Tornadoes · United States · Texas · 2004
F0 tornado, Harris County, Texas, May 1, 2004
This F0 tornado ran 0.1 miles across Harris County on May 1, 2004, touching down at 10:00 AM CDT and reaching 20 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.
F040 to 72 mphthis tornado
Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.
F173 to 112 mph
Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.
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.
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.
F4207 to 260 mph
Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.
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.
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 1, 2004
- Touchdown
- 10:00 AM CDT (15:00 UTC)
- Path length
- 0.1 miles (0.2 km)
- Path width
- 20 yards (18 m)
- Deaths
- 0
- Injuries
- 0
- County
- Harris County
- Touchdown point
- 29.900, -95.070
- Lift-off point
- 29.900, -95.070
- Record number
- 1249
The warnings
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.
| Issued (UTC) | Expired | Product | Office |
|---|---|---|---|
| 13:43 UTC | 15:30 UTC | Flash Flood Warning | HGX |
| 13:50 UTC | 14:30 UTC | Tornado Warning | HGX |
| 16:58 UTC | 19:00 UTC | Flash Flood Warning | HGX |
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 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 12:29 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.
What forecasters said that day
The local office's own words before the tornado touched down, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Houston/Galveston, TX wrote its last area forecast discussion before the tornado touched down at May 1, 10:00 AM CDT, 0 minutes earlier.
Area forecast discussion, May 1, 10:00 AM CDT, 0 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 10 AM CDT SAT MAY 1 2004 .DISCUSSION... HAVE MADE A QUICK UPDATE TO ZONES TO ACCOUNT FOR THE NEW TORNADO WATCH. TOA#143 COVERS THE COASTAL/NEAR COASTAL COUNTIES OF SE TX UNTIL 3PM. HOWEVER...NOT ANTICIPATING THE WATCH TO HOLD OVER THE CWFA THROUGH THE OFFICAL END TIME. KEEPING THE FFA UP FOR THE TIME BEING AS WELL. ADDITIONAL TWEAKING OF ZONES PROBABLY IN THE WORKS THIS AFTN TO ACCOUNT FOR WINDS/TEMPS. 41/45/42 && .HGX WATCHES/WARNINGS/ADVISORIES... TORNADO WATCH COASTAL/NEAR COASTAL ZONES OF SE TX UNTIL 3 PM. FLOOD WATCH ALL OF SOUTHEAST TEXAS THROUGH 6 PM. SCA ALL WATERS THIS AFTERNOON. && .PRELIMINARY POINT TEMPS/POP... COLLEGE STATION (CLL) 72 52 75 50 79 / 80 30 00 00 00 HOUSTON (IAH) 76 56 75 50 79 / 80 60 00 00 00 GALVESTON (GLS) 75 61 74 60 78 / 80 70 10 00 00 &&
Hazardous weather outlook, May 1, 5:13 AM CDT, 4 hours 47 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 513 AM CDT SAT MAY 1 2004 TXZ163-164-176>179-195>200-210>214-226-227-235>238-021200- AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-GALVESTON- GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-MADISON-MATAGORDA-MONTGOMERY- POLK-SAN JACINTO-TRINITY-WALKER-WALLER-WASHINGTON-WHARTON- 513 AM CDT SAT MAY 1 2004 ...SEVERE THUNDERSTORMS AND LOCALLY HEAVY RAINFALL POSSIBLE ACROSS SOUTHEAST TEXAS TODAY... .DAY ONE...TODAY AND TONIGHT. SHOWERS AND THUNDERSTORMS WILL SWEEP THROUGH SOUTHEAST TEXAS TODAY AHEAD OF A COLD FRONT. STRONG TO SEVERE THUNDERSTORMS AND LOCALLY HEAVY RAINFALL ARE POSSIBLE WITH THESE STORMS. THE MAIN SEVERE WEATHER THREAT WILL BE STRONG DAMAGING WINDS AND LARGE HAIL. ISOLATED TORNADOES WILL ALSO BE POSSIBLE WITH THE STRONGER THUNDERSTORMS. RAINFALL AMOUNTS OF 1 TO 2 INCHES WITH ISOLATED 3 TO 4 INCH TOTALS WILL BE POSSIBLE. THE ACTIVITY IS EXPECTED TO MOVE OFF TO THE EAST THIS EVENING ENDING THE SEVERE THUNDERSTORM AND LOCALLY HEAVY RAINFALL THREAT. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE REQUIRED THIS MORNING AND THIS AFTERNOON.
