Alert archive / Florida / Mesoscale Discussions in 2021

Mesoscale Discussion 425

April 24, 2021Duval County, Nassau County, Florida; Camden County, Charlton County, Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 24, 2021, 4:35 PM EDT for Duval County, Nassau County, Florida; Camden County, Charlton County, Georgia. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Apr 24, 2021, 4:35 PM EDT (20:35 UTC)
Expired
Apr 24, 2021, 6:00 PM EDT
In force
85 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 107

Counties Duval County, FL, Nassau County, FL, Camden County, GA, Charlton County, GA

The radar

The Jacksonville radar (KJAX), 25 km from the middle of the area, began a volume at 20:35 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, 8.6 hours before the alert went out and 25 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, Jacksonville, FL at 12:00Z on 2021-04-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Jacksonville, FL at 12:00Z on 2021-04-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 180 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
984 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
180 m²/s²
0-3 km storm-relative helicity
276 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

493 
ACUS11 KWNS 242035
SWOMCD
SPC MCD 242035 
FLZ000-GAZ000-242200-

Mesoscale Discussion 0425
NWS Storm Prediction Center Norman OK
0335 PM CDT Sat Apr 24 2021

Areas affected...far southeast Georgia and northeast Florida

Concerning...Tornado Watch 107...

Valid 242035Z - 242200Z

The severe weather threat for Tornado Watch 107 continues.

SUMMARY...Ongoing cluster of severe thunderstorms with a history of
rotation will continue moving east-southeast through the afternoon.
The most intense storms should be near or east of the coast by 5PM
EDT. A local extension in time for coastal areas may be needed.

DISCUSSION...Ongoing cluster of severe thunderstorms across far
northeast Florida and extreme southwest Georgia will continue moving
east through 5PM EDT. These thunderstorms will continue to pose a
risk of all severe hazards. Given that Tornado Watch #107 is
scheduled to expire at 5PM EDT, a local extension in time may be
needed for coastal areas around Jacksonville, FL, as this
thunderstorm complex moves through.

..Marsh.. 04/24/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...JAX...

LAT...LON   30588257 30958228 31038145 30918050 30418027 30048029
            29948105 30158196 30588257

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 24, 2:00 AM EDTMesoscale DiscussionSPCEscambia, Holmes, Okaloosa, Santa Rosa, Walton, Washington3 hr
Apr 24, 2:00 AM EDTMesoscale DiscussionSPCEscambia, Holmes, Okaloosa, Santa Rosa, Walton, Washington3 hr
Apr 24, 2:23 AM EDTTornado WatchSPCEscambia, Okaloosa, Santa Rosa8 hr
Apr 24, 6:22 AM EDTTornado WatchSPCCalhoun, Gadsden, Holmes, Jackson, Jefferson, Leon and 4 more9 hr
Apr 24, 8:29 AM EDTMesoscale DiscussionSPCHolmes, Jackson, Walton, Washington91 min
Apr 24, 10:10 AM EDTMesoscale DiscussionSPCNassau95 min
Apr 24, 10:35 AM EDTTornado WatchSPCBaker, Columbia, Duval, Hamilton, Nassau, Suwannee7 hr
Apr 24, 12:05 PM EDTMesoscale DiscussionSPCCalhoun, Gadsden, Holmes, Jackson, Jefferson, Leon and 4 more85 min
Apr 24, 2:17 PM EDTSevere Thunderstorm WatchSPCEscambia, Holmes, Jackson, Okaloosa, Santa Rosa, Walton and 1 more8 hr
Apr 24, 4:40 PM EDTMesoscale DiscussionSPCHolmes, Santa Rosa95 min
Apr 24, 2:22 PM EDTMesoscale DiscussionSPCChattooga, Dade, Floyd, Walker113 min
Apr 24, 4:00 PM EDTSevere Thunderstorm WatchSPCBaker, Berrien, Brooks, Calhoun, Chattahoochee, Clay and 30 more6 hr
Apr 24, 5:52 PM EDTSevere Thunderstorm WatchSPCBarrow, Bartow, Butts, Carroll, Chattooga, Cherokee and 26 more4 hr
Apr 24, 6:56 PM EDTMesoscale DiscussionSPCBaker, Calhoun, Clay, Colquitt, Cook, Dougherty and 8 more94 min
Apr 24, 7:13 PM EDTMesoscale DiscussionSPCBarrow, Bartow, Butts, Carroll, Chattooga, Cherokee and 31 more2 hr
Apr 24, 7:47 PM EDTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Berrien, Brantley, Bryan and 12 more118 min

Nearby

Mesoscale Discussions in Florida, 2021Mesoscale Discussions in Georgia, 2021Every mesoscale discussion in 2021

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.