Alert archive / Texas / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 180, NWS Austin/San Antonio, TX

December 20, 1997Atascosa County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at Dec 20, 1997, 5:46 PM CST for Atascosa County, Texas. It was in force for 44 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
Dec 20, 1997, 5:46 PM CST (23:46 UTC)
Expired
Dec 20, 1997, 6:30 PM CST
In force
44 min
Issued by
NWS Austin/San Antonio, TX
Area
Whole counties

County Atascosa County, TX

The radar

The Austin/San Antonio radar (KEWX), 102 km from the middle of the area, began a volume at 23:49 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

TimeReportWhereRemark
Dec 20, 6:00 PM CSTHail 0.75Charlotte, 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Dec 20, 5:30 PM CSTTornado WatchSPC6 hr

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 12:00Z, 11.8 hours before the alert went out and 174 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, Corpus Christi, TX at 12:00Z on 1997-12-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 393 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, Corpus Christi, TX at 12:00Z on 1997-12-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 177 square meters per square second.1939587897117Sfc1 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
393 J/kg
Mixed-layer CIN
-3 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
177 m²/s²
0-3 km storm-relative helicity
206 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.2

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSAT 202349 RRA
SVRSAT
TXC013-210030-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
546 PM CST SAT DEC 20 1997
 
THE NATIONAL WEATHER SERVICE IN AUSTIN/SAN ANTONIO HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  630 PM CST
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTH CENTRAL TEXAS
 
   ...ATASCOSA COUNTY
 
AT 545 PM CST NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
POSSIBLY SEVERE THUNDERSTORM ENTERING ATASCOSA COUNTY BETWEEN HINDES
AND CHARLOTTE MOVING TO THE EAST NORTHEAST AT 30 TO 35 MPH. THIS
STORM WILL REACH JOURDANTON SHORTLY AFTER 600 PM.
 
 
ALTHOUGH NO TORNADOES HAVE BEEN DETECTED WITH THIS STORM...A
TORNADVO WATCH REMAINS IN EFFECT.  SEVERE THUNDERSTORMS CAN AND
OCCASIONALLY DO PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE WARNING
SO BE ON THE LOOKOUT.

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, Dec 20, 5:04 PM CST, 42 minutes before
TXZ186>190-204>206-219-220-210000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
504 PM CST SAT DEC 20 1997

...FLASH FLOOD WATCH CONTINUES UNTIL MIDNIGHT FOR MOST OF SOUTH
CENTRAL TEXAS AND THE TEXAS HILL COUNTRY...

AT 500 PM A LINE OF STRONG THUNDERSTORMS HAD FORMED ALONG A LINE FROM
COTULA TO VANDERPOOL TO NEAR HARPER.  THESE STORMS WERE RAPIDLY
INTENSIFYING AND MOVING TO THE EAST AT 25 TO 30 MPH.

SOME OF THESE THUNDERSTORMS MAY CONTAIN SMALL HAIL...GUSTY
THUNDERSTORM WINDS AND BRIEF HEAVY RAINFALL.

THIS LINE WILL MOVE INTO THE SAN ANTONIO AREA BY 600 PM.

PERSONS IN THE PATH OF THESE STORMS SHOULD BE ON THE LOOKOUT FOR
THREATING WEATHER AND BE PREPARED TO MOVE A PLACE OF SAFETY IF
SUCH IS SIGHTED OR A WARNING IS ISSUED.
Special weather statement, Dec 20, 5:05 PM CST, 41 minutes before
TXZ186>190-204>206-219-220-210000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
504 PM CST SAT DEC 20 1997

...FLASH FLOOD WATCH CONTINUES UNTIL MIDNIGHT FOR MOST OF SOUTH
CENTRAL TEXAS AND THE TEXAS HILL COUNTRY...

AT 500 PM A LINE OF STRONG THUNDERSTORMS HAD FORMED ALONG A LINE FROM
COTULA TO VANDERPOOL TO NEAR HARPER.  THESE STORMS WERE RAPIDLY
INTENSIFYING AND MOVING TO THE EAST AT 25 TO 30 MPH.

SOME OF THESE THUNDERSTORMS MAY CONTAIN SMALL HAIL...GUSTY
THUNDERSTORM WINDS AND BRIEF HEAVY RAINFALL.

THIS LINE WILL MOVE INTO THE SAN ANTONIO AREA BY 600 PM.

PERSONS IN THE PATH OF THESE STORMS SHOULD BE ON THE LOOKOUT FOR
THREATING WEATHER AND BE PREPARED TO MOVE A PLACE OF SAFETY IF
SUCH IS SIGHTED OR A WARNING IS ISSUED.

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 20, 3:25 PM CSTFlash Flood WarningEWXBurnet3 hr
Dec 20, 5:32 PM CSTSevere Thunderstorm WarningEWXFrio43 min

Nearby

Severe Thunderstorm Warnings in Texas, 1997Every severe thunderstorm warning in 1997

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.