CLE issues Area Forecast Discussion (AFD) at Oct 12, 4:18 PM EDT035
FXUS61 KCLE 122018
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
418 PM EDT Sat Oct 12 2024
.SYNOPSIS...
Low pressure will track across northern Ohio tonight along a stalled
frontal boundary. As this system continues east into Pennsylvania on
Sunday it will pull a strong cold front south across the area behind
it. Another trough will settle south across the area on Monday night
bringing a reinforcing shot of cold air.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
A rather diffuse frontal boundary is stalled across Central Ohio this
afternoon. Showers are finally showing a diminishing trend as they
continue to drift southeast across the area. Instability has also
decreased with a narrow ribbon of only 100 MU CAPE except for in far
NW Ohio where values are slightly higher. Low pressure moving into
wester Illinois is forecast to track northeast along the frontal
boundary, passing just south of Lake Erie overnight. The
frontal boundary will lift slightly back to the north ahead of
surface low pressure leaving a tightly packed low level
baroclinic zone over Lake Erie. A few showers will continue to
develop along the boundary as it lifts north, while low level
dry air feeds in from south as noted on satellite imagery by an
area of clear skies across Indiana and west central Ohio. Also
to note is a cluster of thunderstorms over SE Wisconsin which
will continue to track slightly southeast along the instability
gradient towards Lake Erie overnight. Rain will fill in with a
chance of thunderstorms as overrunning strengthens across Lake
Erie tonight. Kept high pops across northern portions of the
forecast area which are likely to be clipped by showers,
especially in NW Pennsylvania where the boundary is likely to
remain. Some areas will have winds develop out of the south
ahead of the low keeping min temperatures for tonight on the
mild side.
Low pressure continues northeast into Pennsylvania on Sunday ahead
of an upper level trough deepening across the Central Great Lakes.
This will pull a cold front south across the area with
increasing north winds and have lowered highs in some of the
northern counties which may not warm at all on Sunday. Given the
strength of the low level front expecting good coverage of
showers despite mid-level dry air that will be overhead during
the daytime hours. By Sunday night the upper trough deepens
across Ohio with 500mb cold pool temperatures of -26C over Lake
Erie. Showers will increase in intensity off Lake Erie with over
1100 J/kg of lake induced CAPE providing sufficient energy for
some thunderstorms. Storm total QPF across northern portions of
the snow belt could see 1-1.5" inches of rain through Monday
morning while inland areas will be less than a half inch.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
The first true blast of cold air this fall will become entrenched
across the region for early and mid next week as deep mid/upper
longwave troughing and an associated closed mid-level low meanders
across the Great Lakes and eastern Canada. This will set up a
prolonged NW flow across the southern and eastern Great Lakes with
lake-effect rain showers, as well as the first snow flakes of the
season in higher elevation areas.
Starting off Monday, strong cold air advection will be pouring
across the region as the strong cold front pushes to the south. A
well-defined shortwave looks to drop across Lower Michigan and Lake
Erie in the morning with a reinforcing surface trough, and this
should generate a burst of showers in most areas. Behind the
shortwave/trough, 850 mb temps look to cool to about -3 C and could
bottom out around -5 C by Tuesday, and with N to NW boundary layer
flow and extreme lake induced instability per NAM BUFKIT soundings,
lake-effect showers will continue at times over the higher
elevations of north central and NE Ohio. Drier air, shear, and some
shortwave ridging Monday afternoon will likely reduce the coverage,
but another shortwave dropping across the region Monday night into
early Tuesday will improve the moisture and lift as the flow becomes
better aligned, so expect heavier, multiple lake-effect rain bands
to set up over the higher terrain areas at that time. Thunder is
likely given the degree of instability, with graupel or small hail
as well. Temperatures in the highest elevations of the central
highlands, interior NE Ohio, and NW PA will allow for wet snowflakes
late Monday night into early Tuesday morning, but do not expect
accumulations at this time. Well aligned N to NW flow and lingering
moist, cyclonic flow will keep the showers going into Tuesday night
over north central and NE Ohio into NW PA (mainly upslope higher
elevations) before drier air and a large area of Canadian high
pressure gradually builds in from the west.
