Alert archive / Georgia / Tornado Watches in 2021

Tornado Watch 39

March 18, 202111 counties in Florida; 38 counties in Georgia

The Storm Prediction Center issued this tornado watch at Mar 18, 2021, 7:53 AM EDT for 11 counties in Florida; 38 counties in Georgia. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Mar 18, 2021, 7:53 AM EDT (11:53 UTC)
Expired
Mar 18, 2021, 1:00 PM EDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 49 counties

Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Jefferson County, FL, Lafayette County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Taylor County, FL, Wakulla County, FL, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Bleckley County, GA, Brooks County, GA, Calhoun 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, Emanuel County, GA, Grady County, GA, Irwin County, GA, Johnson County, GA, Lanier County, GA, Laurens 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, Treutlen County, GA, Turner County, GA, Wheeler County, GA, Wilcox County, GA, Worth County, GA

The radar

The Moody AFB radar (KVAX), 79 km from the middle of the area, began a volume at 11:54 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
60%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
60%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Mar 18, 7:55 AM EDTSevere Thunderstorm WarningTAEBaker, Calhoun, Clay, Dougherty, Early, Quitman and 2 more65 min
Mar 18, 8:19 AM EDTSevere Thunderstorm WarningTAECalhoun, Franklin, Gadsden, Gulf, Leon, Liberty and 1 more56 min
Mar 18, 8:24 AM EDTSevere Thunderstorm WarningTAEGadsden, Leon, Liberty51 min
Mar 18, 9:11 AM EDTSevere Thunderstorm WarningTAEFranklin, Gadsden, Gulf, Jefferson, Leon, Liberty and 1 more64 min

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 00:00Z, 11.9 hours before the alert went out and 114 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 00:00Z on 2021-03-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Tallahassee Rgnl, FL at 00:00Z on 2021-03-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 126 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1019 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
126 m²/s²
0-3 km storm-relative helicity
171 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

166 
WWUS20 KWNS 181150
SEL9  
SPC WW 181150
FLZ000-GAZ000-CWZ000-181700-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 39
NWS Storm Prediction Center Norman OK
750 AM EDT Thu Mar 18 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  The eastern Florida Panhandle and Big Bend
  Southwest and south central Georgia
  Coastal Waters

* Effective this Thursday morning and afternoon from 750 AM until
  100 PM EDT.

* Primary threats include...
  A few tornadoes likely
  Scattered damaging wind gusts to 70 mph likely
  Isolated large hail events to 1 inch in diameter possible

SUMMARY...Clusters of thunderstorms with embedded rotation will
likely persist for the next few hours from the Florida Panhandle
into southwest Georgia, with the potential to produce a few
tornadoes and damaging winds.

The tornado watch area is approximately along and 50 statute miles
east and west of a line from 85 miles northeast of Albany GA to 10
miles southeast of Apalachicola FL. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU9).

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.

&&

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 500. Mean
storm motion vector 24040.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 17, 11:15 PM EDTMesoscale DiscussionSPCEscambia, Okaloosa, Santa Rosa90 min
Mar 18, 12:02 AM EDTTornado WatchSPCBay, Calhoun, Escambia, Holmes, Jackson, Okaloosa and 3 more9 hr
Mar 18, 2:52 AM EDTMesoscale DiscussionSPCEscambia, Holmes, Okaloosa, Santa Rosa83 min
Mar 18, 5:28 AM EDTMesoscale DiscussionSPCBay, Calhoun, Holmes, Jackson, Walton, Washington92 min
Mar 18, 7:32 AM EDTMesoscale DiscussionSPCBay, Calhoun, Franklin, Gadsden, Gulf, Jackson and 6 more58 min
Mar 18, 11:05 AM EDTMesoscale DiscussionSPCColumbia, Dixie, Hamilton, Jefferson, Lafayette, Madison and 2 more115 min
Mar 18, 11:42 AM EDTTornado WatchSPCAlachua, Baker, Bradford, Clay, Columbia, Duval and 7 more6 hr
Mar 18, 10:34 AM EDTMesoscale DiscussionSPCBanks, Barrow, Clarke, Elbert, Franklin, Habersham and 5 more2 hr
Mar 18, 2:08 PM EDTTornado WatchSPCElbert, Lincoln4 hr
Mar 18, 3:10 PM EDTMesoscale DiscussionSPCElbert3 hr

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.