953
FXUS61 KCLE 250817
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
417 AM EDT Sat May 25 2024

.SYNOPSIS...
A warm front will lift north of the area this morning followed by a
cold front sweeping west to east across the area today. High
pressure will build east across the Great Lakes tonight into Sunday
morning. Another low pressure system will track out of the Plains
towards the Central Great Lakes on Monday pulling a stronger cold
front east across the area.

&&

.NEAR TERM /THROUGH SUNDAY/...
Surface low pressure is located just north of Minnesota this morning
with an occluded front extending to lower Michigan. A pseudo warm
front indicated largely by a dewpoint gradient bisects the area with
dewpoints near 60 degrees south of the boundary. Scattered showers
with a few thunderstorms have developed in the last hour across
southern lower Michigan where a 30+ knot low level jet is located
along the warm front. This activity will continue to expand near and
just north of Lake Erie. There is some potential for it to extend
down the axis of the warm front into NE Ohio/NW Pennsylvania this
morning but confidence is not real high in this so will only have
chance pops. Otherwise, the trailing cold front is forecast to reach
NW Ohio around 15Z and move east across the area through
approximately 21Z. With dewpoints in the 60-65 degree range, ML CAPE
values are forecast to reach 1200-1700 J/kg. Thunderstorms could
develop along any remnant boundary that may remain if the initial
round of activity does make it into NE Ohio or it may just develop
along the cold front. The greatest coverage of storms is
expected across NE Ohio and into NW Pennsylvania and this area
remains in a marginal risk of severe weather. Shear values of
25-35 knots will support the potential for both a few marginally
severe wind gusts and hail of a half inch to an inch. One note
to consider it the presence of convection overnight across
Missouri and Kentucky. PW values are forecast to increase to
around 1.5" along the cold front but this activity to the south
could potentially decrease moisture transport along the
boundary. Something to keep an eye on as we monitor conditions
and evaluate the 12Z model cycle. Although temperatures will
average 2-5 degrees cooler than yesterday, humidity will be up
so the airmass will still feel warm and muggy.

As the cold front exits to the east, surface high pressure will
build east across the region tonight into the first half of Sunday.
We look for clouds to clear as deep layer dry air arrives but less
certain on if some fog or stratus may develop with light winds. This
will likely depend on how much rain we get contributing to
boundary layer moisture, but did include a mention of patchy
fog in some favored eastern areas for late tonight. Otherwise
temperatures tonight will dip into the upper 50s.

Throughout the day on Sunday we will be monitoring a leading piece
of shortwave energy lifting out of the Plains. Moisture advection
has slowed down from the previous cycle and was able to slow down
the returning chance of precipitation into the afternoon, and then
mainly confine it to southern and western portions of the forecast
area through the daytime hours. Temperatures and dewpoints
increase again with instability building through the afternoon.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
As previous forecasts have mentioned, unsettled weather is expected
for the end of the this holiday weekend, particularly Sunday night
into Monday. The biggest change with recent model runs is that most
have slowed down the progression of the system over the Plains
northeast, resulting in a bit later onset of showers and
thunderstorms on Sunday. Upper level shortwaves advecting energy
across the area coupled with an area of strong divergence aloft will
aid in the development of convection across the area, although the
confidence in the severe weather aspect of this forecast has
diminished as the adjusted timing now has the storms developing in a
non-diurnally favorable environment, limiting CAPE values. However
with a LLJ of 50-55 knots pushing north across the area Sunday
night/early Monday morning, this may help supplement the support
needed in the low levels to maintain convection. With this set up,
primary concern remain gusty winds and hail, although a tornado is
not out of the realm of possibility. To highlight this concern, SPC
has issued a Day 2 Marginal Risk for areas along and west of I71. In
addition to the severe potential, there is also an ideal setup for
the development of very efficient rainfall with the strongest storms
that develop. Models suggest warm cloud layers growing in excess of
11kft and PWAT values moving across the area of 1.8-2". Current
forecast QPF totals for Sunday through Monday afternoon are 0.8-1.2"
of rainfall, but would expect locally higher totals in the strongest
storms. This heavy rainfall may result in localized flooding and
rises in rivers. To highlight this threat, WPC has issued a Day 2
ERO for much of the area with a Slight Risk across the southwestern
counties and a Marginal Risk for the remainder of the area
(excluding far NE OH and NW PA). Out of all this, the moral of the
story is stay weather aware and have ways to receive warnings Sunday
night into Monday as there is a multi-hazard system that will likely
impact the area.

