CLE issues Area Forecast Discussion (AFD) at Oct 4, 1:37 PM EDT708
FXUS61 KCLE 041737
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
137 PM EDT Fri Oct 4 2024
.SYNOPSIS...
A cold front will sag southeast across the area today, followed
by high pressure tonight through Saturday night. A stronger cold
front will blast through the area Sunday afternoon with cooler
Canadian high pressure building in behind it early next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
12:30 PM Update...
The forecast remains on track this afternoon with no changes.
9:30 AM Update...
The forecast remains on track this morning with no changes
needed. The weak cold frontal boundary is located near the south
shore of Lake Erie and will sag south this afternoon. An
isolated shower cannot be ruled out over NE Ohio and NW PA this
afternoon, but quite a bit of low-level dry air will keep the
main impact only mid and high clouds.
Original Discussion...
Very pleasant and non-impactful early fall weather continues to
end the work week and start the weekend. A weak cold front will
sag across the area through this afternoon as a shortwave trough
zipping across the upper Great Lakes and into southeastern
Canada glances the region. High clouds are exiting to the east
this morning, with more widespread mid to high-level clouds
sweeping across the area in response to the shortwave and front
later this morning into this afternoon. Forcing and moisture
are both limited. Held onto a brief window of 20% POPs along the
lakeshore from extreme northeast OH into Erie County PA this
afternoon just behind the frontal passage, though overall toned
the POPs down a bit. Mainly clear conditions work in tonight
and persist for Saturday behind the front. Winds will be light.
Highs today will be similar to or perhaps slightly (~1F) cooler
than Thursday's values, generally in the mid to upper 70s but
with lower 70s towards northwest PA. Lows tonight mainly in the
50s, but with a few outlying 40s likely and with places like
downtown Cleveland struggling to dip much below 60. Highs
Saturday will range from the upper 60s in PA and far northeast
OH to the low to mid 70s across the rest of northern Ohio.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
High pressure retreats to the east on Saturday night as a fast
moving trough approaches from the west. The pressure gradient
increases overnight with southerly winds also ramping up, and
lifting a warm front north across the area. While temperatures are
forecast to climb into the mid 70s to lower 80s, we also expect to
see an increase in moisture to the region with a narrow corridor of
dewpoints approaching 60 degrees ahead of an approaching cold front.
Deep layer moisture advection does occur ahead of an upper level
trough that forces a cold front east across the area during the
afternoon. Models suggest ML CAPE values of 1000+ along and east of
the I-71 corridor. Breezy conditions will be in place on Sunday both
ahead of and behind the front which may limit the rise in dewpoints
to some extent due to mixing. Lowered/removed pops from a portion of
the area during the morning as most of the area will be capped. As
moistening occurs during the afternoon, the front will likely kick
off at least scattered thunderstorms across the eastern half of the
forecast area. The wind field also increases along the front with 0-
6km bulk sheer values of 40+ knots. Coverage of convection is
somewhat in question across the central and western half of the area
with the higher chances in the far eastern CWA. If we end up with
convection, will need to keep an eye out for a few strong to severe
storms during the mid to late afternoon.
Conditions dry out quickly behind the front as a pretty impressive
dry-slot wraps in through the 850-500mb layer. Westerly winds will
gust to around 30 mph behind the front. Temperatures at 925mb fall
from near 18-20C on Sunday to 9-12C on Monday. High temperatures
behind the front will average about 15 degrees cooler on Monday as
more fall-like conditions return. While we will see some lake effect
cloud on Monday, it will mainly be confined to the far east given
the return to a dry airmass with high pressure building into the
Ohio Valley.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
An upper level trough will be over eastern Canada for much of the
long term period with another shortwave trough crossing the eastern
Great Lakes on Monday night. There is some disagreement with the
placement of the trough during the extended which will impact
temperatures and precipitation potential through the middle of next
week. It looks like temperatures will tend to be slightly below
normal. Overnight lows will be in the 40s most nights and we may
finally see some frost in cooler locations. Given the generally dry
airmass, only have some very low pops in the far eastern counties
next week but a trough position centered closer to Lake Ontario per
several runs of the ECMWF would yield a cooler and wetter
solution.
&&
.AVIATION /18Z Friday THROUGH Wednesday/...
Quiet and VFR flight conditions will continue through the TAF
cycle. A weak cold front will push south of the region by late
this afternoon with high pressure building southward across the
Great Lakes in its wake. This high will remain in control
through Saturday. Only some mid and high clouds are expected
with the front in the area this afternoon.
Winds will become NNW at generally 3 to 8 knots this afternoon
before turning light E to NE tonight and Saturday.
Outlook...Non-VFR possible in isolated to scattered
thunderstorms Sunday afternoon and evening. A few stronger wind
gusts could be possible.
&&
.MARINE...
A weak cold front will cross Lake Erie today with light southerly
winds veering to northwesterly. Overall winds will remain light
today, then veer around to the northeast at 10-20 knots tonight,
making for slightly choppy conditions on the central basin into
Saturday. Winds increase to 15-25 knots out of the south on Saturday
night as a warm front lifts north. This is quickly followed by a
stronger cold front on Sunday with winds shifting to west and
northwest at around 20 knots. A window of Small Craft Advisory
conditions are likely Sunday night with waves of 3-5 feet from
Cleveland to Erie.
Beyond that time frame we get into a little bit of a pattern change
as fall like conditions return with northwest winds and a trough
over the eastern Great Lakes. The strength of this trough will be
monitored.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Sullivan
NEAR TERM...Garuckas/Sullivan
SHORT TERM...KEC
LONG TERM...KEC
AVIATION...Garuckas
MARINE...KEC
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 4, 1:37 PM EDT---------------
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