CLE issues Area Forecast Discussion (AFD) at Oct 9, 7:30 AM EDT754
FXUS61 KCLE 091130
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
730 AM EDT Wed Oct 9 2024
.SYNOPSIS...
A trough across the eastern Great Lakes will weaken today as a ridge
expands across Ohio. High pressure will strengthen over the Great
Lakes through Thursday then build southeast across the
Appalachians through Friday. In it's wake, a warm front will
lift northeastwards across the area on Friday then be followed
by a cold front settling back south into Saturday.
&&
.NEAR TERM /THROUGH THURSDAY/...
Scattered clouds across Northeast Ohio and Northwest
Pennsylvania will give way to clearing skies through the
morning. Additional lake effect clouds will arrive tonight.
Previous discussion...
A dry airmass remains in place across the area with scattered
to locally broken lake effect clouds coming off eastern Lake
Erie this morning. A surface trough over Northeast Ohio early
this morning will depart east into Pennsylvania with surface
high pressure strengthening overhead giving way to clearing
skies today. There will be one more push of low level moisture
that settles south out of Canada tonight as a back door cold
front arrives. Moisture will be mainly confined to near 925mb by
Thursday morning and expected to mix out quickly as surface
high pressure strengthens over the Central Great Lakes. High
temperatures today will be a couple degrees below yesterdays
highs area wide, trending down another 2-3 degrees behind the
weak cold front early Thursday. For lows, we continue to
gradually dip cooler and will have a mix of upper 30s to lower
40s with a few cooler valleys dipping into the mid 30s tonight.
There is some patchy frost in the forecast where temperatures
warrant, with the greatest coverage in Crawford County
Pennsylvania.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
Quiet weather for Thursday night and Friday as high pressure begins
retreating to the southeast but remains in control of our weather.
Thursday night will be chilly with most inland locales dipping into
the mid 30s to lower 40s. A few chillier spots in more sheltered/low
lying areas from the Mansfield/Mt Vernon area points east-northeast
across interior northeast OH/northwest PA may dip into the lower
30s. Locations along the lake will generally stay in the 40s. While
winds will struggle to go calm across northwest OH and near the
lakeshore due to just a bit of a gradient as high pressure retreats,
this is otherwise a decent frost setup from about Lorain to Marion
points east, especially in less urban and lower lying areas. Given
the setup along with current NBM probabilities for lows at or below
36F and 32F, a Frost Advisory is looking likely for a good portion
of the area east of approximately a Lorain to Marion line with
localized freezing temperatures possible in colder spots. Highs on
Friday will warm noticeably into the 70s with mostly sunny skies and
a bit of a southwesterly breeze as 850mb temps warm to 12-14C.
A cold front will sink in from the north late Friday night or very
early Saturday, though with somewhat limited moisture return by that
point and very little upper support only have minimal 20-30% type
POPs spreading into the northern half of the area late Friday night.
A flat shortwave, perhaps associated with a very weak wave of low
pressure, is coming into focus to ride along the front on Saturday
as the front stalls somewhere across northern or central Ohio. This
has warranted the introduction of 30% POPs across most of northern
Ohio for Saturday, with silent 20% POPs for the rest of the area.
POPs then continue/increase a bit for Saturday night as the weak
wave continues across the area. Given how flat this shortwave is the
forecast remains subject to change, though if the solutions
presented by the 0z Euro/Euro Ensemble/CMC are correct these POPs
would need to increase in future updates. Not looking at any
potential for heavy rain or severe wx so a low impact system from a
hazards perspective, just rain potential on a weekend. Lows Friday
night will be much milder than prior nights, largely staying in the
50s. Highs on Saturday are currently projected to range from the mid
60s in Erie, PA to the mid 70s in Findlay and Marion, though that
may depend on how much rain ends up being around. Lows Saturday
night should mainly stay in the 50s with some 40s east.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
Guidance is in decent agreement on the big picture for the long
term...a trough, accompanied by the chilliest airmass of the fall
season so far, will dig into the Great Lakes and Ontario on Sunday
before closing off and only drifting east early next week. We will
still be on the warmer side of the trough on Sunday before getting
into chilly cyclonic flow Sunday night through at least Tuesday.
