466
FXUS61 KCLE 090816
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
416 AM EDT Thu May 9 2024

.SYNOPSIS...
Low pressure is expected to track across southern Ohio today
with a surface trough then lingering over the eastern Great
Lakes into Friday. The next area of low pressure will impact the
region on Saturday.

&&

.NEAR TERM /THROUGH FRIDAY/...
Low pressure is expected to track eastward along a stationary
boundary that looks like it will remain near or just south of
the I-70 corridor. There will still be plenty of warm
advection/isentropic lift to produce a large area of rain that
moves across the region from west to east through the day.
There will be some middle level instability that rides over
northern OH later this morning into the afternoon so there will
be some thunder across the area. Best chances for the thunder
look to be near and south of US 30. Cant rule out an elevated
thunderstorm or two that could produce hail across the extreme
southern CWA but otherwise the severe threat looks to be very
low. Showers will be slow to end from west to east this evening
into the overnight as we wait for an upper level trough to pass
overhead. Greatest chances for continued rain will be across NE
OH into NW PA.

Temperatures through sunrise should settle to the mid 40`s to
mid 50s across the CWA. Not much of a diurnal range today with
thicker cloud cover and rain expected. It likely gets the
warmest near the OH/PA border into NW PA where the rain takes a
bit longer to develop. Highs should range from the mid 50`s to
lower 60`s. Cloud cover persists into tonight but cooler air
does spread into the region in the wake of the low pressure
passing to our south. Lows tonight dip into the 40`s.

The upper level trough should be east of the CWA by Friday
afternoon. Unfortunately we will have to keep so low chances of
showers across the east, mainly near the OH/PA order into NW
PA. THe cloud cover should be slow to thin out on Friday with
some filtered sunshine spreading west to east through the
afternoon. Highs will be a bit below seasonal averages with
upper 50`s to low 60`s anticipated.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
Fair weather is expected CWA-wide Friday evening as a narrow ridge
at the surface and aloft moves E`ward through our region and is
accompanied by stabilizing subsidence. After midnight, rain showers
are possible roughly along and west of I-71 as a trough at the
surface and aloft and embedded shortwave disturbances approach from
the western Great Lakes and vicinity, and moist isentropic ascent
aloft precedes the axes of the shortwave disturbances. Fair weather
is expected to persist farther east. Overnight lows should reach the
upper 30`s to mid 40`s in NW PA and the 40`s to lower 50`s in
northern OH.

The trough aloft and embedded shortwave disturbances traverse the
eastern Great Lakes and Upper OH Valley generally from west to east
and the attendant surface trough affects our region on Saturday
through Saturday night. The trough aloft will reinforce an unusually-
cold air mass across northern OH and NW PA. Periodic and scattered
showers are expected due to moist isentropic ascent preceding the
shortwave trough axes, convergence and associated moist ascent along
surface trough axes releasing potential instability in the lowest 1
km AGL, and the occurrence of self-destructive sunshine late
Saturday morning through early evening. Thermals associated with the
self-destructive sunshine may release enough surface-based CAPE to
trigger isolated thunderstorms. Saturday afternoon`s highs should
reach the upper 50`s to lower 60`s in NW PA and mainly the lower to
mid 60`s in northern OH. Overnight lows should reach the 40F to 50F
range around daybreak Sunday.

Primarily fair weather is expected on Sunday as the troughing at the
surface and aloft exits toward New England and a ridge at the
surface and aloft builds from the Upper Midwest. However, light rain
showers may impact NE OH and NW PA Sunday morning in association
with the passage of one or more shortwave disturbances as the
aforementioned low pressure system exits. Afternoon highs should
reach the 60`s to 70F. Fair weather Sunday evening should give way
to the possibility of rain showers after midnight as the ridge exits
E`ward, another trough at the surface and aloft approaches from the
Upper Midwest, and the trough is preceded by moist isentropic ascent
aloft. Overnight lows should reach the 40`s to lower 50`s in NW PA
and the upper 40`s to mid 50`s in northern OH.

&&

.LONG TERM /MONDAY THROUGH WEDNESDAY/...
Discrepancies in model guidance exist during this period and lead to
reduced forecast confidence. In general, a predominantly cyclonic
W`erly to NW`erly flow aloft should persist over the eastern Great
Lakes and Upper OH Valley, and allow embedded shortwave disturbances
to affect our CWA. At the surface, net troughing should persist and
multiple trough axes accompanying the shortwave disturbances should
sweep through our region. Periodic and isolated to scattered showers
and thunderstorms are expected through the period, especially each
afternoon through early evening because the typical diurnal cycle in
boundary layer temperatures and instability is expected. A net low-
level WAA regime should affect our CWA. Accordingly, daily afternoon
highs are forecast to reach mainly the 70`s. Overnight lows should
reach the 50`s to 60F around daybreak Tuesday and Wednesday
mornings, respectively.

&&

.AVIATION /06Z Thursday THROUGH Monday/...
Low pressure passes to the south of the region today with east
to northwest winds of 8-15 knots. A few higher gusts will be
possible. Winds shift to the north during the evening hours but
should decrease to under 10 knots by 06Z.

CLoud cover will be slow to lower across the region through the
morning but MVFR conditions should develop for many locations after
the rain occurs for a few hours. However the easterly
downsloping flow likely delays the onset of the MVFR conditions
cross NE OH into NW PA into mid to late afternoon. There is a
possibility these areas dont see any MVFR ceilings until the
northerly winds kick in during the evening hours.

Outlook...Non-VFR likely at times in showers and lower clouds
through Friday afternoon, especially NE OH into NW PA. Non-VFR
possible in showers and storms Saturday into Saturday night.

&&

.MARINE...
A Small Craft Advisory remains in effect from 8 AM today to 4 AM
Friday for nearshore waters from Maumee Bay to The Islands and from
8 AM today to 10 AM EDT Friday for nearshore waters from The Islands
to Ripley. NE`erly winds around 10 to 25 knots back gradually toward
N`erly through daybreak Friday as a ridge exits E`ward and a trough
becomes established over Lake Erie in response to a low that is
expected to move from southern IL toward the Mid-Atlantic region.
Waves as large as 3 to 6 feet are expected, especially through the
wee hours of Friday morning. During the balance of Friday, N`erly
winds back gradually to SW`erly and ease to 5 to 10 knots, which
will allow waves to subside to 2 feet or less. Simultaneously, the
trough lingers over Lake Erie during the day on Friday before a
narrow ridge moves E`ward across the lake Friday evening.

Winds around 5 to 15 knots and waves of 3 feet or less are expected
this weekend through Monday. Primarily SW`erly winds veer to NW`erly
on Saturday as a trough moves E`ward across Lake Erie. NW`erly winds
then back to SW`erly or S`erly on Sunday as another ridge moves
E`ward across the lake. S`erly to SW`erly winds persist on Monday as
the ridge begins to exit E`ward and another trough approaches from
the Upper Midwest and Upper Great Lakes.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...Small Craft Advisory from 8 AM this morning to 4 AM EDT Friday
     for LEZ142-143.
     Small Craft Advisory from 8 AM this morning to 10 AM EDT
     Friday for LEZ144>149.

&&

$$

SYNOPSIS...MM
NEAR TERM...MM
SHORT TERM...Jaszka
LONG TERM...Jaszka
AVIATION...MM
MARINE...Jaszka