Alert archive / Texas / Severe Thunderstorm Warnings in 2000

Severe Thunderstorm Warning 106, NWS Austin/San Antonio, TX

April 20, 2000Bexar County, Medina County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at Apr 20, 2000, 4:09 AM CDT for Bexar County, Medina County, Texas. It was in force for 66 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Apr 20, 2000, 4:09 AM CDT (09:09 UTC)
Expired
Apr 20, 2000, 5:15 AM CDT
In force
66 min
Issued by
NWS Austin/San Antonio, TX
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Bexar County, TX, Medina County, TX

The radar

The Austin/San Antonio radar (KEWX), 79 km from the middle of the area, began a volume at 09:11 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Del Rio, TX (KDRT), launched 00:00Z, 9.2 hours before the alert went out and 197 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Del Rio, TX at 00:00Z on 2000-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3020 joules per kilogram.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.
HodographHodograph, Del Rio, TX at 00:00Z on 2000-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -17 square meters per square second.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.
Mixed-layer CAPE
3020 J/kg
Mixed-layer CIN
-172 J/kg
Mixed-layer LCL
2227 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
-17 m²/s²
0-3 km storm-relative helicity
21 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS54 KEWX 200910
SVRSAT
TXC029-325-201015-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
409 AM CDT THU APR 20 2000

THE NATIONAL WEATHER SERVICE IN AUSTIN/SAN ANTONIO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR THE FOLLOWING COUNTIES IN TEXAS...
  MEDINA COUNTY
  BEXAR COUNTY

* UNTIL 515 AM CDT

* AT 409 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 6 MILES SOUTHWEST OF RIO MEDINA...OR ABOUT 7
  MILES NORTHWEST OF CASTROVILLE...MOVING EAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  CASTROVILLE AROUND 415 AM CDT
  LACOSTE AROUND 420 AM CDT
  SEA WORLD AROUND 430 AM CDT
  LACKLAND AFB AROUND 440 AM CDT

VERY LARGE HAIL IS POSSIBLE WITH THIS SEVERE THUNDERSTORM. IF YOU ARE
IN THE PATH OF THE STORM...PUT YOUR CAR IN A GARAGE AND MOVE TO A
SUBSTANTIAL SHELTER.

.END/ LAT...LON 2954 9898 2928 9896 2930 9850 2973 9862

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Austin/San Antonio, TX wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 20, 3:00 AM CDT, 1 hour 9 minutes earlier.

Area forecast discussion, Apr 20, 3:00 AM CDT, 1 hour 9 minutes before
SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
300 AM CDT THU APR 20 2000

LARGE SCALE PATTERN SHOWS A SPLIT FLOW OFF THE WEST COAST WITH ONE
STORM TRACK ACROSS CANADA AND ONE TRACK ACROSS THE CENTRAL U.S.  THE
SOUTHERN TRACK CONTAINS TWO SIGNIFICANT TROUGHS.  THE FIRST TROUGH
IS PASSING US BY TO THE NORTH TODAY AND TONIGHT.  WHILE THE FIRST
ONE RETREATS ANOTHER TROUGH WILL AFFECT THE AREA DURING THE EXTENDED
PERIOD.  FRIDAY WILL BE AN INBETWEEN DAY.

CONVECTION ALONG THE COLD FRONT HAS BEEN DISSIPATING AS THE RAIN
MOVES AWAY FROM ITS DYNAMIC SOURCE.  BUT AS THE FRONT CROSSES THE
AREA TODAY THERE SHOULD BE ENOUGH INSTABILITY FOR SLIGHT CHANCE POPS
OVER THE CENTRAL AND EASTERN ZONES.  SLIGHTLY COOLER BUT MUCH DRIER AIR
WILL SPREAD ACROSS THE AREA BY TONIGHT BUT ABUNDANT SUNSHINE ON
FRIDAY WILL SEE A RAPID RISE IN TEMPS AGAIN.

RETURN FLOW AND LIFT FROM THE APPROACHING SECOND TROUGH SHOULD
PROVIDE MORE CLOUDS BY SATURDAY.  THIS SECOND TROUGH APPEARS TO BE
A LITTLE FARTHER SOUTH THAN THE FIRST ONE SO WE MAY SEE A LITTLE
BETTER CHANCE OF PRECIP BY SUNDAY...BEFORE IT PASSES US BY ON MONDAY.
WILL SEE IF THIS SCENARIO NEEDS ADJUSTING WHEN THE NEW MRF ARRIVES.

PRELIMS...
AUS 86/52/84/55 2000
SAT 88/56/87/60 1000
DRT 92/60/87/62 0000

.EWX...NONE.

16/18

Nearby

Severe Thunderstorm Warnings in Texas, 2000Every severe thunderstorm warning in 2000

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.