Alert archive / Texas / Severe Thunderstorm Warnings in 2011
Severe Thunderstorm Warning 71, NWS Austin/San Antonio, TX
NWS Austin/San Antonio, TX issued this severe thunderstorm warning at May 20, 2011, 8:04 PM CDT for 4 counties in Texas. It was in force for 26 min. 5 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- May 20, 2011, 8:04 PM CDT (01:04 UTC)
- Expired
- May 20, 2011, 8:30 PM CDT
- In force
- 26 min
- Issued by
- NWS Austin/San Antonio, TX
- Area
- Storm-based polygon
Counties Bastrop County, TX, Caldwell County, TX, Hays County, TX, Travis County, TX
The radar
The Austin/San Antonio radar (KEWX), 52 km from the middle of the area, began a volume at 01:05 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| May 20, 8:18 PM CDT | HAIL 1 | 2 Se Driftwood, TX | PEA TO QUARTER SIZE HAIL ALONG WITH AN INCH OF RAINFALL IN LESS THAN AN HOUR. |
| May 20, 8:20 PM CDT | HAIL 1 | 4 Ssw Dripping Springs, TX | PEA TO QUARTER SIZE HAIL NEAR DRIPPING SPRINGS. |
| May 20, 8:20 PM CDT | HAIL 1 | Driftwood, TX | NICKEL TO QUARTER SIZE HAIL |
| May 20, 8:32 PM CDT | HAIL 1 | 2 Se Driftwood, TX | PEA TO QUARTER SIZE HAIL ALONG WITH AN INCH OF RAINFALL IN LESS THAN AN HOUR. |
| May 20, 8:40 PM CDT | HAIL 0.25 | Tanglewood Forest, TX |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 20, 12:28 PM CDT | Severe Thunderstorm Watch | SPC | 10 hr |
The nearest sounding before it
Corpus Christi, TX (KCRP), launched 00:00Z, 1.1 hours before the alert went out and 273 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.
- Mixed-layer CAPE
- 4855 J/kg
- Mixed-layer CIN
- -70 J/kg
- Mixed-layer LCL
- 870 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 59 m²/s²
- 0-3 km storm-relative helicity
- 41 m²/s²
- Significant tornado parameter
- 1.3
- Supercell composite
- 9.0
The text
As transmitted, in the capitals the NWS used until 2016.
884 WUUS54 KEWX 210104 SVREWX TXC021-055-209-453-210130- /O.NEW.KEWX.SV.W.0071.110521T0104Z-110521T0130Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 804 PM CDT FRI MAY 20 2011 THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... EXTREME WEST CENTRAL BASTROP COUNTY... EXTREME NORTH CENTRAL CALDWELL COUNTY... NORTHERN HAYS COUNTY... SOUTH CENTRAL TRAVIS COUNTY... * UNTIL 830 PM CDT. * AT 800 PM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL. THIS STORM WAS LOCATED NEAR DRIFTWOOD...OR NEAR DRIPPING SPRINGS...AND MOVING EAST AT 30 MPH. * SOME LOCATIONS IN THE WARNING INCLUDE BUDA...TANGLEWOOD FOREST... AUSTIN BERGSTROM INT AP...ONION CREEK AND MUSTANG RIDGE. PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER... PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS. && LAT...LON 3023 9766 3004 9762 3005 9815 3016 9817 TIME...MOT...LOC 0104Z 258DEG 24KT 3015 9800 $$
1 follow-up statement
392 WWUS54 KEWX 210117 SVSEWX SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 817 PM CDT FRI MAY 20 2011 TXC021-055-210127- /O.CAN.KEWX.SV.W.0071.000000T0000Z-110521T0130Z/ BASTROP TX-CALDWELL TX- 817 PM CDT FRI MAY 20 2011 ...THE SEVERE THUNDERSTORM WARNING FOR EXTREME NORTH CENTRAL CALDWELL AND EXTREME WEST CENTRAL BASTROP COUNTIES IS CANCELLED... LAT...LON 3012 9776 3007 9811 3017 9812 3023 9766 TIME...MOT...LOC 0117Z 258DEG 24KT 3017 9790 $$ TXC209-453-210130- /O.CON.KEWX.SV.W.0071.000000T0000Z-110521T0130Z/ TRAVIS TX-HAYS TX- 817 PM CDT FRI MAY 20 2011 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM CDT FOR CENTRAL HAYS AND SOUTH CENTRAL TRAVIS COUNTIES... AT 814 PM CDT...NWS METEOROLOGISTS CONTINUED TO DETECT A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL. THIS STORM WAS LOCATED NEAR HAYS...OR NEAR TANGLEWOOD FOREST...MOVING EAST AT 30 MPH. SOME LOCATIONS IN THE WARNING AREA INCLUDE MANCHACA...SAN LEANNA AND ONION CREEK. PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER... PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS. && LAT...LON 3012 9776 3007 9811 3017 9812 3023 9766 TIME...MOT...LOC 0117Z 258DEG 24KT 3017 9790 $$
The office that day
Everything else NWS Austin/San Antonio, TX issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 20, 7:49 PM CDT | Severe Thunderstorm Warning | EWX | Bastrop, Hays, Travis, Williamson | 41 min |
| May 20, 8:27 PM CDT | Severe Thunderstorm Warning | EWX | Caldwell, Hays, Travis | 23 min |
| May 20, 8:58 PM CDT | Severe Thunderstorm Warning | EWX | Hays, Travis | 32 min |
| May 20, 8:59 PM CDT | Severe Thunderstorm Warning | EWX | Bastrop, Lee, Travis, Williamson | 61 min |
| May 20, 9:22 PM CDT | Severe Thunderstorm Warning | EWX | Bastrop, Caldwell, Lee, Travis | 38 min |
| May 20, 10:02 PM CDT | Severe Thunderstorm Warning | EWX | Bastrop, Caldwell | 43 min |
| May 20, 10:32 PM CDT | Severe Thunderstorm Warning | EWX | Caldwell, Guadalupe, Hays | 43 min |
| May 21, 4:58 PM CDT | Severe Thunderstorm Warning | EWX | Burnet, Llano, Williamson | 47 min |
| May 21, 5:44 PM CDT | Severe Thunderstorm Warning | EWX | Burnet, Williamson | 46 min |
| May 21, 6:00 PM CDT | Areal Flood Advisory | EWX | Burnet, Llano | 2 hr |
| May 21, 6:00 PM CDT | Severe Thunderstorm Warning | EWX | Burnet, Llano | 45 min |
| May 21, 6:29 PM CDT | Severe Thunderstorm Warning | EWX | Burnet, Williamson | 46 min |
| May 21, 6:52 PM CDT | Severe Thunderstorm Warning | EWX | Burnet, Williamson | 38 min |
| May 21, 6:59 PM CDT | Tornado Warning | EWX | Burnet | 31 min |
Nearby
Severe Thunderstorm Warnings in Texas, 2011Every severe thunderstorm warning in 2011
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.