567
FXUS61 KCLE 100815
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
415 AM EDT Wed Jul 10 2024

.SYNOPSIS...
The remnants of Beryl will lift across northwest Ohio today,
dragging a cold front across the region this afternoon. A trough
will cross Lake Erie tonight into Thursday morning before high
pressure finally builds in Thursday afternoon. Another trough
will cross the Great Lakes Friday into Saturday.

&&

.NEAR TERM /THROUGH THURSDAY/...
The effects of Beryl are well underway across the region early
this morning. Infrared satellite and water vapor loops show the
remnant surface low centered over Indiana as it phases with a
strong mid/upper shortwave trough lifting across Illinois. This
is allowing the surface low to deepen, and guidance suggests it
deepening to around 1000 mb as it lifts through NW Ohio and
western Lake Erie this afternoon and evening. A large shield of
rain and embedded thunderstorms driven by a 30-40 knot low-level
jet and resultant moist, theta e advection and isentropic ascent
north of a retreating warm front is spreading across NW and
north central Ohio. This will continue moving north to
northeastward at a good clip through 12Z, although NE Ohio and
NW PA are trending toward much less rainfall compared to NW
Ohio, which is unfortunate since moderate drought remains along
and east of I-71. The main concerns between now and 12Z are
isolated areas of rotation within the embedded convective cells
and locally heavy rainfall.

Regarding the rotation and tornado potential, we are seeing a
downward trend compared to earlier tonight since the latest
mesoanalysis shows less than 500 J/Kg of SBCAPE remaining as
well as quite a bit of CIN due to a nocturnal inversion. There
continues to be an impressive amount of shear due to the "spin"
of the low and spiral convective bands, and this combined with
the low-level jet is yielding 40-50 knots of low-level (0-1 Km)
shear and low-level SRH values of 200-400 m2/s2. However, the
limited SBCAPE and inversion is keeping the bulk of the
convection elevated, and therefore, keeping rotation elevated.
Cannot rule out a brief spin up tornado between now and 12Z, but
the threat is likely over.

Regarding heavy rainfall and localized flooding, this threat is
also decreasing. Much of NW Ohio received 1 to 2.5 inches of
rain over the past few hours where Flood Advisories are
currently in effect, but the steadiest and heaviest rain will be
exiting that area by 09Z. Farther east, the showers and
thunderstorms will be more transient, so only expecting 0.25 to
0.50 inches through 12Z in much of north central and NE Ohio
and NW PA.

Once the warm front moves over Lake Erie this morning, a
pronounced dry slot is still expected to move in. This should
greatly diminish precip coverage, so dropped PoPs to mostly
chance after 12Z except likely in NW Ohio where more frequent
additional showers will wrap in. The focus will then shift to
any additional development of convection this afternoon, which
doesn`t look like much. As the low lifts across the western
basin of Lake Erie this afternoon and into southern Ontario this
evening, a trailing cold front will sweep through the region.
The mid-level dry air and poor lapse rates will limit the
recovery of instability ahead of the front despite peaks of
sunshine, but HREF guidance suggests 1000-1500 Joules of MLCAPE
could develop in far NE Ohio and NW PA, so CAMS indicate that
is the most likely area for convection to redevelop and affect
our area if it doesn`t all develop east of the CWA. Deep layer
shear remaining around 40-50 knots and around 20 knots of low-
level shear could support isolated damaging winds and a tornado
if anything can develop in that area before exiting the CWA.
Timing would be roughly 16-19Z. Otherwise, just widely scattered
showers are expected this afternoon and evening.

As the low lifts across southern Ontario tonight and eastern
Ontario Thursday, wrap around moisture will keep scattered
showers going, especially in NE Ohio and NW PA. In fact, a
surface trough looks to cross Lake Erie in the 8-12Z Thursday
timeframe, so raised PoPs to likely in the "snowbelt" areas
east of Cleveland into NW PA late tonight and early Thursday
morning. This QPF will only amount to 0.10 inch or less. Surface
ridging will finally build in from the western Great Lakes
Thursday afternoon, so expect mainly dry conditions in the
afternoon and evening along with cooler and less humid
conditions as the mid/upper trough axis slides into the Great
Lakes.

Highs today will range from the upper 70s to around 80 in NW
Ohio to the low to mid 80s in north central and NE Ohio and NW
PA. Highs Thursday will be in the mid 70s to low 80s with less
humid conditions. Lows tonight will range from the low to mid
60s.


&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
Surface ridging builds in Thursday night as Beryl`s remnant low
continues exiting through Quebec, leading to a quiet Thursday night
and Friday morning. With surface dew points still in the upper
50s/lower 60s and decent radiational cooling conditions thanks to
light winds and mainly clear skies, some radiation fog may develop
late Thursday night into early Friday. Lows Thursday night will
generally range from the low to mid 60s with a few upper 50s across
interior Northeast OH and Northwest PA. A weak shortwave moves
through Friday afternoon. Generally expect the column to be too dry
to see much precip, though can`t rule out an isolated shower or
thunderstorm in the afternoon, mainly across Northwest and North
Central OH. Highs on Friday will generally reach the low to mid 80s.
Behind the weak shortwave Friday night expect weak surface ridging
to regain control, leading to another quiet night with perhaps a bit
of patchy fog yet again. Lows Friday night will perhaps be a couple
of degrees milder than Thursday night, generally reaching the 60s.

