Alert archive / Florida / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 188, NWS Jacksonville, FL

August 20, 2014Clay County, Duval County, Saint Johns County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Aug 20, 2014, 7:32 PM EDT for Clay County, Duval County, Saint Johns County, Florida. It was in force for 32 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 20, 2014, 7:32 PM EDT (23:32 UTC)
Expired: Aug 20, 2014, 8:04 PM EDT
In force: 32 min
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon

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

The radar

The Jacksonville radar (KJAX), 46 km from the middle of the area, began a volume at 23:35 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, 11.5 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-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: 1516 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 755 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 30 m²/s²
0-3 km storm-relative helicity: 66 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Jacksonville, FL wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 2:22 PM EDT, 5 hours 10 minutes earlier.

Area forecast discussion, Aug 20, 2:22 PM EDT, 5 hours 10 minutes before

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Hazardous weather outlook, Aug 20, 2:25 PM EDT, 5 hours 7 minutes before

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In the hours before

Special weather statement, Aug 20, 6:14 PM EDT, 1 hour 18 minutes before

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Special weather statement, Aug 20, 6:41 PM EDT, 51 minutes before

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Special weather statement, Aug 20, 6:58 PM EDT, 34 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 2:11 PM EDT	Heat Advisory	JAX	Baker, Bradford, Flagler, Gilchrist, Nassau, Suwannee and 1 more	30 hr
Aug 20, 6:55 PM EDT	Areal Flood Advisory	JAX	Marion	95 min
Aug 20, 6:58 PM EDT	Special Weather Statement	JAX	Clay	47 min
Aug 20, 7:43 PM EDT	Special Marine Warning	JAX		2 hr
Aug 20, 6:14 PM EDT	Special Weather Statement	JAX	Jeff Davis	46 min
Aug 20, 6:41 PM EDT	Special Weather Statement	JAX	Coffee, Jeff Davis	49 min

Nearby

Severe Thunderstorm Warnings in Florida, 2014 Every severe thunderstorm warning in 2014

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.