Temperatures will be the coldest of the season so far, with highs in
the low/mid 50s Monday (except upper 40s to low 50s in NW PA)
cooling into the upper 40s/low 50s in most areas Tuesday. Lows
Monday night will fall into the upper 30s/low 40s, with some low to
mid 30s in NW PA. Lows Tuesday night will be slightly colder, with
widespread mid 30s away from the lake and upper 30s to low 40s
closer to the lakeshore. NW PA will still see low to mid 30s.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
The aforementioned big Canadian surface high will build east across
the Ohio Valley Wednesday and Thursday in response to the mid/upper
longwave trough axis gradually moving east as a mid/upper ridge
expands across the central CONUS. This will allow conditions to dry
out with slowly moderating temperatures. Lingering lake-effect
showers over NE Ohio and NW PA will end by Wednesday night with dry
conditions then expected through Saturday as the surface high
gradually drifts to the east coast and the upstream mid/upper ridge
builds into the region. This will support further warming for the
end of the week and start of the weekend.
Highs in the upper 40s/mid 50s Wednesday will warm into the mid
50s/low 60s Thursday, mid/upper 60s Friday, and upper 60s/low 70s
Saturday. A freeze is possible in many areas inland from Lake Erie
Wednesday night with the high sliding overhead.
&&
.AVIATION /18Z Saturday THROUGH Thursday/...
Rain showers have filled in across much of the area today as a
stalled frontal boundary extending from near Marion to Mansfield
to Youngstown lifts slightly northward. Thunderstorms have been
widely scattered but a little elevated instability is in place
from near Bowling Green towards Akron. Have added showers to the
forecast as needed this afternoon. Confidence in timing
thunderstorms is low given the limited coverage so will update
for a brief thunderstorm as needed. Most areas will see a break
in precipitation this evening with rain filling in along the
warm front near the south shore of Lake Erie overnight. Rain
will also fill in along a cold front that will move back south
across the area behind the low into Sunday. Ceilings have mostly
improved to VFR with just a few pocket of MVFR. Most areas will
be VFR tonight except at northern terminals. As low pressure
continues east into Sunday, ceilings will lower as a cold front
is pulled south.
Winds today will be northeasterly north of the frontal boundary
with light or southeasterly winds south of the front. Southerly
winds will expand tonight as a warm front lifts back north
towards the south shore of Lake Erie. Winds behind the front on
Sunday will be out of the northwest and breezy for lakeshore
terminals. Marginal low level wind sheer is also possible at the
southern terminals as the low level jet spreads north ahead of
the approaching low, mainly 06-14Z at CAK/YNG.
Outlook...Scattered to periods off and on rain showers will
likely bring non-VFR conditions Sunday through Wednesday
evening
&&
.MARINE...
Winds will continue to shift to the northeast and diminish to
10 to 15 knots by mid to late morning and the current Small
Craft Advisories will likely expire at 12Z this morning. A brief
lull is anticipated before winds become northeasterly and
increase to 15 to 20 knots later this evening into Sunday
morning; a somewhat short- duration Small Craft Advisory will
likely be needed during this time. Yet another lull will occur
mid-morning to early afternoon Sunday before winds once again
increase to 15 to 20 knots by mid- afternoon or early evening.
Winds shift to the northwest increase to 15 to 25 knots Sunday
night through the middle of the weak. The strongest winds will
occur Sunday night through Monday morning and Tuesday afternoon
into early Wednesday. Small Craft Advisories will likely be
issued from Sunday afternoon or evening through Wednesday.
Waterspouts are possible on the lake Sunday night through at least
Tuesday as a trough settles over the region and 850mb temperatures
drop.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory from midnight tonight to 2 PM EDT Sunday
for LEZ142-143.
Small Craft Advisory from midnight tonight to 6 AM EDT Sunday
for LEZ144>149.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC
SHORT TERM...Garuckas
LONG TERM...Garuckas
AVIATION...KEC
MARINE...Garuckas
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 12, 4:18 PM EDT---------------
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