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