Alert archive / Florida / Tornado Watches in 2021

Tornado Watch 441

August 16, 2021Houston County, Alabama; 14 counties in Florida; 10 counties in Georgia

The Storm Prediction Center issued this tornado watch at Aug 16, 2021, 7:33 AM CDT for Houston County, Alabama; 14 counties in Florida; 10 counties in Georgia. It was in force for 13 hr.

The area

The outline as issued.

The facts

Issued
Aug 16, 2021, 7:33 AM CDT (12:33 UTC)
Expired
Aug 16, 2021, 8:43 PM CDT
In force
13 hr
Issued by
the Storm Prediction Center
Strongest gust expected
60 kt
All 25 counties

Houston County, AL, Bay County, FL, Calhoun County, FL, Dixie County, FL, Franklin County, FL, Gadsden County, FL, Gulf County, FL, Jackson 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, Brooks County, GA, Colquitt County, GA, Decatur County, GA, Early County, GA, Grady County, GA, Miller County, GA, Mitchell County, GA, Seminole County, GA, Thomas County, GA

The radar

The Tallahassee radar (KTLH), 45 km from the middle of the area, began a volume at 12:38 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
50%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
10%
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
20%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 16, 2:19 PM CDTFlash Flood WarningTAEBay, Calhoun, Gulf, Washington6 hr
Aug 16, 3:51 PM CDTFlash Flood WarningTAECalhoun, Gulf, Jackson, Liberty, Washington6 hr
Aug 16, 5:19 PM CDTFlash Flood WarningTAEGeneva, Houston6 hr
Aug 16, 6:52 PM CDTFlash Flood WarningTAEDale, Geneva, Henry, Houston4 hr
Aug 16, 8:32 PM CDTFlash Flood WarningTAEHouston4 hr

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, 0.6 hours before the alert went out and 47 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 2021-08-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 368 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 2021-08-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 40 square meters per square second.193958Sfc1 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
368 J/kg
Mixed-layer CIN
-22 J/kg
Mixed-layer LCL
754 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
40 m²/s²
0-3 km storm-relative helicity
30 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

823 
WWUS20 KWNS 161227
SEL1  
SPC WW 161227
ALZ000-FLZ000-GAZ000-CWZ000-170000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 441
NWS Storm Prediction Center Norman OK
825 AM EDT Mon Aug 16 2021

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Extreme southeastern Alabama
  Central and eastern Panhandle of Florida
  Southwestern Georgia
  Coastal Waters

* Effective this Monday morning and evening from 825 AM until 800
  PM EDT.

* Primary threats include...
  A few tornadoes possible

SUMMARY...As Tropical Storm Fred approaches landfall on the FL
Panhandle coastline, the threat for a few tornadoes will increase
with supercells moving inland in northeastern and eastern sectors of
the circulation.

The tornado watch area is approximately along and 70 statute miles
north and south of a line from 30 miles southwest of Marianna FL to
60 miles east of Tallahassee 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.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0 inches. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 13035.

...Edwards

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 16, 6:26 PM CDTMesoscale DiscussionSPCHenry, Houston64 min
Aug 16, 5:26 AM CDTMesoscale DiscussionSPCFranklin3 hr
Aug 16, 9:20 AM CDTMesoscale DiscussionSPCFranklin, Wakulla115 min
Aug 16, 11:36 AM CDTMesoscale DiscussionSPCFranklin, Taylor, Wakulla114 min
Aug 16, 2:55 PM CDTMesoscale DiscussionSPCDixie, Gilchrist, Jefferson, Lafayette, Levy, Taylor2 hr

Nearby

Tornado Watches in Florida, 2021Tornado Watches in Georgia, 2021Tornado Watches in Alabama, 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.