Alert archive / Texas / Flash Flood Warnings in 1987

Flash Flood Warning 10, NWS Austin/San Antonio, TX

May 21, 1987Bexar County, Texas

NWS Austin/San Antonio, TX issued this flash flood warning at May 21, 1987, 6:17 AM CDT for Bexar County, Texas. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
May 21, 1987, 6:17 AM CDT (11:17 UTC)
Expired
May 21, 1987, 9:15 AM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Whole counties

County Bexar 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, 11.3 hours before the alert went out and 171 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, Victoria Regiona, TX at 00:00Z on 1987-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2069 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, Victoria Regiona, TX at 00:00Z on 1987-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.193958Sfc1 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
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 211117
FFWSAT
TXC029-211415-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN ANTONIO TX
617 AM CDT THU MAY 21 1987
 
THE NATIONAL WEATHER SERVICE HAS ISSUED A FLASH FLOOD WARNING
EFFECTIVE UNTIL  915 AM CDT FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTH TEXAS
          ...BEXAR
 
THE BEXAR COUNTY SHERIFFS DEPARTMENT REPORTS LOW WATER CROSSINGS OVER
THE NORTHERN PORTION OF THE COUNTY ARE BEGINNING TO FILL.  ADDITIONAL
HEAVY RAIN IS EXPECTED THROUGH AT LEAST THE NEXT HOUR AS INTENSE
THUNDERSTORMS CONTINUE TO DEVELOP IN WESTERN BEXAR COUNTY.
 
A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR HAS BEEN
REPORTED.
 
REMEMBER...DEATHS DURING FLASH FLOODIN9G ARE FREQUENTLY RELATED TO
MOTORISTS DRIVING INTO FLOODED LOW WATER CROSSINGS OR FROM CHILDREN
PLAYING NEAR FLOODED STREAMS OR DRAINAGE AREAS.

What forecasters said that day

The local office's own words before this flash flood 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 21, 12:44 AM CDT, 5 hours 33 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DEL RIO TX
1244 AM CDT THU MAY 21 1987

...THUNDERSTORMS CONTINUE IN DEL RIO AND VAL VERDE COUNTY...

AT 1240 AM CDT MODERATE THUNDERSTORM ACTIVITY WAS OVER DEL RIO AND
EXTENDED NORTHEAST TO THE VAL VERDE COUNTY LINE. A LARGE THUNDERSTORM
WAS 10 MILES NORTHEAST OF DEL RIO. INTENSE THUNDERSTORMS CONTINUE
EAST OF VAL VERDE COUNTY ALONG HIGHWAY 90. MOVEMENT OF THE STORMS WAS
TO THE NORTHEAST AT 15 MILES AN HOUR.

HEAVY RAIN...GUSTY WINDS...SMALL HAIL AND DANGEROUS LIGHTNING ARE
LIKELY FROM THESE THUNDERSTORMS.
Special weather statement, May 21, 3:25 AM CDT, 2 hours 52 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE DEL RIO TX
325 AM CDT THU MAY 21 1987

AT 320 AM CDT THUNDERSTORMS WERE RAPIDLY FORMING SOUTHWEST OF DEL
RIO. THE CLOSEST THUNDERSTORMS WERE 10 MILES SOUTHWEST WITH THE
LARGEST LOCATED 25 MILES SOUTHWEST OF DEL RIO. MOVEMENT OF THE STORMS
WAS TO THE NORTHEAST AT 15 MILES AN HOUR.

BOATERS ON LAKE AMISTAD SHOULD BE PREPARED TO SEEK SAFE HARBOR AS
THESE THUNDERSTORMS WILL LIKELY MOVE INTO THE LAKE AgREA WITHIN THE
HOUR.

HEAVY RAIN...GUSTY WINDS...SMALL HAIL AND DANGEROUS LIGHTNING ARE
LIKELY FROM THESE THUNDERSTORMS.

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 7:11 PM CDTSevere Thunderstorm WarningEWXWilson64 min
May 20, 7:38 PM CDTSevere Thunderstorm WarningEWXAtascosa, Frio67 min
May 20, 7:42 PM CDTSevere Thunderstorm WarningEWXComal63 min
May 20, 8:34 PM CDTSevere Thunderstorm WarningEWXBlanco, Hays56 min
May 20, 8:50 PM CDTSevere Thunderstorm WarningEWXVal Verde56 min
May 20, 8:56 PM CDTSevere Thunderstorm WarningEWXMaverick64 min
May 20, 9:00 PM CDTTornado WarningEWXUvalde, Zavala60 min
May 20, 9:03 PM CDTSevere Thunderstorm WarningEWXAtascosa, Frio57 min
May 20, 9:27 PM CDTSevere Thunderstorm WarningEWXTravis63 min
May 20, 9:27 PM CDTTornado WarningEWXVal Verde58 min
May 20, 9:47 PM CDTSevere Thunderstorm WarningEWXKinney58 min
May 20, 10:20 PM CDTSevere Thunderstorm WarningEWXVal Verde60 min
May 20, 10:37 PM CDTSevere Thunderstorm WarningEWXEdwards68 min
May 20, 10:42 PM CDTSevere Thunderstorm WarningEWXMedina, Uvalde, Zavala63 min
May 20, 11:47 PM CDTSevere Thunderstorm WarningEWXMedina, Uvalde, Zavala58 min
May 21, 1:00 AM CDTSevere Thunderstorm WarningEWXUvalde60 min
May 21, 6:23 PM CDTSevere Thunderstorm WarningEWXLlano67 min

Nearby

Flash Flood Warnings in Texas, 1987Every flash flood 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.