Alert archive / Florida / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 206, NWS Jacksonville, FL

August 20, 2020Flagler County, Saint Johns County, Florida

NWS Jacksonville, FL issued this severe thunderstorm warning at Aug 20, 2020, 6:45 PM EDT for Flagler County, Saint Johns County, Florida. It was in force for 22 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, 2020, 6:45 PM EDT (22:45 UTC)
Expired
Aug 20, 2020, 7:07 PM EDT
In force
22 min
Issued by
NWS Jacksonville, FL
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Flagler County, FL, Saint Johns County, FL

The radar

The Jacksonville radar (KJAX), 94 km from the middle of the area, began a volume at 22:46 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

Cape Canaveral, FL (KXMR), launched 12:00Z, 10.8 hours before the alert went out and 159 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-pSkew-T log-p diagram, Cape Canaveral, FL at 12:00Z on 2020-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 150 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Cape Canaveral, FL at 12:00Z on 2020-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
150 J/kg
Mixed-layer CIN
-179 J/kg
Mixed-layer LCL
1243 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 19, 8:23 PM EDTSpecial Weather StatementJAXColumbia52 min
Aug 20, 4:16 PM EDTSpecial Weather StatementJAXDuval44 min
Aug 20, 6:16 PM EDTSpecial Weather StatementJAXMarion44 min
Aug 20, 6:24 PM EDTSpecial Weather StatementJAXFlagler51 min
Aug 20, 6:39 PM EDTSpecial Weather StatementJAXSaint Johns51 min
Aug 20, 6:41 PM EDTSpecial Weather StatementJAXDuval49 min
Aug 20, 6:42 PM EDTSpecial Marine WarningJAX63 min
Aug 20, 7:45 PM EDTSpecial Weather StatementJAXMarion45 min
Aug 20, 1:58 PM EDTSpecial Weather StatementJAXGlynn62 min
Aug 20, 2:25 PM EDTSpecial Weather StatementJAXCharlton50 min

Nearby

Severe Thunderstorm Warnings in Florida, 2020Every 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.