CLE issues Area Forecast Discussion (AFD) at Oct 21, 7:36 AM EDT625
FXUS61 KCLE 211136
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
736 AM EDT Tue Oct 21 2025
.SYNOPSIS...
Low pressure will move into the Upper Great Lakes today with a
series of cold fronts sweeping east across the area through tonight.
A broad upper trough will set up across the eastern United States
through mid-week before finally shifting off the East Coast on
Friday. Surface high pressure will build into the Ohio Valley
Friday through Saturday.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Low pressure is moving into the Upper Peninsula of Michigan this
morning with a cold front extending south across Lake Michigan into
Indiana. Scattered showers can be seen on radar imagery along the
cold front and these are expected to spread east across our forecast
area through noon. This broken line of showers will move through
fairly quickly, then give way to mostly sunny skies for several
hours as a deep layer dry slot wraps in behind it. The cold front
this morning is located along the leading edge of an upper level
trough advancing into the region.
A stronger piece of shortwave energy moving through the base of the
trough will move into northwest Ohio late this afternoon and swing
east. This is accompanied by a return of deeper moisture(although
still not impressive) and a -26C cold pool at 500mb. Scattered to
numerous showers with steep lapse rates and isolated thunderstorms
will return late this afternoon into tonight. The showers will
be high based with a nearly inverted-V type appearance. Westerly
winds will be breezy today with gusts of 20 to locally 30 mph.
Showers this evening could cause some locally higher wind gusts
of 30-45 mph. Another break in precipitation is expected
overnight while southwesterly flow starts to align across Lake
Erie. This will be the beginning of a prolonged lake effect rain
event as the upper level trough parks over the Great Lakes
Region. Several parameters come together including warm lake
temperatures in the mid 60s, lake to 850mb delta T of around 20,
and a prolonged period of convergence across the lake. Heavier
rain showers are more likely to be focused over Lake Erie on
Wednesday as a meso-low over Michigan enhances the southwesterly
flow to the east before rotating across Lake Erie on Wednesday
evening. Elsewhere the airmass will be cooler with highs in the
upper 40s to lower 50s. Windy conditions are likely as the
gradient tightens up and westerly wind could gust to between
30-40 mph, resulting in brisk conditions and wind chills near 40
degree. Sufficient moisture and instability remain in the broad
cyclonic flow to expect continued showers, especially during
the afternoon.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
The passage of a trough both at the surface and aloft may be
sufficient to focus the band of showers from Lake Erie onshore. This
band will produce efficient rainfall and will be heavy at times.
Surface based instability over the warm lake will range from 800-
1500 J/kg and a dominant band is expected to set up along the
shoreline into Thursday before starting to become more multi-banded
as the trough axis shifts onshore. Adjustments will be needed to the
precipitation forecast but rainfall amounts of 1-3 inches are
possible with the highest amounts in northern Ashtabula and Erie
Counties.
Upper level trough axis become oriented towards New England through
the day on Thursday and a ridge of high pressure at the surface
building from the Upper Midwest to the Ohio Valley. The trend
will be towards lighter showers that cover more of the snowbelt
with northwest flow. Deeper moisture strips away Thursday night
and showers will tend to diminish on Friday morning. Much of the
area will be dry on Friday with mostly sunny to partly cloudy
skies.
Portions of Northwest and North Central Ohio will see temperatures
in the lower 30s on Thursday night, expanding to most of the area on
Friday night. Uncertainty in the coverage of frost on Thursday night
with this cold airmass will be due to questions about cloud cover
and amount of boundary layer mixing. Friday night has better
potential for a widespread frost with nearly calm winds if we don't
end up with too much cloud cover.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
The weekend will start off under the influence of surface high
pressure. The area could be clipped by a shortwave on Saturday night
that could try to kick off a few showers but chances of
precipitation remain low through the weekend. We are watching the
interaction between continued troughiness over New England and a
closed upper level low lifting out of the southern Plains. The
forecast favors temperatures trending gradually up over the weekend
to near normal values on Monday.
&&
.AVIATION /12Z Tuesday THROUGH Saturday/...
Generally VFR expected through tonight outside of ongoing light
rain showers and showers/isolated thunderstorms later this
afternoon/evening. The first round of showers will exit to the
east later this morning with limited reductions to MVFR. A post-
frontal trough will sweep east across terminals later this
evening (~20Z/Tue through ~04Z/Wed) bringing another round of
showers and isolated thunderstorms to terminals. Have a TEMPO
group in place for any MVFR/IFR that occurs with evening round
of showers and isolated thunderstorms. The parent low pressure
system will linger across the Great Lakes region allowing for
periods of lake enhanced/effect rain showers to impact
terminals. Opted for a VCSH for now at terminals downwind of
Lake Erie to account for any lake effect precipitation behind
the post-frontal trough tonight.
Gusty southwesterly to westerly winds will persist across
terminals through the TAF period with sustained winds 10-15
knots gusting to 20-25 knots.
Outlook...Periods of non-VFR are expected Tuesday night through
Saturday as scattered to widespread rain showers and isolated
thunderstorms accompany disturbances. In addition, localized
lake-effect rain showers and perhaps occasional lake-effect
thunderstorms will impact the Snowbelt of NE OH/NW PA and
vicinity Wednesday through at least Friday and result in
periodic non-VFR conditions.
&&
.MARINE...
Hazardous marine conditions will persist through this week as low
pressure glides east across the Great Lakes region. Confidence in
gale force winds has increased enough for Gale Watch to be issued
across the central basin of Lake Erie for Wednesday afternoon and
evening. Small Craft Advisories remain in effect across the
remainder of Lake Erie through much of the week and will expire from
west to east Thursday morning through early Friday morning.
Southerly winds 15-25 knots early this morning will turn
southwesterly behind a cold front through late this morning while
increasing to 25-30 knots. Strong southwesterly winds will persist
through Wednesday with a period of 35+ knot winds possible across
the central and eastern basins Wednesday afternoon and evening.
Elevated westerly to northwesterly winds 20-25 knots will remain on
the lake through Thursday night before diminishing to 10-15 knots by
Friday afternoon.
Given the prolonged period of strong southwesterly winds a Low Water
Advisory will likely be needed as water levels drop below the
critical mark of -1 inch above low water datum. Additionally,
airmass change behind the cold front and lingering surface troughing
will promote ideal conditions for waterspouts to develop Tuesday
night into Thursday morning.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...Small Craft Advisory until 4 AM EDT Thursday for LEZ142>144.
Small Craft Advisory until 11 AM EDT Wednesday for LEZ145>148.
Gale Watch from Wednesday morning through Wednesday evening
for LEZ145>148-165>168.
Small Craft Advisory until 10 AM EDT Friday for LEZ149.
&&
$$
SYNOPSIS...10
NEAR TERM...10
SHORT TERM...10
LONG TERM...10
AVIATION...13
MARINE...13
Source:
CLE issues Area Forecast Discussion (AFD) at Oct 21, 7:36 AM EDT---------------
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