Terminals should vastly remain dry and VFR through the
TAF window, but can't rule out lake effect rain showers to reach
KERI and KCLE early Sunday morning. Conditions should remain
VFR in lake effect showers, though there remains the potential
for MVFR to occur at KERI.
Westerly to northwesterly winds 8-12 knots will occasionally
gust to 18-22 knots through sunset tonight. Winds will then turn
southwesterly and diminish to 5 knots or less. Winds return
westerly to northwesterly Sunday morning generally between 8-10
knots.
Outlook...Non-VFR possible with lake effect rain and clouds in
NW PA and NE OH on Sunday.
&&
.MARINE...
Elevated westerly to northwesterly winds 15-25 knots will
remain over Lake Erie through Sunday night. Onshore flow will
allow for wave heights to build to 3-6 feet through the weekend.
A Small Craft Advisory and Beach Hazards Statement remains in
effect across the central and eastern basins and corresponding
lakeshore counties through Sunday evening. Waterspouts remain
possible in any lake effect rain showers tonight into Sunday.
An expansive area of high pressure will build across the Great
Lakes region Sunday night and persist across the Northeast into
early next week. Winds become light and variable on Monday
before favoring an offshore component Tuesday and Wednesday as
the high builds overhead.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement through Sunday evening for OHZ010>012-
089.
PA...Beach Hazards Statement through Sunday evening for PAZ001.
MARINE...Small Craft Advisory until 8 PM EDT Sunday for LEZ145>149.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...13
MARINE...13
Source:
CLE issues Area Forecast Discussion (AFD) at Sep 6, 3:35 PM EDT---------------
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