Alert archive / Texas / Severe Thunderstorm Warnings in 1996

Severe Thunderstorm Warning 23, NWS Austin/San Antonio, TX

April 20, 1996Bexar County, Comal County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at Apr 20, 1996, 11:11 AM CDT for Bexar County, Comal County, Texas. It was in force for 64 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Apr 20, 1996, 11:11 AM CDT (16:11 UTC)
Expired: Apr 20, 1996, 12:15 PM CDT
In force: 64 min
Issued by: NWS Austin/San Antonio, TX
Area: Whole counties

Counties Bexar County, TX, Comal County, TX

The radar

The Austin/San Antonio radar (KEWX), 37 km from the middle of the area, began a volume at 16:14 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.

What was reported inside it

Time	Report	Where	Remark
Apr 20, 11:20 AM CDT	Hail 0.75	Leon Spgs, TX

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 4.2 hours before the alert went out and 235 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 236 J/kg
Mixed-layer CIN: -522 J/kg
Mixed-layer LCL: 1600 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 234 m²/s²
0-3 km storm-relative helicity: 391 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSAT 201613
SVRSAT
TXC029-091-201715-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1111 AM CDT SAT APR 20 1996
 
THE NATIONAL WEATHER SERVICE IN AUSTIN/SAN ANTONIO HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1215 PM CDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN SOUTH CENTRAL TEXAS
 
   ...NORTHERN BEXAR COUNTY...COMAL COUNTY
 
AT 1105 AM CDT DOPPLER WEATHER RADAR INDICATED A SEVERE THUNDERSTORM
BETWEEN LEON SPRINGS AND BOERNE ALONG THE BEXAR AND KENDALL COUNTY LINE
MOVING TO THE EAST AT 20 MPH. THIS STORM WILL MOVE INTO THE BULVERDE
AREA AROUND 1130 AM.
 
SEVERE THUNDERSTORM WINDS CAN REACH SPEEDS OVER 60 MPH.  THESE WINDS
BLOW DOWN TREES...POWER LINES...AND SEVERELY DAMAGE MOBILE HOMES...
SOMETIMES BUILDINGS.  VERY LARGE HAIL CAN INJURE ANYONE CAUGHT
OUTSIDE.

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.

In the hours before

Special weather statement, Apr 20, 6:50 AM CDT, 4 hours 21 minutes before

TXZ168>173-183>194-202>209-217>225-228-202330-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
650 AM CDT SAT APR 20 1996

THERE IS A SLIGHT CHANCE OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EARLY THIS EVENING OVER PORTIONS OF THE HILL COUNTRY AND SOUTH
CENTRAL TEXAS.

A WEAK UPPER LEVEL DISTURBANCE WILL MOVE ACROSS CENTRAL TEXAS LATE
TODAY..EASING A FRONTAL BOUNDARY SOUTHWARD ACROSS THE RISK AREA.
WIDELY SCATTERED SHOWERS AND THUNDERSTORMS WILL FOCUS ALONG AND TO
THE NORTH OF THE BOUNDARY BY LATE AFTERNOON.  LOW LEVEL MOISTURE FROM
THE GULF WILL HELP ADD FUEL TO TRIGGER AND SUSTAIN DEVELOPMENT.

LIMITING FACTORS FOR SEVERE WEATHER DEVELOPMENT TODAY INCLUDE A
STABLE LAYER IN THE LOWER LEVELS WHERE THE TEMPERATURE ACTUALLY RISES
WITH HEIGHT..CALLED AN INVERSION LAYER. FOR SEVERE THUNDERSTORMS TO
DEVELOP THIS INVERSION MUST BE PENETRATED BY LOW LEVEL FORCING OF AIR
UPWARD. IT REMAINS TO BE SEEN WHETHER OR NOT THE UPPER LEVEL DYNAMICS
ALONG WITH THE FRONTAL UPLIFT WILL BE SUFFICIENT TO PENTRATE THIS
STABLE LAYER..THUS IGNITING THE SEVERE ACTIVITY.

STAY TUNED TO YOUR LOCAL RADIO..TV OR TUNE TO NOAA WEATHER RADIO FOR
THE LATEST ON THIS DEVELOPING SEVEREF WEATHER SITUATION.

The office that day

Everything else NWS Austin/San Antonio, TX issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 20, 3:55 AM CDT	Severe Thunderstorm Warning	EWX	Fayette	50 min
Apr 20, 4:00 AM CDT	Severe Thunderstorm Warning	EWX	Guadalupe	45 min
Apr 20, 4:40 AM CDT	Severe Thunderstorm Warning	EWX	Fayette	65 min
Apr 20, 4:55 AM CDT	Severe Thunderstorm Warning	EWX	Gonzales, Guadalupe	65 min
Apr 20, 10:19 AM CDT	Severe Thunderstorm Warning	EWX	Bandera	41 min
Apr 20, 10:39 AM CDT	Severe Thunderstorm Warning	EWX	Kendall	66 min

Nearby

Severe Thunderstorm Warnings in Texas, 1996 Every severe thunderstorm warning in 1996

Sources

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