Area Forecast Discussion
Issued by NWS Cleveland, OH

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FXUS61 KCLE 252011
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
411 PM EDT Mon Mar 25 2024

.SYNOPSIS...
High pressure ridging down from the Canadian Maritimes will
slide eastward this today as low pressure centered over the
Central Plains approaches the Upper Midwest and western Great
Lakes region. This low will lift a warm front northeast across
the region on late tonight into early Tuesday, followed by a
cold front Tuesday night into Wednesday. High pressure builds
back across the region late Wednesday and Thursday.

&&

.NEAR TERM /THROUGH TUESDAY NIGHT/...
A busy near term period is on tap as a strong Spring storm
system lifts through the Upper Midwest and northern Great Lakes.
Water vapor loops this afternoon show this feature developing
nicely with an impressive mid/upper shortwave trough progressing
from the Rockies into the southern and central Plains. This is
supporting a deepening surface low in the vicinity of KS, NE,
and MO, with broad warm/moist advection out ahead of it driving
showers across the MS Valley. As the parent shortwave swings
toward the Upper Midwest tonight, the left exit of a 140-160
knot H3 jet streak combined with the shortwave taking on a
negative tilt will lead to the surface low rapidly deepening
below 990 mb by early Tuesday as it moves into the Upper Midwest.
The surface low will mature to around 988 mb by midday before
starting to slowly fill as it lifts across Lake Superior Tuesday
afternoon and evening. It will then become vertically stacked as
the shortwave closes off, with the stacked cyclone drifting
slowly toward James Bay Tuesday night. The following are impacts
with this system by period:

[Late tonight into Tuesday afternoon]
As the aforementioned dynamics approach the area late tonight
and Tuesday morning, a 50-65 knot low-level jet will punch
across NW and north central Ohio in response to the upper
forcing. This will drive a warm front across the region from SW
to NE Tuesday morning into the afternoon, with strong moisture
advection and isentropic ascent supporting widespread showers
ahead of this boundary. The QPF has continued to trend less,
both due to the more progressive nature of the system and very
marginal at best elevated CAPE to work with late tonight and
Tuesday, so do not expect flooding issues since the rain should
be mostly stratiform and progressive. However, the
aforementioned forcing and warm/moist advection as the boundary
lifts through will allow it to rain everywhere, so have likely
to categorical PoPs reaching the I-75 corridor after 08Z, the
I-71 to I-77 corridors by 12Z, and the OH/PA line by 15Z or so.
Most areas will only see 0.25 to 0.50 inches of QPF, with
locally higher amounts in NE Ohio and NW PA where the
progression may slow a bit early Tuesday afternoon. A dry slot
is expected to wrap into the region as we become entrenched
briefly in the warm sector Tuesday afternoon, so expect most areas
to see dry time by mid afternoon, with far eastern Ohio and
western PA drying out by late afternoon and evening where the
rain lingers longer. The bigger impact from late tonight into
Tuesday afternoon is winds. As the aforementioned low-level jet
impinges on the region late tonight and Tuesday morning, S to SE
winds will increase to 15-25 knots with gusts over 30 knots.
Downslope areas of Erie County, PA have the best chance to see
gusts exceed 40 knots during this period since SE winds are most
favorable there, so issued a Wind Advisory there from 04 to 16Z.
There is uncertainty for the lakeshore areas of Cuyahoga, Lake,
and Ashtabula Counties, as well as for parts of NW and north
central Ohio downwind of the central highlands. These areas can
see enough downsloping for winds to reach 40 knots in these
types of set ups, but number 1 - would like to see a stronger
850 mb jet, and number 2 - the showers during the morning will
add to the inversion making it harder to mix. Nevertheless, the
HREF ensemble means suggest wind gusts nearing 40 knots are
possible, especially in the 08-14Z timeframe, and the HREF 75th
and 90th percentiles have gusts near or over 50 mph. At this
time, kept max gusts around 35 knots, but this will be
monitored. Winds will gradually subside Tuesday afternoon and
evening as the low-level jet lifts out.

