SPC MD 1542
[html]MD 1542 CONCERNING SEVERE THUNDERSTORM WATCH 481...482... FOR SOUTHERN ARKANSAS....NORTHERN LOUISIANA...CENTRAL MISSISSIPPI
Mesoscale Discussion 1542
NWS Storm Prediction Center Norman OK
0537 PM CDT Thu Jul 21 2022
Areas affected...southern Arkansas....northern Louisiana...central
Mississippi
Concerning...Severe Thunderstorm Watch 481...482...
Valid 212237Z - 220000Z
The severe weather threat for Severe Thunderstorm Watch 481, 482
continues.
SUMMARY...Potential still exists for strong thunderstorm development
with gusty winds to spread into portions of north central
Mississippi through 8-10 PM CDT.
DISCUSSION...A weak low-level convergence zone extending from parts
of northeastern Oklahoma into southeastern Arkansas has beco*e the
focus for increasingly widespread intense thunderstorm development
the past couple of hours, in the presence of steep lapse rates and
large CAPE. Beneath the enlarging, cold cloud tops, consolidating
outflow has been spreading radially outward from an area centered
roughly west-southwest of Hot Springs, AR.
Deep-layer mean flow is weakly sheared and not particularly
conducive to organized convective development, but there is a
north-northwesterly co*ponent around 10 kt across the Ozark Plateau
through the lower Mississippi Valley. This favors the southeastward
advancing segment of the convective outflow for most likely renewed
thunderstorm development as it gradually spreads out from initiating
convection, particularly with the more moist and potentially
unstable environment centered over the lower Mississippi Valley. So
the High Resolution Rapid Refresh depiction of stronger convection
developing along the surface boundary through southeastern Arkansas
into north central Mississippi through 01-03Z seems plausible, but
it is not certain.
..Kerr.. 07/21/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...BMX...MEG...JAN...LZK...SHV...
LAT...LON 34279318 34079194 34089121 34279004 33428826 32628852
32418980 32469099 33149277 33619353 34279318
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Source: SPC MD 1542 (http://ht**://www.spc.noaa.gov/products/md/md1542.html)