CLE issues Area Forecast Discussion (AFD) at Jul 22, 9:23 PM EDT143
FXUS61 KCLE 230123
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
923 PM EDT Mon Jul 22 2024
.SYNOPSIS...
A cold front will cross Wednesday night into early Thursday.
Ahead of the front, weak disturbances will bring sporadic rain
chances. High pressure builds in Friday through Sunday.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
930 PM...
Rain showers are exiting east of the area this evening, with
recent satellite imagery depicting quite a bit of clearing skies
across northern OH. Did increase the coverage of fog overnight
slightly and wouldn't be surprised to see it dense in spots,
especially across NE OH/NW PA where surface dew points are more
elevated.
Previous Discussion...
A weak shortwave is evident on water vapor imagery in the
vicinity of southern MI and northwestern OH this afternoon.
Ahead of the shortwave, modest forcing for ascent and moisture
advection is leading to a shield of clouds and generally light
rain showers that will continue lifting northeast through the
evening. While the low-level airmass ahead of the rain remains
dry, have had enough sites report light but measurable amounts
upstream to maintain a period of 40-50% POPs across much of
northeast OH and northwest PA through the late afternoon or
evening. Conditions are drier farther west and southwest...a few
convective cells have developed over southeast Michigan and may
leak into northwest Ohio over the next few hours but should
dissipate with the setting of the sun. Expect a mainly dry
overnight as the shortwave exits to the northeast with clearing
skies and light winds. With light winds and clearing skies we
should see at least some patchy fog develop late tonight into
early Tuesday, especially in more sheltered and less urban
locations. However, dew points are somewhat low for a July fog
set-up and skies won't completely clear so am not confident in
more widespread or dense fog. Expect lows in the 60s tonight.
Our somewhat unsettled pattern continues for Tuesday after what
should be a dry morning start. A weak warm front will lift
north across the area and we'll get into the left-exit quadrant
of a jet streak lifting out of the Ohio Valley during the
afternoon. These two features will add a bit of weak lift and
daytime heating will contribute to modest but uncapped
instability. Most hi-res models depict scattered afternoon
convection, especially from parts of north central OH east-
northeast across northeast OH. This general idea seems
reasonable with the forecast bringing 30-50% POPs in generally
along and east of a Norwalk to Marion line Tuesday afternoon or
early evening with lower POPs or no mention into northwest Ohio.
Expect activity to once again die as the sun sets Tuesday
evening. The combination of modest instability (1000-1500 J/KG
of MLCAPE), steep low-level lapse rates, some negative
downdraft buoyancy (600-900 J/KG of DCAPE) and 20-30 knots of
deep-layer shear may allow for one or two stronger storms
capable of gusty winds Tuesday afternoon or early evening. We
aren't outlooked for a severe risk by the SPC and the overall
concern is fairly low, though there may be just enough juice to
keep an eye on the radar Tuesday afternoon and early evening.
Highs on Tuesday will generally reach the low to mid 80s with
dew points increasing a couple clicks or so from today.
Rain chances diminish and exit east Tuesday night, leading to a
mainly quiet forecast with lows settling into the mid 60s to
near 70. There may again be a bit of patchy fog Tuesday night.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Cyclonic flow aloft and embedded shortwave disturbances affect our
CWA on Wednesday through Thursday. The axis of a prominent shortwave
trough should advance SE'ward from the Upper Great Lakes and
vicinity around daybreak Wednesday morning to near northeastern NY
and southwestern PA by sunset Thursday evening. This will cause the
cyclonic mid/upper-level flow to veer from WSW'erly to NW'erly over
our region. At the surface, a very weak trough lingers over/near the
eastern Great Lakes and Upper OH Valley, and a cold front sweeps
SE'ward through our CWA Wednesday evening through late Thursday
morning. Behind the front, a ridge builds from the western Great
Lakes and vicinity through sunset Thursday evening. Intervals of
sunshine/daytime heating and low-level warm/moist air advection from
the Gulf of Mexico should allow late afternoon highs to reach the
80's on Wednesday. Overnight lows should reach the 60's to lower
70's around daybreak on Thursday. Late afternoon highs on Thursday
should reach the mid 70's to lower 80's due, in part to weak low-
level CAA behind the cold front.
Isolated/scattered and organized showers/thunderstorms are expected
on Wednesday through Thursday as low-level convergence/ascent along
the cold front and pre-front surface trough axes release weak to
moderate instability in the warm/moist sector boundary layer amidst
moderate to strong deep layer bulk shear. In addition, a Lake Erie
lake breeze front is expected to advance several miles inland from
northeastern Cuyahoga County through Erie County, PA late Wednesday
morning through early evening and act as a focus for shower/storm
development. A few severe storms are possible in this thermodynamic
and kinematic environment, especially Wednesday afternoon through
early evening, when daytime heating/convective mixing of the
warm/moist sector boundary layer will allow MUCAPE to be maximized,
including sizable MUCAPE in the hail growth zone, and DCAPE to reach
moderate to strong magnitudes amidst steep low-level lapse rates.
