Alert archive / Texas / Severe Thunderstorm Warnings in 2003

Severe Thunderstorm Warning 42, NWS Austin/San Antonio, TX

April 20, 2003Zavala County, Texas

NWS Austin/San Antonio, TX issued this severe thunderstorm warning at Apr 20, 2003, 4:03 AM CDT for Zavala County, Texas. It was in force for 57 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Apr 20, 2003, 4:03 AM CDT (09:03 UTC)
Expired
Apr 20, 2003, 5:00 AM CDT
In force
57 min
Issued by
NWS Austin/San Antonio, TX
Area
Counties, with a storm outline in the text

County Zavala County, TX

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this severe thunderstorm warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Del Rio, TX (KDRT), launched 00:00Z, 9.1 hours before the alert went out and 113 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, Del Rio, TX at 00:00Z on 2003-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1268 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, Del Rio, TX at 00:00Z on 2003-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -78 square meters per square second.1939587897Sfc1 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
1268 J/kg
Mixed-layer CIN
-49 J/kg
Mixed-layer LCL
1819 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
-78 m²/s²
0-3 km storm-relative helicity
75 m²/s²
Significant tornado parameter
-0.1
Supercell composite
-2.9

Open this sounding in Storm Lab

The text

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

734 
WUUS54 KEWX 200903
SVRSAT
TXC507-201000-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
402 AM CDT SUN APR 20 2003

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR THE FOLLOWING COUNTIES IN TEXAS...
  ZAVALA

* UNTIL 500 AM CDT

* AT 402 AM...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM 10 MILES SOUTHWEST OF LA PRYOR...MOVING
  EAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE...
  NEAR LA PRYOR AT 415 AM

LARGE HAIL IS POSSIBLE WITH THIS SEVERE THUNDERSTORM. IF YOU ARE IN 
THE PATH OF THE STORM...PUT YOUR CAR IN A GARAGE AND MOVE TO A 
SUBSTANTIAL SHELTER.


LAT...LON 2903 10007 2866 10006 2867 9943 2906 9945

$$

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.

NWS Austin/San Antonio, TX wrote its last area forecast discussion before this severe thunderstorm warning went out at Apr 20, 2:40 AM CDT, 1 hour 23 minutes earlier.

Area forecast discussion, Apr 20, 2:40 AM CDT, 1 hour 23 minutes before
SOUTH CENTRAL TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
240 AM CDT SUN APR 20 2003

EARLY THIS MORNING CONVECTION WAS FIRING FROM DEL RIO SOUTHWARD TO
NORMANDY MOVING NORTHEAST TOWARDS BRACKETTVILLE. THE DRYLINE JUST
WEST OF DEL RIO WAS PROVIDING THE LOW LEVEL FOCUS FOR CONVECTIVE
DEVELOPMENT...TRIGGERED BY A VORT MAX IN THE SOUTHWEST FLOW ALOFT
MOVING OUT OF MEXICO.  THE 00Z DRT SOUNDING HAD A PW OF 1.05 INCHES.
THE COLD FRONT HAS MOVED THRU SAN ANGELO AND BROWNWOOD AND WILL BE
ENTERING THE HILL COUNTRY BEFORE SUNRISE. THE FRONT WILL PROVIDE
ADDITIONAL LOW LEVEL FOCUS FOR SCATTERED CONVECTION TODAY. THE COLD
FRONT WILL CONTINUE TO SINK SOUTHWARD TOWARDS THE COAST TODAY
BECOMING STATIONARY OVER SOUTH TEXAS. THE MOIST SOUTHWEST FLOW ALOFT
AND SHALLOW DEPTH OF THE COOL AIRMASS WILL ENABLE AN OVERRUNNING
PATTERN TO DEVELOP KEEPING MUCH OF THE CWFA CLOUDY THRU MONDAY. THE
FRONT WASHES OUT TUESDAY WITH GULF RETURN FLOW BECOMING ESTABLISHED.
A SERIES OF STRONGER SHORT WAVES IN THE SOUTHWEST FLOW ALOFT WILL
TRAVERSE THE CWFA WEDNESDAY AND THURSDAY INCREASING THE CHANCE FOR
TSTMS. RIDGING IN THE UPPER LEVELS OCCURS FRIDAY AND SATURDAY IN
RESPONSE TO THE NEXT UPPER TROF DROPPING DOWN INTO CALIFORNIA. THIS
WILL RESULT IN DRY WEATHER FOR FRIDAY AND SATURDAY.

PRELIMINARY NUMBERS...
AUS 074/054 072/051 068 31244
SAT 076/058 073/055 076 32344
DRT 081/058 077/059 069 22344

.EWX...NONE.

13/03
Hazardous weather outlook, Apr 19, 5:39 AM CDT, 22 hours 24 minutes before
TXZ171>173-183>194-202>209-217>225-228-201100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
539 AM CDT SAT APR 19 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS EVENING
AND TONIGHT EAST OF A LINE ROUGHLY FROM MOUNTAIN HOME TO VANDERPOOL
TO SABINAL TO FRIO TOWN TO DILLEY.  THUNDERSTORMS WILL FIRE ALONG
THE DRYLINE AND WORK EASTWARD.  THE MAIN THREATS FOR SEVERE WEATHER
WILL BE LARGE HAIL AND DAMAGING WINDS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS EVENING MAINLY IN THE EASTERN
HILL COUNTRY AND OVERNIGHT IN SOUTH CENTRAL TEXAS.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
WEATHER FEATURES WILL PRODUCE A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS SUNDAY NIGHT AND MONDAY AND A CHANCE ON TUESDAY.
HOWEVER...NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 20, 3:11 AM CDTSevere Thunderstorm WarningEWXMaverick19 min

Nearby

Severe Thunderstorm Warnings in Texas, 2003Every severe thunderstorm warning in 2003

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.