130
FXUS61 KCLE 231327
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
927 AM EDT Sun Jun 23 2024

.SYNOPSIS...
A cold front will move east this afternoon before high pressure
builds in for Monday and Tuesday. Another cold front associated with
a low pressure over Ontario will move east across the area on
Wednesday before high pressure returns for the end of the work
week.

&&

.NEAR TERM /THROUGH MONDAY/...
9:25 AM Update...
Line of showers and thunderstorms that brought some isolated
strong wind gusts earlier this morning is continuing to track
east out of our local forecast area. First glance of 12Z data is
continuing to indicate that there will be some redevelopment of
showers and thunderstorms across the eastern half of the
forecast area this afternoon and early evening. A fairly moist
environment with dew points hovering around 70 degrees
contributing to moderate instability with MUCAPE values between
1500-2000 J/kg and roughly 25-30 knots of 0-6 km bulk shear
should support damaging wind gusts and isolated large hail.

630 AM Update...
Decaying showers and thunderstorms continue to move east across
the area this morning, producing wind gusts generally between
25-35 mph. Rainfall totals with this line all appears to be
0.25" or less as a result of the quick moving line. Behind this
initial line of storms, conditions are clearing out although
temperatures remain quite cool in the upper 60s to low 70s. The
big question going into later this morning/afternoon is how well
the atmosphere will be able to rebound ahead of the cold front
which currently extends south across western Michigan into
northwest Indiana. If the area can rebound enough to see
marginal instability, the strong isentropic lift with the front
could be enough to establish some additional storms along and
east of I71. Confidence is pretty low at this point that the
atmosphere will rebound enough to produce widespread severe
weather, but will need to monitor the mesoscale environment over
the next couple hours to really get a feel for the severe
potential this afternoon. Stay tuned for updates to the
forecast throughout today.

Previous Discussion...
Currently, a broad trough aloft is providing support for a surface
low pressure to continue to move northeast through the western Great
Lakes region. The area currently lingers in the warm sector of the
low pressure with temperatures across the area in the 80s and
dewpoints lingering in the mid to upper 60s. Looking upstream across
northern Indiana, a line of convection continues to track east,
gradually weakening in terms of intensity, but still maintaining
widespread thunderstorms with gusty winds and lightning. A LLJ of 40-
45 knots has moved across the area resulting in non-convective gusty
winds up to 20 knots this morning. This LLJ and mid-level support
should be enough to maintain the line of convection, where locally
higher gusts are possible. In the heaviest storms, expect very
efficient rainfall of over 1"/hr as PWAT values climb over 2" and
warm cloud layers deepen to over 13 kft. With this overall limited
instability this morning, still expecting a general weakening trend
with locally higher wind gusts and heavy rain possible.

The trickier part of the forecast is for this afternoon as the
aforementioned line of convection exits east of the area late
morning. This afternoon, the cold front is expected to push east
across the area, stirring up another potential round of scattered
convection. Many ingredients, including a moist boundary layer,
increasing instability to 1000-1500 J/kg, and a lingering LLJ will
couple with strong isentropic ascent along the boundary to provide
enough support for additional storms development along and east of I-
71. Primary concern with any storms that develop with be strong
damaging winds, although with effective shear values of 20-30 knots
isolated large hail cannot be ruled out. In addition to the severe
potential, the PWAT values remaining over 2" and deep warm cloud
layers will produce heavy rainfall. In areas that received
precipitation with the initial round of storms, may see some
flooding especially in urban and low lying areas. The biggest
question mark with this forecast is in regards to how fast the
atmosphere will be able to recover behind the initial round of
convection. Widespread clouds are expected today which typically
would limit instability and potentially limit convection, but given
the strong surface lift and moisture rich environment confidence is
low that the clouds will have as strong of an effect. To highlight
these threats, SPC has issued a Slight Risk SWO for the far eastern
counties and a Marginal Risk SWO for the remainder of the areas
along and east of I-71. In addition, WPC has issued a Day 1 Marginal
ERO for those far eastern counties.

Showers and thunderstorms should primarily dissipate once the cold
front pushes east late this evening. A few showers and storms may
linger into late evening, but with a northwest flow becoming
established across the area, colder 850mb temperatures near 10C will
begin to push across Lake Erie and transition the lingering
precipitation to primarily be lake enhanced with limited thunder
potential. By mid-Monday morning all precipitation should end across
the area as high pressure becomes established over the area.

High temperatures today and Monday return to more seasonal, climbing
into the low 80s for much of the area with the portions of the
eastern counties possibly only reaching into the upper 70s.
Overnight lows tonight will drop into the low 60s.

