Alert archive / Georgia / Tornado Watches in 2021

Tornado Watch 11

February 18, 202112 counties in Florida; 36 counties in Georgia

The Storm Prediction Center issued this tornado watch at Feb 18, 2021, 7:45 AM CST for 12 counties in Florida; 36 counties in Georgia. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Feb 18, 2021, 7:45 AM CST (13:45 UTC)
Expired
Feb 18, 2021, 3:00 PM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 48 counties

Bay County, FL, Calhoun County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Jackson County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Atkinson County, GA, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Brooks County, GA, Calhoun County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Crisp County, GA, Decatur County, GA, Dodge County, GA, Dooly County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Irwin County, GA, Jeff Davis County, GA, Lanier County, GA, Lee County, GA, Lowndes County, GA, Miller County, GA, Mitchell County, GA, Montgomery County, GA, Pulaski County, GA, Seminole County, GA, Sumter County, GA, Telfair County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Toombs County, GA, Turner County, GA, Wheeler County, GA, Wilcox County, GA, Worth County, GA

The radar

The Moody AFB radar (KVAX), 85 km from the middle of the area, began a volume at 13:47 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
30%

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 1.8 hours before the alert went out and 89 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Tallahassee Rgnl, FL at 12:00Z on 2021-02-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 104 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tallahassee Rgnl, FL at 12:00Z on 2021-02-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 387 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
104 J/kg
Mixed-layer CIN
-77 J/kg
Mixed-layer LCL
497 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
387 m²/s²
0-3 km storm-relative helicity
410 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3

Open this sounding in Storm Lab

The text

As transmitted.

236 
WWUS20 KWNS 181343
SEL1  
SPC WW 181343
FLZ000-GAZ000-CWZ000-182100-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 11
NWS Storm Prediction Center Norman OK
845 AM EST Thu Feb 18 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Florida Panhandle
  Southern Georgia
  Coastal Waters

* Effective this Thursday morning and afternoon from 845 AM until
  400 PM EST.

* Primary threats include...
  A couple tornadoes possible
  Isolated damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms are forecast to intensify today with some of
the stronger storms potentially capable of an isolated risk for
damaging gusts and possibly a couple of tornadoes.

The tornado watch area is approximately along and 60 statute miles
east and west of a line from 75 miles northeast of Albany GA to 30
miles south southwest of Apalachicola FL. For a complete depiction
of the watch see the associated watch outline update (WOUS64 KWNS
WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 10...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 23030.

...Smith/Edwards

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 17, 10:18 PM CSTMesoscale DiscussionSPCBay, Calhoun, Escambia, Gulf, Okaloosa, Santa Rosa and 2 more2 hr
Feb 18, 1:49 AM CSTTornado WatchSPCBay, Calhoun, Franklin, Gadsden, Gulf, Holmes and 7 more6 hr
Feb 18, 4:54 AM CSTMesoscale DiscussionSPCBay, Gulf2 hr
Feb 18, 7:09 AM CSTMesoscale DiscussionSPCBay, Calhoun, Franklin, Gadsden, Gulf, Jackson and 4 more2 hr
Feb 18, 10:35 AM CSTMesoscale DiscussionSPCGadsden, Jefferson, Leon, Liberty, Wakulla115 min
Feb 18, 12:43 PM CSTMesoscale DiscussionSPCJefferson, Madison, Taylor92 min

Nearby

Tornado Watches in Georgia, 2021Tornado Watches in Florida, 2021Every tornado watch in 2021

Sources

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.