While agreement on the very broad big picture is there, agreement on
the finer details is not. The first point of disagreement is how
strong a potential wave of low pressure gets over the southern/
eastern Great Lakes Sunday into Sunday night. The GFS has a much
stronger system, leading to greater potential for rain showers on
Sunday and gusty winds Sunday afternoon into Sunday night. The prior
ECMWF model run had a similar solution. Unfortunately, the newest
run of the ECMWF and recent runs of the CMC sharply contract that,
with a much weaker wave of low pressure leading to potential for a
drier Sunday with less wind overall. The source of this sharp
disagreement in solutions appears to be differing ideas on whether
to focus more of the jet energy with the incoming trough on the lead
wave Saturday into Saturday night or the potential stronger low
pressure Sunday into Sunday night. Either way, it will be chillier
and likely somewhat breezy and showery behind the system for Monday
and Tuesday as the larger trough remains over the region, though
differences in wind speed/direction and how much synoptic moisture
can linger are there in the guidance. Overall, carry partly to
mostly cloudy skies with some low (20-40%) POPs at times Monday and
Tuesday, with higher POPs of 40-70% east-southeast of Lake Erie due
to the expectation of some lake enhancement to any shower activity.
Highs should still climb well into the 60s to perhaps lower 70s in
spots on Sunday. Highs on Monday and Tuesday will be stuck in the
50s as 850mb temperatures dip to 0 to -2C, with some potential for
the highest terrain in far northeast OH and northwest PA to stay in
the 40s on Tuesday. Overnight lows will generally settle into the
upper 30s and 40s early next week. The potential for some wind and
clouds makes it uncertain if parts of the area can cool further and
see renewed frost concerns next week, though it's not ruled out
yet.
&&
.AVIATION /12Z Wednesday THROUGH Sunday/...
Scattered clouds near 4K feet are in place across Northeast Ohio
and Northwest Pennsylvania. Ceilings may briefly go broken but
the trend will be to clear through the morning. A little
thicker cloud deck at 3-5K feet is expected in far eastern Ohio
and Northwest Pennsylvania tonight but have kept ceilings VFR.
Can not rule out some pockets of MVFR, especially farther east,
but confidence was too low to include at this time.
Light winds this morning will develop out of the northwest today
at around 10 knots. Can not rule out a few gusts to around 20
knots, mainly in the east at CLE/ERI. Winds will decrease after
22Z and veer to more northeasterly overnight.
Outlook...Scattered rain showers with non-VFR possible Saturday
night and Sunday.
&&
.MARINE...
West to northwest winds will be brisk today with 10-15kt common west
of Cleveland and 15-20kt common farther east, perhaps up to 25kt in
the PA and NY waters at times. Winds will shift more north-
northeast this evening as a trough drops across the lake before
subsiding to 10kt or less into Thursday. It will be choppy across
most of the lake today east of the Islands, particularly from
Willowick points east where 3-6 feet waves are expected, prompting a
Small Craft Advisory through early Thursday morning. High pressure
will lead to tranquil marine conditions Thursday into Friday
morning.
A cold front is expected to drop across the lake late
Friday night. Southwest winds will pick up to 15-25 knots Friday
afternoon and evening ahead of the front, especially east of the
Islands. Winds will turn more northerly into Saturday morning while
subsiding to less than 15 knots. A Small Craft Advisory may be
needed Friday night into early Saturday for some zones, mainly east
of Avon Lake. A brief period of more tranquil conditions is expected
during the day Saturday into Saturday night.
A strong cold front will push across the lake Sunday afternoon or
evening. Guidance disagrees on if a wave of low pressure will
develop along the front on Sunday which impacts the wind forecast.
At the least, strong cold advection should yield a period of 15-25kt
winds out of a west-northwest direction late Sunday through Monday
before gradually subsiding Tuesday into Wednesday. Small Craft
Advisories will likely be needed. A stronger low pressure could
bring a brief period of winds to 30kt or greater late Sunday or
Sunday night, though confidence in this scenario is much lower.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EDT Thursday for LEZ147>149.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...KEC
MARINE...Sullivan
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 9, 7:30 AM EDT---------------
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