Mesoscale Discussion 603

Issued

May 12, 2021, 9:17 AM CDT (14:17 UTC)

Expired

May 12, 2021, 11:15 AM CDT

In force

118 min

Issued by

the Storm Prediction Center

Concerning

Severe thunderstorm watch 168

The Tallahassee radar (KTLH), 52 km from the middle of the area, began a volume at 14:18 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

388 
ACUS11 KWNS 121417
SWOMCD
SPC MCD 121417 
GAZ000-FLZ000-ALZ000-121615-

Mesoscale Discussion 0603
NWS Storm Prediction Center Norman OK
0917 AM CDT Wed May 12 2021

Areas affected...The Florida Panhandle and southwest Georgia

Concerning...Severe Thunderstorm Watch 168...

Valid 121417Z - 121615Z

The severe weather threat for Severe Thunderstorm Watch 168
continues.

SUMMARY...Isolated damaging winds remain possible with the ongoing
line of storms across WW 168, but a gradual weakening trend is
expected through early afternoon. Additional convection is possible
along the FL coast and across south-central GA later today. While
confidence is low, trends will be monitored.

DISCUSSION...An organized line of storms continues to move
east/northeastward across the FL Panhandle and into southwest GA,
but has produced little in the way of measured wind gusts over the
past hour with no wind damage recently reported. While this line
continues to display reasonable organization in reflectivity and
velocity structure with no noticeable cloud top warming, it is
moving into a less favorable thermodynamic environment across
southern GA where MUCAPE values are between 250-500 J/kg - possibly
due to cooler low-level temperatures. While deep-layer shear between
30-40 knots remains supportive for maintaining the line, weak
low-level flow sampled by regional VWPs suggests a near-term cold
pool intensification is unlikely. The general expectation is that
this line will continue to pose a threat for isolated damaging wind
gusts across north FL and southwest GA for the next 1-2 hours. It is
possible that re-intensification can occur early this afternoon once
daytime heating augments low-level instability, but increasing cloud
cover introduces uncertainty into this scenario. Additional
convection is possible along the remnant outflow boundary over the
FL coast where better instability and supportive deep-layer shear
are noted. However, it is unclear whether forcing for ascent along
the boundary will be sufficient for a robust severe threat. A
downstream watch is not currently anticipated, but trends will
continue to be monitored through the late morning.

..Moore.. 05/12/2021

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

ATTN...WFO...JAX...FFC...TAE...

LAT...LON   31568533 31918486 32068395 32018314 31798246 31058232
            30628239 30168319 29958385 29708459 29478512 29878567
            30268586 30978563 31568533

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The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.