859
FXUS61 KCLE 260814
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
414 AM EDT Sun May 26 2024

.SYNOPSIS...
Low pressure will track northeast from the Mississippi Valley
toward the central Great Lakes today and tonight, lifting a warm
front into the area today followed by a cold front on Monday. A
few disturbances will cross the area Tuesday into Wednesday
before high pressure returns Thursday.

&&

.NEAR TERM /THROUGH MONDAY/...
Areas of dense fog have developed across interior NW PA and NE
OH, primarily in river valleys and locations that received
rainfall on Saturday. A Dense Fog Advisory is in effect for
inland zones including Geauga and Portage counties east, however
a period of patchy dense fog is possible in Summit, Lake, and
far eastern Cuyahoga counties right around sunrise. The advisory
ends at 10 AM, but it`s likely that most fog is gone by 8 or 9
AM since diurnal mixing will kick in pretty quickly.

The forecast becomes quite challenging later today. A warm
front will lift north into at least the southern half of the
area today as low pressure lifts northeast from the Mississippi
Valley towards the central Great Lakes with a shortwave crosses
the area along the warm front late this afternoon into this
evening. The shortwave will lift a line of showers and
thunderstorms into southwestern zones at around 21Z/5 PM. There
has been quite a shift in guidance in the last 12-24 hours with
most CAMs hinting at a bit more instability across the area and
the better LLJ support over the area this afternoon into early
to mid evening rather than overnight, which could result in an
earlier window for severe weather potential and perhaps slightly
higher chances since convection will be occuring during a more
diurnally favorable period. With that being said, stronger
convection to the south could rob the area of additional
moisture and destabilization will depend on the location of the
warm front when the shortwave crosses the area. If
destabilization does occur, damaging wind gusts will be the
primary threat but can`t rule out large hail in the Slight Risk
area. Instability wanes with the loss of diurnal heating this
evening, so the severe weather risk should diminish as the
storms track northeast. There may be enough helicity/shear for
an isolated tornado threat in the western half of the area. If a
scenario with higher low level moisture pans out, heavy
rainfall will be possible but the flooding threat will be low
since storms will be quite progressive.

The line should exit the area shortly before midnight. The next
round of showers and thunderstorms will likely clip the area
overnight into Monday morning as an MCS tracks across the Ohio
Valley and a pre-frontal shortwave ripples across the region.
The nocturnal severe weather risk has shifted south into the
Ohio Valley where the MCS will take advantage of the best LLJ
and instability. Will need to keep an eye on guidance and
mesoscale features throughout the day though, especially if the
afternoon/earlier evening convection does not materialize. Any
precip may less progressive and PWAT values as high as 1.5
inches may result in locally heavy rainfall and a low-end
flooding threat, primarily south of US-30.

The aforementioned low will track northeast across the central
Great Lakes Monday and its cold front will cross the CWA Monday
morning and afternoon. Scattered showers/storms remain likely in
the eastern half of the local area Monday morning and afternoon
and can`t rule out a few stronger storms in far eastern zones
as the front begins to exit during peak heating. By that time,
the best forcing/instability will likely be to the east of the
area so the severe weather threat is low in NW OH/NW PA.

Today`s highs will be in the low to mid 80s with overnight lows
in the 60s. Temps will be a bit cooler Monday and anticipate
maximum temps in the mid 70s.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Shortwave troughs will continue to move along the parent upper level
trough for much of the short term period, resulting in additional
potential for showers and thunderstorms on Tuesday and Wednesday.
Initially on Monday night, a few lingering showers are possible
across the eastern counties as a surface cold front moves east of
the area, but any dry period will be shortly lived as another
shortwave advects energy across the area Tuesday morning. The best
chance of showers and thunderstorms on Tuesday should be downwind of
a northwest flow across Lake Erie, but with diurnally instability
and enough moisture elsewhere, cannot rule out additional showers
and thunderstorms over the remainder of the area through Tuesday
night. On Wednesday, another weak cold front will move southeast
across the area, marking the transition to a dry period for the end
of the week. By Wednesday night, high pressure and an associated
upper level ridge will finally be pushing east and drying out the
area.

