CLE issues Area Forecast Discussion (AFD) at Jul 19, 2:28 AM EDT801
FXUS61 KCLE 190628
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
228 AM EDT Sat Jul 19 2025
.SYNOPSIS...
A warm front lifts northeast across the area on Saturday,
followed by a cold front on Sunday. High pressure builds in for
Monday and Tuesday. A warm front crosses on Wednesday, ushering
in additional heat and humidity.
&&
.NEAR TERM /THROUGH SATURDAY NIGHT/...
The flat shortwave that provided for a rainier than expected
Friday along and south of the US 30 corridor is exiting. This
will allow weak surface high pressure to take control through
the night, bringing partly to mostly clear skies and dry
conditions. With light to nearly calm winds expected tonight
and relatively small temperature and dew point spreads already
in place, conditions will be conducive to fog development late
tonight into very early Saturday. The potential for some clouds
to linger through the night casts uncertainty, though did add
fog to the forecast for more rural and lower-lying inland
locales. It will be another pleasant night, with lows ranging
from the upper 50s in rural interior PA and even extreme
northeastern OH to the low to mid 60s across most of the area.
Active weather returns later Saturday afternoon into Saturday
night. A warm front will lift across the area on Saturday,
bringing the area into the warm sector and allowing moderate
instability (MLCAPE 1000-2000 J/KG) to build into Northwest and
Central OH by late afternoon. A later warm frontal passage will
likely lead to a CAPE gradient with a decrease across Northeast
OH and Northwest PA. A shortwave will approach out of the
southern Great Lakes late Saturday afternoon and cross the area
the first half of Saturday night. The main focus for shower and
storm potential will likely develop over MI and IN Saturday
afternoon, well within the warm sector and closer to the lift
with the approaching shortwave, and spread east-southeast across
Northwest and North Central OH late Saturday afternoon and
evening. Guidance suggests this convection will likely grow
upscale into a cluster or MCS (mesoscale convective system),
which makes sense given some forcing, fairly high atmospheric
moisture, and uncapped instability. Some cells may develop
ahead of any line or MCS moving in from the west, given
gradually increasing forcing and some low-level warm air
advection ongoing across the area. However, the main focus for
widespread/organized convection is expected to be activity
moving in from MI/IN late in the day into the evening. Have
likely to categorical (60-80%) POPs spreading into Northwest OH
late afternoon/evening, spreading east-southeast into the night.
Lower POPs spread east a bit quicker mid-later afternoon to
account for any development ahead of the main MCS/line.
We'll see a drying trend overnight as the shortwave and
convection exit to the east-southeast. However, leave some lower
chances (generally 20-30%) in the forecast through the night to
account for the cold front approaching from the north-
northwest. Higher POPs through the night are found over and near
Lake Erie into Northeast OH and Northwest PA as the front
pushes over the lake, where the warm waters of the lake may
assist in maintaining a local max in instability overnight.
Conditions are somewhat supportive of both a severe weather and
locally heavy rainfall/flash flood threat Saturday afternoon
and evening, reflected by dueling Slight Risks from the SPC and
WPC for severe weather and excessive rainfall respectively. In
terms of severe weather, moderate instability (but skinny
provides owing to very weak mid-level lapse rates), fairly
mixed low-levels, modest to moderate DCAPE of 700-1000 J/KG,
and marginal shear (deep-layer shear of 25-35kt, with weak
low-level shear and storm relative helicity) support loosely
organized convection with potential for wet microbursts. There
is just enough deep-layer shear for rotating updrafts, so don't
want to entirely rule out isolated large hail and perhaps a
tornado, though overall feel this is a somewhat lower-end severe
threat with damaging winds being the most likely hazard across
the board. The Slight Risk of severe weather feels most
appropriate across Northwest and Central OH, with lower
confidence farther east/northeast. Precipitable water values of
1.70-1.90" are above seasonal averages, though quite not as
high as what we enjoyed earlier this week. Deep warm cloud
depths and relatively skinny instability profiles suggest
potential for torrential rates with storms. Storms are expected
to move at 20-30kt, though there are some hints at repeated
storms across parts of Northwest and Central OH during the late
afternoon/early evening. That could lead to some localized 2-3"+
totals and an isolated flash flood concern, though overall
confidence in these types of totals (both location and
magnitude) is on the lower side.
Highs on Saturday will reach the mid to upper 80s, with peak
heat index values in the low to mid 90s across most of our Ohio
counties (80s into PA). Lows Saturday night will generally
range from the upper 60s to lower 70s.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
The cold front is expected to be draped from Northwest OH
across southern Lake Erie early Sunday and will sag south-
southeast across the area through early evening. With very
little large scale forcing or jet support, have a gradual
increase to 40-50% type POPs from north to south across the area
Sunday afternoon to account for isolated to scattered
shower/storm potential. If anything, these POPs may have a bit
of room to trend down, and the current lack of any outlooks for
excessive rainfall or severe weather seems reasonable given
minimal forcing. High pressure builds in for Sunday night and
the start of the week, bringing cooler and quieter conditions
with much more comfortable dew points.
Highs on Sunday will generally reach the low to mid 80s, warmer
to the south. Lows Sunday night will be noticeably cooler,
ranging from the upper 50s to mid 60s for most. Highs on Monday
will generally reach the upper 70s and lower 80s, with another
pleasant night Monday night with many inland locales dipping
into the 50s. The northeastern edge of a heat dome will begin
spreading towards the local area Monday night, so will need to
watch for remnant convection to spread in from the northwest.