A more active northwest flow aloft looks to develop starting
Saturday and Saturday night as ridging builds over the central U.S.
The atmosphere on Saturday may still be too dry and stable for much
convection so only bring a slight chance (20%) POP into the I-75
corridor late in the day, though do expand 20-30% POPs southeast
towards Cleveland and Mansfield Saturday night due to potential for
a remnant MCS to spill in from the northwest at some point. Highs on
Saturday will warm into the mid to upper 80s, with lows Saturday
night generally in the mid 60s to near 70.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
A very warm and potentially unsettled period of weather is in store
to end the weekend and start next week. The area will be situated
between ridging over the central and southern U.S. and broad
troughing over eastern Canada and the Northeast, with occasional
shortwaves riding through the flow. Expect above average
temperatures with a fair amount of humidity for this period along
with off and on thunderstorm chances. Timing of higher thunderstorm
chances in such a fast-moving pattern is a fool`s errand 4-7 days
into the future, though generally have a mix of 20-50% POPs Sunday
through Tuesday, relatively higher during each afternoon and evening
but not dropping off completely at night. We will be on the edge of
a hot and humid, unstable airmass, especially Monday and Tuesday,
with moderate shear at times on the edge of stronger flow aloft to
our north. Given this, potential for severe weather will need to be
monitored Sunday through Tuesday (with Monday and Tuesday the more
concerning of these three days). This may include the potential for
more organized MCS/s to drop in from the northwest.

&&

.AVIATION /06Z Wednesday THROUGH Sunday/...
Messy TAF forecast as a large area of showers and thunderstorms
moves north to northeastward across the region early this
morning associated with the remnants of Beryl. Cigs will slowly
drop as the rain moves in, but the lower vis should be confined
to the heavier downpours, so went with mainly low end VFR to
MVFR conditions with the rain early this morning timed from
southwest to northeast. The steadiest showers are likely to
occur before 12Z followed by a break to scattered showers as a
pronounced dry slot moves in, but expect showers to fill back in
decently for a few hours from late morning into the afternoon,
so kept cigs mainly MVFR out west with low end VFR in the east.
Periods of IFR are possible in NW Ohio. By this evening into
tonight, showers will finally become widely scattered, but
lingering moisture will likely result in pockets of low cigs and
vis, so started to introduce IFR by early tonight.

E to NE winds will become gusty this morning with an increase to
10-15 knots and gusts over 20 knots while turning more southerly
by mid morning into the afternoon. Winds then turn more westerly
late this afternoon and this evening with speeds of 10-20 knots
gusting to 20-25 knots. Winds will gradually diminish tonight.

Outlook...Periodic showers/thunderstorms with non-VFR expected
tonight through Thursday and Saturday night into Sunday.

&&

.MARINE...
Active marine conditions are expected through Thursday as Beryl`s
remnant low moves over or near Lake Erie. A warm front will lift
across Lake Erie this morning ahead of the remnant low with strong
easterly flow for a few hours ahead of the warm front. Waves will
briefly build to 2-5 feet from the open waters of the central basin
into the open and nearshore waters of the western basin early this
morning, for which a Small Craft Advisory is in effect until 10 AM.
Showers and thunderstorms are likely ahead of the warm front through
about 8 or 9 AM, with some potential for a waterspout or two over
the southern portions of the lake. Winds will briefly lull this
morning behind the warm front.

A cold front will cross the lake from west to east immediately ahead
of Beryl late this morning into this afternoon, shifting winds to
the south-southwest at 10-20 knots and building 2-4 or 3-5 footers
over the open waters east of The Islands this afternoon. Current
impression is we will not need renewed Small Craft Advisories for
this marginally strong offshore flow, though a few hi-res models do
have more solid 20-25 knot winds this afternoon. If that verifies,
we may need to raise the next round of advisories earlier than
currently expected. A few thunderstorms may re-develop ahead of the
cold front in the midday and early afternoon timeframe east of
Cleveland. Beryl`s remnant low and a sharp trailing trough axis will
cross over western Lake Erie late this afternoon and evening, before
the low exits northeast into southern Ontario overnight tonight into
Thursday and drags the trough axis east across the rest of the lake.
Behind the low and trough axis winds will shift to the west-
northwest and increase to 15-25 knots through Thursday morning,
gradually subsiding from west to east Thursday afternoon and
evening. A brief period of sustained winds to near 30 knots is
possible across the western and central basin tonight if Beryl`s
remnant low is as strong as some models currently depict. If we
don`t need them for the gusty southerly winds this afternoon, Small
Craft Advisories and accompanying high rip current/Beach Hazards
Statements will be needed for most or all nearshore zones beginning
from west to east late today into tonight and will be issued when we
expire or cancel this morning`s headline for the western basin.
Expect the headlines through much of the day Thursday east of the
Islands, with headlines potentially coming down earlier in the day
farther west. Waves may reach 4-7 feet tonight into Thursday in the
central and eastern basins, with 2-4 or 3-5 footers this evening and
tonight in the western basin.

Quiet marine conditions are expected to return Thursday night and
persist through early Sunday. Southwest winds will turn a bit brisk
at 10 to 20 knots at times Sunday through Tuesday. Thunderstorm
chances will increase too, with some potential for one or two
clusters of organized/strong thunderstorms to move across the lake
from the west/northwest between late Sunday and Tuesday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...Small Craft Advisory until 10 AM EDT this morning for
     LEZ142>144.

&&

$$

SYNOPSIS...Garuckas
NEAR TERM...Garuckas
SHORT TERM...Sullivan
LONG TERM...Sullivan
AVIATION...Garuckas
MARINE...Sullivan