333
FXUS61 KCLE 200213
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
1013 PM EDT Sun May 19 2024

.SYNOPSIS...
A cold front approaches from the northwest this evening before
lifting to the north as a warm front on Monday. A stronger cold
front will cross through the region Wednesday night.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
9:30 PM Update...

Convection near Lucas and Wood Counties continues to hang on.
There is almost no shear available due to the weak wind fields,
but it continues to regenerate along the low-level convergence
of the synoptic front and numerous outflow boundaries. Locally
heavy rain in excess of 2 inches could occur where the cells
persist over the next hour or two before waning instability
finally allows it to dissipate. Temperatures look good
overnight, so no changes were made.

6:30 PM Update...

The forecast remains on track this evening. Chance PoPs in NW
Ohio this evening still look good with the broken line of
convection currently over northern Indiana and SE Michigan. This
activity will sink into the region over the next 1-2 hours and
could produce brief heavy rain and gusty winds given MUCAPE up
to 2000 J/Kg and high DCAPE up to 1400 J/Kg. However, the cold
frontal boundary is already stalling as it runs into building
mid/upper ridging, so the convection will not make it any
farther than NW Ohio before it moves away from the upper support
and diurnal cooling sets in. Everything should be largely
dissipated by 03 or 04Z.

Original Discussion...

A very warm May afternoon with everyone outside of a lake breeze
along the eastern lakeshore surging well into the 80s, with the
Toledo area approaching 90. A weak cold front will approach
Northwest Ohio this evening before lifting well to our north as
a warm front on Monday. Outside of the front itself forcing is
limited, but cumulus are percolating along it from Indiana into
southeast lower Michigan with a few showers / storms attempting
to fire. Expect isolated to scattered activity to fill in and
sag towards the Toledo area this evening before gradually
dissipating between sunset and midnight due to a lack of forcing
and gradual stabilization with the loss of daytime heating. Very
weak shear and forcing preclude any kind of organized severe
weather threat, but steep low-level lapse rates and large DCAPE
do suggest a strong to locally damaging downburst can`t be ruled
out with the strongest cell or two. Greatest concern for a
stronger storm is just northwest of our area, but it`s worth
watching if any stronger storms to drift towards Toledo this
evening. Some guidance tries re-firing a few showers in the
vicinity of North Central Ohio during the pre-dawn Monday,
perhaps as modest warm air advection kicks in and interacts with
any lingering outflow boundaries from this evening`s activity.
Confidence in this scenario is very low so left mentionable POPs
out of the forecast after midnight. The rest of northern OH and
northwestern PA will confidently remain dry tonight with very
patchy river valley fog from eastern OH into western PA.

The Monday and Monday night period will remain very warm and
generally dry beneath strong ridging aloft. Expect plenty of sun
to start the day Monday. Strong heating of a fairly moist
airmass will yield modest to moderate, uncapped CAPE into Monday
afternoon. It`s hard to find much forcing, though the
combination of a lake breeze, a very subtle vort max (evident on
multiple models at 250mb), and modest low-level warm air
advection could be enough for isolated to widely scattered
storms to develop across northern and perhaps western portions
of the forecast area during the afternoon. Have slight chance to
low chance (20-30%) POPs to cover this, highest along and just
inland from the central lakeshore. Like today, shear and forcing
will be quite weak which will generally limit any severe
weather threat if storms can develop Monday. However, the
thermodynamics could still support a couple of stronger
downbursts and perhaps marginal hail with the most intense
cells...most likely with any cells that fire on and get a boost
from the lake breeze. Look for activity to gradually diminish
after sunset Monday night given a general lack of forcing.

Lows tonight will range from the mid to upper 50s in a few
interior valleys from Northeast OH into Northwest PA to the mid
to even upper 60s along and west of I-71. Highs on Monday well
into the 80s, with potential to get close to 90 from Cleveland
west towards Toledo and Findlay, assuming showers / storms don`t
become more widespread than expected. Lows Monday night will
stay in the 60s, with a few spots (such as Cleveland and
Northwest OH) struggling to cool much below 70. It will
certainly feel like summer to start the work week!

