ZCZC SPCSWOMCD ALL
ACUS11 KWNS 180810 
SPC MCD 180810 
LAZ000-MSZ000-180945-

Mesoscale Discussion 0669
NWS Storm Prediction Center Norman OK
0310 AM CDT Tue May 18 2021

Areas affected...portions of southeast LA

Concerning...Severe potential...Watch unlikely 

Valid 180810Z - 180945Z

Probability of Watch Issuance...20 percent

SUMMARY...A brief, weak tornado is possible across parts of
southeast Louisiana early this morning.

DISCUSSION...Showers and thunderstorms across southeast LA have
shown transient, weak rotation the past hour or so. Overall, this
activity is occurring in weak instability and modest shear. However,
low level southeasterly winds around 20-30 kt are resulting in
modest low level hodograph curvature. Furthermore, surface dewpoints
near 70 F are aiding in moderate low level instability with a
corridor of 0-3 km MLCAPE around 100-125 J/kg evident in latest
mesoanalysis. Poor low level lapse rates and overall marginal
larger-scale environment will limit longevity/intensity of organized
cells. However, the moist/unstable low levels amid somewhat
favorable low level shear could result in a brief/weak tornado. The
overall threat is expected to remain limited, and a watch is not
expected at this time.

..Leitman/Hart.. 05/18/2021

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

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

LAT...LON   29649079 30299049 30569011 30608983 30438948 29898952
            29258972 28909014 28789071 28869106 29119114 29649079 

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