LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Mon Jun 26 2023
Valid 261200Z - 271200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF
THE MID ATLANTIC...
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST WY
INTO SOUTHWEST SD AND NORTHWEST NE...
...SUMMARY...
Scattered severe thunderstorms are likely across the Mid-Atlantic
states this afternoon and evening. Damaging gusts and large hail
will be the primary hazards.
...Synopsis...
Little change in the large-scale pattern is expected across the
CONUS today. A relatively deep upper trough will remain over much of
the eastern CONUS, as an embedded deep-layer cyclone approaches the
upper Great Lakes region. An upper ridge will persist over the
southern High Plains, while an upper trough remains over much of the
West. A cold front will move across parts of the OH/TN Valleys, Mid
Atlantic, and Northeast.
...Mid Atlantic into parts of the Northeast...
Multiple rounds of thunderstorms will be possible later today across
parts of the Mid Atlantic and Northeast, within a favorably unstable
environment (with preconvective MLCAPE generally 1000-2000 J/kg) in
advance of the cold front. The strongest deep-layer flow associated
with the upper trough will be displaced well to the south and west,
but 30-40 kt midlevel flow will support some modest effective shear
across the region, especially where low-level flow remains somewhat
backed. A mix of storm clusters and perhaps a few marginal
supercells are expected through the afternoon into the early
evening. Damaging winds are expected to be the most likely hazard,
though any sustained discrete cells may also pose a threat of hail
and perhaps a tornado or two.
...Carolinas...
Somewhat stronger instability and deep-layer shear are expected
across parts of the Carolinas later today (compared to areas farther
north), though storm coverage may tend to decrease with southward
extent. MLCAPE in excess of 2000 J/kg and effective shear of 30-40
kt will support some initial supercell potential, with relatively
steep midlevel lapse rates supporting a hail threat, including the
potential for isolated very large hail. A tornado or two will also
be possible with any sustained supercell, though there will be a
tendency for upscale growth into one or more clusters, with an
increasing threat for damaging gusts as storms move eastward toward
the coast.
...Northern WY/Southeast MT into western SD/northwest NE...
A narrow zone of modest low-level moisture return and moderate
destabilization is expected this afternoon across parts of the
central/northern High Plains into southern MT, along the western
periphery of a surface ridge. Effective shear is forecast to
increase into the 30-40 kt range, as low-level southeasterly flow
veers to modest southwesterlies aloft. Widely scattered thunderstorm
development is possible late this afternoon into the evening, with a
few supercells and/or modestly organized clusters possible. Large
hail (possibly greater than 2 inches in diameter) and localized
severe gusts are expected to be the primary threats.
...Southeast OK into the ArkLaMiss region...
Strong to potentially severe storms may be ongoing at the start of
the period this morning across the ArkLaMiss region, within an
environment characterized by large elevated buoyancy and sufficient
effective shear for storm organization. Some threat for hail and/or
locally damaging gusts could linger through the morning, before
storms weaken or move offshore of the Gulf Coast.
Another round of somewhat elevated convection is possible late
tonight near/north of the remnant surface boundary from southeast OK
into the ArkLaMiss, within a weak low-level warm-advection regime.
Strong elevated buoyancy and sufficient effective shear within a
northwesterly flow regime may support a renewed risk of hail and
locally damaging gusts into early Tuesday morning.
...Southern High Plains...
Isolated storm development is possible across the southern High
Plains, within a hot and well-mixed environment. Any deep convection
would pose a threat for isolated downbursts. Any sustained cells
could also eventually pose a hail threat, though storm longevity
appears limited at this time within this weakly forced regime.
..Dean/Lyons.. 06/26/2023
Read more CHECK UPDATE ZOOM GRAPHIC
http://dlvr.it/SrDsdG
