ACUS01 KWNS 091300
SWODY1
SPC AC 091258

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0658 AM CST Sat Mar 09 2024

Valid 091300Z - 101200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF
NORTHERN AND NORTHWESTERN FLORIDA TO SOUTHERN NORTH CAROLINA...

...SUMMARY...
A few tornadoes and damaging to severe thunderstorm gusts are
possible through early evening across parts of the Southeast States.

...Synopsis...
A progressive, fairly well-amplified mid/upper-level pattern will
persist through the period over the CONUS. A positively tilted
shortwave trough was evident in moisture-channel imagery over parts
of the Ozarks and AR to southwest TX. The eastern part will split
off eastward, as a northern-stream shortwave trough digs
southeastward across the upper Mississippi Valley/Great Lakes
region. The southern perturbation will cross the Mid-South and
Tennessee Valley regions today, reaching the southern Appalachians
by 00Z as a more diffuse, elongated trough and vorticity banner
within a broader area of cyclonic flow. The northern trough will
develop a closed 500-mb low tonight over the Upper Great Lakes and
Lower MI, contributing to a large area of cyclonic flow by 12Z over
most of the East.

At the surface, 11Z analysis showed a low over Lake Huron with
occluded front/trough southward to another low over west-central GA.
From that low, a cold front extended southwestward across the
western FL Panhandle, and a warm front was drawn eastward over
extreme southern SD to adjoining Atlantic waters. The southern low
should ripple northeastward across central parts of SC/NC by 21Z
today, with its definition muddled somewhat by convective processes
just to the south and southeast. By 00Z, the low should reach
northeastern VA, with cold front across the eastern Carolinas,
southern GA, and the FL coastal bend, to the central/southwestern
Gulf.

...Southeastern CONUS...
Occasional severe thunderstorms -- within a broader area of
convection described below -- will offer the greatest severe threat
today, in the forms of a few tornadoes and sporadic damaging to
severe gusts.

An ongoing convective band was apparent across southern GA and parts
of the FL Panhandle,ahead of the cold front and along and south of
the warm front. See SPC tornado watch 34 and related mesoscale
discussions for near-term coverage of this activity. The associated
belt of relatively maximized low-level lift will remain the
principal focus for continued development through the day, as it
shifts eastward across the outlook area, and also, extends
northeastward over parts of the Carolinas. Moisture is increasing
in the proximal part of the foregoing boundary layer (inflow
region), and surface dewpoints in the upper 60s to low 70s F will
become common south of the activity in the next few hours -- where
not already present. That, as well as cloud-muted diurnal heating,
will boost preconvective MLCAPE into the 1000-1500 J/kg range,
collocated with favorable deep shear (effective-shear magnitudes
60-70 kt). Low-level hodographs will remain large, even where
surface flow veers somewhat to south-southwest as the low shifts
eastward. The main limiting factor for even greater severe
potential will be the messy, training nature of convective mode.
However, embedded mesocirculations (supercells or small LEWP/bow
features) will post the greatest tornado and wind threat locally.

Some potential remains for development of strong-severe
thunderstorms behind the initial convective band, and in a
destabilizing airmass over eastern SC and southeastern NC this
afternoon. While more uncertain in terms of coverage and longevity,
the buoyancy/shear parameter space still looks favorable for
supercell potential with any sustained convection. As such, that
part of the "slight" level probabilities will be maintained for now,
with yet-to-develop mesoscale trends likely influencing the threat.

..Edwards/Jewell.. 03/09/2024

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