CLE issues Area Forecast Discussion (AFD) at Jul 31, 4:32 AM EDT309
FXUS61 KCLE 310832
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
432 AM EDT Wed Jul 31 2024
.SYNOPSIS...
A small upper ridge will briefly build in today into early
Thursday from the Lower Ohio Valley into the Eastern Great Lakes.
On Friday, a vigorous shortwave trough will dive down from the
Upper Midwest through the Lower Great Lakes and linger through
Saturday. Another upper level ridge will build eastward from the
Central Plains into the Ohio Valley late this weekend.
&&
.NEAR TERM /THROUGH THURSDAY/...
The forecast now through Thursday afternoon is a little more
uncertain than usual due to some variability in the high-res
model guidance at this time. We are starting off this morning
quiet with some subsidence in the atmosphere because yesterday's
weather system has exited eastward from the area. There are some
lingering stratus over NWPA but that should lift out fairly
quickly by sunrise this morning.
Our day will start out with plenty of sunshine with mostly clear
skies over the region. An upper level ridge near the Mid-
Mississippi River Valley this morning will start to nose in from
the southwest today through early Thursday with mid level height
rises. We have a light southwesterly low level flow and that
will continue for the next couple of days advecting in
tropical moisture and lots of humidity. Later today with the
high moisture levels, our skies will become partly cloudy this
afternoon. Temperatures will rise into the upper 80s and lower
90s by this afternoon. Due to so much low level moisture to work
with, there could be a few isolate to widely scattered pop up
showers or storms this afternoon and early evening. Surface
dewpoints will remain in the lower to middle 70s and that will
help push heat indices into the upper 90s to 100 degrees over
parts of NWOH this afternoon.
This afternoon and evening timeframe is when the forecast
confidence is somewhat lower regarding the potential of a MCS
or complex of thunderstorms developing over the Midwest today
and tracking east-southeastward into the Ohio Valley later
today. Most of the model guidance have fairly good agreement and
indicate this potential MCS if it develops may track along a
Theta-E gradient that will be located southwest of our local
area. Depending on the evolution of this possible MCS and
interaction with mesoscale boundaries, our far southwestern
counties closer to west central and central Ohio could be
clipped with this system. The greater potential for severe
weather will be towards the Ohio River and southwest Ohio. SPC
has much of northern Ohio in a marginal risk outlook later today
and tonight for the threat for isolated damaging wind gusts
with any strong to severe storm that may develop in our area.
Moderate instability expected with MLCAPE values reaching
1500-2000 J/KG, weak shear up to 25 knots, and PWAT values
around 1.5" over NWOH and NCOH later today. So we will keep an
any an eye on trends but it is looking that the MCS that
develops and moves through the Ohio Valley later today will just
miss our area or could clip a few southwestern counties.
We will become a little better positioned in the west-northwest
flow on Thursday for more active weather potentially moving in
later in the day, especially heading into the evening hours.
That slight bump up in the upper level ridge nosing into our
region will put our area more in the possible storm track. We
may have some lingering widely scattered or isolated showers and
storms through the overnight into Thursday morning. We will
start out the day with partly cloudy skies and quickly warm up
into the upper 80s to near 90 degrees again on Thursday before
any showers and storms move in to cool things off. CAMs and
high-res model guidance shows another disturbance moving
eastward through the Midwest and Lower Great Lakes Thursday.
The alignment looks to be a little more aiming for Ohio and our
attention will be watching this possible MCS from the southern
Michigan and northern Indiana area Thursday afternoon. It may
start to move into NWOH by late afternoon and more so into the
evening. Gusty winds, locally heavy rainfall, and lightning will
also be possible with the storms late Thursday. The atmosphere
will also have better thermodynamics to work with with MLCAPE
2000-3000 J/kg, shear up to 30 knots, and PWATs climbing above
1.75". SPC has northern Ohio also in a day 2 marginal risk or
threat for severe storms with damaging wind gusts as the main
hazard.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
The short term period has the potential to be very active, with
multiple rounds of showers and thunderstorms possible Thursday night
through Saturday night. In this forecast update, the severe weather
chances appear to be decreasing while the heavy rain threat is
increasing.
