Alert archive / Florida / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 196, NWS Jacksonville, FL

August 14, 2020Saint Johns County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Aug 14, 2020, 4:08 PM EDT for Saint Johns County, Florida. It was in force for 37 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 14, 2020, 4:08 PM EDT (20:08 UTC)
Expired: Aug 14, 2020, 4:45 PM EDT
In force: 37 min
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Saint Johns County, FL

The radar

The Jacksonville radar (KJAX), 70 km from the middle of the area, began a volume at 20:09 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, 8.1 hours before the alert went out and 183 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: 1773 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 824 m above ground
0-6 km bulk shear: 2 kt
0-1 km storm-relative helicity: -40 m²/s²
0-3 km storm-relative helicity: -35 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 14, 3:22 PM EDT, 46 minutes earlier.

Area forecast discussion, Aug 14, 3:22 PM EDT, 46 minutes before

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In the hours before

Local storm report, Aug 14, 3:31 PM EDT, 37 minutes before

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Special weather statement, Aug 14, 3:40 PM EDT, 28 minutes before

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Local storm report, Aug 14, 3:46 PM EDT, 22 minutes before

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Local storm report, Aug 14, 3:53 PM EDT, 15 minutes before

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Special weather statement, Aug 14, 3:57 PM EDT, 11 minutes before

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Local storm report, Aug 14, 3:59 PM EDT, 9 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 14, 2:05 PM EDT	Special Weather Statement	JAX	Clay	40 min
Aug 14, 2:51 PM EDT	Special Marine Warning	JAX		54 min
Aug 14, 3:08 PM EDT	Special Weather Statement	JAX	Duval	52 min
Aug 14, 3:12 PM EDT	Special Marine Warning	JAX		63 min
Aug 14, 3:14 PM EDT	Special Weather Statement	JAX	Marion	46 min
Aug 14, 3:33 PM EDT	Special Marine Warning	JAX		87 min
Aug 14, 3:40 PM EDT	Special Weather Statement	JAX	Nassau	50 min
Aug 14, 3:44 PM EDT	Special Marine Warning	JAX		61 min
Aug 14, 3:46 PM EDT	Severe Thunderstorm Warning	JAX	Duval, Nassau	29 min
Aug 14, 3:57 PM EDT	Special Weather Statement	JAX	Marion	48 min
Aug 14, 4:12 PM EDT	Special Weather Statement	JAX	Putnam	48 min
Aug 14, 4:37 PM EDT	Special Marine Warning	JAX		53 min
Aug 14, 4:50 PM EDT	Special Marine Warning	JAX		55 min
Aug 14, 4:56 PM EDT	Areal Flood Warning	JAX	Flagler, Putnam	84 min
Aug 14, 4:58 PM EDT	Special Weather Statement	JAX	Saint Johns	47 min
Aug 14, 5:01 PM EDT	Special Weather Statement	JAX	Flagler	44 min
Aug 14, 12:24 PM EDT	Special Weather Statement	JAX	Echols	36 min
Aug 14, 1:43 PM EDT	Special Weather Statement	JAX	Echols	32 min

Nearby

Severe Thunderstorm Warnings in Florida, 2020 Every severe thunderstorm warning in 2020

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.