F0 tornado, Bay St Louis, Mississippi, September 20, 1998

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.

Rating

F0

Date

September 20, 1998

Touchdown

9:50 AM CDT (14:50 UTC)

Path length

0.1 miles (0.2 km)

Path width

30 yards (27 m)

Deaths

0

Injuries

0

Property damage

$10,000

County

Hancock County

Touchdown point

30.320, -89.330

Lift-off point

30.320, -89.330

Record number

1308

A tropical depression that formed in the central Gulf of Mexico on September 17th strengthened to a minimal tropical storm named Hermine on the morning of the 18th. Tropical Storm Hermine meandered in the Gulf of Mexico for a period of time before beginning a slow north northeast motion that brought it ashore in the early morning hours of the 20th near Cocodrie, LA in Terrebonne Parish. Tropical Storm Hermine then drifted north over southeast Louisiana and was downgraded to a tropical depression 50 miles northwest of New Orleans during the evening of the 20th. Winds associated with Hermine were of minimal tropical storm force and were mainly contained in squalls. A peak wind gust of 46 mph in a squall was measured just off the southeast coast of Louisiana at the Burrwood NOAA C-MAN station near the mouth of the Mississippi River at 1139 CST on September 19th.Two tornadoes developed in rainbands associated with Tropical Storm Hermine on September 20th. The first tornado occurred around 0730 CST 10 miles south of Poplarville, MS and destroyed two mobile homes, damaged seven cars, and caused one injury. A second weak tornado briefly touched down near Bay St. Louis, MS around 0850 CST resulting in only minor damage.Isolated flash flooding also occurred with Tropical Storm Hermine on September 20th when 4 to 5 inches of rain fell on areas of Walthall county. Sections of a few roadways in southern Walthall county were briefly under water including Mississippi Highway 27 which was covered by up to a foot of water in places.

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

No tornado warning for this county appears in the archive as in force at the moment the tornado touched down. One was issued for the county at another hour that day.

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 Storm Prediction Center had this point in a General Thunderstorms Risk. The outlook in force was issued at 10:27 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 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.

The live radar over the trackEvery 1998 tornado in MississippiEvery tornado in Mississippi since 1950Warnings in force in Mississippi nowThe forecast where you are

2 more were confirmed in the United States that day.

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.

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