Alert archive / Florida / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 253, NWS Jacksonville, FL

August 21, 20094 counties in Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Aug 21, 2009, 4:32 PM EDT for 4 counties in Florida. It was in force for 58 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 21, 2009, 4:32 PM EDT (20:32 UTC)
Expired: Aug 21, 2009, 5:30 PM EDT
In force: 58 min
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon

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

The radar

The Jacksonville radar (KJAX), 31 km from the middle of the area, began a volume at 20:36 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

Cape Canaveral, FL (KXMR), launched 12:00Z, 8.5 hours before the alert went out and 224 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: 1482 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 902 m above ground
0-6 km bulk shear: 6 kt
0-1 km storm-relative helicity: 28 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 office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 8:05 PM EDT	Special Weather Statement	JAX	Flagler	25 min
Aug 21, 2:48 AM EDT	High Surf Advisory	JAX	Flagler, Nassau	48 hr
Aug 21, 1:47 PM EDT	Special Weather Statement	JAX	Union	28 min
Aug 21, 1:50 PM EDT	Special Weather Statement	JAX	Alachua	40 min
Aug 21, 3:06 PM EDT	Special Weather Statement	JAX	Flagler	39 min
Aug 21, 3:08 PM EDT	Special Weather Statement	JAX	Baker	52 min
Aug 21, 3:35 PM EDT	Special Weather Statement	JAX	Marion	25 min
Aug 21, 3:45 PM EDT	Special Marine Warning	JAX		2 hr
Aug 21, 3:47 PM EDT	Special Weather Statement	JAX	Nassau	43 min
Aug 21, 3:53 PM EDT	Special Weather Statement	JAX	Putnam	37 min
Aug 21, 3:59 PM EDT	Severe Thunderstorm Warning	JAX	Nassau	61 min
Aug 21, 4:02 PM EDT	Special Weather Statement	JAX	Marion	43 min
Aug 21, 4:05 PM EDT	Special Weather Statement	JAX	Clay	40 min
Aug 21, 4:11 PM EDT	Severe Thunderstorm Warning	JAX	Marion	49 min
Aug 21, 4:25 PM EDT	Special Weather Statement	JAX	Duval, Nassau	50 min
Aug 21, 4:27 PM EDT	Special Weather Statement	JAX	Putnam	48 min
Aug 21, 4:36 PM EDT	Severe Thunderstorm Warning	JAX	Clay, Flagler, Putnam, Saint Johns	54 min
Aug 21, 4:40 PM EDT	Special Marine Warning	JAX		2 hr
Aug 21, 4:56 PM EDT	Special Weather Statement	JAX	Marion	34 min
Aug 21, 5:30 PM EDT	Areal Flood Advisory	JAX	Clay, Duval, Putnam, Saint Johns	2 hr
Aug 21, 5:30 PM EDT	Special Weather Statement	JAX	Saint Johns	45 min
Aug 21, 5:37 PM EDT	Special Weather Statement	JAX	Marion	23 min
Aug 21, 5:44 PM EDT	Special Weather Statement	JAX	Putnam	31 min
Aug 21, 6:13 PM EDT	Special Weather Statement	JAX	Putnam, Saint Johns	32 min
Aug 21, 6:34 PM EDT	Special Weather Statement	JAX	Flagler	26 min
Aug 21, 7:17 PM EDT	Special Weather Statement	JAX	Putnam	28 min
Aug 21, 2:25 PM EDT	Special Weather Statement	JAX	Ware	35 min
Aug 21, 3:19 PM EDT	Special Weather Statement	JAX	Atkinson	26 min
Aug 21, 3:23 PM EDT	Special Weather Statement	JAX	Coffee	37 min
Aug 21, 3:44 PM EDT	Areal Flood Advisory	JAX	Atkinson, Bacon, Clinch, Coffee, Ware	2 hr
Aug 21, 3:51 PM EDT	Special Weather Statement	JAX	Atkinson	39 min
Aug 21, 3:56 PM EDT	Special Weather Statement	JAX	Camden	49 min
Aug 21, 4:00 PM EDT	Special Weather Statement	JAX	Glynn	30 min
Aug 21, 4:06 PM EDT	Severe Thunderstorm Warning	JAX	Camden, Glynn	39 min
Aug 21, 4:08 PM EDT	Special Weather Statement	JAX	Atkinson	52 min
Aug 21, 4:18 PM EDT	Areal Flood Advisory	JAX	Camden, Glynn	117 min
Aug 21, 5:53 PM EDT	Special Weather Statement	JAX	Jeff Davis	52 min

Nearby

Severe Thunderstorm Warnings in Florida, 2009 Every severe thunderstorm warning in 2009

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.