Models are beginning to come into agreement of the location and
timing of an upper-level low which is expected to move east across
the Upper Midwest Thursday night, reaching the vicinity of just west
of Lake Erie by Friday night. If this current track holds, it
suggests that the better dynamics and wind field for severe weather
potential will be found at the base of the trough south and
southwest of the area. Thunderstorms are expected to fire along a
west to east-oriented stationary boundary/pseudo warm front ahead of
the low Thursday night into Friday morning across the Lower Great
Lakes and Ohio Valley. The environment will be primed for heavy rain
with skinny and tall CAPE profiles, a W to WSW low-level jet
becoming near parallel to the front, and abnormally-high PWATs around
2.0 inches. Currently, the WPC day 2 heavy rain outlook clips our
far southwest area in a slight risk, though could see this expanded
further north if confidence in convective placement grows.
By Friday, the upper-level low will be directly overhead across
Northwest Ohio, with plenty of moisture remaining for widespread
showers and thunderstorms throughout the day. It certainly looks
like an all-day washout for much of the area. Currently in an SPC
SWODY3 marginal outlook for the far south, though think this will be
a more of a continuation of the heavy rain threat rather than a
severe threat with the better dynamics found to the south and east
of the area. The upper-level low/trough will gradually move east
across northern Ohio Friday night into Saturday, shifting the threat
for more widespread showers and thunderstorms further south and
east. Current thinking is the best potential for showers and
thunderstorms on Saturday afternoon and evening will be generally
along and east of the I-71 corridor. Once again, this appears to be
more of a heavy rain threat rather than severe.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
The active pattern appears to come to a close on Sunday as the upper-
level trough exits into New England and becomes absorbed into a
longer-wave trough across Ontario and Quebec. Will hold on to some
slight chance/isolated shower and thunderstorm activity on Sunday as
the surface cold front still remains to the north. The cold front
will finally move south across the area on Monday. Limited moisture
should keep precipitation chances at bay, though could certainly see
some low-PoPs in the forecast at some point if trends persist.
Tuesday is beginning to look a bit more interesting as there is
relatively good agreement (for day 7 purposes) that a surface low
may move east across the Great Lakes. There will be favorable mid
and upper-level dynamics at play to support organized thunderstorms,
though large uncertainty exists on the degree of instability.
&&
.AVIATION /06Z Wednesday THROUGH Sunday/...
We are expect mainly VFR conditions for this morning through
this evening. We may see some light, shallow fog with
visibility perhaps down between 3sm and 5sm for a few TAF sites
this morning between 9z and 12z. We have mentioned this
possibility in TEMPO at select sites. There are MVFR ceilings
between 1500 and 3000 feet still lingering around ERI early this
morning. This stratus should lift out and scattered around by
12z or sunrise this morning.
The forecast becomes somewhat uncertain with a low confidence
forecast late this afternoon into this evening. We have chances
for widely scattered convection that could develop with the
afternoon heating across the area. We are not confident enough
to place that potential in any TAFs with timing and coverage at
this time. It will be something we will monitor trends in
forecast guidance and may be something to add with the next TAF
update if needed. Otherwise, we will keep the ceilings VFR for
now through this evening. Winds will be from the southwest or
west 5 to 10 knots today and around 5 knots this evening into
overnight. There will likely be a lake breeze switching the wind
direction from the northwest up to 10 knots during the
afternoon for ERI. We will take another look at CLE where there
also could be a light lake breeze but did not included it in the
TAF with this update.
Outlook...Non-VFR possible in scattered and periodic showers
and thunderstorms Thursday through Sunday.
&&
.MARINE...
Outside of thunderstorms, the marine period appears quiet through
the weekend with flow generally 10 knots or less and waves less than
2 feet. Confidence remains low on strong thunderstorms impacting the
lake. A few stronger isolated to scattered thunderstorms will be
possible this afternoon and evening and again for Thursday evening
and overnight. Looking at primarily a wind threat with any
storms.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Griffin
NEAR TERM...Griffin
SHORT TERM...Kahn
LONG TERM...Kahn
AVIATION...Griffin
MARINE...Kahn
Source:
CLE issues Area Forecast Discussion (AFD) at Jul 31, 4:32 AM EDT---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