These factors combined with projected melting levels near 10.5kft
AGL indicate any severe storm will be capable of producing damaging
convective wind gusts and marginally-severe hail. Shower and
thunderstorm potential is expected to end gradually from northwest
to southeast Thursday morning through early evening as the low-level
cold front moves SE'ward and is followed by stabilizing subsidence
accompanying the building low-level ridge.
Cyclonic NW'erly mid/upper-level flow and embedded shortwave
disturbances continue to affect our region Thursday night. However,
the aforementioned low-level ridge continues to build from the
western Great Lakes and be accompanied by stabilizing subsidence. As
a result, fair weather is expected to grace our entire CWA.
Overnight lows are expected to reach mainly the mid 50's to lower
60's around daybreak Friday as nocturnal cooling is complemented by
continued weak low-level CAA.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
Fair weather is expected on Friday through Sunday night as a ridge
aloft builds gradually from the north-central United States and
vicinity while the surface portion of this ridge continues to impact
our region. Simultaneously, the core of the surface ridge moves from
the Great Lakes region toward Atlantic waters near the northeast
United States and Canadian Maritimes. As a result, net low-level WAA
will impact our region and contribute to moderating temperatures.
Sufficient daytime heating of land surrounding ~76F Lake Erie and a
weak synoptic MSLP gradient are expected to allow a lake breeze to
occur over/within several miles of the lake during the late morning
through early evening hours of Saturday and Sunday, respectively.
Late afternoon highs in the mid 70's to lower 80's on Friday are
expected to be followed by daily highs mainly the 80's this weekend.
Overnight lows are expected to reach mainly the mid 50's to lower
60's Friday night and mainly the 60's Saturday and Sunday nights,
respectively.
The ridge aloft is expected to weaken over/near our region on Monday
as it is broken-down by a shortwave trough approaching from the
Upper Midwest. Accordingly, the aforementioned surface ridge is
forecast to weaken over/near our CWA. Odds still favor fair weather,
but a few showers/thunderstorms associated with the upstream
disturbance's attendant surface trough axis may overspread our
region generally from the west and encounter sufficient instability
amidst moderate deep layer bulk shear. Late afternoon highs should
reach the 80's to lower 90's as daytime heating is complemented by
continued low-level WAA.
&&
.AVIATION /00Z Tuesday THROUGH Saturday/...
VFR across the TAf sites early this evening with primarily VFR
to persist through the TAF period. A brief period of MVFR to IFR fog
is possible at CAK/YNG tonight into early Tuesday morning with
the calm winds and clearing skies. Confidence remains too low
elsewhere for inclusion at this time. Otherwise, another round
of isolated to scattered showers and thunderstorms is expected
to develop Tuesday afternoon, with the highest coverage expected
to initiate off the lake breeze. Have higher confidence in vcts
at CLE/ERI closer to the lake breeze with lesser confidence at
MFD/CAK/YNG and thus and will maintain vcsh.
Winds are light early this evening, less than 10 knots. Winds
will become light and variable overnight, less than 5 knots.
Winds will favor a southwest direction Tuesday afternoon, 5 to
10 knots. A lake breeze will shift winds towards the north to
northwest late Tuesday morning/early afternoon at CLE/ERI.
Outlook...Non-VFR possible in scattered thunderstorms Wednesday
afternoon and evening. Non-VFR may linger Thursday morning
across the far southeast in isolated to scattered showers and
thunderstorms.
&&
.MARINE...
Winds no stronger than 5 to 15 knots and waves less than 3 feet are
expected through Saturday. A very weak trough lingers over/near Lake
Erie through Tuesday, which will cause winds to be variable in
direction. These variable winds will include a lake breeze through
this early evening and again during the late morning through early
evening hours of Tuesday. Winds are expected to become SE'erly
Tuesday evening and veer to SW'erly overnight as a warm front sweeps
N'ward across the lake. SW'erly winds veer gradually to NW'erly
Wednesday evening through Thursday morning as a cold front moves
SE'ward across Lake Erie. Behind the cold front, a ridge builds from
the Upper Midwest and vicinity through Saturday. This will cause
NW'erly winds to veer gradually to NE'erly during the rest of
Thursday through Thursday night. Winds are then expected to become
variable in direction on Friday through Saturday as the MSLP
gradient weakens considerably once again.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Sullivan
NEAR TERM...Kahn/Sullivan
SHORT TERM...Jaszka
LONG TERM...Jaszka
AVIATION...Kahn
MARINE...Jaszka
Source:
CLE issues Area Forecast Discussion (AFD) at Jul 22, 9:23 PM EDT---------------
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