SPC AC 051708
Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1208 PM CDT Mon Jun 05 2023
Valid 061200Z - 071200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS PARTS OF THE
SIERRAS/GREAT BASIN...SOUTHERN HIGH PLAINS...NORTHEASTERN GEORGIA
INTO SOUTH CAROLINA...AND SOUTH FLORIDA ....
Isolated strong to severe thunderstorms may occur Tuesday across
parts of the Sierras/Great Basin, southern High Plains, northeastern
Georgia into South Carolina, and south Florida.
Overall upper pattern is forecast to remain relatively stagnant on
Tuesday, with upper ridging center over the northern Plains, an
upper low over central/southern CA, and expansive cyclonic flow over
much of the northeast CONUS. Surface pattern across the CONUS will
be void of any influential features, with only modest lee troughing
across the High Plains and the deepest area of low pressure over
Nova Scotia. Even with this stagnant large-scale pattern and
unremarkable surface pattern, a few more subtle features could still
result in a few strong to severe thunderstorms.
Thunderstorm development is forecast Tuesday afternoon as sea-breeze
boundaries move through a destabilized airmass. Slightly stronger
mid-level southwesterly flow is anticipated across southern FL on
Tuesday, contributing to the potential for more updraft organization
and isolated damaging downbursts.
...Northwest CA into the Great Basin...
A shortwave trough rotating through the CA upper low will contribute
to increase thunderstorm coverage and low severe-thunderstorm
potential across the western Great Basin Tuesday afternoon and
evening. Low-level moisture will be modest, but increasing mid-level
moisture and cold mid-level temperatures will boost buoyancy,
helping support stronger updrafts. Additionally, high cloud bases
atop a deeply mixed boundary layer will aid in the development of
strong downdrafts, with damaging gusts as the primary threat across
the region. Given the cold mid-level temperatures, a few isolated
instances of hail are also possible.
...South Carolina into Western Georgia...
This region is expected to be on the southern edge of any stronger
westerly flow aloft while on the northern extent of the better
low-level moisture and buoyancy. Overlap between these features,
coupled with ascent attendant to a weak, southward-progressing
surface trough, may result in a few stronger storms during the
afternoon and evening. Steep low-level lapse rates suggest damaging
gusts will be the primary severe risk.
...Southern High Plains...
Despite limited low-level moisture, afternoon thunderstorm
development is still anticipated over the higher terrain of the
southern Rockies. Isolated development is possible along the lee
trough as well. Veering wind profiles will contribute to 20 to 30 kt
of effective bulk shear, which should be enough for a few more
organized/robust updrafts. Additional storm development, with higher
coverage south into the TX Trans Pecos region, is expected during
the evening as a shortwave trough progresses into the region.
Isolated hail and a strong gust or two are possible with this
activity as well.
Shortwave trough rotating around the upper low centered over Nova
Scotia is expected to move through the Northeast during the early
afternoon. Low-level moisture will be modest, but cold mid-level
temperatures will still support limited buoyancy and the potential
for a few thunderstorms. Shear will also be weak, with the marginal
nature of the overall environmental conditions limiting the severe
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