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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCLE 211959
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
359 PM EDT Sun Apr 21 2024

.SYNOPSIS...
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High pressure will persist through Monday night before a low
pressure system tracks east through the Great Lakes region on
Tuesday. This low will move a warm front north Tuesday morning
followed by a cold front Tuesday night. A surface trough will
linger over the area on Wednesday before high pressure builds in
Thursday.
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&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
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With high pressure remaining dominant over the region, the near
term period will remain quiet with no precipitation expected.
Some lingering clouds this afternoon has kept conditions a bit
chillier than initially expected, with most areas only reaching
into the low to mid 40s. Looking upstream and in northwest Ohio,
skies are clearing and allowing a couple places to reach 50.
This clearing trend will continue to push east into the early
overnight hours, allowing for mostly clear skies tonight. This
will allow for increased radiational cooling and temperatures to
drop into the low to mid 30s. With weak winds also expected,
there is high confidence in areas of frost forming inland across
the area. As a result, a Frost Advisory has been issued for the
entire area (excluding the lakeshore zones/counties) from 2-8AM
Monday.

On Monday, skies are expected to be partly cloudy allowing for
temperatures to climb into the upper 50s to low 60s, which is
near the average temperature for this time of year. Monday night
lows are expected to be a bit warmer, only dropping into the
40s which will eliminate any additional frost concerns in the
immediate future.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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A potent shortwave trough embedded in cyclonic W`erly to NW`erly
flow aloft approaches our CWA from the Upper Midwest and Upper Great
Lakes on Tuesday before advancing generally E`ward across northern
OH and NW PA Tuesday night. At the surface, the attendant trough
overspreads our region from the north and west, and the cold front
is still forecast to sweep generally E`ward through our CWA Tuesday
night. Scattered and periodic rain showers are expected due to moist
isentropic ascent aloft, ahead of the front, and low-level
convergence/associated moist ascent along the front. These lifting
mechanisms should release enough elevated instability for the
development of isolated thunderstorms Tuesday evening into the
predawn hours of Wednesday morning. Behind the front, lake-enhanced
rain showers are possible generally southeast of Lake Erie, in/near
the snowbelt and amidst a sufficiently-cold/moist low/mid-level
atmospheric column and the seeder-feeder process over/downwind of
Lake Erie. Daytime highs should reach mainly the upper 50`s to mid
60`s on Tuesday. Overnight lows are expected to reach the lower to
upper 30`s in NW PA and the mid 30`s to lower 40`s in northern OH.
No frost formation is expected due in part to abundant cloud cover
and breezy surface winds.

Primarily fair weather and considerable clearing of sky are expected
on Wednesday through Wednesday night as a ridge at the surface and
aloft builds from the Upper Midwest and vicinity, and is accompanied
by stabilizing subsidence. Lingering lake-enhanced rain showers,
perhaps mixed with wet snowflakes in the higher terrain of NW PA,
are expected to end by midday across NE OH and NW PA as pronounced
dry air advection occurs at the surface and aloft. No snow
accumulations are expected. Net CAA at the surface and aloft is
expected to be accompanied by daytime highs in the 40`s to lower
50`s on Wednesday and overnight lows in mainly the mid 20`s to lower
30`s around daybreak Thursday, especially inland from Lake Erie.
Considerable clearing, a weakening synoptic MSLP gradient, and the
much drier air mass accompanying the ridge will promote efficient
radiational cooling Wednesday night into Thursday morning. At least
patchy frost formation is expected inland from Lake Erie.
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&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
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Fair weather is expected on Thursday through Thursday night as the
ridge aloft continues to build from the north-central United States,
the core of the attendant surface ridge shifts from the eastern
Great Lakes toward New England, and this surface ridge continues to
influence our CWA. A net low-level WAA regime on the backside of the
surface ridge is forecast to contribute to daytime highs reaching
the upper 40`s to upper 50`s on Thursday. Overnight lows should
reach mainly the 30`s during the wee hours of Friday morning before
temperatures moderate slightly toward daybreak as the WAA regime
strengthens.

