CLE issues Area Forecast Discussion (AFD) at Oct 10, 9:10 AM EDT447
FXUS61 KCLE 101310
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
910 AM EDT Thu Oct 10 2024
.SYNOPSIS...
High pressure will build over the Great Lakes and Ohio Valley
today into tonight. A warm front will lift northeastward across
the region on Friday. A stronger cold front will sweep across
the region Sunday bringing much cooler, fall-like weather
early next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
9:10 AM EDT Update...
Forecast remains valid per latest trends in obs and model
guidance. No changes appeared necessary.
Previous Discussion...
A quiet weather pattern will be around the next couple of days
thanks to a large high pressure that is currently over the
Upper Great Lakes this morning. The center of this high pressure
will track southeastward through the Great Lakes region into
northern Ohio by this evening. Skies are clear this morning and
will remain that way through Friday. We may see a few small fair
weather clouds try to sprinkle the skies this afternoon and
again Friday afternoon but overall we are expecting mostly sunny
skies today and tomorrow.
It is starting off chilly for areas away from the immediate
lakeshore and urban areas with weather stations reporting mid to
upper 30s in the favored cooler spots and valleys. One note to
mention, we cancelled the frost advisory for the 2 counties
zones in NWPA early this morning. There are two reasons for that
early cancellation. The temperatures in far NW PA did not get
as cool as much as previously forecasted overnight due to
lingering lake effect clouds. The second reason was to be
proactive and issue a larger frost advisory for NE OH and NW PA
for tonight's potential frost. The Temperatures will be a touch
cooler than seasonable averages for mid October today. High
temps will range from the upper 50s over NW PA and far NE OH.
Low 60s are expected for north-central OH and mid 60s for NW OH
for high temps this afternoon.
Clear skies and light winds with a dewpoints in the low to mid
30s is a good setup for patchy to areas of frost for the Central
Highlands region and most of NE OH and NW PA. Obviously the
immediate lakeshore communities will not have to worry about
frost with this round of cooler weather thanks to lake water
temps still in the mid to upper 60s. We have the initial frost
advisory for areas along and east of I-71. Friday morning temps
will start out in the lower to mid 30s across most of NE OH and
NW PA as well as central OH. NW OH will stay a few degrees
above that in the upper 30s to lower 40s late tonight into early
Friday morning. High pressure will move towards the East Coast
on Friday and a warm front will lift across the region. After a
frosty start Friday morning for some folks, afternoon
temperatures will make a very nice recovery into the upper 60s
for NW PA and low 70s for NE OH. It will be even warmer for
north-central and NW OH, with mid to upper 70s for high temps
Friday afternoon with mostly sunny skies.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
A cold front will sag in from the north Friday night before stalling
over northern or central Ohio into Saturday. Upper support and
moisture will be limited with the initial frontal passage. Enough
models still have just a bit of QPF over Lake Erie or our adjacent
northern land zones to justify a 20% POP for late Friday night into
early Saturday morning, though many areas may just see an increase
in clouds and wind shift with the front. A flat shortwave ahead of
an approaching larger upper trough is expected to track along the
front Saturday afternoon into Saturday night. Moisture depth will
improve some, with the added support from the shortwave contributing
to greater potential for a light QPF rain event near and north the
stalled frontal spreading in from the west during the day Saturday
and continuing east Saturday night. Have 20-30% POPs spreading into
most of northern Ohio on Saturday as it's uncertain how quickly
we'll moisten enough to start seeing rain, with POPs increasing to
40-60% area-wide Saturday night as confidence increases. Nothing
hazardous but it is rain potential on a weekend.
A potent upper trough will carve out over the Great Lakes Sunday
into Sunday night, pushing a strong cold front through the area and
ushering in the chilliest airmass of the relatively young autumn
season for early next week. Guidance still disagrees on the degree
of cyclonegenesis over the eastern Great Lakes ahead of the digging
trough Sunday into Sunday night, with some of the disagreement still
seemingly tied to how amplified the weaker lead shortwave that will
bring our initial rain chances Saturday-Saturday night is. However,
there is better agreement in low pressure developing just to our
north/northeast on Sunday and likely deepening below 1000mb by some
point Sunday night. This increases confidence in shower potential
for Sunday, especially from northeastern OH into northwestern PA
where 60-70% POPs are in the forecast with lower but still
mentionable (30-50%) chances farther west/southwest with the front.
As the low pressure pulls away Sunday night we'll get into cold air
advection and perhaps some wrap-around moisture amid west-northwest
cyclonic flow. This will focus the greatest shower chances east and
southeast of Lake Erie into northeast OH/northwest PA where likely
to categorical (60-80%) POPs are in the forecast. Don't completely
remove POPs outside of the lake effect in the somewhat moist
cyclonic flow, though POPs and potential QPF are noticeably lower
outside of where the lake will contribute to the showers.
Lows Friday night will be much milder than recent nights, mainly in
the 50s with a few 40s possible in a few cooler spots in far
northeast OH/northwest PA. Highs Saturday will generally rise into
the 60s to perhaps low 70s, dependent on how long rain does or
doesn't hold off. Lows Saturday night will range from the mid to
upper 40s in northwest PA to the low to mid 50s towards Findlay and
Marion. Highs on Sunday should still rise into the 60s to perhaps
near 70 south if there are breaks in the showers/clouds. Lows Sunday
night will get into the 40s. Wind gusts in the initial push of cold
air advection Sunday afternoon into Sunday night may exceed 30 MPH,
though unless we see trends for much more robust cyclogenesis
should remain safely below advisory criteria.
