Venango, Pennsylvania Weather Forecast Discussion

377
FXUS61 KCLE 071721
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
121 PM EDT Sun Sep 7 2025
.SYNOPSIS...
A trough lingers over and very near Lake Erie as a ridge builds
slowly from the north-central United States and Lower Missouri
Valley today. The ridge then affects our entire region and Lake
Erie tonight through at least Tuesday. Simultaneously, the embedded
high pressure center wobbles northeastward from near the Lower
Missouri Valley and through the southern Great Lakes to New
England.
&&
.NEAR TERM /THROUGH MONDAY/...
Mid Morning Update...
Added likely to categorical POPS from the east suburbs of
Cleveland through southern Lake, Geauga, inland Ashtabula,
northern Trumbull, southern Erie, and Crawford Counties over
the next few hours as a lake-effect rain band sinks southward.
This is associated with the mid/upper trough axis sliding toward
the eastern Great Lakes allowing a surface trough to push
across the lake. Expanded the high POPS south and westward into
the west and south side of Cleveland as the band pushes inland
through late morning before shorter fetch, weakening
convergence, and decreasing moisture weaken the band by this
afternoon. Brief heavy rain will occur within the band. The rest
of the forecast remains on track.
Original Discussion...
WSW`erly flow aloft veers to WNW`erly over our entire region by
this late evening as a shortwave trough axis moves from the
western Great Lakes early this morning to western NY and western
PA by late this evening. During the remainder of today through
Monday, WNW`erly flow aloft and embedded/subtle shortwave
troughs affect our CWA as a ridge builds slowly from the
northern and central Great Plains and eventually the Upper and
Mid MS Valley. At the surface, a trough lingers over and very
near Lake Erie today as the ridge builds slowly from the north-
central United States and Lower MO Valley. Tonight through
Monday, the surface ridge affects our entire region as the
embedded high pressure center wobbles generally NE`ward from
near the Lower MO Valley to central NY by sunset Monday evening.
This weather pattern evolution at the surface and aloft will
maintain net low-level CAA across our region through tonight and
then support the development of weak net low-level WAA on
Monday. Despite intervals of sunshine, late afternoon highs are
expected to reach only the lower 60`s to near 70F today and the
mid 60`s to lower 70`s on Monday. In between, overnight lows
should reach mainly the lower 40`s to lower 50`s around daybreak
Monday.
Primarily fair weather is expected during the near-term period
as stabilizing subsidence accompanies the above-mentioned
surface ridge. However, a W`erly to NW`erly, but primarily
WNW`erly, mean low-level flow of sufficiently-cold/moist air
over/downwind of Lake Erie should allow periodic lake-effect
rain showers to impact the snowbelt and vicinity in NE OH and NW
PA, but especially the primary snowbelt, today into tonight.
The lake-effect rain showers should be heavy at times today as
periods of greater/deeper low-level moisture preceding low-level
shortwave trough axes contribute to periodic greater lake-induced
CAPE (LICAPE) of moderate magnitude. Based on latest trends in
model guidance, the potential for lake-effect thunderstorms now
appears to be minimal as model soundings suggest LICAPE will
primarily be limited (i.e. less than 200 J/kg) within the
primary electrical charge separation zone. However, cannot
totally rule-out a few instances of lake-effect lightning during
the daylight hours of today. During this evening, periodic
lake-effect rain showers will become lighter as LICAPE wanes
via a lowering subsidence inversion and low-level dry air
advection. During the predawn hours of Monday morning, lingering
and light lake-effect rain showers streaming generally ESE`ward
over and downwind of Lake Erie, across the primary snowbelt and
vicinity, are expected to end as LICAPE continues to wane for
the same aforementioned reasons.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
The aforementioned ridge aloft will continue to build into our
region from the west Monday night and then begin to exit slowly
E`ward through Wednesday as a shortwave trough approaches from
the north-central United States. At the surface, our region
remains along the western flank of the ridge. Fair weather is
expected as stabilizing subsidence accompanies the ridge. This
evolution of the weather pattern at the surface and aloft will
allow net low- level WAA to impact northern OH and NW PA. Lows
mainly in the lower 40`s to lower 50`s around daybreak Tuesday
will be followed by late afternoon highs in the 70`s. On
Wednesday, lows mainly in the mid 40`s to mid 50`s around
daybreak are expected to be followed by late afternoon highs in
the 70`s to lower 80`s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
During Wednesday night through Thursday morning, the axis of the
above-mentioned shortwave trough and a weak attendant cold front
are still expected to move generally SE`ward through our region.
Latest trends in model guidance and our official forecast
continue to indicate rather dry air at and near the surface
should prevent measurable rainfall from accompanying the passage
of the cold front and shortwave trough axis. Lows should reach
mainly the upper 40`s to mid 50`s around daybreak Thursday.
During the rest of Thursday through Saturday, predominantly
NW`erly to N`erly flow aloft is expected over our region as a
ridge aloft builds slowly from the central United States. At the
surface, the ridge is expected to impact our region as the
embedded high pressure center moves from near James Bay toward
New England. Behind the weak cold front, negligible air mass
change is expected on Thursday through Friday, while weak net
low-level WAA should become established across our region Friday
night through Saturday as we become located along the western
flank of the surface ridge. As a result, daily late afternoon
highs are expected to reach the 70`s to lower 80`s on Thursday
through Saturday. Daily lows should reach mainly the mid 40`s to
mid 50`s around daybreak Friday and Saturday, respectively.
Stabilizing subsidence accompanying the ridge is expected to
promote fair weather.
&&
.AVIATION /18Z Sunday THROUGH Friday/...
Expansive high pressure builds across the region leading to
persistent dry weather across most terminals. Lingering
surface trough across Lake Erie will likely lead to another
brief window of lake effect rain showers to impact KERI (roughly
~06-12Z/Mon). Confidence in reductions below VFR remains low at
this time. Northwesterly winds this afternoon and evening at
8-10 knots will quickly become light and variable tonight as the
high builds overhead. Winds will favor a southerly component on
Monday while remaining at 5 knots or less.
Outlook...VFR expected through Friday.
&&
.MARINE...
An expansive area of high pressure will build across the Great
Lakes region before gliding east of Lake Erie on Tuesday. The
high will continue to influence the eastern Great Lakes as it
remains in the vicinity of the region through this week.
Northwesterly winds 10-15 knots this afternoon and evening will
diminish to 5-10 knots as the high builds overhead. Winds will
remain northerly on Monday before flow turns offshore Monday
night as the high builds eastward. A cold front moves south
across the lake Wednesday into Thursday with northeast flow
favored Thursday and Friday.
A weak surface trough will linger across Lake Erie through
early Monday morning. This will keep conditions favorable for
waterspouts in any lake effect rain shower that develops tonight
into early Monday morning.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Jaszka
NEAR TERM...Garuckas/Jaszka
SHORT TERM...Jaszka
LONG TERM...Jaszka
AVIATION...13
MARINE...13

NWS CLE Office Area Forecast Discussion