Tornadoes · United States · Mississippi · 1999

F0 tornado, Savannan, Mississippi, May 30, 1999

This F0 tornado ran 0.5 miles across Pearl River County on May 30, 1999, touching down at 12:09 PM CDT and reaching 30 yards wide. It killed nobody.

The rating scale

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

  1. F040 to 72 mphthis tornado

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

  2. F173 to 112 mph

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

  3. F2113 to 157 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. F3158 to 206 mph

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

  5. F4207 to 260 mph

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

  6. F5261 to 318 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. Unrated

    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
F0
Date
May 30, 1999
Touchdown
12:09 PM CDT (17:09 UTC)
Path length
0.5 miles (0.8 km)
Path width
30 yards (27 m)
Deaths
0
Injuries
0
County
Pearl River County
Touchdown point
30.730, -89.480
Lift-off point
30.730, -89.480
Record number
435

What the Weather Service recorded

A tornado was observed by fire department personnel touching down in open country near the community of Savannah. No damage was reported.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

14 minutes of warning. NWS LIX issued a tornado warning for this county at 16:55 UTC, 14 minutes before the tornado touched down, in force until 17:25 UTC.

Issued (UTC)ExpiredProductOffice
16:55 UTC17:25 UTCTornado WarningLIX

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 General Thunderstorms Risk. The outlook in force was issued at 16:30 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.

Slidell Radar S, LA (KSIL), 12:00Z

5.2 hours before the tornado, 57 km from the path. May 30, 1999.

Skew-T log-pSkew-T log-p diagram, Slidell Radar S, LA at 12:00Z on 1999-05-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 744 joules per kilogram, CIN -16, lifted condensation level 865 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Slidell Radar S, LA at 12:00Z on 1999-05-30The 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 33 square meters per square second, 0 to 6 km bulk shear 13 knots.1939Sfc1 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
744 J/kg
Mixed-layer CIN
-16 J/kg
Surface CAPE
259 J/kg
Mixed-layer LCL
865 m above ground
0-6 km bulk shear
13 kt
0-1 km bulk shear
10 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
74 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
5.4 K/km

Open this sounding in Storm Lab

Slidell Radar S, LA (KSIL), 00:00Z

6.8 hours after it, 57 km from the path. May 31, 1999.

Skew-T log-pSkew-T log-p diagram, Slidell Radar S, LA at 00:00Z on 1999-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 596 joules per kilogram, CIN -19, lifted condensation level 1087 meters above ground. Wind barbs in knots down the right edge.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. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Slidell Radar S, LA at 00:00Z on 1999-05-31The 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 50 square meters per square second, 0 to 6 km bulk shear 18 knots.1939Sfc1 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
596 J/kg
Mixed-layer CIN
-19 J/kg
Surface CAPE
2075 J/kg
Mixed-layer LCL
1087 m above ground
0-6 km bulk shear
18 kt
0-1 km bulk shear
9 kt
0-1 km storm-relative helicity
50 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
6.7 K/km

Open this sounding in Storm Lab

The surface observations

Bogalusa (BXA), 38 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
15:53 UTC7568 6 kt1020-RA
16:16 UTC69.86840° 5 kt1020-RA BR
16:23 UTC71.669.840° 4 kt1020
16:53 UTC737070° 4 kt1019.6
17:31 UTC71.668220° 12 kt181021+RA BR
17:37 UTC69.866.2220° 12 kt181021+RA BR
17:44 UTC69.866.2230° 7 kt161020.7+RA BR
17:53 UTC7067280° 3 kt1020.7RA BR
18:00 UTC69.866.20° 0 kt1020.7-RA BR
18:12 UTC69.868300° 5 kt1020.7-RA
18:41 UTC69.866.20° 0 kt1020.3RA BR
18:53 UTC7069360° 4 kt1020.3-RA

From the Iowa Environmental Mesonet's archive of airport observations.

This ground now

The live radar over the trackEvery 1999 tornado in MississippiEvery tornado in Mississippi since 1950Warnings in force in Mississippi nowThe forecast where you are

The other tornadoes of May 30, 1999

11 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 307:30 AM EDTF0Brevard, FL0.130$40,000
May 3012:15 PM EDTF0Monroe, FL0.00
May 3012:15 PM EDTF0Monroe, FL0.00
May 301:54 PM CDTF0Arkansas, AR0.10
May 301:25 PM MDTF0Laramie, WY0.250$2,000
May 306:15 PM CDTF0Dixon, NE0.150
May 306:30 PM CDTF1Fort Bend, TX1.0100$100,000
May 307:13 PM CDTF1Dawson, NE5.0100$50,000
May 308:15 PM CDTF0Jefferson Parish, LA0.20$1,000
May 309:50 PM CDTF1Lavaca, TX0.230$10,000
May 3010:15 PM CDTF1Lavaca, TX0.120$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.