631 
FXUS61 KCLE 301928
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
328 PM EDT Mon Sep 30 2024

.SYNOPSIS...
A trough will linger over the area through tonight before a cold 
front moves east on Tuesday into Tuesday night. High pressure builds 
over the area on Wednesday and Thursday before a weak cold front 
moves east on Friday. High pressure returns for the start of the 
weekend.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
An upper level trough will continue to influence the weather across 
the area as it continues to drift east through tonight. Overall 
impacts should remain fairly minimal with gloomy, cloudy skies 
persisting across the area. The exception to this is across the far 
southeastern tier of counties where enhanced moisture and weak 
forcing continues to produce light rain showers. As this trough 
departs to the east tonight, a very favorable environment will 
develop for dense fog to form. With winds expected to become calm 
and low level moisture remaining quite expansive, the cooling 
diurnal temperatures should easily reach saturation. The highest 
confidence in widespread fog development remains west of I-77 with 
patchy dense fog still possible east of the corridor. Lowered 
visibilities will have the potential to impact the Tuesday morning 
commute and motorists should allow for additional travel time. The 
good news is that this fog should quickly dissipate by mid-morning 
as warming temperatures aid in mixing, although clouds are expected 
to linger. 

By Tuesday afternoon, the overall pattern will finally become 
progressive again, shifting the aforementioned trough/low off the 
Mid-Atlantic Coast and allowing another upper-level trough to 
traverse the region. A cold front associated with this trough will 
push east across the area early Tuesday evening through the 
overnight hours. Overall CAPE (about 500 J/kg) and shear values (20-
25 knots remain limited with this system, but strong isentropic lift 
and mass convergence along the boundary will allow for a line of 
showers to develop. There is a potential for a few rumbles of 
thunder, especially in the evening hours, but no severe storms are 
expected with this system. Enhanced gradient along the boundary 
coupled with the given mesoscale conditions, wind gusts may 
occasionally climb into the 25-40 mph range, but not expecting 
anything stronger than that. Precipitation totals with this round of 
showers will be highest across northern counties, but still only 
range from 0.1-0.2". Showers will gradually diminish from west to 
east Tuesday night as high pressure begins to build over the area 
Wednesday morning. 

High temperatures on Tuesday will climb into the mid 60s to mid 70s, 
with the warmest temperatures across western counties. Tonight's 
lows will remain mild and humid, dropping into the upper 50s to low 
60s, but Tuesday night they will be notably cooler, dropping into 
the mid 40s to low 50s.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Quiet and dry conditions are expected through the short term period 
as surface high pressure settles in behind a passing cold front 
Wednesday morning which will usher in noticeably-less humid weather. 
The air mass behind the cold front will not be particularly cold, 
though will be enough to drop highs slightly below average into the 
upper 60s to near 70 on Wednesday. Temperatures will return near to 
slightly above normal in the low to mid-70s by Thursday. Average to 
slightly below-average lows in the upper 40s to lower 50s are 
expected.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
The long term period appears more active, with several upper-level 
troughs traversing eastward across the Great Lakes. The first trough 
and associated surface cold front will arrive Friday into Saturday 
which could result in some light rain showers, particularly across 
the eastern half of the area. The second and more potent upper-level 
trough is expected to arrive by the end of the weekend into early 
next week, with higher confidence in precipitation coverage across 
the area. Not anticipating any major pushes of colder upper-level 
air to be released southward into the area with any of these systems 
with the DESI LREF suggesting only low probabilities of 850 mb 
temperatures falling below 4 degrees C.

Temperatures will remain near to slightly above average for the long 
term period, generally in the low to mid-70s with lows in the upper 
40s to lower 50s.

&&

.AVIATION /18Z Monday THROUGH Saturday/...
The aviation forecast through at least Tuesday morning remains
less than desirable. Currently, widespread MVFR ceilings with
patches of high end IFR are being observed as remnants of Helene
continue to drift off the Mid-Atlantic Coast, spreading cloud
cover across the area in the meantime. There is a potential for
terminals to briefly rebound to low-end VFR conditions this
evening with ceilings generally 3500-5000 feet expected. Aside
from this, there is a potential for light showers to impact the
southeastern terminals (KYNG and KCAK) this afternoon, but
highest confidence was at KYNG so opted to only include in this
TAF but will continue to monitor the northern progression of the
showers this afternoon. 

By midnight tonight, winds will become light and variable with
quite a bit of moisture lingering over the area ahead of an
approaching boundary late Tuesday. This moist airmass (dewpoints
lingering in the 60s) coupled with radiational cooling is
expected to result in widespread fog potential, especially along
and west of I77. Highest confidence in fog impact is at KTOL,
KFDY, and KMFD where visibilities could fall to 1/2SM or less.
At KCAK and KYNG, fog will likely reduce visibilities, but given
slightly more wind confidence isn't as high to drop it lower
than 1SM. At KCLE and KERI and additional terminals near the
lakeshore, there is confidence that some MVFR conditions may
sneak in, especially lowering ceilings, but given the warm lake
and subsequent warmer temperatures near the lakeshore, not
expecting dense fog there. All fog should begin to diminish near
sunrise on Tuesday and visibilities should return to P6SM by
15/16Z for all terminals. However, ceilings will likely linger
in the MVFR range with general light and variable winds for
Tuesday.

Outlook...Periods of non-VFR possible through Tuesday night.

&&

.MARINE...
Mainly quiet marine conditions are expected into the weekend. The 
exception will be a brief period late Tuesday evening into Wednesday 
morning as winds abruptly shift towards the north and northwest 
behind a cold front, 15 to 25 knots. A Small Craft Advisory will be 
needed for this timeframe. Otherwise, not anticipating any 
additional headlines at this time. Another cold front is expected to 
arrive across the lake by the end of the week, though winds are not 
anticipated to be as strong, with northerly flow of 10 to 15 knots. 

For late tonight into Tuesday morning, there is also a low chance 
for fog to develop along the western basin of Lake Erie.

&&

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

&&

$$

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