Mesoscale Discussion 254

Issued

Mar 25, 2021, 11:00 AM CDT (16:00 UTC)

Expired

Mar 25, 2021, 1:00 PM 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, Livingston Parish, LA, Orleans Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, Hancock County, MS, Harrison County, MS, Pearl River County, MS, Stone County, MS

112 
ACUS11 KWNS 251600
SWOMCD
SPC MCD 251600 
MSZ000-LAZ000-251800-

Mesoscale Discussion 0254
NWS Storm Prediction Center Norman OK
1100 AM CDT Thu Mar 25 2021

Areas affected...Southeast Louisiana and southern Mississippi

Concerning...Severe potential...Watch possible 

Valid 251600Z - 251800Z

Probability of Watch Issuance...40 percent

SUMMARY...Developing thunderstorms near the Baton Rogue, LA area may
continue to strengthen through the late morning hours. However, it
is unclear if these storms will pose a substantial severe threat.
Conditions will be monitored, and a watch is possible.

DISCUSSION...Thunderstorms have begun to develop along a weak
confluence axis noted in surface observations across southeast LA.
The 12 UTC LIX sounding, as well as recent RAP mesoanalysis, reveal
a favorable environment for organized convection with around 2000
J/kg MLCAPE, 60 to 70 knots of effective bulk shear, and ESRH values
on the order of 300 m2/s2. Satellite and lightning trends show
strengthening convection that suggest this cluster of storms may
persist for 2-3 hours. Although these storms reside in a very
favorable environment, deep-layer flow parallel to the confluence
axis is currently favoring a clustered storm mode that will likely
evolve into a more linear mode. While a hail/wind threat will
persist, the tornado threat is less certain. Storm mode trends will
be monitored in the coming hours, and a watch is possible if trends
suggest semi-discrete/embedded supercells can be maintained and pose
a more robust severe threat.

..Moore/Hart.. 03/25/2021

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

ATTN...WFO...MOB...JAN...LIX...LCH...

LAT...LON   29829156 30319131 30869082 31019041 31018961 30988909
            30848889 30618885 30118935 29858983 29649035 29439082
            29449136 29829156

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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.