Valid 262000Z – 271200Z
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
AL…WESTERN GA AND PORTIONS OF THE FL PANHANDLE THROUGH THIS
EVENING…
…SUMMARY…
Locally damaging wind gusts and a brief tornado are possible through
early evening across parts of eastern Alabama, western Georgia and
the Florida Panhandle.
…Mid-South to Southeastern States…
The center of what was once TS Olga is located near the TN/KY state
line just west of KHOP as of 1930z. Strong gusts have occurred
across parts of MS and TN as the low lifted northward this morning
and early afternoon. Given the tight pressure gradient in place
across the Lower OH Valley into middle TN, strong gusts may continue
through the afternoon as background flow is very strong. Little
lightning has occurred north of the MS/AL border were MUCAPE is
generally less than 200 J/kg and is not expected to foster
deep/intense convection. As such, the Marginal risk area has been
removed from TN and has been confined to eastern AL/western GA and
the FL Panhandle where still modest, but greater instability is in
place ahead of the eastward-advancing cold front. Across this area,
VWP data continues to indicate curved low level hodographs in a very
moist boundary layer. While upper forcing will continue to weaken,
sufficient instability and shear exists for a couple of strong
storms capable of locally damaging gusts and possibly a brief
tornado into early evening.
..Leitman.. 10/26/2019
.PREV DISCUSSION… /ISSUED 1125 AM CDT Sat Oct 26 2019/
…Southeast…
A small convective cluster is ongoing just north of a deepening
surface cyclone over northeast MS. While instability was meager as
sampled earlier by the 12Z Jackson, MS sounding and recent AMDAR
soundings near Memphis and Nashville, a plume of upper 60s surface
dew points does extend into western TN. It is plausible that this
convective cluster may persist northward into western TN through
early afternoon before instability becomes negligible with northern
extent. Locally strong gusts should be the main hazard.
Well southeast of the cyclone, a low-topped convective band is
ongoing along a sharp cold front across southwest AL with somewhat
higher tops and lightning discharge over the northern Gulf. Despite
low to mid 70s surface dew points, poor lapse rates above the
boundary layer will be a limiting factor to deeper convection
inland. Low-level wind profiles per area VADs have begun to weaken
as the surface cyclone and associated shortwave trough rapidly eject
north-northeast towards the Midwest and Great Lakes. This suggests
low probability tornado/wind potential will probably only exist
through late afternoon in the FL Panhandle.
Additional low-topped convection may attempt to develop between the
coastal band along the front and the cluster near the surface
cyclone. Modest boundary-layer heating is occurring amid some cloud
breaks across central and southern AL. This should support a
conditional threat for a brief tornado and locally damaging wind
later this afternoon into early evening across parts of
east-central/northeast AL into northwest GA.
$$