Alert archive / Florida / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 220, NWS Tallahassee, FL

August 20, 2021Walton County, Florida

NWS Tallahassee, FL issued this severe thunderstorm warning at Aug 20, 2021, 2:34 PM CDT for Walton County, Florida. It was in force for 56 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 20, 2021, 2:34 PM CDT (19:34 UTC)
Expired: Aug 20, 2021, 3:30 PM CDT
In force: 56 min
Issued by: NWS Tallahassee, FL
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

County Walton County, FL

The radar

The Eglin Afb radar (KEVX), 31 km from the middle of the area, began a volume at 19:33 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.

The nearest sounding before it

Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 7.6 hours before the alert went out and 185 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 675 J/kg
Mixed-layer CIN: -74 J/kg
Mixed-layer LCL: 1045 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 27 m²/s²
0-3 km storm-relative helicity: 41 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

982 
WUUS52 KTAE 201934
SVRTAE
FLC131-202030-
/O.NEW.KTAE.SV.W.0220.210820T1934Z-210820T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Tallahassee FL
234 PM CDT Fri Aug 20 2021

The National Weather Service in Tallahassee has issued a

* Severe Thunderstorm Warning for...
  Southern Walton County in the Panhandle of Florida...

* Until 330 PM CDT.

* At 234 PM CDT, a severe thunderstorm was located near Crestview,
  moving southeast at 15 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Santa Rosa Beach, De Funiak Springs, Eglin Air Force Base,
  Freeport, Pond Creek, Oakwood Hills, Portland, Alpine Heights,
  Villa Tasso, Blue Mountain Beach, De Funiak Spring Airport,
  Seaside, Rock Hill, Pleasant Ridge, Gulf Pines, Bunker, Grayton
  Beach, Argyle, Sandestin and Mossy Head.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3038 8633 3042 8631 3039 8626 3040 8623
      3042 8627 3039 8610 3044 8616 3047 8613
      3046 8619 3050 8620 3048 8622 3046 8639
      3082 8639 3074 8604 3070 8603 3070 8596
      3024 8614 3029 8634 3034 8640 3040 8640
TIME...MOT...LOC 1934Z 294DEG 15KT 3068 8657 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

11-MM

1 follow-up statement

361 
WWUS52 KTAE 202025
SVSTAE

Severe Weather Statement
National Weather Service Tallahassee FL
325 PM CDT Fri Aug 20 2021

FLC131-202035-
/O.EXP.KTAE.SV.W.0220.000000T0000Z-210820T2030Z/
Walton FL-
325 PM CDT Fri Aug 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN WALTON COUNTY WILL
EXPIRE AT 330 PM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with this thunderstorm.

LAT...LON 3038 8633 3042 8631 3039 8626 3040 8623
      3042 8627 3039 8610 3044 8616 3047 8613
      3046 8619 3050 8620 3048 8622 3046 8639
      3082 8639 3074 8604 3070 8603 3070 8596
      3024 8614 3029 8634 3034 8640 3040 8640
TIME...MOT...LOC 2025Z 294DEG 15KT 3059 8635 

$$

The office that day

Everything else NWS Tallahassee, FL issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 20, 3:38 PM CDT	Special Weather Statement	TAE	Holmes, Washington	67 min
Aug 20, 4:37 PM CDT	Special Weather Statement	TAE	Calhoun, Liberty	38 min
Aug 20, 5:00 PM CDT	Severe Thunderstorm Warning	TAE	Calhoun, Liberty	30 min
Aug 20, 6:19 PM CDT	Special Weather Statement	TAE	Wakulla	41 min

Nearby

Severe Thunderstorm Warnings in Florida, 2021 Every severe thunderstorm warning 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.