High temperatures on Tuesday will climb into the upper 60s to low
70s for much of the area before cooling behind the departing cold
front to only reach into the 60s on Wednesday. Overnight lows will
also gradually cool from the mid to upper 50s on Monday night to the
mid 40s by Wednesday night.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
A dominant upper level ridge and associated surface high pressure
over the central portion of the US will act as the primary moderator
of weather through the long term period. This will allow for at
least a couple dry days, but will also result in temperatures again
climbing to above normal for this time of year with highs reaching
into the upper 70s to low 80s by Saturday. There is a bit of
difference in the timing of the progression of the ridge, but either
way it looks to remain over the area.

&&

.AVIATION /06Z Sunday THROUGH Thursday/...
Patchy fog has begun to develop east of KCLE to KCAK and expect
fog to expand for the rest of the overnight hours through right
around sunrise. Fog will generally remain confined to areas
that received precipitation on Saturday. Have IFR fog in the
TAFs at KCAK and KYNG, however there will likely be a period of
LIFR conditions at these terminals. KERI is still a bit tricky
since fog will likely sneak into at least inland Erie County PA
and possibly develop over Lake Erie, but there`s still some
uncertainty in how far north and south the fog reaches. It`s
possible that KERI largely remains at VFR/MVFR with a brief
period of IFR near sunrise. Relative humidity values may be high
enough for a brief period of MVFR fog at KCLE/KMFD, although
the likelihood is too low to include in the TAF. Fog will
quickly dissipate when daytime mixing develops shortly after
sunrise.

A line of showers and thunderstorms will lift northeast into
the area late this afternoon or early this evening (~21Z) and
reach NW PA before Midnight. Maintained VCTS/TEMPO TSRA in the
TAFs for now since there`s still some uncertainty in timing and
coverage. Can`t rule out a few stronger gusts mainly at
KTOL/KFDY, but will leave any strong gusts out of the TAF until
confidence increases. There will likely be a brief break in
precipitation before the next round of showers/storms begin to
lift into the area towards the very end of the TAF period.

Outlook...Non-VFR possible in showers and thunderstorms
late Sunday night into Monday. Periodic Non-VFR conditions may
persist in scattered showers and thunderstorms on Tuesday and
Wednesday.

&&

.MARINE...
Low pressure over the Plains will move northeast towards the region
today, extending a warm front north of Lake Erie this afternoon.
This will result in east winds of 5-10 knots transitioning to south-
southwest winds at 10-15 knots which will persist into Monday. On
Monday, a cold front will move east, again shifting the winds to
gain a more westerly component and increasing to 15-20 knots for the
nearshore waters and up to 25 knots for the open waters. With an
established onshore component, waves will build to 3-5 feet
throughout the day on Monday, additionally creating hazardous
swimming conditions with an increased risk of rip currents. One or
two additional weak cold front will move east across the area on
Tuesday and Wednesday, keeping winds from west-northwest, but
gradually weakening them to 10-15 knots by Wednesday morning. This
period will likely need a Small Craft Advisory, but held off for one
more forecast period to get a better handle on timing.

Late Wednesday into Thursday, high pressure will build across the
region, allowing for winds on Lake Erie to persist on Thursday from
the north-northwest at 10-15 knots before weakening to below 10
knots through the end of the week.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Dense Fog Advisory until 10 AM EDT this morning for OHZ013-014-
     022-023-033.
PA...Dense Fog Advisory until 10 AM EDT this morning for PAZ002-003.
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...Maines
NEAR TERM...Maines
SHORT TERM...Campbell
LONG TERM...Campbell
AVIATION...Maines
MARINE...Campbell