Alert archive / Florida / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 60, NWS Jacksonville, FL

April 15, 2020Duval County, Nassau County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Apr 15, 2020, 7:43 AM EDT for Duval County, Nassau County, Florida. It was in force for 12 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: Apr 15, 2020, 7:43 AM EDT (11:43 UTC)
Expired: Apr 15, 2020, 7:55 AM EDT
In force: 12 min
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

Counties Duval County, FL, Nassau County, FL

The radar

The Jacksonville radar (KJAX), 1 km from the middle of the area, began a volume at 11:46 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 00:00Z, 11.7 hours before the alert went out and 3 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: 1469 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 989 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 157 m²/s²
0-3 km storm-relative helicity: 185 m²/s²
Significant tornado parameter: 1.4
Supercell composite: 7.8

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 Apr 15, 4:15 AM EDT, 3 hours 28 minutes earlier.

Area forecast discussion, Apr 15, 4:15 AM EDT, 3 hours 28 minutes before

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In the hours before

Special weather statement, Apr 15, 3:27 AM EDT, 4 hours 16 minutes before

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Special weather statement, Apr 15, 4:05 AM EDT, 3 hours 38 minutes before

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Special weather statement, Apr 15, 5:07 AM EDT, 2 hours 36 minutes before

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Special weather statement, Apr 15, 5:44 AM EDT, 1 hour 59 minutes before

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Special weather statement, Apr 15, 6:10 AM EDT, 1 hour 33 minutes before

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Special weather statement, Apr 15, 7:40 AM EDT, 3 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
Apr 14, 8:32 PM EDT	Special Weather Statement	JAX	Columbia, Suwannee	43 min
Apr 14, 8:50 PM EDT	Special Marine Warning	JAX		55 min
Apr 14, 9:36 PM EDT	Special Marine Warning	JAX		23 min
Apr 14, 10:31 PM EDT	Special Marine Warning	JAX		21 min
Apr 15, 12:26 AM EDT	Special Weather Statement	JAX	Gilchrist	49 min
Apr 15, 2:01 AM EDT	Special Weather Statement	JAX	Suwannee	44 min
Apr 15, 2:09 AM EDT	Severe Thunderstorm Warning	JAX	Suwannee	36 min
Apr 15, 2:36 AM EDT	Tornado Warning	JAX	Columbia, Suwannee	24 min
Apr 15, 2:44 AM EDT	Severe Thunderstorm Warning	JAX	Columbia, Suwannee, Union	46 min
Apr 15, 3:27 AM EDT	Special Weather Statement	JAX	Baker	48 min
Apr 15, 4:05 AM EDT	Special Weather Statement	JAX	Suwannee	40 min
Apr 15, 5:07 AM EDT	Special Weather Statement	JAX	Columbia	38 min
Apr 15, 5:44 AM EDT	Special Weather Statement	JAX	Baker	31 min
Apr 15, 6:10 AM EDT	Special Weather Statement	JAX	Duval	65 min
Apr 15, 7:40 AM EDT	Special Weather Statement	JAX	Duval	20 min
Apr 15, 7:43 AM EDT	Special Marine Warning	JAX		35 min
Apr 15, 9:16 AM EDT	Special Marine Warning	JAX		59 min
Apr 15, 10:00 AM EDT	Special Weather Statement	JAX	Baker	60 min
Apr 15, 10:25 AM EDT	Special Weather Statement	JAX	Nassau	20 min
Apr 15, 10:40 AM EDT	Special Weather Statement	JAX	Union	50 min
Apr 15, 10:47 AM EDT	Special Weather Statement	JAX	Duval	13 min
Apr 15, 10:49 AM EDT	Special Marine Warning	JAX		56 min
Apr 15, 11:52 AM EDT	Special Weather Statement	JAX	Bradford	53 min
Apr 15, 12:11 PM EDT	Special Marine Warning	JAX		2 hr
Apr 15, 12:16 PM EDT	Special Weather Statement	JAX	Alachua	44 min
Apr 15, 12:28 PM EDT	Special Weather Statement	JAX	Saint Johns	47 min
Apr 15, 12:45 PM EDT	Severe Thunderstorm Warning	JAX	Alachua, Bradford, Clay, Flagler, Putnam, Saint Johns	60 min
Apr 15, 12:57 PM EDT	Special Weather Statement	JAX	Marion	48 min
Apr 15, 1:42 PM EDT	Special Weather Statement	JAX	Flagler, Marion, Putnam	48 min
Apr 15, 1:49 PM EDT	Small Craft Advisory	JAX		49 hr
Apr 15, 2:10 PM EDT	Severe Thunderstorm Warning	JAX	Marion	35 min
Apr 15, 2:13 PM EDT	Special Marine Warning	JAX		62 min
Apr 15, 2:23 PM EDT	Special Weather Statement	JAX	Flagler	22 min
Apr 15, 2:44 PM EDT	Special Weather Statement	JAX	Marion	46 min
Apr 15, 7:51 AM EDT	Special Weather Statement	JAX	Charlton	39 min
Apr 15, 8:01 AM EDT	Severe Thunderstorm Warning	JAX	Charlton, Clinch, Ware	29 min
Apr 15, 8:23 AM EDT	Special Weather Statement	JAX	Charlton	37 min
Apr 15, 9:02 AM EDT	Special Weather Statement	JAX	Camden	13 min
Apr 15, 9:17 AM EDT	Special Weather Statement	JAX	Camden	13 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.