Severe Storm Outlook Narrative (AC)
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831
ACUS02 KWNS 280602
SWODY2
SPC AC 280600

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Fri Jun 28 2024

Valid 291200Z - 301200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF OH/PA
INTO NORTHERN WV AND WESTERN NY...

...SUMMARY...
Scattered damaging winds and a couple tornadoes are possible on
Saturday from parts of Ohio into northern West Virginia, central and
western Pennsylvania, and western New York.

...Parts of the Ohio Valley and Northeast...
A mid/upper-level shortwave trough and related surface low are
forecast to move from parts of the upper Midwest into Ontario/Quebec
on Saturday, while a trailing shortwave will move southeastward
across the upper Great Lakes during the evening. One or more
convectively enhanced shortwave troughs may move eastward within a
belt of westerly midlevel flow from parts of the Midwest/Ohio Valley
into the Northeast. A cold front trailing from the primary surface
low will move eastward across parts of the Midwest, Ohio Valley, and
Great Lakes, and eventually into parts of the Northeast by Sunday
morning.

Rich low-level moisture is forecast to stream northeastward
along/ahead of the cold front, aided by a belt of relatively strong
southwesterly 850 mb flow. Midlevel lapse rates are expected to
remain weak, but low 70s F dewpoints and modest diurnal heating
could support pockets of at least moderate buoyancy by mid/late
afternoon, though the influence of early-day convection on
destabilization continues to result in uncertainty regarding the
forecast.

There is some potential for morning convection to gradually
intensify through the day, within a moist and favorably sheared
environment. Isolated damaging wind and possibly a brief tornado
could accompany the strongest storms into early afternoon.

Scattered thunderstorms may redevelop during the afternoon from OH
into western PA, with more isolated development possible along the
trailing front into the lower OH Valley. Deep-layer shear will be
sufficient for organized convection, and a few supercells and/or
organized clusters could develop and move eastward during the
afternoon into the evening, with a threat of scattered damaging
wind. Some tornado threat could also evolve, especially from eastern
OH into western PA/NY, where low-level shear/SRH will remain
favorable through the day into the early evening.

The Slight Risk has been expanded somewhat to the north and east,
where confidence is currently greatest in a corridor of organized
severe potential, with potential for damaging winds and a couple
tornadoes.

...Central Great Lakes...
As the trailing shortwave trough moves across the Great Lakes Sunday
evening, there is some potential for at least isolated storm
development from eastern WI into MI and northern IL. With favorable
deep-layer shear in place, isolated severe storms will be possible.
Greater probabilities may eventually be needed for a portion of this
region, depending on trends regarding storm coverage lingering
instability into late afternoon/early evening.

...Ozark Region into the south-central Plains...
Strong buoyancy is forecast to develop during the afternoon along
the trailing cold front from parts of southern KS/MO into northern
OK/AR. Deep-layer flow is expected to be rather weak, but modest
veering with height may support effective shear of 20-30 kt near the
front. Storm coverage along the front in this region remains
somewhat uncertain, but isolated strong to severe storms will be
possible, with a threat of localized damaging gusts and possibly
some hail. A couple stronger storms may also develop within a
post-frontal regime across parts of the southern/central High
Plains. A corridor of higher probabilities may eventually be needed,
if confidence increases regarding the most favored corridor for
frontal convection.

..Dean.. 06/28/2024

$$