Source: US National Oceanic and Atmospheric Administration
SPC AC 290551
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1251 AM CDT Thu May 29 2025
Valid 301200Z – 311200Z
…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE EASTERN GULF COAST STATES…GEORGIA…CAROLINAS AND VIRGINIA…
…SUMMARY…
Scattered severe storms with wind damage, large hail, and a couple
tornadoes will be possible Friday afternoon and evening from parts
of the Eastern Gulf Coast to the Mid-Atlantic.
…Georgia/Carolinas/Mid-Atlantic/Gulf Coast States…
At mid-levels, a trough will move across the Ohio and Tennessee
Valleys, as a jet streak translates eastward across the Southeast.
Ahead of the trough, a moist and unstable airmass will be in place
from the central Gulf Coast northeastward into the Carolinas and
Mid-Atlantic. Surface dewpoints in the mid to upper 60s F will
likely result in moderate destabilization across much of this
airmass by midday. Scattered thunderstorm development, aided by
topographic forcing, is expected to take place in the southern and
central Appalachians during the early afternoon. Convection will
move eastward into the lower elevations of the Atlantic Coastal
states during the mid to late evening, where a severe threat will
likely develop. The increase in large-scale ascent and deep-layer
shear associated with the approaching mid-level jet will be a driver
for the severe threat Friday afternoon and evening.
NAM forecast soundings along the instability axis during the
afternoon suggest that MLCAPE will peak near 1500 J/kg, and that 0-6
km shear will increase into the 50 to 60 knot range. While the
low-levels are forecast to remain veered to the southwest, strong
speed shear will be present in the 850 to 500 mb layer. This will be
favorable for supercells and bowing line segments. 0-3 km lapse
rates are forecast to peak near 7.5 C/km, which will support a
potential for damaging wind gusts. Supercells will also be capable
of producing isolated large hail, especially in areas where the
maximum potential for surface heating is realized. Although
low-level shear is not expected to be that strong, any supercell
that becomes intense could produce a brief tornado. The severe
threat is expected to move eastward onto the Atlantic Coastal Plain
in the late afternoon, and toward the Atlantic Coast during the
evening.
…Western Great Lakes…
At mid-levels, flow is forecast to become north-northwesterly over
the upper Mississippi Valley and western Great Lakes, in the wake of
an exiting trough. At the surface, a post-frontal airmass will be
located over the western Great Lakes, where flow will be
northwesterly. A pocket of locally higher surface dewpoints is
forecast from eastern Wisconsin into lower Michigan. Within this
pocket, weak instability is expected to develop along the western
edge of the higher surface dewpoints, along and inland from the
western shore of Lake Michigan. Along this north-to-south corridor,
surface heating and low-level convergence will make convective
initiation likely during the afternoon. Forecast soundings at 21Z
from Chicago to Milwaukee have 0-3 km lapse rates peaking near 8.5
C/km, which will be favorable for isolated marginally severe gusts.
In addition, 500 mb temps will be relatively cold near -17C, which
could also support a potential for hail with the stronger updrafts.
..Broyles.. 05/29/2025
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