LIVE MAP (ABOVE) ... SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0100 AM CDT Tue May 09 2023
Valid 091200Z - 101200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE SOUTHERN/CENTRAL PLAINS...AND EASTERN NORTH CAROLINA INTO FAR
SOUTHEASTERN VIRGINIA...
...SUMMARY...
Scattered severe thunderstorms with a large hail and damaging wind
threat should occur today across parts of the southern/central
Plains, and eastern North Carolina into far southeastern Virginia.
...Southern/Central Plains...
Upper ridging will generally prevail over much of the Plains today,
with a subtle shortwave trough forecast to advance over portions of
the northern/central Plains and Upper Midwest. A weak surface low
should remain centered over southeastern CO and vicinity through the
day, with low-level moisture forecast to return northward in tandem
with a diffuse warm front across KS into perhaps far southern NE. A
dryline is also expected to mix eastward across the southern High
Plains through this afternoon.
Elevated convection may be ongoing at the start of the period later
this morning in a weak low-level warm advection regime across
southern NE into northern KS. With MUCAPE expected to increase
across this area as the low-level moisture returns northward, these
early-day thunderstorms may pose an isolated threat for large hail.
If this activity can persist, it may eventually become surface based
along/near the front across northern into eastern KS. An increasing
threat for large to very large hail and severe/damaging winds gusts
would occur if this scenario unfolds, as both instability and
effective bulk shear will support supercells. Upscale growth into an
MCS also appears possible, but details on convective evolution
remain uncertain.
Although less confidence exists in convective initiation along the
front/dryline intersection in western KS and vicinity due to
nebulous large-scale ascent, there still appears to be enough
conditional potential to support maintaining Slight Risk caliber
severe probabilities for both large hail and damaging winds across
this area. The probability for any thunderstorms to develop farther
south along the length of the dryline into the TX Panhandle and west
TX appears highly conditional, with little convective signal in most
guidance.
...Eastern Carolinas into Southeastern Virginia...
A shortwave trough will move east-southeastward across the
Mid-Atlantic today. A belt of enhanced west-northwesterly mid-level
flow will accompany this feature, and provide support for sufficient
deep-layer shear to foster thunderstorm organization. Although
surface winds will be veered mostly to west-northwesterly across the
Carolinas and southeastern VA, there should still be adequate
low-level moisture in place for weak to moderate instability to
develop in concert with daytime heating.
Most guidance shows convection developing across parts of
southeastern VA into eastern NC this afternoon along/near a surface
trough. A mix of multicells and perhaps a few supercells appears
possible, with a threat for both severe hail and damaging winds. A
small bowing cluster may develop and pose a greater wind threat with
time into eastern NC. Less confidence exists with southward extent
into SC regrading overall convective coverage and intensity.
...Texas/Louisiana Gulf Coast...
At least one remnant MCV from prior convection will likely be
present along part the TX Gulf Coast at the start of the period this
morning. Although this region will be under the influence of upper
ridging and large-scale subsidence, there should still be potential
for scattered to numerous thunderstorms due to the presence of rich
low-level moisture and the influence/subtle ascent associated with
the MCV and various sea breezes. Any thunderstorms that can develop
in this moderate/strong instability but weak deep-layer shear
environment will have the potential to produce isolated damaging
winds and perhaps marginally severe hail.
..Gleason/Lyons.. 05/09/2023
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