Alert archive / Texas / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 94, NWS Austin/San Antonio, TX

May 20, 1987Wilson County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at May 20, 1987, 7:11 PM CDT for Wilson County, Texas. It was in force for 64 min.

The area

The counties it named.

The facts

Issued: May 20, 1987, 7:11 PM CDT (00:11 UTC)
Expired: May 20, 1987, 8:15 PM CDT
In force: 64 min
Issued by: NWS Austin/San Antonio, TX
Area: Whole counties

County Wilson County, TX

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Victoria Regiona, TX (KVCT), launched 00:00Z, 0.2 hours before the alert went out and 121 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: 2069 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 921 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: 13 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KSAT 210011
SVRSAT
TXC493-210115-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE SAN ANTONIO TX
711 PM CDT WED MAY 20 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM WARNING
EFFECTIVE UNTIL 815 PM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTH TEXAS
          ...WILSON
 
AT 710 PM CDT...A SEVERE THUNDERSTORM WAS INDICATED BY RADAR IN
WESTERNF WILSON COUNTY...ALONG US HIGHWAY 181...JUST WEST OF THE CITY
OF FLORESVILLE.  MOVEMENT HAS BEEN SLOW AND ERRATIC.  GOLF-BALL SIZED
HAIL HAS BEEN REPORTED AT CALAVERAS LAKE IN EASTERN BEXAR COUNTY IN A
THUNDERSTORM JUST WEST OF THE WILSON COUNTY STORM.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55 MPH...HAIL
3/4 INCH OR MORE IN DIAMETER...FREQUENT LIGHTNING AND VERY HEAVY
RAIN.
 
WHEN A THUNDERSTORM THREATENS...SEEK SHELTER INSIDE A HOME OR
BUILDING AWAY FROM DOORS AND WINDOWS.  REFRAIN FROM USING ELECTRICAL
APPLIANCES.
 
YOU SHOULD ASK THE NEAREST LAW ENFORCEMENT AGENCY TO RELAY YOUR
SEVERE WEATHER REPORTS TO THE LOCAL NATIONAL WEATHER SERVICE OFFICE.
 
PLEASE LISTEN TO YOUR LOCAL RADIO...TV OR NOAA WEATHER RADIO STATION
FOR LATER STATEMENTS OR WARNINGS REGbARDING THIS SEVERE WEATHER EVENT.

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, May 20, 5:14 PM CDT, 1 hour 57 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANTONIO TX
515 PM CDT WED MAY 20 1987

HONDO RADAR INDICATES A THUNDERSTORM HAS DEVELOPED IN THE DILLEY AREA...
IN SOUTHERN FRIO COUNTY...DURING THE PAST HALF HOUR.

THIS THUNDERSTORM LIKELY CONTAINS SMALL HAIL...FREQUENT LIGHTNING...
GUSTY WINDS AND LOCALLY HEAVY RAIN WHICH MAY CAUSE LOCALIZED FLOODING
OF LOW-LYING AREAS IN AND AROUND DILLEY AND SOUTHERN FRIO COUNTY.  THE
FRIO RIVER MAY COLLECT SOME OF THIS RUNOFF AND REFLECT SMALL RISES
DOWNSTREAM BELOW DILLEY TONIGHT.

THE MOVEMENT OF THIS THUNDERSTORM IS TOWARD THE NORTHEAST...WHICH WILL
TRACK IT ALONG INTERSTATE 35.  TRAVEL BETWEEN DEVINE...PEARSALL AND
DILLEY MAY BE RESTRICTED BY HEAVY RAIN...SLICK ROADWAYS AND REDUCED
VISIBILITY FOR ANOTHER HOUR OR SO.

ADDITIONAL STATEMENTS OR WARNINGS WILL BE ISSUED AS CONDITIONS
WARRANT...SO PLEASE STAY TUNED.

Special weather statement, May 20, 6:06 PM CDT, 1 hour 5 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN ANTONIO TX
610 PM CDT WED MAY 20 1987

HONDO RADAR INDICATES A THUNDERSTORM HAS DEVELOPED BETWEEN SAN ANTONIO
AND FLORESVILLE...IN EXTREME WESTERN WILSON COUNTY.

