F0 tornado, Rancho Viejo, Texas, May 31, 2001

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

May 31, 2001

Touchdown

3:45 PM CDT (20:45 UTC)

Path length

0.1 miles (0.2 km)

Path width

25 yards (23 m)

Deaths

0

Injuries

0

County

Cameron County

Touchdown point

26.080, -97.550

Lift-off point

26.080, -97.550

Record number

176

An airplane pilot and an emergency technician both sighted a tornado between San Benito and Rancho Viejo.

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

37 minutes of warning. NWS BRO issued a tornado warning for this county at 20:08 UTC, 37 minutes before the tornado touched down, in force until 20:45 UTC.

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 20:05 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.

NWS Brownsville, TX wrote its last area forecast discussion before the tornado touched down at May 31, 2:45 PM CDT, 1 hour earlier.

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
245 PM CDT THU MAY 31 2001

SHORT TERM...SEVERAL MESOSCALE FEATURES THIS AFTERNOON SEEM TO BE
DRIVING FORCE OF EARLY AFTERNOON AND CURRENT SHOWER AND THUNDERSTORM
ACTIVITY. SHORTWAVE TROUGH CONTINUES TO MOVE SOUTHEAST INTO WESTERN
PORTIONS OF SOUTH TX. BRUNT OF CONVECTION OVER SE TEXAS ASSOC WITH
UPPER TROUGH OVER EASTERN HALF OF TX. WEAK COLD FRONT CURRENTLY OVER
NORTH CENTRAL TEXAS WITH OUTFLOW BOUNDARY APPROACHING THE COASTAL
BEND EXTENDING NORTHEAST INTO PORTIONS OF SOUTHEAST TX. SEABREEZE
FRONT HAS MOVED INTO WESTERN PORTIONS OF COUNTIES ALONG THE COAST.
SHOWERS AND THUNDERSTORMS THAT DEVELOPED ALONG THE SEABREEZE EARLIER
HAVE REMAINED BEHIND THE SEABREEZE OVER THE COASTAL SECTIONS. VIS
SATELLITE IMAGES AND RADAR REFLECTIVITIES INDICATE A GRAVITY WAVE
HAS MOVED INTO WESTERN AND CENTRAL PORTIONS OF DEEP SOUTH TEXAS.
MOIST AND UNSTABLE ATMOSPHERE IN COMBINATION WITH MESOSCALE AND
UPPER LEVEL FEATURES WARRANT SLIGHT POPS TONIGHT...AS CONVECTION IS
ALSO DEVELOPING OVER NORTHEAST MEXICO. WINDS SHOULD BE LIGHT ENOUGH
TOMORROW TO WARRANT ANOTHER ROUND OF SEABREEZE CONVECTION FOR
EASTERN ZONES. OTHERWISE...NORTHWEST FLOW ALOFT WITH UPPER RIDGE
OVER THE WESTERN U.S. SHIFTING EASTWARD TO INCREASE SUBSIDENT AIR
WITH DRIER MID AND UPPER LEVELS MIXING DOWN TO THE SURFACE SATURDAY.
WINDS INCREASE SLIGHTLY IN RESPONSE TO TIGHTER PRESSURE GRADIENT
WHICH WILL TEND TO INHIBIT THE SEABREEZE SATURDAY. TEMPS CONTINUE TO
BE ABOVE NORMAL.

EXTENDED...UPPER LEVEL RIDGE SETTLES OVER SOUTH TX SUNDAY AS A ZONAL
FLOW DEVELOPS ACROSS THE SOUTHERN TIER OF THE NATION. AN UPPER
TROUGH DROPS INTO THE NORTHERN PLAINS MONDAY AS WEAKNESS IN THE
UPPER RIDGE DEVELOPS OVER THE VALLEY. ANOTHER WEAK COLD FRONT MOVES
INTO NORTH TEXAS MONDAY NIGHT AND IS LIKELY TO STALL OVER CENTRAL TX
TUESDAY. 12Z AVN RUN CONTINUES TO INDICATE PRECIP LIKELY ASSOC
W/SEABREEZE AND WEAKNESS IN UPPER RIDGE AS UPPER TROUGH MOVES INTO
THE MIDWEST. WILL KEEP SLIGHT CHANCE OF PRECIP TUE/WED FOR NOW.

MARINE...SE WIND NEAR 10 KNOTS OFFSHORE WITH 4 FOOT WAVES CURRENTLY.
LOW PRESSURE DEVELOPING OVER WEST TEXAS AND THE HIGH PRESSURE RIDGE
OVER THE GULF OF MEXICO...WILL GRADUALLY INCREASE THE PRESSURE
GRADIENT OVER THE LOWER TEXAS COAST THE NEXT SEVERAL
DAYS...PRODUCING A SLIGHT INCREASE IN SE WINDS. NO SIGNIFICANT
CHANGES EXPECTED FROM PREVIOUS FCST.

PRELIMINARY NUMBERS...
BRO BU 076/093 076/094 076 11000
HRL BU 075/095 075/096 075 11000
MFE BU 076/097 076/098 076 10000
RGC BU 075/100 075/101 075 10000
SPI BU 077/086 077/087 077 10000

AXVIATION-MARINE...YURA.69/PUBLIC-SYNOPTIC...CASTILLO.61
MESO...WATKINS

INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO

.BRO...NONE.

In the hours before

TXZ248>257-312359-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1120 AM CDT THU MAY 31 2001

AN UNSTABLE AND MOIST ATMOSPHERE...ALONG WITH A SEABREEZE AND
OUTFLOW BOUNDARIES...WILL PRODUCE A CHANCE FOR SCATTERED SHOWERS AND
THUNDERSTORMS THIS AFTERNOON.  ALTHOUGH SEVERE WEATHER IS NOT
ANTICIPATED OVER THE AREA TODAY...COLD TEMPERATURES ALOFT MAY ALLOW
FOR SMALL HAIL TO ACCOMPANY SOME OF THE THUNDERSTORMS.  IN
ADDITION...WEAK WINDS ALOFT WILL HELP PRODUCE HEAVY DOWNPOURS WITH
SOME ISOLATED ONE TO TWO INCH RAIN REPORTS.

LAW ENFORCEMENT OFFICIALS AND SPOTTER GROUPS OVER DEEP SOUTH
TEXAS...SHOULD TRACK THE AFTERNOON SHOWER AND THUNDERSTORM
DEVELOPMENT IN CASE SPOTTER ACTIVATION WOULD BECOME NECESSARY.

YURA

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.

Harlingen International Airport (HRL), 20 km from the path, in the two hours either side.

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

The Brownsville radar (KBRO), 23 km away, was scanning. The volume nearest the touchdown began at 20:47 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.

The live radar over the trackEvery 2001 tornado in TexasEvery tornado in Texas since 1950Warnings in force in Texas nowThe forecast where you are

9 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.