Mesoscale Discussion 0118
NWS Storm Prediction Center Norman OK
0228 PM CST Sun Jan 22 2017
Areas affected...east-central AL into west-central GA
Concerning...Tornado Watch 21...
Valid 222028Z - 222200Z
The severe weather threat for Tornado Watch 21 continues.
SUMMARY...Strong to severe thunderstorms will spread northeast from
east-central AL into west-central GA, including the greater Atlanta
metro area over the next 1-2 hours. While the greatest severe risk
should remain south of the ATL area, strong wind gusts and small
hail cannot be ruled out. Additionally, at least a low-end tornado
threat will exist across southern portions of the MCD area.
DISCUSSION...A line of storms located very near the surface low
center across east-central AL will continue to pivot northeast into
adjacent west-central GA, including the great Atlanta area. The
thermodynamic environment across this area is unimpressive, being
just north of the better warm sector across parts of central and
southern GA. However, this line of storms has been rather intense
with strong winds and small hail indicated by radar. In fact, even
in the stratiform rain region to the north and west, BHM measured a
35 kt gust. Furthermore, on the southern end of line, some cells
have occasionally exhibited low-level rotation. This is not too
surprising given shear profiles which have large, curved hodographs,
especially in the lowest 3km. In fact, the FFC VWP showed nearly 400
m2/s2 0-1km SRH. Given the degree of deep layer shear, modest lapse
rates per 18z BMX and FFC RAOBs, at least some continuation of
strong wind gusts and perhaps some small hail appears possible as
storms track toward the Atlanta area in the next 1-2 hours.
Additionally, at least a low-end threat for a tornado can not be
ruled out, especially across southern portions of the MCD area.
LAT...LON 33628582 33788488 33708449 33518431 33298411 32868416
32488443 32318475 32488536 33308599 33468602 33628582