Alert archive / Texas / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 80, NWS Austin/San Antonio, TX

May 10, 1999Williamson County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at May 10, 1999, 11:01 AM CDT for Williamson County, Texas. It was in force for 59 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, 11:01 AM CDT (16:01 UTC)
Expired: May 10, 1999, 12:00 PM CDT
In force: 59 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 16:02 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, 4.0 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-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: 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.

999 
WUUS1 KSAT 101603 RRA
SVRSAT
TXC491-101700-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1101 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 NOON

* AT 11 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A SEVERE THUNDERSTORMS OVER PARTS OF WILLIAMSON COUNTY...
  MOVING AND DEVELOPING TO THE SOUTH AND EAST AT 20 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, 5 hours 1 minute 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.

Issued	Product	Office	Counties	Lasted
May 9, 11:07 PM CDT	Severe Thunderstorm Warning	EWX	Edwards, Val Verde	58 min
May 9, 11:58 PM CDT	Severe Thunderstorm Warning	EWX	Edwards	62 min
May 10, 12:18 AM CDT	Tornado Warning	EWX	Edwards	62 min
May 10, 12:25 AM CDT	Flash Flood Warning	EWX	Edwards	3 hr
May 10, 12:56 AM CDT	Severe Thunderstorm Warning	EWX	Burnet, Llano	59 min
May 10, 1:08 AM CDT	Severe Thunderstorm Warning	EWX	Edwards	62 min
May 10, 10:02 AM CDT	Severe Thunderstorm Warning	EWX	Williamson	58 min
May 10, 1:37 PM CDT	Flash Flood Warning	EWX	Burnet, Llano	3 hr
May 10, 2:08 PM CDT	Flash Flood Warning	EWX	Williamson	2 hr
May 10, 2:40 PM CDT	Severe Thunderstorm Warning	EWX	Travis, Williamson	65 min
May 10, 3:49 PM CDT	Severe Thunderstorm Warning	EWX	Lee	56 min
May 10, 4:50 PM CDT	Flash Flood Warning	EWX	Williamson	3 hr
May 10, 5:05 PM CDT	Severe Thunderstorm Warning	EWX	Travis, Williamson	45 min
May 10, 6:57 PM CDT	Severe Thunderstorm Warning	EWX	Caldwell, Gonzales, Guadalupe	48 min

Nearby

Severe Thunderstorm Warnings in Texas, 1999 Every 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.