Valid 152000Z – 161200Z
…NO SEVERE THUNDERSTORM AREAS FORECAST…
Isolated thunderstorms may occur across parts of southern Louisiana
and Mississippi late tonight into early Sunday morning.
Latest short-term guidance suggests isolated thunderstorms may occur
the in the last few hours of the period (09-12Z) across parts of
southern LA/MS. Weak low-level warm advection will be occurring
across this region. About 100-300 J/kg MUCAPE may develop as
mid-level temperatures gradually cool with the approach of a strong
southern-stream upper jet from the west.
.PREV DISCUSSION… /ISSUED 1030 AM CST Sat Feb 15 2020/
Isolated to scattered showers are expected to continue in the
offshore waters and adjacent coastal area through tonight. Weak
mid-level lapse rates as sampled by the 12Z Miami observed sounding
and a lack of greater large-scale ascent is likely to preclude the
development of deeper convection and thunderstorms.
…Central/southern Louisiana vicinity…
A few lightning flashes cannot be entirely ruled near coastal
Louisiana around the end of the period, but overall thunderstorm
potential is still currently expected to remain low (sub-10
percent). Strengthening warm advection will result in an increase in
convective showers overnight. Sufficient moistening may
occur for scant elevated buoyancy towards the end of the period.
However, the presence of a rather dry 600-500 mb layer beneath
relatively warm 400-mb temperatures /near the -20 C level/ suggests
that convection may remain too shallow to yield charge separation
for lightning prior to 12Z Sunday.