Alert archive / Texas / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 79, NWS Austin/San Antonio, TX

May 10, 1999Williamson County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at May 10, 1999, 10:02 AM CDT for Williamson County, Texas. It was in force for 58 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
May 10, 1999, 10:02 AM CDT (15:02 UTC)
Expired
May 10, 1999, 11:00 AM CDT
In force
58 min
Issued by
NWS Austin/San Antonio, TX
Area
Whole counties

County Williamson County, TX

The radar

The Ft Hood radar (KGRK), 22 km from the middle of the area, began a volume at 15:03 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

Fort Worth, TX (KFWD), launched 12:00Z, 3.0 hours before the alert went out and 245 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, Fort Worth, TX at 12:00Z on 1999-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 8 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, Fort Worth, TX at 12:00Z on 1999-05-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 126 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
8 J/kg
Mixed-layer CIN
-449 J/kg
Mixed-layer LCL
927 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
126 m²/s²
0-3 km storm-relative helicity
276 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 101502 RRA
SVRSAT
TXC491-101600-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1002 AM CDT MON MAY 10 1999

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

* SEVERE THUNDERSTORM WARNING FOR...
  WILLIAMSON COUNTY IN TEXAS

* UNTIL 1100 AM CDT

* AT 1000 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A SEVERE THUNDERSTORM MOVING INTO NORTHWEST WILLIAMSON COUNTY...D
  DEVELOPING EASTWARD NEAR 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  OVER PARTS OF WILLIAMSON COUNTY IN THE NEXT HOUR

DAMAGING WINDS AND LARGE HAIL ARE LIKELY. GO INSIDE A STURDY
BUILDING AND STAY AWAY FROM WINDOWS!

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 10, 6:00 AM CDT, 4 hours 2 minutes before
TXZ171-172-183>190-102300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
600 AM CDT MON MAY 10 1999

A FEW SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY THROUGH TONIGHT.
A MOIST AND UNSTABLE AIR MASS WILL REMAIN IN PLACE AND CREATE
THE POTENTIAL FOR ADDITIONAL SHOWERS AND THUNDERSTORMS ACROSS SOUTH
CENTRAL TEXAS AND THE HILL COUNTRY TODAY AND TONIGHT. INSTABILITIES
AND VERTICAL WIND SHEAR WILL BE SUFFICIENT FOR SEVERE WEATHER...BUT
THE LACK OF A SURFACE FOCUSING MECHANISM WILL LIKELY PREVENT THE
THUNDERSTORMS THAT DEVELOP FROM BECOMING SEVERE.

RAINFALL FROM THESE THUNDERSTORMS WILL TYPICALLY BE IN THE 1/4 TO
3/4 INCH RANGE WITH LOCAL AMOUNTS OVER AN INCH POSSIBLE.  THE
STRONGER STORMS COULD PRODUCE SMALL HAIL...GUSTY WINDS...AND
FREQUENT LIGHTNING.

THE HAZARDOUS WEATHER OUTLOOK NORMALLY WILL BE UPDATED BY MEANS OF
THE ZONE FORECASTS...SHORT TERM FORECAST...WATCHES...WARNINGS AND
ADVISORIES.  THE HAZARDOUS WEATHER OUTLOOK ITSELF WILL BE UPDATED
ONLY IF UNEXPECTED HAZARDOUS WEATHER DEVELOPS OR IF EXPECTED
HAZARDOUS WEATHER NO LONGER IS FORECAST TO DEVELOP.

FOR INFORMATION ON WEATHER THREATS IN AREAS SURROUNDING SOUTH CENTRAL
TEXAS...PLEASE REFER TO THE HAZARDOUS WEATHER OUTLOOKS FROM NWS
OFFICES IN MIDLAND...SAN ANGELO...FORT WORTH...HOUSTON/GALVESTON
AND CORPUS CHRISTI.

The office that day

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

IssuedProductOfficeCountiesLasted
May 9, 11:07 PM CDTSevere Thunderstorm WarningEWXEdwards, Val Verde58 min
May 9, 11:58 PM CDTSevere Thunderstorm WarningEWXEdwards62 min
May 10, 12:18 AM CDTTornado WarningEWXEdwards62 min
May 10, 12:25 AM CDTFlash Flood WarningEWXEdwards3 hr
May 10, 12:56 AM CDTSevere Thunderstorm WarningEWXBurnet, Llano59 min
May 10, 1:08 AM CDTSevere Thunderstorm WarningEWXEdwards62 min
May 10, 11:01 AM CDTSevere Thunderstorm WarningEWXWilliamson59 min
May 10, 1:37 PM CDTFlash Flood WarningEWXBurnet, Llano3 hr
May 10, 2:08 PM CDTFlash Flood WarningEWXWilliamson2 hr
May 10, 2:40 PM CDTSevere Thunderstorm WarningEWXTravis, Williamson65 min
May 10, 3:49 PM CDTSevere Thunderstorm WarningEWXLee56 min
May 10, 4:50 PM CDTFlash Flood WarningEWXWilliamson3 hr
May 10, 5:05 PM CDTSevere Thunderstorm WarningEWXTravis, Williamson45 min
May 10, 6:57 PM CDTSevere Thunderstorm WarningEWXCaldwell, Gonzales, Guadalupe48 min

Nearby

Severe Thunderstorm Warnings in Texas, 1999Every severe thunderstorm warning in 1999

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.