958
FXUS61 KCLE 050540
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
140 AM EDT Sat Oct 5 2024

.SYNOPSIS...
A weak cold front will settle into the Tennessee Valley tonight
as high pressure builds across the Great Lakes region. This high
will move east Saturday night as a warm front lifts across the
region. This will be followed by a strong cold front crossing
the region Sunday, with Canadian high pressure building across
the Great Lakes in its wake for early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
900 pm update...
The forecast remains on track with no adjustments needed at this
time.

700 pm update...
There are no forecast adjustments needed with this evening
update. The high and mid level clouds associated with an upper
level shortwave over the Eastern Great Lakes will slowly clear
out this evening.

Previous discussion...
Dry and very pleasant Fall weather will continue through the first
half of the weekend as a large area of Canadian high pressure takes
control.

Starting off this afternoon, a weak mid/upper shortwave trough is
crossing the northern and central Great Lakes. This is pushing a
weakening cold front southward through the region. The current
position of the boundary is roughly from Findlay to Youngstown and
will continue to the Ohio River Valley this evening before washing
out over the Tennessee Valley by Saturday. Upstream, a strong 1026
mb surface high is already building into the western Great Lakes
behind the front, and this high will continue to build south and
eastward across the central Great Lakes and Ohio Valley tonight and
Saturday. Lift from an 80-100 knot H3 jet streak tied to the
shortwave over central Lower Michigan is driving a band of weak
radar returns behind the front (Ana Front) over Lake Erie and NW
Ohio this afternoon, but none of the surface observations are
showing precipitation reaching the ground. Forecast soundings
continue to show abundant low-level dry air through the evening, so
removed the mention of slight chance PoPs this afternoon and
evening. Cannot rule out a sprinkle, but generally dry weather is
expected.

Mid-level clouds will clear out quickly tonight as the high builds
in, so expect a fairly cool night with lows in the low/mid 50s near
Lake Erie and generally low 50s inland, except upper 40s in interior
NE Ohio and NW PA. Light northerly flow across the lake will keep
temps slightly milder than they otherwise could be given the long
nights at this time of year. Mostly sunny and pleasant conditions
will continue Saturday with highs generally in the low/mid 70s,
except upper 60s in far NE Ohio and NW PA.

By Saturday night, the surface high will drift into the eastern
Great Lakes as a strong mid/upper trough digs across the Upper
Midwest. The left exit of a 110-120 knot H3 jet streak rounding the
base of the trough will support a fairly deep surface low
progressing into northern Ontario. Expect return southerly flow and
warm air advection to kick in keeping lows in the mid/upper 50s in
NW and north central Ohio while mid 40s to low 50s hold on in NE
Ohio and NW PA. Most of the showers should hold off until Sunday,
but increasing mid-level moisture advection and isentropic ascent
could lead to a few showers in NW and north central Ohio and over
Lake Erie toward sunrise as a warm front lifts across the region, so
included slight chance to chance PoPs.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
High pressure will continue to build eastward off the coast of New
England as an upper level trough moves in from the North Central
Plains/Southern Canada. The trough will initially be quick moving as
it enters the Great Lakes region Sunday during the day. The system
has been trending quicker each model run. The corresponding surface
cold front will be in the western portion of the CWA by midday and
exit out of the east in the evening. Ahead of the cold front there
will be some decent southerly winds as the warm front has pushed
northward. Temperatures will reach the low 80s for the western
counties and high 70s out east with dewpoints approaching the 60s if
not a few degrees above. Areas east of I-77 look to have a better
chance at thunderstorms as the speed of the front will limit the
moisture return across the western portion of the CWA. Models have
been showing surface CAPE of around 1000J/kg for the eastern
counties into PA with SRH of 100-150 m2/s2 in the lower 1 km. PoPs
have been increased across NE OH and NW PA to account for this,
whereas the western half PoPs have been limited. Due to this, there
is a chance for marginal severe weather across NW PA in the late
afternoon/evening.

Behind the cold front, the atmosphere dries out fairly quickly as
dry air moves in from the northwest and high pressure builds to the
southwest across the mid-Mississippi Valley. Dewpoints will drop
down into the low 40s across the CWA overnight into Monday morning
due to a large dry slot in the mid-levels. Temperatures will follow
the same trend as highs for Monday will be 15 degrees lower than
Sunday into the mid 60s and lows into the mid to low 40s. There may
be a chance for lake effect showers across NE OH/NW PA with the
northwesterly winds Monday night, though with the significant dry
air moving in, it is seen as less likely and have opted for slight
PoPs.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The upper level trough will slow over eastern Canada through most of
the week and bring a shortwave across the Great Lakes Tuesday into
Wednesday. There will be a 500mb vort max moving across eastern Lake
Erie throughout the day on Tuesday bringing an increase chance of
PoPs in the most NE counties of the CWA. High pressure will build
eastward across the Ohio River Valley on Wednesday keeping the
region dry and decreasing the precipitation potential. High
temperatures will be slightly below normal and gradually increase
throughout the week to being a few degrees above normal by Friday.
Low temperatures will be in the low 40s mid week with some areas
seeing the high 30s, and will be in the mid 40s by the end of the
week.

&&

.AVIATION /06Z Saturday THROUGH Wednesday/...
A subtle low-level trough axis is causing a small patch of
clouds in the FL015-025 range from near MFD across northeast OH
to near ERI, where a broken MVFR ceiling is being observed. This
feature should slowly push south with clouds gradually
subsiding early this morning. This feature isn`t modeled well,
though held on to MVFR for a few hours at ERI (which may be
pessimistic) before going VFR. Left all others VFR, though
these clouds may briefly get into CAK and YNG too. CAK has been
observing MVFR vsby due to enough near-surface moisture for a
bit of BR and have this continuing through sunrise before mixing
out to VFR. Light north-northeast winds early this morning will
shift easterly into the day today and southeasterly tonight.

Outlook...Non-VFR possible in isolated to scattered
thunderstorms Sunday afternoon and evening. A few stronger wind
gusts could be possible.

&&

.MARINE...
High pressure is building across the lakes today behind the cold
front that moved through during the day today. Winds have shifted
around to the north-northwest and have remained fairly light.
Through the night, winds will pick up to be 10-15 knots and veer to
the northeast making for some choppy conditions for the central
basin for Saturday. As a warm front moves northward Saturday night
into Sunday, winds will shift out of the south and increase to 15-20
knots. Sunday afternoon into the evening, a strong cold front will
move across the lakes shifting the winds to be northwesterly at 15-
25 knots. A Small Craft Advisory will be needed for the areas east
of Lorain into Erie PA for Sunday into Monday. Choppy conditions
will persists on Monday but will slowly subside as the winds trend
down. The rest of the period will be less active, though a trough
and shortwave will need to be monitor for Tuesday into Wednesday for
the central/eastern basins.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.

&&

$$

SYNOPSIS...Garuckas
NEAR TERM...Garuckas/Griffin
SHORT TERM...Kennedy
LONG TERM...Kennedy
AVIATION...Sullivan
MARINE...Kennedy