On Monday morning a cold front associated with the aforementioned
low pressure tracking northeast through the region will move east
across the area, gradually reducing the chances of precipitation
from west to east through Monday night. This will be short lived as
the upper level trough still over the region pivots again, moving
another shortwave trough and associated cold front east across the
area. There is a potential for thunder given the diurnally favorable
timing of this secondary cold front, however overall forcing and a
slightly drier airmass should keep much of the thunder activity
limited. These showers may possibly continue through Tuesday night,
although should become less widespread. The threat for very
efficient rainfall will diminish on Tuesday, not posing additional
flooding concerns.

High temperatures throughout the period will begin in the mid to
upper 70s on Monday, but behind the cold front will only climb into
the upper 60s to low 70s on Tuesday. Overnight lows will follow a
similar trend falling into the low to mid 60s on Sunday night and
then gradually cooling to drop into the low 50s by Tuesday
night.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A similar story continues into the start of the long term period as
the same upper level trough continues to pivot over the Great Lakes
region, moving additional shortwaves across the area. This support
coupled with diurnally favorable timing should be enough to support
additional showers and isolated thunderstorms through Wednesday, but
finally high pressure will begin to push east and allow showers to
diminish from west to east Wednesday night. This high will remain
over the region through Friday, allowing for a period of dry
weather. With this transition in systems, temperatures will again
gradually climb to above normal by the end of the period with highs
on Friday forecast to approach 80 across the western CWA.

&&

.AVIATION /06Z Saturday THROUGH Wednesday/...
Earlier cluster of showers and thunderstorms moving out of
Indiana dissipated before reaching the area. A warm front
extends from roughly Grand Rapids MI to Columbus OH and will
lift north across the area overnight. So far only an isolated
thunderstorm or two is located across SW Ohio and could see a
stray storm develop along the warm front through the morning
hours but confidence is low in this occurrence. Held onto a VCSH
mention at CLE/YNG earlier in the day in case something
develops along the warm front with a TEMPO at ERI. Otherwise it
looks like VFR conditions will persist until the cold front
approaches late morning through the afternoon. Not sure if
activity will fire as far west as TOL/FDY with the earlier
timing meaning less instability will be in place. Higher
confidence for thunderstorms is at eastern Ohio terminals and
extends to a lesser extent to CLE/MFD. Included VCTS at north
central Ohio airports and will need to add TEMPOs for
thunderstorms as confidence in initiation timing/placement.
Eastern sites stand the best chance for a few stronger storms
with gusts to 40+ knots and IFR visibilities in heavy rain.
Conditions are expected to dry behind the front and expecting
skies to trend towards clearing for Saturday night.

Winds will be out of the south to southeast through 15Z, then
out of the southwest/west, eventually shifting to northwest
behind the front. Winds will generally be 10 knots or less with
a few gusts to 20 knots possible outside of thunderstorms.

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

&&

.MARINE...
A warm front lifting north of Lake Erie this morning will allow
winds to become southwest at 5-10 knots before a cold front moves
east this evening and gradually shifts winds to be northwesterly at
5-10 knots. On Sunday another system approaches the region,
initially resulting in easterly winds of 5-10 knots ahead of an
approaching warm front, but as this boundary moves north of the lake
winds will again shift to become southwesterly at 10-15 knots. As
the parent low moves northeast across the western Great Lakes region
Sunday night into Monday, the pressure gradient will strengthen and
result in winds increasing to 15-20 knots. On Monday, an associated
cold front will move east, shifting winds to west-northwest and
continuing at 15-20 knots. This period is the next to monitor for
the potential of marine headlines, especially given the holiday and
potential for increased boating traffic. With a shift to more
onshore flow Monday night through Wednesday, waves will also build
to 4-6 feet in the nearshore zones across the central and eastern
basins which will likely increase the potential for rip currents. On
Wednesday night, high pressure begins to build east over the area,
allowing for winds to diminish to 5-10 knots through Friday.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...None.

&&

$$

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