Alert archive / Florida / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 171, NWS Jacksonville, FL

July 26, 2018Saint Johns County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Jul 26, 2018, 2:37 PM EDT for 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 counties it named.

The facts

Issued: Jul 26, 2018, 2:37 PM EDT (18:37 UTC)
Expired: Jul 26, 2018, 3:00 PM EDT
In force: 23 min
Issued by: NWS Jacksonville, FL
Area: Storm-based polygon
Hail: 0.75 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 18:40 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, 6.6 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: 775 J/kg
Mixed-layer CIN: -56 J/kg
Mixed-layer LCL: 1118 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 52 m²/s²
0-3 km storm-relative helicity: 57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.9

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 Jul 26, 9:11 AM EDT, 5 hours 26 minutes earlier.

Area forecast discussion, Jul 26, 9:11 AM EDT, 5 hours 26 minutes before

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In the hours before

Special weather statement, Jul 26, 11:27 AM EDT, 3 hours 10 minutes before

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Local storm report, Jul 26, 11:29 AM EDT, 3 hours 8 minutes before

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Special weather statement, Jul 26, 1:06 PM EDT, 1 hour 31 minutes before

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Special weather statement, Jul 26, 1:55 PM EDT, 42 minutes before

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Special weather statement, Jul 26, 2:07 PM EDT, 30 minutes before

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Special weather statement, Jul 26, 2:31 PM EDT, 6 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
Jul 26, 10:54 AM EDT	Rip Current Statement	JAX	Duval, Flagler, Nassau	9 hr
Jul 26, 11:27 AM EDT	Special Weather Statement	JAX	Gilchrist	33 min
Jul 26, 1:06 PM EDT	Special Weather Statement	JAX	Union	24 min
Jul 26, 1:25 PM EDT	Severe Thunderstorm Warning	JAX	Bradford, Union	15 min
Jul 26, 1:55 PM EDT	Special Weather Statement	JAX	Putnam	35 min
Jul 26, 2:07 PM EDT	Special Weather Statement	JAX	Flagler	38 min
Jul 26, 2:29 PM EDT	Special Marine Warning	JAX		61 min
Jul 26, 2:31 PM EDT	Special Weather Statement	JAX	Saint Johns	44 min
Jul 26, 2:55 PM EDT	Special Marine Warning	JAX		66 min
Jul 26, 3:03 PM EDT	Special Marine Warning	JAX		87 min
Jul 26, 4:28 PM EDT	Special Marine Warning	JAX		32 min
Jul 25, 8:29 PM EDT	Areal Flood Advisory	JAX	Appling, Pierce, Wayne	61 min
Jul 26, 2:54 PM EDT	Special Weather Statement	JAX	Camden	36 min
Jul 26, 4:01 PM EDT	Areal Flood Advisory	JAX	Glynn	59 min

Nearby

Severe Thunderstorm Warnings in Florida, 2018 Every severe thunderstorm warning in 2018

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.