In the hours before
Special weather statement, May 1, 9:48 AM CDT, 12 minutes before
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX 948 AM CDT SAT MAY 1 2004 GMZ330-335-350-355-370-375-TXZ200-213-214-226-227-235>238-012000- BRAZORIA-CHAMBERS-FORT BEND-GALVESTON-GALVESTON BAY-HARRIS-JACKSON- LIBERTY-MATAGORDA-MATAGORDA BAY- WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM- WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM- WATERS FROM HIGH ISLAND TO FREEPORT 20 NM TO 60 NM- WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-WHARTON- 948 AM CDT SAT MAY 1 2004 ...TORNADO WATCH HAS BEEN ISSUED FOR THE SOUTHERN AND COASTAL PORTIONS OF SOUTHEAST TEXAS UNTIL 300 PM CDT... THE STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR THE FOLLOWING SOUTHEAST TEXAS COUNTIES...BRAZORIA...CHAMBERS...FORT BEND...GALVESTON...HARRIS...JACKSON...LIBERTY...MATAGORDA AND WHARTON. THIS TORNADO WATCH REPLACES THE TORNADO WATCH THAT WAS PREVIOUSLY IN EFFECT FOR ALL OF SOUTHEAST TEXAS UNTIL 1000 AM CDT. A WARM AND UNSTABLE AIR MASS IS IN PLACE OVER THE AREA...ALLOWING THUNDERSTORMS TO DEVELOP OVER THE COASTAL WATERS AND ADJACENT LAND AREAS. WIND FIELDS ARE FAVORABLE FOR ISOLATED TORNADOES WITH THE STRONGEST STORMS. IN ADDITION TO THE SEVERE WEATHER THREAT...LOCALLY HEAVY RAINFALL MAY LEAD TO FLOODING...AND A FLOOD WATCH IS IN EFFECT FOR ALL OF SOUTHEAST TEXAS UNTIL 600 PM CDT. STAY TUNED TO YOUR LOCAL RADIO OR TELEVISION STATION...NOAA WEATHER RADIO...OR VISIT OUR WEB SITE AT WWW.SRH.NOAA.GOV/HGX FOR MORE INFORMATION.
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.
Lake Charles Mun, LA (KLCH), 12:00Z
3.0 hours before the tornado, 182 km from the path. May 1, 2004.
- Mixed-layer CAPE
- 326 J/kg
- Mixed-layer CIN
- -239 J/kg
- Surface CAPE
- 172 J/kg
- Mixed-layer LCL
- 978 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 153 m²/s²
- 0-3 km storm-relative helicity
- 263 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 9.3
- 0-3 km lapse rate
- 4.7 K/km
Lake Charles Mun, LA (KLCH), 00:00Z
9.0 hours after it, 182 km from the path. May 2, 2004.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- -38484 J/kg
- Surface CAPE
- 10 J/kg
- Mixed-layer LCL
- 899 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km bulk shear
- 18 kt
- 0-1 km storm-relative helicity
- 63 m²/s²
- 0-3 km storm-relative helicity
- -95 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
- 0-3 km lapse rate
- 4.9 K/km
The radar
The Houston radar (KHGX), 48 km away, was scanning. The volume nearest the touchdown began at 15:02 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.
This ground now
The live radar over the trackEvery 2004 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are
The other tornadoes of May 1, 2004
9 more were confirmed in the United States that day.
| Date | Time | Rating | Where | Path (mi) | Width (yd) | Deaths | Injuries | Damage |
|---|---|---|---|---|---|---|---|---|
| May 1 | 1:00 AM CDT | F0 | Boone, AR | 3.5 | 25 | |||
| May 1 | 4:24 AM CDT | F1 | Wayne, MO | 0.2 | 50 | $10,000 | ||
| May 1 | 8:45 AM CDT | F1 | Harris, TX | 0.5 | 45 | 1 | $280,000 | |
| May 1 | 9:12 AM CDT | F0 | Harris, TX | 0.1 | 20 | |||
| May 1 | 3:10 PM CDT | F0 | Hancock, IA | 3.0 | 50 | |||
| May 1 | 3:43 PM CDT | F1 | Jefferson Davis, MS | 9.0 | 300 | $30,000 | ||
| May 1 | 4:02 PM CDT | F1 | Covington, MS | 0.7 | 75 | $30,000 | ||
| May 1 | 4:03 PM CDT | F1 | Walthall, MS | 9.0 | 100 | $70,000 | ||
| May 1 | 4:32 PM CDT | F1 | Jefferson Davis, MS | 6.0 | 100 | $10,000 |
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.