MD 0274 CONCERNING TORNADO WATCH 49… FOR PORTIONS OF SOUTHERN LA…SOUTHERN/CENTRAL MS…AND SOUTHWESTERN AL
Mesoscale Discussion 0274
NWS Storm Prediction Center Norman OK
0312 AM CDT Fri Mar 18 2022
Areas affected...Portions of southern LA...southern/central MS...and
southwestern AL
Concerning...Tornado Watch 49...
Valid 180812Z - 181015Z
The severe weather threat for Tornado Watch 49 continues.
SUMMARY...An isolated threat for tornadoes and damaging winds should
continue to shift eastward across southern Louisiana/Mississippi.
Downstream watch issuance will probably be needed.
DISCUSSION...Ongoing low-level warm advection related storms have
struggled to intensify over the past couple of hours. This is likely
due to most convection moving quickly northward into a less unstable
airmass in southern MS. Still, a gradual increase in low-level
moisture has occurred ahead of these storms, with 08Z surface
observations indicating low to mid 60s dewpoints have advanced into
parts of southeastern LA and southern MS. It remains unclear when,
or if, this convection will become truly surface based, with latest
RAP forecast soundings across this region continuing to suggest mid
60s surface dewpoints will be needed for this to occur. Even so,
recent VWPs from KLIX/KDGX show impressive low-level hodograph
curvature, with 0-1 km SRH exceeding 400 m2/s2. If updrafts can
overcome the lingering boundary-layer inhibition, then they would be
capable of low-level rotation and producing a few tornadoes. Given
the strength of the low-level winds (40-50 kt), isolated strong to
damaging winds may also occur.
It appears that the best forcing associated with the low-level jet
and an ejecting shortwave trough farther west may tend to remain
displaced to the north of the greatest low-level moisture/surface
warm sector. Still, some overlap of weak but sufficient boundary
layer instability coupled with strong low-level and deep-layer shear
should support a continued severe threat with eastward extent across
southern LA/MS/AL over the next several hours. Accordingly, a
downstream Tornado Watch will probably be needed.
..Gleason/Grams.. 03/18/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MOB...JAN...LIX...LCH...
LAT...LON 30169084 30119191 30979216 31499125 32129055 32558976
32618916 32508862 32018812 31188794 30748840 30368962
30169084
