MD 1174 CONCERNING SEVERE POTENTIAL…WATCH POSSIBLE FOR NORTHWEST THROUGH SOUTHEASTERN LOUISIANA AND ADJACENT PORTIONS OF SOUTHWESTERN MISSISSIPPI
Mesoscale Discussion 1174
NWS Storm Prediction Center Norman OK
0944 AM CDT Tue Jun 20 2023
Areas affected...northwest through southeastern Louisiana and
adjacent portions of southwestern Mississippi
Concerning...Severe potential...Watch possible
Valid 201444Z - 201715Z
Probability of Watch Issuance...40 percent
SUMMARY...Intensifying thunderstorms posing increasing risk for
large hail and locally strong downbursts is possible through Noon-1
PM CDT. Trends are being monitored for the possibility of a severe
weather watch.
DISCUSSION...Thunderstorms have recently initiated in a narrow
corridor east- southeast of Shreveport, LA through the Gulfport, MS
vicinity. This appears roughly aligned with a baroclinic zone
around 850 mb, likely aided by forcing for ascent associated with
weak frontogenesis and/or warm advection. A subtle mid-level short
wave impulse has been apparent in recent water vapor loops, and is
now digging southeastward across the Ark-La-Tex region.
This initially elevated convective development probably is still
being forced through a relatively warm layer centered around 700 mb.
However, the continued southeastward progression of the mid-level
wave may erode this capping layer. Furthermore, latest Rapid
Refresh suggests that boundary-layer warming with insolation will
result in increasingly negligible inhibition in a narrow corridor
immediately south of ongoing convection through 16-18Z.
As this occurs, potential exists for rapidly intensifying
thunderstorm development, increasingly rooted in a boundary-layer
becoming characterized by large CAPE in excess of 3000 J/kg.
Although deep-layer shear beneath 30-40 kt northwesterly mid-level
flow is modest, the environment still appears conducive to a risk
for large hail and locally damaging downbursts with strongest storms
into early afternoon.
..Kerr/Hart.. 06/20/2023
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...JAN...LIX...LCH...SHV...
LAT...LON 32209350 31969250 31549153 31209062 30908995 29658804
29258822 29379000 30339158 31219274 31769348 32209350