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
An active short term period is in store as an upper low moves into
the Great Lakes region Tuesday night into Wednesday. For Tuesday, a
surface boundary will lift across the region accompanied by a weak
upper level shortwave. This will support scattered showers and
isolated thunderstorms across Northern Ohio Tuesday afternoon. By
Wednesday, the surface low will occlude over the Upper Midwest while
its accompanying cold front stalls out in the vicinity of
Illinois/Indiana. As the front remains stalled, robust southerly
flow will continue to fuel a warm and moist airmass characterized by
dewpoints in the lower 60s and temperatures in the upper 80s. The
timing of the frontal passage continues to slow down with the front
not entering western counties until late Wednesday night. Given the
warm and humid airmass in place with MLCAPE values progged between
1500-2000 J/kg accompanied by bulk shear values of 30-35 kts, a
severe weather threat remains on the table for Wednesday. An
inhibiting factor will be cloud debris from earlier convection early
Wednesday which could minimize destabilization across Northern Ohio.

Unseasonably warm temperatures are expected in the short term period
with highs reaching the mid 80s to near 90s degrees on Tuesday.
Still some uncertainty with the precipitation forecast on Tuesday,
but those who remain dry and mainly sunny could flirt with 90
degrees Tuesday afternoon. Warm again on Wednesday ahead of the cold
front passage, though more expansive cloud cover with scattered
showers and storms during the day Wednesday will keep highs closer
to the low to mid 80s. Warm overnight lows on Tuesday night into the
upper 60s to lower 70s turn cooler behind the frontal passage
Wednesday night as they settle in the low 60s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
Quieter long term period as PoPs exit from west to east behind the
frontal passage Thursday. A ridge of high pressure builds overhead
by Friday and will keep us dry to end the week. Precipitation comes
back into the forecast for next weekend as the previous cold front
lifts back north as a warm front. Near normal temperatures through
the long term in the mid to upper 70s for highs and mid to upper 50s
for lows.

&&

.AVIATION /00Z Monday THROUGH Friday/...
VFR will generally prevail at all sites through the period. The
exception is KTOL and KFDY which may see a thunderstorm over
the terminals within the next 1 to 3 hours causing brief drops
to MVFR or lower, as well as KERI which could see some MVFR mist
late tonight. Regarding the thunderstorms, there is currently a
broken line from central Indiana to western Lake Erie. If these
affect KTOL and KFDY, it would be between now and 03Z at the
latest, but they will be weakening with east and southeastward
extent, so kept the mention to VCTS in the TAFs. Regarding the
mist late tonight around KERI, confidence is also fairly low. We
mixed out deeper this afternoon, so no dense fog is expected
tonight, but HREF guidance suggests light NE flow off Lake Erie
below a lingering inversion could cause some lower visibilities
late tonight, so added 5SM to the KERI TAF. If anything lower
occurs, it should not last long. Most areas will stay dry
Monday, but an isolated thunderstorm is possible along the lake
breeze boundary in the afternoon around KCLE.

Light and variable winds tonight will become S to SW at 5-10
knots Monday.

Outlook...Mainly VFR expected outside of any thunderstorms.
Isolated thunderstorms are possible Monday and Tuesday
afternoons. Scattered to numerous thunderstorms are more likely
Wednesday afternoon and evening.

&&

.MARINE...
Quiet conditions continue on Lake Erie to end the weekend and begin
the week as high pressure remains overhead. A warm front will lift
north across the lake Monday and allow for winds to become
southeasterly at 5-10 knots. Low pressure lifts northeastward toward
the Northern Great Lakes Tuesday into Wednesday. This low will drag
a cold front east across the lake Wednesday night into Thursday.
Winds remain generally southerly ahead of the frontal passage but
increase to 10-20 knots during the day Wednesday. Winds then turn
westerly at 10-15 knots behind the front for Thursday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Air Quality Alert until midnight EDT Monday night for
     OHZ010>014-020>022-089.
PA...None.
NY...None.
MARINE...None.

&&

$$

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