SPC MD 1820


MD 1820 Image

Mesoscale Discussion 1820
NWS Storm Prediction Center Norman OK
0705 PM CST Sun Nov 29 2020

Areas affected...The Florida Panhandle

Concerning...Severe potential...Watch unlikely 

Valid 300105Z - 300300Z

Probability of Watch Issuance...20 percent

SUMMARY...Convection moving onshore and into a helicity-rich
environment will continue to pose a tornado threat over the next few
hours for the central Florida Panhandle.

DISCUSSION...Recent regional radar imagery shows scattered shallow
convection continuing to move onshore into the central FL Panhandle.
These storms are primarily developing along the pre-frontal
confluence axis in the vicinity of a deepening surface low north of
the Mobile, AL region and south of a surface warm front that is
gradually mixing north across the FL Panhandle and into southern
AL/GA. Recent RAP Mesoanalysis suggests sufficient instability is in
place across the central FL Panhandle (roughly 500-1000 J/kg
MLCAPE), but the 00 UTC TLH sounding shows very limited instability
further east, suggesting that the favorable thermodynamic
environment is rather limited spatially and confined closer to the
confluence axis over the central Panhandle and perhaps along the
coast where slightly higher theta-e air is noted. Despite
instability limitations, strong deep layer shear and ample low-level
helicity (approximately 300 m2/s2 0-1 km SRH sampled from the KTLH
VWP) will continue to support an inland tornado threat.

The tornado potential will also likely be conditional on the
development and maintenance of discrete convection within the open
warm sector or along the confluence axis where forcing for ascent
has been stronger. Given the propensity for long storm residence
times and destructive storm interactions along this boundary, the
number of potential tornadic storms may be limited. Due to the
limited spatial scope of this threat and storm mode concerns, a
watch is not anticipated. However, a small corridor with a favorable
environment for severe convection is expected to persist through the
evening hours across the FL Panhandle and into north FL as the low
continues to deepen.

..Moore/Grams.. 11/30/2020

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


LAT...LON   30948597 30928536 30648492 30328458 29968461 29678493
            29578526 29718558 29968585 30198613 30288631 30758619

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