Tornadoes · United States · Florida · 2017

Unrated tornado, Saint Johns County, Florida, May 24, 2017

This Unrated tornado ran 0.6 miles across Saint Johns County on May 24, 2017, touching down at 8:53 AM EDT and reaching 25 yards wide. It killed nobody.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mph

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unratedthis tornado

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
Unrated
Date
May 24, 2017
Touchdown
8:53 AM EDT (12:53 UTC)
Lifted
8:54 AM EDT (12:54 UTC)
On the ground
1 minutes
Path length
0.6 miles (1.0 km)
Path width
25 yards (23 m)
Deaths
0
Injuries
0
County
Saint Johns County
Touchdown point
29.696, -81.230
Lift-off point
29.700, -81.220
Record number
1705240653-01

The warnings

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down.

The county was under a tornado watch, issued at 10:56 UTC and running to 19:00 UTC.

Issued (UTC)ExpiredProductOffice
20:19 UTC20:45 UTCMarine WarningJAX
00:00 UTC07:45 UTCSmall Craft AdvisoryJAX
08:59 UTC09:44 UTCMarine WarningJAX
10:49 UTC11:45 UTCMarine WarningJAX
10:56 UTC19:00 UTCTornado WatchJAX
11:46 UTC12:30 UTCMarine WarningJAX
14:09 UTC15:00 UTCMarine WarningJAX
17:24 UTC19:30 UTCMarine WarningJAX
19:00 UTC21:47 UTCSevere Thunderstorm WatchJAX

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a Slight Risk, with a 0.02 chance of a tornado within 25 miles. The outlook in force was issued at 06:04 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Jacksonville, FL (KJAX), 12:00Z

0.9 hours before the tornado, 100 km from the path. May 24, 2017.

Skew-T log-pSkew-T log-p diagram, Jacksonville, FL at 12:00Z on 2017-05-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 868 joules per kilogram, CIN -13, lifted condensation level 752 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Jacksonville, FL at 12:00Z on 2017-05-24The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 178 square meters per square second, 0 to 6 km bulk shear 48 knots.19395878Sfc1 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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
868 J/kg
Mixed-layer CIN
-13 J/kg
Surface CAPE
2253 J/kg
Mixed-layer LCL
752 m above ground
0-6 km bulk shear
48 kt
0-1 km bulk shear
31 kt
0-1 km storm-relative helicity
178 m²/s²
0-3 km storm-relative helicity
193 m²/s²
Significant tornado parameter
1.2
Supercell composite
9.7
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

Jacksonville, FL (KJAX), 00:00Z

11.1 hours after it, 100 km from the path. May 25, 2017.

Skew-T log-pSkew-T log-p diagram, Jacksonville, FL at 00:00Z on 2017-05-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 136 joules per kilogram, CIN -138, lifted condensation level 1242 meters above ground. Wind barbs in knots down the right edge.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Jacksonville, FL at 00:00Z on 2017-05-25The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 161 square meters per square second, 0 to 6 km bulk shear 52 knots.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. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
136 J/kg
Mixed-layer CIN
-138 J/kg
Surface CAPE
3204 J/kg
Mixed-layer LCL
1242 m above ground
0-6 km bulk shear
52 kt
0-1 km bulk shear
53 kt
0-1 km storm-relative helicity
161 m²/s²
0-3 km storm-relative helicity
109 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.6
0-3 km lapse rate
6.1 K/km

Open this sounding in Storm Lab

The radar

The Jacksonville radar (KJAX), 99 km away, was scanning. The volume nearest the touchdown began at 12:51 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
14:22 UTCFUNNEL CLOUDBostwickPutnam, FLCITIZEN REPORTED SEEING A FUNNEL CLOUD.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2017 tornado in FloridaEvery tornado in Florida since 1950Warnings in force in Florida nowThe forecast where you are

The other tornadoes of May 24, 2017

26 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 249:45 AM EDTEF1Whitfield, GA1.6200$20,000
May 2410:47 AM EDTEF0Gordon, GA0.390$10,000
May 2410:50 AM EDTEF0Gordon, GA0.390$30,000
May 2411:16 AM EDTEF0Gilmer, GA0.130$8,000
May 2411:43 AM EDTEF0Fannin, GA0.135$7,000
May 2411:36 AM CDTEF0Smith, TN2.575$50,000
May 242:05 PM EDTEF0Laurens, GA2.3240$25,000
May 242:40 PM EDTEF1Saluda, SC2.975
May 243:04 PM EDTEF2Saluda, SC12.1250
May 243:26 PM EDTEF0Iredell, NC1.150$10,000
May 243:41 PM EDTEF2Iredell, NC3.2100$250,000
May 244:14 PM EDTEF2Davie, NC5.92251$9.6 million
May 243:19 PM CDTEF1Lancaster, SC to NC8.150$100,000
May 244:48 PM EDTEF0Cook, GA1.1568$5,000
May 244:52 PM EDTEF2Stokes, NC16.1700$20 million
May 247:47 PM EDTEF0Warren, OH0.225
May 248:11 PM EDTEF1Lawrence, OH3.0100$100,000
May 248:26 PM EDTEF0Greene, OH2.640$3,000
May 248:27 PM EDTEF0Fayette, OH0.725
May 248:30 PM EDTEF0Greene, OH2.225
May 249:06 PM EDTEF0Greene, OH1.690$2,000
May 249:12 PM EDTEF0Clark, OH1.190$100,000
May 249:16 PM EDTEF1Clark, OH0.4300$250,000
May 249:20 PM EDTEF1Miami, OH4.1300$50,000
May 2410:03 PM EDTEF1Miami, OH1.9160$5,000
May 2411:09 PM EDTEF1Toombs, GA4.2440$50,000

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.