Nankin, Ohio Weather Forecast Discussion

950
FXUS61 KCLE 201141
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
741 AM EDT Sat Sep 20 2025
.SYNOPSIS...
High pressure will slowly drift from Ontario and Quebec across
New England by Sunday. This will allow low pressure to move from
the Upper Midwest today into the northern Great Lakes by Sunday
night and Monday. A warm front will lift across the region
tonight and Sunday ahead of the low before a cold front slowly
sweeps eastward Monday into Tuesday.
&&
.NEAR TERM /THROUGH SUNDAY/...
Quiet weather will continue today with somewhat breezy
conditions, especially near the lakeshore, as ENE flow increases
due to a tighter pressure gradient between strong surface high
pressure building from eastern Canada into New England and a
lingering cutoff low offshore of the Mid Atlantic. This will
support gusts of 20-25 knots in NW Ohio and along the lakeshore
this afternoon as mixing deepens. The continued warm and drought
conditions combined with the gusty winds and a well-mixed
boundary layer this afternoon will lead to lower dew points
than suggested by NBM, so used the NBM 10th percentile dew
points in the 16 to 00Z timeframe. This will give minimum RH
values of 30-40% along and south of the U.S. 30 corridor and in
interior NE Ohio and NW PA. Winds will not be strong enough for
any fire weather statements, but given the tinder dry soils and
trees and brush already drying out/dropping leaves, it is
something to be aware of. Highs today will again top out in the
mid 70s to around 80 in NE Ohio and NW PA, with low to mid 80s
across the rest of the region. Some upper 80s will occur along
and south of U.S. 30 and in NW Ohio.
The pattern will finally start to change tonight as the strong
surface ridge to the NE slowly loses its grip in response to the
high pressure center exiting offshore of New England by late
Sunday. This will allow the large mid/upper cutoff low currently
spinning over the Upper Midwest to slowly progress into the
northern Great Lakes by Sunday night. As it does so, low-level
flow will turn more southerly to allow the old frontal boundary
over the Ohio Valley today to return north as a warm front
tonight and Sunday. Mid-level moisture advection and isentropic
ascent will lead to increasing clouds tonight, but given how dry
the antecedent airmass is and the tendency for guidance to
overdo low-level moisture return in droughts, think most areas
will stay dry tonight other than a few scattered sprinkles. With
this in mind, continued the trend of slowing POPS. The better
low-level moisture finally arrives Sunday, and it will turn
noticeably humid with dew points rising into the 60s. This
combined with daytime heating will generate a few hundred
joules of MLCAPE, so expect scattered showers and thunderstorms
to finally blossom in coverage across the area, with peak
coverage in the afternoon. It will not rain everywhere, but it
will at least be the start of a pattern that supports some rain.
Highs Sunday will warm into the low/mid 80s areawide after a
mild night tonight with lows in the upper 50s/low 60s.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
The closed mid/upper low will reach the northern Great Lakes
Sunday night and Monday. This will pull a trailing cold front
into northern Ohio by Monday morning, but the frontal boundary
will be slow to move east given the cutoff nature of the low and
strong surface and upper ridging along the New England coast.
This is good news for rain chances since multiple, subtle
shortwaves will traverse the front and lead to elevated coverage
of showers and thunderstorms through at least early Tuesday. As
of now, the best chance still appears to be Sunday night and
Monday as a 60-80 knot upper jet streak rotates around the base
of the low placing northern Ohio and NW PA under the favorable
right entrance region for enhanced ascent ahead of the front.
Kept likely to categorical POPS Sunday night and Monday, with
some areas likely to see over 1 inch of rain during this time.