&&
.LONG TERM /MONDAY THROUGH WEDNESDAY/...
A longwave trough will settle over eastern Canada and the eastern
U.S. for Monday and Tuesday as surface low pressure exits towards
Atlantic Canada. The trough will start exiting east towards midweek
as surface high pressure builds in. Guidance is in better agreement
on the overall pattern early next week compared to a day ago, though
finer details will certainly still change at this range. Expect
chilly and somewhat moist north to northwest cyclonic flow on Monday
to gradually back to a more west-northwesterly direction Tuesday and
Wednesday. Various vort maxes and associated subtle surface troughs
will drop through Monday and Tuesday before the longwave trough
starts shifting east. This setup will support occasional lake effect
showers through at least early Wednesday, with activity starting to
wane on Wednesday if high pressure builds in as currently expected.
Showers may be pretty widespread as far west as Sandusky and
Mansfield in the north-northwest flow on Monday before gradually
shifting east Tuesday and Wednesday. The trough aloft will steepen
lapse rates enough that there should be hit or miss showers outside
of the lake effect Monday into Tuesday, especially during the
afternoon hours when diurnal heating will help enhance low-level
instability a bit. The airmass will likely be its chilliest Monday
night and Tuesday when 850mb temperatures will dip to -2 to -4C with
1000-500mb thickness values bottoming as low as 530dm. Not unheard-
of for mid-October but solidly chilly for the calendar. Fans of
winter weather will note that both values would typically support
snow as the precip type in the middle of winter...the boundary layer
is much warmer in October which will cause the showers to largely
fall as rain, though at the least a bit of small hail or graupel
could be possible in any more robust lake effect showers, especially
Monday evening through Tuesday morning when temperatures aloft
appear coldest. Our "forecast builder" did give about 4 grid points
of a rain/show mix late Monday night in the highest terrain of
eastern Crawford County PA and did leave it as the temperatures
aloft, as progged, could support a few wet flakes out there.
Temperatures will be cooler than normal for this period with highs
in the 50s and lows in the 30s to low 40s. It remains possible if
not likely that the higher elevations across far northeast OH and
northwest PA stay in the 40s for highs on Tuesday. It will be
somewhat breezy Monday and Tuesday but nothing hazardous. While the
airmass is chilly enough for frost/freeze concerns the first half of
next week, the potential for some wind and clouds does cast quite a
bit of uncertainty. Overall, this potential may be highest closer to
midweek when surface high pressure builds closer to the area.
&&
.AVIATION /12Z Thursday THROUGH Monday/...
VFR conditions will prevail for this early morning TAF aviation
weather update. A large high pressure system over the Great
Lakes region is dominating our weather pattern and will
continue to bring nice, quiet flying conditions today through
Friday. Mostly clear skies conditions will also continue along
with light winds of 4 to 8 knots. Generally winds will start
out from the north or northeast direction today gradually
becoming easterly or southeasterly by Friday morning. Most areas
will see a period of calm or light and variable winds this
evening as the center of the high pressure tracks across
northern Ohio.
Outlook...Scattered rain showers with non-VFR conditions
possible late Saturday into Sunday associated with a cold front.
Lake Effect clouds and scattered rain showers will be likely
Sunday through Tuesday night, especially downwind of Lake Erie
and the Snowbelt region.
&&
.MARINE...
North-northeast winds will gradually diminish today. Still some 3
footers early this morning in the central nearshore waters, though
waves are also gradually subsiding. High pressure will be in control
and keep the lake tranquil through Friday morning. A cold front will
sink across the lake Friday night. Southwest winds will pick up to
15-25 knots Friday afternoon and evening ahead of the front,
generally stronger farther east. Winds will flip around to the north
late Friday night into Saturday behind the front, with winds
diminishing fairly quickly by morning. Waves will build to 3-6 feet
in the central and eastern basins in the southwest flow ahead of the
front Friday afternoon and evening, with a brief period of onshore
flow right behind the front Friday night. This will likely prompt a
Small Craft Advisory, especially from Avon Lake points east.
Another brief lull in conditions is expected Saturday through a
portion of Sunday. A strong cold front will cross the lake on
Sunday, followed by a good push of cold air advection behind a
developing low pressure over the eastern Great Lakes. This low
pressure will exit towards Atlantic Canada early next week. While
guidance still disagrees on how quickly the low pressure will deepen
Sunday into Sunday night, the strong cold front and associated cold
air advection over the warm lake will support an increase in winds
to out of the north or northwest to 15-25 knots Sunday afternoon
into Sunday night. Chilly cyclonic flow continues through at least
early Wednesday before high pressure tries to start nosing in,
keeping brisk west to northwest flow going through at least early
Wednesday before potentially subsiding. Small Craft Advisories will
likely be needed for most or all of the lake starting some point on
Sunday through Sunday night, with decent potential for the
advisories to need to linger well into next week east of The
Islands. There is some potential for a brief period of stronger
winds to 30kt or so Sunday afternoon or night if the low pressure
deepens quicker than currently projected, though this scenario is
low confidence (20%) and the forecast reflects a weaker
solution.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Frost Advisory from midnight tonight to 9 AM EDT Friday for
OHZ010-013-014-020>023-029>033-037-038-047.
PA...Frost Advisory from midnight tonight to 9 AM EDT Friday for
PAZ002-003.
MARINE...None.
&&
$$
SYNOPSIS...Griffin
NEAR TERM...Griffin/Jaszka
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Griffin
MARINE...Sullivan
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 10, 9:10 AM EDT---------------
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