THIS THUNDERSTORM LIKELY CONTAINS SMALL HAIL...FREQUENT LIGHTNING...
GUSTY WINDS AND LOCALLY HEAVY RAIN WHICH MAY CAUSE LOCALIZED FLOODING
OF LOW-LYING AREAS BETWEEN SAN ANTONIO AND FLORESVILLE.  FISHERMEN AND
BOATERS CLOSE TO BRAUNIG LAKE AND CALAVERAS LAKE SHOULD SEEK SHELTER
AND MOVE TO SHORE AND AWAY FROM THE WATER AT ONCE.

THE MOVEMENT OF THIS THUNDERSTORM WILL TAKE IT ACROSS EXTREME EASTERN
BEXAR COUNTY...TO THE EAST OF THE CITY OF SAN ANTONIO.  MOTORISTS ON
US 181 SHOULD BE ALERT FOR REDUCED VISIBILITIES IN HEAVY RAIN...AS
WELL AS SLICK AND WET ROADS AND HIGHWAYS.

ADDITIONAL STATEMENTS OR WARNINGS WILL BE ISSUED AS CONDITIONS
WARRANT...SO PLEASE STAY TUNED.

Local storm report, May 20, 7:04 PM CDT, 7 minutes before

STORM REPORT
NATIONAL WEATHER SERVICE SAN ANTONIO TX
700 PM CDT WED MAY 20 1987

TIME         EVENT

 540 PM      PEA SIZE HAIL AT DERBY...FRIO COUNTY
 618 PM      MARBLE SIZE HAIL IN DILLEY...FRIO COUNTY
 619 PM      MARBLE SIZE HAIL AT FAIRVIEW...WILSON COUNTY
 625 PM      PEA SIZE HAIL IN CHARLOTTE...ATASCOSA COUNTY
 626 PM      PEA SIZE HAIL AT LAKE CALAVARAS...BEXAR COUNTY
 630 PM      HAIL SIZE UNKNOWN...WESTERN WILSON COUNTY
 635 PM      S4 INCH DIAMETER HAIL AT DILLEY...FRIO COUNTY
 647 PM      PEA TO GOLF BALL SIZE HAIL SOUTHEAST OF LAKE CALAVARAS
             ...BEXAR COUNTY

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 7:38 PM CDT	Severe Thunderstorm Warning	EWX	Atascosa, Frio	67 min
May 20, 7:42 PM CDT	Severe Thunderstorm Warning	EWX	Comal	63 min
May 20, 8:34 PM CDT	Severe Thunderstorm Warning	EWX	Blanco, Hays	56 min
May 20, 8:50 PM CDT	Severe Thunderstorm Warning	EWX	Val Verde	56 min
May 20, 8:56 PM CDT	Severe Thunderstorm Warning	EWX	Maverick	64 min
May 20, 9:00 PM CDT	Tornado Warning	EWX	Uvalde, Zavala	60 min
May 20, 9:03 PM CDT	Severe Thunderstorm Warning	EWX	Atascosa, Frio	57 min
May 20, 9:27 PM CDT	Severe Thunderstorm Warning	EWX	Travis	63 min
May 20, 9:27 PM CDT	Tornado Warning	EWX	Val Verde	58 min
May 20, 9:47 PM CDT	Severe Thunderstorm Warning	EWX	Kinney	58 min
May 20, 10:20 PM CDT	Severe Thunderstorm Warning	EWX	Val Verde	60 min
May 20, 10:37 PM CDT	Severe Thunderstorm Warning	EWX	Edwards	68 min
May 20, 10:42 PM CDT	Severe Thunderstorm Warning	EWX	Medina, Uvalde, Zavala	63 min
May 20, 11:47 PM CDT	Severe Thunderstorm Warning	EWX	Medina, Uvalde, Zavala	58 min
May 21, 1:00 AM CDT	Severe Thunderstorm Warning	EWX	Uvalde	60 min
May 21, 6:17 AM CDT	Flash Flood Warning	EWX	Bexar	3 hr
May 21, 6:23 PM CDT	Severe Thunderstorm Warning	EWX	Llano	67 min

Nearby

Severe Thunderstorm Warnings in Texas, 1987 Every severe thunderstorm warning in 1987

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.