700 
FXUS61 KCLE 030502
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
102 AM EDT Thu Oct 3 2024

.SYNOPSIS...
High pressure through Thursday night. A mainly dry cold front 
passes through the southern Great Lakes Friday. High pressure 
Saturday. Strong cold front Sunday with cooler air early next 
week.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...

1:01 AM EDT Update...

Most of the forecast remains valid per latest trends in obs and
model guidance. However, used the latest NBM 50th percentile
forecast guidance for updating our low temperature forecast for
this morning. Radiational cooling has been occurring at a
slightly faster rate than depicted in the previous forecast Expect
that to remain the case through daybreak this morning amidst 
clear to mainly clear sky, weak or calm surface winds, and 
limited low-level moisture on the synoptic scale. The 
expectation of cooler low temperatures means the potential for 
patchy radiation fog development around daybreak this morning 
has increased along/near most of the eastern and southern border
of our CWA. In addition, localized river valley steam fog is 
expected to develop by daybreak. Any fog will then dissipate via
diurnal convective mixing of the boundary layer by mid-morning.

Previous Discussion...

High pressure builds into the southern Great Lakes, then drifts to 
the east coast during the near term forecast period. Largely a low 
RH column, so cloud cover will be limited overall through the 
period. Good radiative cooling tonight, but the boundary layer is 
too dry for fog to develop in the valleys. This, combined with the 
low dewpoint air will bring lows in the 40s, to near 40F in the far 
eastern portions of our NW PA counties, and low to mid 50s for the 
lakeshore areas. 850mb temperatures rise into the lower teens for 
Thursday, translating to lower to middle 70s for most of the area 
as surface winds turn southwesterly. POPs zero for the period.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... 
Mainly quiet weather is expected through the short term period.
A weak cold front will move east across the area on Friday, 
though it appears the highest chances for any precipitation will
be found just northeast of the region across western NY as high
pressure quickly builds in from the west. Near to slightly 
above average temperatures are expected for Friday and Saturday 
with highs in the low to mid- 70s and seasonable lows in the 
upper 40s to lower 50s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Slightly more active weather will arrive for the long term period as 
a stronger cold front sweeps east across the region on Sunday. DESI 
cluster analysis reveals some low joint probabilities of favorable 
CAPE/Shear overlap for some stronger storms in the afternoon hours. 
Forecast hodographs appear mainly long which would yield a wind 
threat, though can't discount slight curvature in the lowest 3km to 
support a rotating updraft or two. Will continue to monitor trends, 
particularly in timing, as it appears the latest model guidance has 
shifted the threat ever so slightly towards the east (i.e. trending 
faster). Confidence is also low on the amount of low-level moisture 
available as a tropical disturbance in the Gulf may stunt moisture 
return northwards into the Upper OH Valley. 

Behind the front, a much cooler air mas will arrive, characterized 
by 850 mb temperatures falling between 0 and 2 degrees C. Do have 
some low-PoPs across the snowbelt, though it appears trends would 
favor more on the side of cloud cover versus precipitation given a 
lack of mid-level moisture present. Apart from Sunday, below-average 
temperatures are anticipated behind the cold front through 
Wednesday, with highs in the 60s and perhaps even upper 50s across 
far NW PA. Will need to monitor low temperature trends for Monday 
and Tuesday nights with the NBM showing moderate probabilities of 
minTs less than 37 degrees, particularly across inland areas.st
Ohio and 70% out east in Northeast Ohio and Northwest 
Pennsylvania. A pattern change is expected as this upper- level 
trough brings in colder air. Highs in the 60s and low in the 40s
will make it feel more like October on Monday and Tuesday. Some
lingering lake effect rain showers may be possible downwind of 
Lake Erie in Northeast Ohio and Northwest Pennsylvania on Monday
and Monday night.

&&

.AVIATION /06Z Thursday THROUGH Monday/...
Fair weather and mainly VFR expected through 06Z/Fri. At the 
surface, our region remains along the western flank of a high 
pressure ridge as a cold front approaches from the Upper Midwest
and western Great Lakes. Our regional surface winds trend calm 
or light and variable through 12Z/Thurs. Thereafter, surface winds 
trend S'erly to SW'erly around 5 to 10 knots. Localized river 
valley steam fog formation is expected and localized radiation 
fog formation is possible through ~12Z/Thurs. However, no TAF 
sites are expected to be affected by fog. Any fog will dissipate
via daytime heating by 14Z/Thurs.

Outlook...Isolated rain showers with non-VFR possible Friday
night. Scattered thunderstorms and/or rain showers with non-VFR
possible this Sunday through Monday.

&&

.MARINE...
A mainly quiet marine period is in store through much of the weekend 
with no headlines anticipated until late Sunday behind a strong cold 
front. A weaker cold front will cross the lake on Friday which will 
usher in north to northeast flow of near 15 knots, though think 
waves should top out around 3 feet. Otherwise, southerly flow of 15 
to 20 knots on Sunday will abruptly shift towards the northwest by 
late Sunday into Monday behind a strong cold front, with winds 
increasing to near 20 knots. A Small Craft Advisory will likely be 
needed late Sunday through much of Monday.

&&

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

&&

$$

SYNOPSIS...26
NEAR TERM...Jaszka/26
SHORT TERM...Kahn
LONG TERM...Kahn
AVIATION...Jaszka
MARINE...Kahn