Alert archive / Florida / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 74, NWS Jacksonville, FL

May 11, 2021Clay County, Duval County, Saint Johns County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at May 11, 2021, 5:30 PM EDT for Clay County, Duval County, Saint Johns County, Florida. It was in force for 23 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: May 11, 2021, 5:30 PM EDT (21:30 UTC)
Expired: May 11, 2021, 5:53 PM EDT
In force: 23 min
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Clay County, FL, Duval County, FL, Saint Johns County, FL

The radar

The Jacksonville radar (KJAX), 52 km from the middle of the area, began a volume at 21:32 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

Jacksonville, FL (KJAX), launched 12:00Z, 9.5 hours before the alert went out and 54 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: 125 J/kg
Mixed-layer CIN: -74 J/kg
Mixed-layer LCL: 1340 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

567 
WUUS52 KJAX 112130
SVRJAX
FLC019-031-109-112215-
/O.NEW.KJAX.SV.W.0074.210511T2130Z-210511T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Jacksonville FL
530 PM EDT Tue May 11 2021

The National Weather Service in Jacksonville has issued a

* Severe Thunderstorm Warning for...
  Northern St. Johns County in northeastern Florida...
  Eastern Clay County in northeastern Florida...
  Southeastern Duval County in northeastern Florida...

* Until 615 PM EDT.

* At 530 PM EDT, a severe thunderstorm was located over Fruit Cove,
  moving east at 20 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Green Cove Springs, Fruit Cove, World Golf Village, Sawgrass, South
  Ponte Vedra, Nocatee, Bayard, Durbin, Guana River State Park and
  Vilano Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2997 8167 3014 8163 3020 8133 2994 8127
TIME...MOT...LOC 2130Z 269DEG 16KT 3008 8160 

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

23

1 follow-up statement

716 
WWUS52 KJAX 112153
SVSJAX

Severe Weather Statement
National Weather Service Jacksonville FL
553 PM EDT Tue May 11 2021

FLC019-031-109-112203-
/O.CAN.KJAX.SV.W.0074.000000T0000Z-210511T2215Z/
St. Johns FL-Clay FL-Duval FL-
553 PM EDT Tue May 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN ST. JOHNS...EASTERN
CLAY AND SOUTHEASTERN DUVAL COUNTIES IS CANCELLED...
                
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 has been cancelled.  However gusty winds and
heavy rain are still possible with this thunderstorm.

LAT...LON 2997 8167 3014 8163 3020 8133 2994 8127
TIME...MOT...LOC 2151Z 269DEG 16KT 3008 8148 

$$

23

The office that day

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

Issued	Product	Office	Counties	Lasted
May 11, 1:36 PM EDT	Special Weather Statement	JAX	Columbia	54 min
May 11, 1:40 PM EDT	Special Weather Statement	JAX	Alachua, Gilchrist	50 min
May 11, 2:29 PM EDT	Special Weather Statement	JAX	Alachua	46 min
May 11, 3:31 PM EDT	Special Weather Statement	JAX	Bradford, Union	44 min
May 11, 3:35 PM EDT	Special Weather Statement	JAX	Marion	40 min
May 11, 4:21 PM EDT	Special Weather Statement	JAX	Flagler	39 min
May 11, 4:28 PM EDT	Special Weather Statement	JAX	Bradford, Union	47 min
May 11, 4:40 PM EDT	Special Weather Statement	JAX	Duval	50 min
May 11, 4:49 PM EDT	Severe Thunderstorm Warning	JAX	Clay, Duval, Saint Johns	41 min
May 11, 4:56 PM EDT	Special Marine Warning	JAX		94 min
May 11, 5:00 PM EDT	Special Weather Statement	JAX	Flagler	45 min
May 11, 5:10 PM EDT	Special Marine Warning	JAX		65 min
May 11, 5:22 PM EDT	Special Marine Warning	JAX		53 min
May 11, 5:52 PM EDT	Special Weather Statement	JAX	Alachua	38 min
May 11, 7:16 PM EDT	Special Weather Statement	JAX	Marion	44 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.