ACUS01 KWNS 141952
SWODY1
SPC AC 141950

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 PM CDT Tue May 14 2024

Valid 142000Z - 151200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN THE TN VALLEY
AND NORTH FL...

...SUMMARY...
Isolated damaging winds and large hail will be possible across the
Tennessee Valley into this evening, and in north Florida overnight.

...20Z Update...
Primary change with this update is across FL with adjustments to the
ongoing level 2-SLGT risk. Convection has largely struggled over
land this afternoon along the outflow that trails into south FL from
clusters in the western Atlantic. Meanwhile, an MCS over the
north-central Gulf has persisted longer than most 12Z guidance
suggested but does appear to be decaying based on satellite trends.
In the near-term, instability remains limited to the northeast of
the Gulf MCS and in the wake of the earlier outflow across
north/central FL. But eventually, destabilization will occur from
the south and west. Overnight, convective development should
increase along the low-level baroclinic zone in the northeast Gulf
to north FL. Fast mid to upper-level southwesterlies should support
a couple mid-level supercells. The recovering instability should
yield a primary threat of large hail overnight, but a tornado and
isolated damaging winds will be possible as well.

..Grams.. 05/14/2024

.PREV DISCUSSION... /ISSUED 1128 AM CDT Tue May 14 2024/

...FL through tonight...
An initial MCS moved over north FL/southeast GA earlier this morning
and has now weakened, with a trailing outflow boundary to the
southwest across north FL.  Other storm clusters across the eastern
Gulf of Mexico have been moving eastward along the outflow boundary,
though most of these storms have tended to weaken before approaching
the west central FL Gulf coast.  There will still be some potential
for new storm development this afternoon along the outflow boundary,
as well as along the Atlantic coast sea breeze across east central
FL.  Wind damage with 55-70 mph gusts will be the main threat with
the storms along the outflow boundary.  Sufficiently long and
relatively straight hodographs will also support some potential for
isolated splitting storms capable of producing isolated damaging
gusts and some hail along the Atlantic coast sea breeze.

Additional storms will be possible overnight across north FL.  Will
maintain a SLGT risk for wind damage potential with any additional
clusters overnight, though there is uncertainty regarding the
influence of ongoing/diurnal storms farther to the south.

...TN Valley region through late evening...
A midlevel trough over the lower-middle MS Valley will move eastward
today toward the lower OH/TN Valleys, along with an associated
surface cyclone and trailing/weak cold front/trough.  Pockets of
surface heating along and east of the surface trough will boost
MLCAPE into the 500-1500 J/kg range this afternoon, in an
environment with sufficient vertical shear for a mix of small storm
clusters and a few supercells.  These storms will be capable of
producing occasional large hail of 1-1.5 inches in diameter and
damaging outflow gusts near 60 mph.

...Central High Plains and vicinity through late evening...
A midlevel trough with embedded perturbations over ID and WY will
move east-southeastward toward the central High Plains through
tonight.  Low-level moisture will remain somewhat limited, but
surface heating/deep mixing will contribute to inverted-V profiles
with sufficient buoyancy for high-based thunderstorms capable of
producing isolated strong-severe outflow gusts of 50-60 mph this
afternoon through late evening.

...Northern New England this afternoon...
Surface heating and modest low-level moisture along and south of the
main cloud band may support isolated strong thunderstorm development
for a few hours this afternoon.  Isolated/marginally severe hail and
wind damage will be possible given MLCAPE near 500 J/kg, steepening
low-level lapse rates, cool midlevel temperatures and effective bulk
shear near 30 kt.

...The Caprock to the Edwards Plateau in TX this evening...
Very isolated thunderstorm development will be possible along a
diffuse dryline.  Forcing for ascent and moisture will remain
limited, but a high-based storm or two could pose a marginal
wind/hail threat for a couple of hours this evening.

$$