|Mesoscale Discussion 1058|
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Mesoscale Discussion 1058
NWS Storm Prediction Center Norman OK
0340 PM CDT Fri Jun 16 2017
Areas affected...MS...western AL...eastern LA...eastern
Concerning...Severe Thunderstorm Watch 338...
Valid 162040Z - 162245Z
The severe weather threat for Severe Thunderstorm Watch 338
SUMMARY...The risk for severe storms continues across Watch 338.
DISCUSSION...Convective coverage and intensity are increasing across
northwest and north-central MS, where sufficient density and areal
coverage of convective plumes are fostering cold pool amalgamation.
At least loosely organized clusters may evolve from this activity
and spread south-southeastward into a boundary layer characterized
by high theta-e. The presence of 20-30 kt of 4-6-km above-ground
flow indicated by the Jackson VAD wind profile supports this notion
of modest convective organization. Additional more isolated to
widely scattered convection is developing farther south, as
boundary-layer circulations have strengthened amid minimal MLCINH.
As the aforementioned convection ingests inflow characterized by
SBCAPE of 3000-5000 J/kg -- aided by 7.5-8.5 C/km midlevel lapse
rates overlying lower/middle 70s surface dewpoints -- convection
should continue intensifying. With the potential for more
cluster-mode convection becoming apparent, damaging wind gusts
should be the primary hazard -- particularly given DCAPE over 1500
J/kg in some areas amid the aforementioned large SBCAPE. Severe hail
may also accompany the strongest incipient updrafts.
There may be a tendency for the primary corridor of greatest
severe-wind risk to extend through parts of central MS into the late
afternoon hours, especially if upscale convective growth were to
continue. Later this afternoon into the evening, this potential
cluster of storms -- and/or additional preceding developing
storms -- could spread south/southeast of the Watch with a severe
risk. If the risk for more organized convection with severe
potential were to become apparent in these areas, some consideration
could be given to additional Watch issuance.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 33059198 34689084 35268968 35078858 33958816 32128792
30848830 30488967 30599116 31429194 33059198
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