843
FXUS61 KCLE 061120
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
720 AM EDT Sat Jul 6 2024

.SYNOPSIS...
Low pressure over the Central Great Lakes will depart to the
northeast today, allowing high pressure to build into the Ohio
Valley tonight. High pressure will remain in control through
Monday as it moves towards New England. Low pressure will pull a
weak cold front east across the area on Tuesday.

&&

.NEAR TERM /THROUGH SUNDAY/...
Skies are clear except for some stratus in eastern portions of
the forecast area. Lowered cloud cover slightly but still think
partly cloudy will be the best way to characterize sky cover
for today.

Previous discussion...
An upper level trough over the Central Great Lakes this morning will
weaken as it lifts northeast into Quebec through tonight. Surface
low pressure over Lake Huron will pull a weak cold front across the
area this morning. Water vapor imagery shows dry mid-level air ahead
of the trough which will overspread the local area today and serve
as a limiting factor for showers/convection. The exception may be
across Northwest Pennsylvania towards midday where convergence
with the front will be enhanced downwind of Lake Erie and may
kick off a few showers for inland portions of Erie and Crawford
Counties. Elsewhere a scattered to broken cumulus field will
develop as low level moisture wraps in behind the front within
the broad cyclonic flow. Enough breaks in the clouds are
expected for high temperatures to still reach the low 80s for
most of northern Ohio and upper 70s in NW Pennsylvania. The
front will be more noticeable due to a drop in dewpoints today
which will fall from near 70 on Friday to the low 60s this
afternoon.

Clouds will tend to clear with the loss of daytime heating tonight
although scattered clouds may continue off the east end of Lake
Erie. Otherwise high pressure will strengthen over the Ohio Valley
and maintain dry conditions for Sunday. Seasonal temperatures in the
low to mid 80s can be expected.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
The southern Great Lakes region will be largely influence by broad
mid/upper troughing stretching from SE Canada into the Plains
battling persistent mid/upper ridging over the Mid Atlantic and SE
CONUS. This pattern will persist well into next week, keeping
seasonably warm and humid conditions in place while allowing the big
heat to stay suppressed well to the south.

Surface ridging will exit into the eastern Great Lakes Sunday night
and Monday allowing for return southerly flow, but its influence
will still keep dry conditions areawide. Chances for showers and
thunderstorms will start to gradually increase Monday night, and
especially Tuesday as a shortwave progresses through the broader
mid/upper trough. This shortwave will move through the southern
Great Lakes Tuesday into Tuesday night with an accompanying 70-80
knot H3 jet streak supporting a modest surface low crossing the
central Great Lakes. This feature will push a cold front into the
region Tuesday, but the shortwave is trending less amplified in all
deterministic guidance which will likely cause the front to stall
nearby as it becomes oriented parallel with the mid/upper flow. This
makes timing of the front uncertain, but given the aforementioned
jet support and at least moderate instability (MLCAPE 1000-1500
J/Kg) and seasonably high PWATs, expect good potential for
convection Tuesday. With all of this in mind, went a little lower on
PoPs Tuesday but still in the high chance range. A few strong to
severe storms are possible Tuesday afternoon and evening given the
jet support likely yielding at least moderate deep layer effective
shear, but the degree of organization will depend on how much cloud
cover is present, outflow boundaries, and the timing in which the
front sags into the area. Chances for showers and thunderstorms will
continue Tuesday night as the front remains in the region, but
coverage should be less with the loss of daytime heating.

Highs Monday will warm into the upper 80s/low 90s as warm air
advection increases ahead of the front, cooling into the low/mid 80s
Tuesday with abundant cloud cover expected. Lows Sunday night will
fall into the low/mid 60s, with upper 60s/low 70s expected Monday
night and mid/upper 60s Tuesday night.

&&

.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
Uncertainty really increases in the Wednesday through Friday
timeframe regarding the coverage of any showers and thunderstorms.
The frontal boundary is likely to remain somewhere between the Ohio
Valley and southern Great Lakes as it orients parallel to the west-
southwesterly mid/upper flow. This is due to the broad mid/upper
longwave trough getting sandwiched between persistent ridging over
the Mid Atlantic and SE CONUS and another large ridge over the
Rockies. This elongated trough may evolve into a closed low over the
Plains by Thursday or Friday which will meander underneath ridging
expanding east from the Rockies, but the exact evolution is
uncertain. At the same time, this pattern could draw moisture
northeastward into the Ohio Valley from the remnants of Beryl which
would ultimately result in much higher rain chances late in the
week. For now, kept PoPs in the slight chance to chance range
Wednesday through Friday, with the highest values during daytime
heating, but most areas will likely stay dry. Temperatures will stay
seasonably warm and humid with highs in the upper 70s/low 80s
Wednesday warming into the low/mid 80s Thursday and mid/upper 80s
Friday. Dew points will frequently hover around the mid/upper 60s.

&&

.AVIATION /12Z Saturday THROUGH Wednesday/...
Areas of stratus with MVFR visibilities are in place at some of
the terminals in NE Ohio this morning. Expect visibilities to
return to VFR quickly after 12Z and any broken stratus to
scatter out by 13Z. Have trended the sky cover slightly more
optimistic for today with only a brief window of MVFR at TOL.
Otherwise, expecting SCT-BKN clouds in the 3500-6000 range. A
few showers may still develop over inland portions of NW
Pennsylvania so included a VCSH at ERI but these should be
brief and moving away from the terminal. Otherwise dry
conditions are expected across the rest of the area.

Southwest winds of 5-10 knots this morning may veer to 250-270
degrees with some gusts to around 20 knots through 22Z. Winds
will be 5 knots or less tonight as high pressure builds into the
region.

Outlook...Non-VFR possible in scattered showers and thunderstorms
Tuesday through Wednesday.

&&

.MARINE...
Quiet conditions are expected on the lake over the next 5 days as
pressure gradients remain weak. W to SW winds will increase to 10-15
knots today, building 2 to 3 foot waves in the central and eastern
basins, but these winds will quickly diminish to 5-10 knots tonight
before becoming light and variable by late Sunday. E to SE winds
will increase to 5-10 knots Sunday night and Monday before turning
SW at 10-15 knots by Tuesday then N at 10-15 knots by Wednesday.

The best chance for thunderstorms on the lake is Tuesday as a weak
cold front sags into the area, and these could produce locally
higher winds and waves in and near any of the thunderstorms.

&&

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

&&

$$

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