Area Forecast Discussion Issued by NWS Cleveland, OH
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000
FXUS61 KCLE 191030
AFDCLE
Area Forecast Discussion
National Weather Service Cleveland OH
630 AM EDT Tue Mar 19 2024
.SYNOPSIS...
A weak ridge exits eastward before a cold front sweeps eastward
through northern Ohio and northwest Pennsylvania this evening
through the wee hours of Wednesday morning. Behind the front, a
trough lingers over our region before a ridge builds from the
northern Great Plains Wednesday night into Thursday. The ridge
then exits eastward Thursday night through Friday as a low
pressure system overspreads our region from the northern and
central Great Plains.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
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6:30 AM EDT Update...
Forecast remains valid per latest trends in obs and model
guidance. No changes appeared necessary.
Previous Discussion...
W`erly to NW`erly flow aloft and embedded shortwave disturbances
affect our region through Wednesday. At the surface, a weak
ridge exits toward New England and vicinity before a cold front
sweeps E`ward through our CWA this evening through the wee hours
of Wednesday morning. Behind the front, a trough lingers
over/near the eastern Great Lakes, including our CWA, before a
ridge begins to build from the northern Great Plains by early
evening. Intervals of sunshine and low-level WAA ahead of the
cold front will allow this afternoon`s highs to reach the upper
30`s to lower 40`s in NW PA and the lower 40`s to near 50F in
northern OH, with the warmest readings expected in our I-75
corridor counties. Diurnal convective mixing of the boundary
layer tapping into stronger flow aloft will allow SW`erly
surface winds to gust up to 30 to 45 mph late this morning
through early evening. The strongest gusts are expected roughly
along and west of I-71. Latest HREF runs indicate the chance of
advisory-criteria gusts of at least 46 mph is 10% or less in
our CWA. Low-level CAA behind the front will contribute to
overnight lows reaching the upper 20`s to mid 30`s around
daybreak Wednesday. Afternoon highs on Wednesday should reach
only the lower to mid 30`s in NW PA and the mid 30`s to lower
40`s in northern OH as low-level CAA persists.
Lake-effect snow showers persist amidst a sufficiently-cold/moist
mean low-level flow over/downwind of ~7C Lake Erie. This LES
will transition into lake-enhanced snow (LEnS) later this
morning through afternoon as moist-isentropic ascent preceding
an approaching shortwave trough axis generates snow-producing
clouds farther aloft, leading to the seeder-feeder process. The
LES/LEnS will continue to shift N`ward as the mean low-level
flow backs from WNW`erly to SW`erly ahead of the aforementioned
and prominent shortwave trough approaching from the western
Great Lakes and vicinity. Accordingly, LES/LEnS should shift
offshore NE OH/NW PA by late morning. The LES/LEnS will be
steady at times courtesy of the seeder-feeder process and low-
level convergence along bands` major axes allowing moderately-
strong ascent to be maximized in a cloudy DGZ at least 0.5 km
deep periodically. LES/LEnS, perhaps mixed with rain, is then
expected to remain offshore our CWA through this afternoon as
mean low-level flow remains SW`erly ahead of the shortwave
trough. Once the shortwave trough axis crosses Lake Erie this
evening and moves farther E`ward overnight tonight, lake-enhanced
precip will shift back S`ward into the primary snowbelt of NE
OH/NW PA and vicinity, and transition back to pure LES by
daybreak Wednesday as lake-induced thermodynamics remain
favorable, mean low-level flow cools while veering from SW`erly
to W`erly, and the seeder-feeder process ceases as mid-level
moisture plummets. Outside the lake-effect/enhanced precip, fair
weather is expected in northern OH, including along the cold
front as the front encounters a relatively-dry air mass.
However, isolated snow/rain showers are possible in NW PA where
model guidance continues to indicate the front should encounter
greater low-level moisture. Additional snow accumulations
through daybreak Wednesday are expected to be two inches or
less.
On Wednesday, the mean low-level flow of sufficiently-cold/moist
air over/downwind of Lake Erie should veer from WNW`erly to
NW`erly and allow LES showers to impact NW PA, NE OH, and
portions of north-central OH. These LES showers may mix with a
few raindrops during the afternoon, especially in northern OH.
Precip should mainly be light, but steadier LES is possible in
NW PA Wednesday afternoon/early evening when an upstream
moisture connection to Lake St. Clair may target that area.