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
A dry, stable pattern will allow for a pleasant night on Monday with
temperatures falling below 60 degrees for a large portion of the
forecast area - first time in about 2 weeks! Unfortunately, the
remainder of the short term period will feature a more active
pattern and return to warmer temperatures and high humidity. Surface
high pressure will move east for Tuesday and return flow across the
region will allow for temperatures to soar back into the upper 80s
to lower 90s and dew points reach the 60s again. A minor shortwave
will move through the region on Tuesday and allow for some small
shower and storm chances, but the main show appears to be on
Wednesday as better synoptic forcing will enter the region with a
larger upper trough and surface cold front. Have PoPs increasing to
likely and even categorical for Tuesday night into Wednesday. Have
come concern about severe weather potential for Wednesday, as the
present consensus for the timing of the main synoptic forcing
features is Wednesday afternoon and evening, which coincides with
peak heating of the day with upper 80s and near 70s dew points that
would support a fairly robust thermodynamic environment for storms.
This day will be one to watch moving forward.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
Thursday should be a repeat of Monday with high pressure entering
behind the main synoptic system, allowing for a dry, stable
environment with cooler than normal temperatures and pleasant
conditions. The surface high will shift east on Friday as the ridge
axis enters and return flow once again enters the region with highs
achieving the mid to upper 80s again. A shortwave will override the
ridge later on Friday into Saturday, followed by a stronger upper
trough for the weekend. This will once again contribute to an active
pattern with increasing storm potential for the weekend.

&&

.AVIATION /12Z Sunday THROUGH Thursday/...
Predominantly VFR conditions continue across the area this
morning as a line of showers along I-71 will continue to push
east. In the heaviest of these showers, visibilities have
briefly dropped to IFR distances but have quickly recovered
given the fast moving nature of the line. In addition, isolated
wind gusts greater than 30 knots have been reported at some
terminals.

Shifting gears to the forecast for this TAF period there will be
a continued chance of showers and thunderstorms as additional
convection is expected to redevelop along the cold front late
this morning into the afternoon. The cold front currently
extends south across western Michigan and northwest Indiana.
Southwest winds ahead of this front will continue to increase to
12-15 knots, gusting between 20-25 knots for most terminals
today. As the cold front approaches, additional showers and
thunderstorms may develop which may briefly reduce visibilities.
In addition, ceilings are expected to lower to MVFR heights with
the passage of the boundary. Confidence is high in the ceilings
lowering, but given this mornings convection confidence is
fairly low at this point with placement and timing of any
additional convection this afternoon. The best chance remains
for the eastern terminals.

As the cold front moves east of the area late this afternoon,
showers will cease and conditions will gradually rebound to
widespread VFR. Winds behind the front will shift to become
northwesterly and initially be 12-15 knots, gusting up to 20
knots. Near 00Z all winds will calm to 5-10 knots from the
northwest, which will persist through the remainder of this TAF
period.

Outlook...Non-VFR possible in scattered showers and
thunderstorms across Northeast Ohio and Northwest Pennsylvania
Sunday night into Monday. Additional non-VFR possible in showers
and thunderstorms Tuesday evening through Wednesday.

&&

.MARINE...
After a rather benign marine weather week, the weather will be more
active this week with several windows for marine headlines, several
widespread storm chances, and generally increased winds across the
lake. For today, southwest flow will increase ahead of a cold front
this morning, winds will get close to 20 kt and will have a Small
Craft Advisory for the winds starting this morning. The front and
convection will cross the region later today and onshore flow will
increase wave action, which will allow for a longer period for the
Small Craft Advisory and these areas will be the land zones with the
Beach Hazards Statement for increased swimming risk with the higher
waves. Have tweaked the areas and timing of the marine hazards this
morning just slightly to align with the current wind and wave
forecasts. High pressure across the region on Monday will allow for
decreasing northwest flow during the day, followed by light and
variable flow overnight. Return flow on the back side of the high on
Tuesday will allow for increasing south to southwest winds and there
are some minor chances for showers and storms. A potent cold front
will enter for Wednesday and bring widespread showers and storms to
the region. Southwest flow will increase ahead of the front to at
least 15 kt during the day on Wednesday. Winds will shift to the
northwest behind the front on Wednesday night and will increase
waves. This window could potentially need a Small Craft, but the
forecast remains below at this time. High pressure will return to
the region for Thursday and bring decreasing northerly flow.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Beach Hazards Statement through late tonight for OHZ010>012-
     089.
PA...Beach Hazards Statement through late tonight for PAZ001.
NY...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for
     LEZ142>144.
     Small Craft Advisory until 4 AM EDT Monday for LEZ145>147.
     Small Craft Advisory until 4 AM EDT Monday for LEZ148-149.

&&

$$

SYNOPSIS...Campbell
NEAR TERM...Campbell/Iverson
SHORT TERM...Sefcovic
LONG TERM...Sefcovic
AVIATION...Campbell
MARINE...Sefcovic