By Monday night and Tuesday, the cold front should be into PA
and NY as a deepening mid/upper trough dropping through eastern
Canada attempts to absorb the cutoff low. This is where
uncertainty increases in terms of the coverage of rain. The best
forcing will be east of the region by Tuesday morning, but
guidance is continuing to struggle to resolve the movement of
the cutoff low through mid week and whether or not it gets
absorbed by the trough or retrogrades toward the Midwest and
OH/TN Valleys. Overall, scattered showers will still be around
since rather deep moisture looks to remain through Tuesday, but
given the uncertainty and best forcing likely east of the
region, limited POPS to no higher than likely Monday night and
Tuesday. Somewhat drier air Tuesday night further lowers
coverage, so NBM chance POPS were reasonable.
Highs will stay in the mid/upper 70s Monday and Tuesday given
the clouds and precip, with lows in the upper 50s/low 60s Sunday
night and Monday night cooling slightly into the mid 50s to
around 60 Tuesday night.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
As described above, the pattern becomes much more complicated
with high uncertainty and therefore low confidence for mid and
late week. In general, consensus is for the mid/upper trough
over eastern Canada to lift out as broad mid/upper ridging
builds across much of Canada, with the old cutoff low possibly
drifting toward the Midwest and OH/TN Valley regions to the
south of the Canadian ridge. However, the details are unclear,
with some guidance developing a new cutoff low altogether over
the Mississippi Valley late in the week as the old one gets
absorbed, so made no changes to NBM POPS or temperatures
Wednesday through Friday. This yields highs in the low to mid
70s, somewhat muggy conditions, and daily chances for at least
widely scattered showers/storms. Any more defined periods of
beneficial rain cannot be resolved at this time.
&&
.AVIATION /12Z Saturday THROUGH Wednesday/...
Areawide VFR conditions are observed and expected to continue
through the TAF period with upper-level cirrus building in.
There is around 10-20% chance of showers starting late this
afternoon through the overnight hours as isolated showers
develop near a warm front that will lift northward across the
area. Did not include VCSH/SHRA mention in any TAFs yet due to
expected isolated nature but may be a possible addition to
future TAFs, especially for western TAF sites. A couple models,
such as the HRRR and NAM Nest, even show a few thunderstorms
between I-75 and I-71. Other models have nothing, so would like
to see more consistency before adding anything to TAFs.
Light winds out of the east and northeast this morning. These winds
strengthen to around 10-12 knots downwind of Lake Erie, i.e.
near the lakeshore and in Northwest Ohio, including KTOL, KFDY,
KCLE, and KERI mainly during the afternoon. Following the
passage of the warm front, winds veer to out of the south late
tonight. Downsloping at KERI will result in stronger winds there
with gusts up to 20 knots.
Outlook...Non-VFR with scattered showers and thunderstorms are
possible Sunday afternoon through Wednesday.
&&
.MARINE...
A stationary remains south of Lake Erie as high pressure over
the Ontario/Quebec region pushes southeast towards to the New
England region. East-northeast winds in the 10-15 knot range
this morning will increase to 15-25 knots from this afternoon
through tonight, producing waves of around 3-5 ft in the Lake
Erie nearshore zones. For this reason, a small craft advisory
and beach hazard statement will be in effect for most of Lake
Erie.
The front will lift north across Lake Erie late tonight into
early Sunday morning, with southerly flow ensuing. Speeds will
generally be around 15 knots, though brief periods of 20 knots
will be possible Sunday night, especially in the eastern basin
(latest model guidance indicates a 30-50% chance of >20 knots).
Flow becomes southwesterly Monday and Tuesday as high pressure
becomes anchored to the east coast before a Tuesday cold frontal
passage leads preceded east-northeast flow on Wednesday. Marine
conditions are likely to remain below headline criteria after
Monday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement from noon EDT today through late
     tonight for OHZ007-009>012-089.
PA...Beach Hazards Statement from noon EDT today through late
     tonight for PAZ001.
MARINE...Small Craft Advisory from noon today to 2 AM EDT Sunday for
     LEZ142>149.
&&
$$
SYNOPSIS...Garuckas
NEAR TERM...Garuckas
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...Saunders
MARINE...Saunders

NWS CLE Office Area Forecast Discussion