Mesoscale Discussion 90

Issued

Jan 21, 2017, 12:06 PM CST (18:06 UTC)

Expired

Jan 21, 2017, 2:00 PM CST

In force

114 min

Issued by

the Storm Prediction Center

The Robins AFB radar (KJGX), 79 km from the middle of the area, began a volume at 18:07 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.

• Tornado Watch 13Jan 21, 12:55 PM CST
• Tornado Watch 14Jan 21, 1:10 PM CST

998 
ACUS11 KWNS 211806
SWOMCD
SPC MCD 211806 COR
SCZ000-GAZ000-FLZ000-ALZ000-212000-

Mesoscale Discussion 0090
NWS Storm Prediction Center Norman OK
1206 PM CST Sat Jan 21 2017

Areas affected...portions of central GA into the FL panhandle

Concerning...Tornado Watch 12...

Valid 211806Z - 212000Z

CORRECTED FOR WATCH TYPE

The severe weather threat for Tornado Watch 12 continues.

SUMMARY...The threat for damaging winds and tornadoes will continue
across WW 12. Local aerial extension of the watch may be needed
depending in how fast segments of the line surge eastward.
Otherwise, trends will be monitored for possible watch issuance in
the next hour or so for parts of GA/SC.

DISCUSSION...A robust line of storms extending from central GA
southwestward into the central FL panhandle will continue to pose a
threat for damaging winds, and potentially several tornadoes. Over
the last couple of hours several mesovortex features have been noted
along the line, especially the GA portion. Effective SRH along the
line of 200-500 m2/s2 has been noted in 17z mesoanalysis and
confirmed by regional VWP data. This favorable environment for
low-level rotation is expected to shift east with the line through
the afternoon, maintaining the tornado threat. Furthermore, damaging
winds will also continue to be a concern, especially as line
segments continue to surge eastward where partly cloudy skies have
allowed for continued heating and modest steepening of low-level
lapse rates across southern and eastern GA into the eastern FL
panhandle. Some local areal extension of the watch may be needed
depending on where/if segments of the line surge eastward faster
than expected. Otherwise, a new watch may be needed downstream of WW
12 across portions of SC and southeast GA in the next hour or so.

..Leitman/Hart.. 01/21/2017

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

ATTN...WFO...CHS...CAE...JAX...FFC...TAE...

LAT...LON   33728338 33898216 33488134 32738066 31558099 30638241
            29938414 29818477 29718551 30328609 30918557 31438467
            32158401 32818372 33398378 33618367 33728338

Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in Florida, 2017Mesoscale Discussions in South Carolina, 2017Every mesoscale discussion in 2017

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.