[Tuesday evening and Tuesday night]
As the stacked low lifts toward James Bay Tuesday night, the
trailing cold front will sweep across our region. Shear will be
very impressive in response to a coupled 140-150 knot H3 jet
structure between the lower Ohio Valley and Great Lakes driving
another 50-60 knot low-level jet ahead of the front. This will
lead to deep layer (0-6 Km) shear of 60-70 knots and effective
shear values well over 50 knots. This will easily support a
damaging wind risk in a low-topped squall line Tuesday evening
into Tuesday night, but the degree of shear combined with low-
level (0-1 Km) helicity of 350-450 m2/s2 could also support
brief tornadoes. The big question is instability. Dew points
will be a solid 10 degrees lower compared to the March 14 event,
and HREF ensemble means only show 100-150 joules of SBCAPE
getting into NW Ohio Tuesday evening before quickly waning
overnight. This is both due to lower dew points and a lack of an
EML. This makes the severe weather threat very conditional.
There is a window for the instability to build a little higher
in NW Ohio Tuesday afternoon and evening since the morning
showers will end sooner, so the latest SWODY 2 marginal risk
being pulled eastward into NW Ohio looks reasonable. The best
risk for a line of strong/severe convection is in NW Ohio
Tuesday evening, with storms quickly weakening as they get east
of I-75 Tuesday night. Even so, gusty winds are possible
anywhere with the line Tuesday night given the shear. Again, the
severe risk is low confidence and very conditional, but if
SBCAPE can get higher, then a bigger wind and tornado threat
cannot be ruled out.

Highs will generally range from the mid 50s to low 60s Tuesday,
with the warmest in NW Ohio. Lows tonight and Tuesday night will
range from the low to upper 40s.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
A cooler and quiet period is expected in the wake of a cold front
that will have swept just east of the area early Wednesday. Cooler
and drier air will spread into the region on Wednesday but there
could be a few lingering post-frontal showers over northeast OH and
nw PA in the morning. Temperatures will be about 10 degrees cooler
than on Tuesday. Freezing temperatures are expect Wednesday night
with seasonable readings expected on Thursday as weak high pressure
builds into the region. High temperatures will range from the mid
40s to lower 50s.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Dry weather is expected on Friday as a mainly zonal flow prevails
aloft with a ridge of high pressure at the surface over the eastern
Great Lakes and upper Ohio Valley. High temperatures will warm and
range from the upper 40s near ERI to near 60 at FDY.

Moisture will increase Friday night and Saturday as high pressure
moves to the east while a weak cold front drops south into the area.
POPs will increase to the 40-60% range across the area but amounts
are expected to be rather light and less than a tenth of an inch.

A cold front will drop south Saturday night and high pressure will
build south into the region on Sunday. Mainly dry conditions are
expected. Sunday will be seasonably cool with highs from the mid 40s
along the lakeshore to the mid 50s south of US Route 30.

On Monday, wet weather will return as low pressure in the mid-
Mississippi Valley moves into the region. POPs will increase to the
50-65% range across the region with high temperatures mainly in the
50s.

Model consistency appears to be rather high for this period.

&&

.AVIATION /18Z Monday THROUGH Saturday/...
VFR will prevail across all TAF sites through tonight. Showers
will gradually spread across the region from west to east late
tonight and Tuesday morning, but cigs will be slow to lower, so
suspect it will take until late morning for MVFR cigs to start
developing in most areas. MVFR visibilities are likely in the
heaviest showers before then. There will be a dry slot working
across the area after mid morning, so tapered the showers down
to VCSH from west to east by late morning/early afternoon. The
steadier showers will of course hold longer in NE Ohio and NW
PA.

The main concern is winds. S to SE winds will increase to 15-20
knots tonight with gusts over 30 knots at times late tonight and
Tuesday morning. The strongest gusts will occur around KFDY,
KMFD, and KERI where downsloping will aid in 35-40 knot gusts,
especially KERI where gusts over 40 knots are expected.

Outlook...Non-VFR possible in rain showers Tuesday afternoon
through early Wednesday.

&&

.MARINE...
Winds will increase from the southeast tonight to 15-25 knots as
high pressure moves off the mid-Atlantic coast and low pressure
moves into the western Great Lakes. A small craft advisory has been
issued from midnight for 24 hours or until midnight Wednesday. The
mainly southeast to south flow will minimize the wave heights at the
lakeshore or beginning of the fetch while the largest waves are
expected well away from the southern lakeshore.

A cold front will cross the lake Tuesday night and winds will veer
to the west-southwest and diminish to around 15 knots on Wednesday
and further weaken to 5-10 knots by Thursday morning. High pressure
will build over the lake Thursday and Friday with light winds.

On Saturday, a cold front will approach the lake from the north.
Light winds ahead of the front will become northerly after the
frontal passage toward evening.

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...Wind Advisory from midnight tonight to noon EDT Tuesday for
     PAZ001-002.
NY...None.
MARINE...Small Craft Advisory from midnight tonight to midnight EDT
     Tuesday night for LEZ142>149.

&&

$$

SYNOPSIS...Garuckas
NEAR TERM...Garuckas
SHORT TERM...LaPlante
LONG TERM...LaPlante
AVIATION...Garuckas
MARINE...LaPlante


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