SPC AC 161628
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1128 AM CDT Mon May 16 2022
Valid 161630Z - 171200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS PARTS OF THE
MID-ATLANTIC AND NORTHEAST...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EASTERN NM AND THE
Scattered damaging winds, isolated severe hail, and a couple brief
tornadoes are likely into early evening across parts of the
Mid-Atlantic and Northeast States. Scattered severe wind gusts and
isolated large hail are also possible across a portion of the
southern High Plains during the late afternoon and evening.
...Mid-Atlantic and Northeast...
A shortwave trough over the Upper OH Valley/Lower Great Lakes will
progress east-northeast into New England by tonight, as an
associated surface cyclone deepens across the Saint Lawrence Valley
and a trailing cold front likewise moves east and offshore tonight.
Low to mid 60s boundary-layer dewpoints are common ahead of the
front and moderate surface heating in cloud breaks will support a
plume of 500-1500 J/kg MLCAPE. Deep-layer flow/vertical shear will
increase with the approach of the midlevel trough from the west,
contributing to an environment supportive of organized line segments
and some supercell structures.
Scattered thunderstorms are ongoing within the warm conveyor regime
ahead of the cold front across central PA into western NY. This
activity will likely be the primary focus for damaging wind
potential as it likely intensifies east across PA/NJ/NY. Additional
thunderstorms should develop farther south, perhaps in multiple
waves, emanating first off the lee trough and later along the cold
front. With greater deep-layer shear across the Lower Mid-Atlantic
region and potentially somewhat higher buoyancy if cloud breaks can
become more pronounced, a mix of both isolated large hail along with
scattered damaging winds are expected.
...Southern High Plains...
Low-level moisture has spread westward into central NM on
post-frontal easterly flow. Despite low-amplitude mid-level ridging,
weak lee cyclogenesis and heating/mixing within the initially moist
air mass will reduce convective inhibition this afternoon and allow
scattered high-based thunderstorm development across the eastern
half of NM. Storms will gradually grow upscale and spread eastward
on consolidating outflows. Inverted-V profiles with large DCAPE
(near 1500 J/kg) will favor scattered severe outflow gusts, some of
which may reach 70-80 mph prior to the convection slowly weakening
after dusk in the Panhandles to northwest TX.
...Central to northern High Plains, northern Rockies, and eastern
Subtle embedded speed maxima will continue to move from the northern
Great Basin/Pacific Northwest to the northern Rockies/High Plains,
atop a weak baroclinic zone from central ID to southern MT. A
lingering low to mid-level moisture plume and surface heating in
cloud breaks will support MLCAPE up to about 500 J/kg, within a
corridor of effective bulk shear of 30-40 kt and largely straight
hodographs. This environment will support isolated to scattered
storms this afternoon/evening focused on southern MT and far
northern WY, some of which could have low-end/splitting supercell
characteristics with marginally severe hail and localized severe
Farther south, a few high-based storms may form this afternoon
across northern UT and the central High Plains area of eastern
CO/WY. Inverted-V profiles will favor a microburst threat with any
deep convection in this corridor during the late afternoon to early
...Southern LA vicinity...
A weak MCV drifting southeast from western LA may enhance sea-breeze
thunderstorm development across southern LA this afternoon. With
moderately large buoyancy and persistence of modest mid-level
northerlies, a few storms in this region may produce isolated severe
hail and damaging winds from wet microbursts.
A low-amplitude upper trough extends from central FL into the
eastern Gulf with a belt of stronger mid to upper-level
south-southwesterlies across the southeast portion of the peninsula.
A few strong storms are possible with marginally severe hail and
localized damaging winds.
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