Overall confidence is low and the forecast currently is dry.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A heat dome centered over the mid-Mississippi Valley will flex
its muscles through Thursday, before enough troughing builds
into New England to shift the heat back a bit farther to the
southwest to end the week. The main focus for the long term
period will be a combination of heat and convection.
In terms of convective potential, low potential for remnant
convection to spill in from the northwest on the periphery of
the building heat ridge persists through Tuesday night. However,
confidence is low and POPs are generally 20% or less, allowing
the forecast to read as dry (20% POPs are "silent" in the
extended). A warm front lifts through on Wednesday, which may
bringing with it somewhat increased convective potential.
However, rising mid-level heights and generally minimal model
QPF lead to low confidence, so again only have "silent" 20%
POPs for Wednesday. Greater potential is evident Thursday into
Friday as troughing begins building into New England, pushing
the westerlies south and closer to the area and allowing a cold
front to approach. Confidence in timing and coverage of any
convection isn't high that far out, so have some broad-brushed
30-50% (chance) POPs both Thursday and Friday. Given the hot and
humid airmass am not expected a shortage of instability across
the region, so will need to keep an eye on severe weather
potential, especially Thursday and Friday afternoons.
Temperatures begin climbing towards the mid and upper 80s on
Tuesday, though dew points will remain reasonable. Dew points
climb towards and likely over 70F at times starting Wednesday
and until the cold front sags through towards the end of the
week. 850mb temperatures near 20C Wednesday through Friday
support highs in the low to perhaps mid 90s each day, with the
warm dew points suggesting overnight lows will stay in the 70s,
particularly Wednesday and Thursday nights. The potential exists
for at least parts of the area to reach Heat Advisory criteria
(heat index of 100-104F for two or more hours) each day
Wednesday through Friday, with lower potential to reach Warning
criteria (heat index of 105F+ for two or more hours). The
airmass appears quite moisture-rich, so do not expect a mixing
out of dew points to save us from ugly heat index values as much
as sometimes happens. However, convective potential does add a
wrench to the high temperature forecast. The main message is
that another round of hot, humid weather is distinctly possible
Wednesday through Friday of next week, though that considerable
uncertainty exists regarding the specifics. Stay tuned.
&&
.AVIATION /06Z Saturday THROUGH Wednesday/...
W'erly flow aloft and embedded disturbances affect our region
through 06Z/Sun. Variable amounts of mid-level and especially
upper-level cloudiness will precede the axes of these
disturbances. At the surface, a ridge continues to exit
generally E'ward as a weak low moves generally E'ward from the
northern Great Plains to central Lower MI through 06Z/Sun. The
exiting ridge and low track will allow a warm front to sweep
NE'ward through our region between ~13Z/Sat and ~16Z/Sat.
Our regional winds trend calm or light and variable ahead of the
warm front. These weak or calm surface winds combined with
pockets of clear sky and residual low-level moisture from recent
rainfall should allow areas of radiation mist and fog to impact
northern OH between ~08Z/Sat and ~12Z/Sat. This includes KTOL,
KFDY, KMFD, KCAK, and KYNG. MVFR to LIFR conditions are expected
in the mist/fog. Lingering stratocumuli and associated MVFR
ceilings in interior northern OH should exit generally E'ward by
~12Z/Sat. Behind the warm front, S'erly to SW'erly winds around
5 to 10 knots are expected in our area through 06Z/Sun.
Fair weather is expected for the time being in northern OH and
NW PA. However, as the aforementioned low moves generally
E'ward, multiple clusters or a line of showers and
thunderstorms should develop along the low's trailing cold
front upstream of our region this afternoon and then persist
generally E'ward across our region between ~21Z/Sat through
06Z/Sun. These storms should produce brief/erratic surface wind
gusts up to 30 to 50 knots. Behind the clusters or line of
convection, additional scattered showers and isolated
thunderstorms are possible through 06Z/Sun as the cold front
eventually approaches our region from the southwestern Great
Lakes and Mid MS Valley. Brief downpours and MVFR to LIFR
should accompany showers and storms. Note: nocturnal cooling and
residual low-level moisture from the expected rainfall should
permit gradual development of widespread stratus and associated
MVFR ceilings, especially west of the longitude of KCAK, between
~03Z/Sun and 06Z/Sun.
Outlook...Non-VFR possible with additional and periodic showers
and thunderstorms on Sunday and perhaps Sunday night. Fair
weather and VFR likely this Monday through Wednesday.
&&
.MARINE...
The lake remains between high pressure to the north and a stationary
boundary to the south and north to northeast flow will continue on
the lake through tonight. The front will lift north as a warm front
on Saturday and allow for south to southwest flow to develop with
some southwest winds of 15 kts or so with the long fetch of the lake
in play. A cold front will cross the lake Saturday night into Sunday
and north to northwest flow will take over with some 1 to 3 ft waves
building by Sunday afternoon and evening. High pressure will arrive
again for Monday and Tuesday and north to northeast flow will become
favored again. High pressure will pass to the east on Tuesday night
and a warm front will lift north across the lake for Wednesday,
allowing for offshore flow to return.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Sullivan
NEAR TERM...Sullivan
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Jaszka
MARINE...Sefcovic
Source:
CLE issues Area Forecast Discussion (AFD) at Jul 19, 2:28 AM EDT---------------
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