Mesoscale Discussion 238

Issued

Mar 23, 2021, 9:41 AM CDT (14:41 UTC)

Expired

Mar 23, 2021, 11:45 AM CDT

In force

2 hr

Issued by

the Storm Prediction Center

Concerning

Severe potential...watch possible

Chance of a watch

40%

Counties Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, West Baton Rouge Parish, LA

061 
ACUS11 KWNS 231442
SWOMCD
SPC MCD 231441 
LAZ000-231645-

Mesoscale Discussion 0238
NWS Storm Prediction Center Norman OK
0941 AM CDT Tue Mar 23 2021

Areas affected...Southeast LA

Concerning...Severe potential...Watch possible 

Valid 231441Z - 231645Z

Probability of Watch Issuance...40 percent

SUMMARY...Ongoing line of storms will continue eastward across
southeast LA. Damaging wind gusts and/or a brief tornado or two are
possible within this line, and trends are being monitored for
possible watch issuance.

DISCUSSION...Regional radar imagery shows a loosely organized
convective line from southwest MS southwestward through the
southwest LA Coast. Several bowing segments have been noted within
this line, resulting mostly from the decay previous supercells. The
influence of the surging cold pool and resulting warm-air advection
can also be seen in the deepening convection over Lafayette and St.
Martin parishes.

Thus far embedded storms have been quick to loose their more
cellular characteristics as the cold pool undercuts updrafts and
promotes an elevated, outflow dominant storm mode. Even with this
outflow-dominant storm mode, very strong low-level vertical shear
(i.e. 0-1 km SRH over 450 m2/s2 on the 1419Z LIX VAD) is resulting 
organized updrafts. Additionally, thin cloud cover downstream could
result in modest heating, while ongoing moisture advection persists
as well. Resulting increase in buoyancy could favor a more
surface-based storm mode along the leading edge of the cold pool,
which would result in an increased threat for damaging wind gusts
and perhaps a brief tornado or two. Observational trends across this
region are being monitored closely and a watch may eventually be
needed to cover this severe potential.

..Mosier/Hart.. 03/23/2021

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

ATTN...WFO...LIX...LCH...

LAT...LON   29969219 30559140 30849051 30398973 29359027 29469261
            29969219

Mesoscale Discussions in Louisiana, 2021Every mesoscale discussion in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.