The ridge aloft traverses our region on Friday through Friday night
and should then exit slowly E`ward this upcoming weekend.
Simultaneously, one prominent shortwave trough should de-amplify and
shift NE`ward from the central and southern Great Plains toward QC
and another prominent shortwave trough should amplify as it shifts
from near the Pacific NW and northern CA toward the Great Plains. At
the surface, our region should reside along the western flank of the
aforementioned ridge. However, a warm front will sweep N`ward
through our CWA Friday through Friday night and usher-in a
warmer and more-humid air mass. The low-level return flow of
warm/humid air from the southern Gulf Stream and Gulf of Mexico,
between the departing ridge and the troughing generally to our
west, will undergo isentropic ascent over our region and release
at least weak instability in the process, including elevated
instability. This pattern will contribute to the generation of
periodic rain showers and thunderstorms this Friday through
upcoming weekend. In addition, low-level convergence along weak
surface trough axes accompanying the first prominent shortwave
trough and more-subtle shortwave troughs, and skirting our
region, should also contribute to shower/storm development. Net
low-level WAA will contribute to a warming trend, which is
expected to include daytime highs reaching mainly the 60`s to
70F on Friday and mainly the 70`s to lower 80`s on Sunday.
Overnight lows should reach the mid 40`s to mid 50`s around
daybreak Saturday and the 50`s to lower 60`s around daybreak
Sunday.
-- End Changed Discussion --

&&

.AVIATION /18Z Sunday THROUGH Friday/...
VFR conditions will continue to persist through this TAF period.
Mid level clouds have begun to erode in northwest Ohio which
will push east across the area through tonight, allowing most
terminals to observe clear skies. West-northwest winds of 5-10
knots will weaken to light and variable tonight. They will shift
to become sustained from the southwest at 5-10 knots by early
afternoon on Monday.

Outlook...Non-VFR possible in showers Tuesday. Non-VFR may
persist into early Wednesday.

&&

.MARINE...
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A ridge builds E`ward from the Upper Midwest through Monday.
However, a weakening cold front will sweep SE`ward across Lake
Erie tonight before dissipating just south and east of the lake
by daybreak Monday. SW`erly winds around 10 to 20 knots shift to
NW`erly and ease to 10 knots or less by daybreak Monday. On
Monday, winds of 10 knots or less become variable in direction.
Waves as large 3 to 6 feet in the far-eastern portion of Lake
Erie, including waters from Ripley to Buffalo, and 3 feet or
less elsewhere, subside to 2 feet or less basin-wide by daybreak
Monday.

Winds become S`erly to SW`erly around 15 to 25 knots on Monday night
through Tuesday as the ridge departs generally E`ward and interacts
with a cold front approaching from the west. Waves build to as large
as 4 to 7 feet and will trend largest in open U.S. waters and
Ontario waters where fetch is maximized. Another Small Craft
Advisory will be needed. SW`erly winds of 15 to 25 knots veer
to NW`erly Tuesday night as the cold front sweeps E`ward across
the lake and waves remain as large as 4 to 7 feet. NW`erly to
NE`erly winds are expected to ease gradually to about 5 to 15
knots on Wednesday through Wednesday night as another ridge
builds from the Upper Midwest. Waves subside to 3 feet or less
by nightfall Wednesday evening. The ridge begins to exit slowly
E`ward on Thursday through Friday as a warm front approaches
Lake Erie from the south-central United States and vicinity.
Winds should remain around 5 to 15 knots and vary between
primarily NE`erly and SE`erly. Waves should remain 3 feet or
less.
-- End Changed Discussion --

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
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OH...Frost Advisory from 2 AM to 8 AM EDT Monday for OHZ003-006-008-
     010-011-013-014-017>023-027>033-036>038-047.
PA...Frost Advisory from 2 AM to 8 AM EDT Monday for PAZ002-003.
NY...None.
MARINE...None.
-- End Changed Discussion --

&&

$$

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