Additional snow accumulations are forecast to be a coating to
two inches. The greatest snow accumulations should be focused
in the colder higher terrain of NW PA.-- End Changed Discussion --
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
With an upper trough still curling over the Northeast United States
on Wednesday night into Thursday with northwest flow over the Great
Lakes region, some lake effect snow showers will still be possible
in Northeast Ohio and Northwest PA through the first part of
Thursday. Snow accumulations seem limited with just scattered snow
showers expected, but they will continue to keep a persistent little
snow pack in some of the higher terrain of the NE OH and NW PA snow
belt. The upper trough pulls away from the region on Thursday and
high pressure will be aggressive to build into the forecast area on
Thursday allowing for a largely dry forecast. With an origin from
the northwest, temperatures on Thursday will be cold and generally
remaining in the 30s across the area. Another upper trough of the
northern stream jet will dip toward the area on Friday. This feature
will pick up a shortwave moving through the southern stream over the
Gulf Coast states. This combination should allow for a broader low
pressure system to move through the eastern CONUS and bring some
rain chances on Friday with some warmer temperatures toward the 40s.
Depending on how much the northern flow can pick up this system,
there could try to be enough cold air over the northern half of the
area to allow for initial precipitation type on Friday to be some
snow before transitioning all to rain. Impacts from any snow appear
limited at this time.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
Generally speaking, the weekend forecast appears uneventful at this
time. The late week system should be exiting to the east on Saturday
morning and some lake enhanced precipitation could remain into NW
PA. However, high pressure seems aggressive to build into the region
and have a largely dry forecast for Saturday and the daytime hours
on Sunday. The next upper trough will enter the central CONUS on
Sunday night into Monday and will support the next low pressure
system that will target the forecast area for early next week. Have
increasing PoPs Sunday night through Monday night with the highest
later on Monday. Temperatures through the period should be fairly
seasonable for the 4th weekend of March.
&&
.AVIATION /12Z Tuesday THROUGH Saturday/...
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At the surface, a weak ridge exits E`ward before a cold front
sweeps E`ward through northern OH and NW PA between ~22Z/Tues
and ~05Z/Wed. Behind the front, a trough lingers over our region
through 12Z/Wed. W`erly to WNW`erly regional surface winds back
to SW`erly behind the surface ridge axis and remain around
10-15 knots with gusts up to 20-25 knots at times. After
14Z/Tues, SW`erly surface winds are expected to increase to
15-25 knots and gust up to 25-35 knots through ~22Z/Tues. Once
the cold front passes, regional surface winds veer to W`erly and
ease to around 10-15 knots. These post-front winds should gust
up to 20-25 knots in the immediate lee of Lake Erie, including
at KERI.
Widespread low clouds with ceilings near 3kft to 5kft AGL
continue to exit E`ward with the passage of the aforementioned
surface ridge axis and should exit the rest of our region by
14Z/Tues. Lingering lake-effect snow showers and associated
VFR/MVFR low-level ceilings streaming generally E`ward from
Lake Erie continue to shift gradually N`ward and should be
offshore northern OH and NW PA by ~13Z/Tues as mean low-level
flow backs from W`erly to SW`erly. However, behind the cold
front, lake-effect snow showers and associated VFR/MVFR low-
level ceilings should redevelop and stream generally E`ward
across far-NE OH and NW PA between ~06Z and ~12Z/Wed.
As for the cold front, limited low-level moisture should permit
a dry front passage in northern OH. However, isolated snow
showers, perhaps mixed with rain, may accompany the front in NW
PA. Visibility is expected to vary between VFR and MVFR in precip.
Outlook...Non-VFR expected with periods of snow and/or rain on
Wednesday through Saturday.-- End Changed Discussion --
&&
.MARINE...
A trough remains across the eastern Great Lakes and brisk westerly
winds remain across the entire basin, allowing for a Small Craft
Advisory to continue across the nearshore zones. A low pressure
system north of Lake Superior will dive southeast across the Great
Lakes today and back winds to the southwest. Winds will lessen a bit
tonight and there could be a brief window without the need for a
Small Craft headline and will maintain the 00z end time tonight. The
low will start to move east through Canada and extend a cold front
across the lake on Wednesday to allow for elevated northwest flow to
return. An extended or new Small Craft Advisory will be needed for
Wednesday into Thursday with high winds and waves. High pressure
will build into the region for Thursday to lighten winds and allow
for more calm weather to return to the lake. A low pressure system
will move through the region on Friday and some easterlies may be
expected. The system will depart for the weekend and northwest flow
will return and there could be room for another Small Craft headline
to be needed. Overall, it is certainly a more active pattern typical
of the winter more than the spring.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
NY...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for
LEZ142>149.
&&
$$
SYNOPSIS...Jaszka
NEAR TERM...Jaszka
SHORT TERM...Sefcovic
LONG TERM...Sefcovic
AVIATION...Jaszka
MARINE...Sefcovic