812
ACUS11 KWNS 092010
SWOMCD
SPC MCD 092010
ARZ000-092215-

Mesoscale Discussion 1218
NWS Storm Prediction Center Norman OK
0310 PM CDT Sun Jun 09 2024

Areas affected...parts of northwestern through north central
Arkansas

Concerning...Severe potential...Watch possible

Valid 092010Z - 092215Z

Probability of Watch Issuance...60 percent

SUMMARY...Intensifying convection, including one or two storms at
least occasionally taking on supercell structure, appears likely
through 4-6 PM CDT.  This may pose a risk for large hail, locally
damaging wind gusts and perhaps some potential for producing a
tornado.

DISCUSSION...Deepening convective development, including recent
initiation of thunderstorm activity, is ongoing northwest of
Russellville AR.  This is where low-level convergence has become
maximized near the intersection of a southward advancing cold front
and the stalling western flank of convective outflow from overnight
convection.

Beneath 30-35 kt west-northwesterly flow around 500 mb, surface
temperatures are warming through the lower/mid 90s F in a narrow
corridor just to the southwest of the outflow boundary, extending
across and east-southeast of the Little Rock area.  This is
occurring beneath a remnant plume of elevated mixed-layer air, where
seasonably high boundary-layer moisture content appears to be
contributing to mixed-layer CAPE on the order of 2000-3000 J/kg.

It is possible that this is being aided by forcing for ascent
associated with a subtle mid/upper perturbation.  Regardless, there
appears sufficient deep-layer shear to support intensifying
convection and the evolution of at least transient supercell
structures with increasing inflow of the unstable boundary-layer
air.  This likely will pose a risk for severe hail, locally strong
surface gusts and perhaps at least some risk for a tornado while
slowly propagating east-southeastward through 4-6 PM CDT.

..Kerr/Gleason.. 06/09/2024

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MEG...LZK...TSA...

LAT...LON   35829425 35949391 36079321 35819217 35339092 34389147
            35079328 35209385 35479434 35829425