209
FXUS61 KCLE 200102
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
902 PM EDT Thu Sep 19 2024

.SYNOPSIS...
High pressure will continue to influence the region through Friday.
A weak cold front will approach Friday night before dissipating as
the ridge remains in control through the weekend. Low pressure will
track northeast out of the Plains across the Central Great Lakes
during the early part of next week.

&&

.NEAR TERM /THROUGH FRIDAY NIGHT/...
9:00 PM Update...
Forecast remains on track as high pressure remains over the
region. Overnight lows will dip into the upper 50s, low to mid
50s across interior NW Pennsylvania. Still expecting for patchy
fog to develop with the best chance of fog occurring in the
Toledo area.

Previous discussion...
High pressure remains over the area with cumulus clouds seen on
satellite imagery inland and a lake shadow down wind of Lake
Erie. A few light echos have been noted on radar near the
Pennsylvania/New York border but will not amount to more than a
few sprinkles in eastern Erie County PA late this afternoon.
Otherwise skies will clear overnight with a few patches of fog
returning again. Most likely area of fog will be towards Toledo
with light easterly flow off the lake trapping increased
moisture below the inversion before winds veer slightly to
southeasterly. The coverage of fog is expected to be a little
lower as slightly drier air tries to work in from the west.

Upper level ridge axis will shift just east of the area on Friday.
We will see a little return flow develop on the back side of surface
high pressure and ahead of a weak front approaching from the west.
It was interesting to note this morning that both the 06Z and 12Z
GFS was initializing with nearly a 10 degree low bias in dewpoints
upstream across Illinois. While temperatures are forecast to trend 2-
4 degrees warmer on Friday, the GFS MOS guidance was much warmer
than other sources, possibly due in part to these initialization
problems upstream. Kept the forecast in line with the previous
forecast values and leaned towards other guidance sources given
the initialization concerns on the GFS. Highs will be above
normal on Friday ranging from low 80s east to upper 80s or even
90 in the southwest fringe. Winds should be light enough that
lake breezes will develop again during the afternoon.

Surface low pressure will approach Hudson Bay on Friday night. A
weakening front will extend southward into the area and be on our
doorstep Friday evening. A narrow ribbon of moisture advection will
be focused into the area bringing the chance of a few showers or
possibly a thunderstorm on Friday night. Considerable moistening of
the airmass will need to occur before rain reaches the ground but
weak instability with MU CAPE values of 300-700 J/kg does spread
east across the forecast area. Raised pops slightly and expanded
east a little faster as the associated shortwave trough crosses
Lake Erie. Outside of any thunderstorms, rainfall amounts will
be light with generally a tenth of an inch or less.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
A shortwave will continue to track through the region on Saturday.
With a decent lift and dew points well into the mid 60s, there will
be a chance of PoPs for the central and western portion of the CWA.
Don`t expect much in the way of measurable precipitation with this
system as it will be moving fairly quick and the weakening boundary.
There will be break in between system Sunday with a small ridge
building in behind the shortwave with drier conditions. A more
potent system will begin to enter the region Sunday night as a low
pressure system moves northeastward from the Great Plains. The NBM
has trended up on the chance of precipitation for the day on Sunday,
though if any, it will be localized to the western counties of the
CWA. That being said, PoP chances have been bumped up to chance for
the areas west of I-71. Temperatures for Saturday and Sunday will
still be in the mid to upper 80s and overnight lows in the mid
60s.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Monday we will see the greatest chance of precipitation as a cold
front pushes into the region in the afternoon/evening. There is more
confidence in increasing to high 50 PoPs during this time period for
the majority of the CWA during one point or another Monday/Tuesday.
There will be some decent instability with the frontal boundary as
it pushes through, so there will be chance of general thunderstorms
but don`t expect any severe at this time. Precipitation chances
should diminish overnight into Tuesday though will pick up again
into Wednesday as the surface low stalls out to the east. Depending
on when/where the low starts to stall we be the main factor in which
areas of the CWA will see showers Wednesday and Thursday. Will keep
watch on rain totals as WPC has introduced a MRGL ERO for the CWA
for Monday/Tuesday. Temperatures should start to fall off with this
system and a northerly flow afterwards with highs being in the mid
70s and lows in the mid 60s.

&&

.AVIATION /00Z Friday THROUGH Tuesday/...
VFR conditions across terminals will continue through this
evening before patchy fog develops early Friday morning.
Highest confidence for fog to impact a terminal will be TOL
where visibilities could dip to IFR/LIFR. Elsewhere,
FDY/MFD/CAK/YNG, have less confidence in fog developing but not
enough to not mention MVFR vis entirely. Any fog that develops
will diminish by daybreak Friday morning.

Winds remain light through the TAF period with southeasterly
winds tonight briefly turning southerly to southwesterly Friday
morning and afternoon. A lake breeze is once again likely to
turn winds northerly to northeasterly at CLE/ERI Friday
afternoon.

Outlook...Primarily VFR expected through Sunday. Non-VFR
possible in showers Sunday night through Tuesday, but this is
low confidence for now.

&&

.MARINE...
There will continue to be a easterly flow across the lake with the
high pressure situated to the east. A lake breeze should develop
Friday afternoon/evening, but will be weaker than previous days with
the approaching cold front. During the overnight hours winds will
shift out of the southeast at 5-10 kts. The cold front on Saturday
will be fairly weak, so impacts for the lake should be minimal.
Sunday afternoon should see another day of a lake breeze setting up
before another cold front moves into the region on Monday. Ahead of
the front winds will be generally out of the south at 10-15kts until
the boundary crosses the area and flow shifts to be more northerly
into the mid-week. At this time, no small craft headlines are
expected but there may be some windows with the approaching system
early next week.

&&

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

&&

$$

SYNOPSIS...KEC
NEAR TERM...KEC/Iverson
SHORT TERM...Kennedy
LONG TERM...Kennedy
AVIATION...Iverson
MARINE...Kennedy