Alert archive / Texas / Tornado Warnings in 2018

Tornado Warning 3, NWS Austin/San Antonio, TX

May 20, 2018Williamson County, Texas

NWS Austin/San Antonio, TX issued this tornado warning at May 20, 2018, 8:33 AM CDT for Williamson County, Texas. It was in force for 27 min. 3 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, 2018, 8:33 AM CDT (13:33 UTC)
Expired: May 20, 2018, 9:00 AM CDT
In force: 27 min
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.75 in

County Williamson County, TX

The radar

The Ft Hood radar (KGRK), 42 km from the middle of the area, began a volume at 13:33 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, 8:41 AM CDT	TORNADO	3 Ne Leander, TX	AMATEUR RADIO OPERATOR REPORTS SHINGLE DAMAGE TO A HOME, AN ABOVE GROUND POOL DEMOLISHED, AND A TREE DOWN AT 3336 HERO WAY IN LEANDER, TX.
May 20, 8:41 AM CDT	TORNADO	3 Ne Leander, TX	REPORT OF ROOF DAMAGE TO THREE STRUCTURES AT 3450 HERO WAY IN LEANDER, TX.
May 20, 8:43 AM CDT	TORNADO	5 E Liberty Hill, TX	WILLIAMSON COUNTY EMC REPORTS TREE DAMAGE AT THE SANTA RITA RANCH NORTH SUBDIVISION OFF OF RONALD REAGAN BLVD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Fort Worth, TX (KFWD), launched 12:00Z, 1.6 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: 383 J/kg
Mixed-layer CIN: -80 J/kg
Mixed-layer LCL: 769 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 125 m²/s²
0-3 km storm-relative helicity: 145 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.5

Open this sounding in Storm Lab

The text

As transmitted.

802 
WFUS54 KEWX 201333
TOREWX
TXC491-201400-
/O.NEW.KEWX.TO.W.0003.180520T1333Z-180520T1400Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Austin/San Antonio TX
833 AM CDT SUN MAY 20 2018

The National Weather Service in Austin San Antonio has issued a

* Tornado Warning for...
  Northwestern Williamson County in south central Texas...

* Until 900 AM CDT
    
* At 833 AM CDT, a severe thunderstorm capable of producing a tornado
  was located near Leander, or 7 miles north of Cedar Park, moving
  north at 15 mph.

  HAZARD...Tornado. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely. 

* Locations impacted include...
  Georgetown, Leander, Liberty Hill, Andice and Seward Junction. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 3059 9778 3059 9786 3080 9792 3080 9773
TIME...MOT...LOC 1333Z 181DEG 13KT 3062 9783 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

PLATT

2 follow-up statements

152 
WWUS54 KEWX 201340
SVSEWX

Severe Weather Statement
National Weather Service Austin/San Antonio TX
840 AM CDT SUN MAY 20 2018

TXC491-201400-
/O.CON.KEWX.TO.W.0003.000000T0000Z-180520T1400Z/
Williamson TX-
840 AM CDT SUN MAY 20 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 900 AM CDT FOR
NORTHWESTERN WILLIAMSON COUNTY...
    
At 837 AM CDT, the Leander Fire Department reported a tornado was 
located near Leander, or 8 miles north of Cedar Park, moving north 
at 15 mph.

HAZARD...Damaging tornado. 

SOURCE...Fire Department confirmed tornado. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

Locations impacted include...
Georgetown, Leander, Liberty Hill, Andice and Seward Junction. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement or an interior room on the lowest floor of a sturdy
building. Avoid windows. If you are outdoors, in a mobile home, or in
a vehicle, move to the closest substantial shelter and protect
yourself from flying debris.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 3060 9779 3060 9786 3080 9792 3080 9773
TIME...MOT...LOC 1337Z 181DEG 13KT 3063 9783 

TORNADO...OBSERVED
HAIL...<.75IN

$$

PLATT

618 
WWUS54 KEWX 201358
SVSEWX

Severe Weather Statement
National Weather Service Austin/San Antonio TX
858 AM CDT SUN MAY 20 2018

TXC491-201408-
/O.EXP.KEWX.TO.W.0003.000000T0000Z-180520T1400Z/
Williamson TX-
858 AM CDT SUN MAY 20 2018

...THE TORNADO WARNING FOR NORTHWESTERN WILLIAMSON COUNTY WILL EXPIRE
AT 900 AM CDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with this thunderstorm.

LAT...LON 3060 9779 3060 9786 3080 9792 3080 9773
TIME...MOT...LOC 1358Z 167DEG 18KT 3073 9786 

$$

PLATT

The office that day

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

Issued	Product	Office	Counties	Lasted
May 20, 10:47 AM CDT	Areal Flood Advisory	EWX	Burnet	3 hr
May 20, 12:09 PM CDT	Areal Flood Advisory	EWX	Val Verde	3 hr
May 20, 12:20 PM CDT	Special Weather Statement	EWX	Edwards	55 min
May 20, 12:56 PM CDT	Flash Flood Warning	EWX	Edwards, Val Verde	3 hr
May 20, 1:03 PM CDT	Special Weather Statement	EWX	Kinney	42 min
May 20, 1:04 PM CDT	Areal Flood Advisory	EWX	Comal, Hays	116 min
May 20, 1:32 PM CDT	Severe Thunderstorm Warning	EWX	Kinney, Uvalde	58 min
May 20, 1:39 PM CDT	Areal Flood Advisory	EWX	Bastrop, Travis	3 hr
May 20, 1:59 PM CDT	Areal Flood Advisory	EWX	Kinney	2 hr
May 20, 2:31 PM CDT	Severe Thunderstorm Warning	EWX	Uvalde	59 min
May 20, 3:14 PM CDT	Areal Flood Advisory	EWX	Uvalde	3 hr
May 20, 3:30 PM CDT	Special Weather Statement	EWX	Medina	60 min
May 20, 4:01 PM CDT	Areal Flood Advisory	EWX	Medina	3 hr
May 20, 4:07 PM CDT	Areal Flood Advisory	EWX	DeWitt, Fayette, Gonzales, Lavaca	3 hr
May 20, 5:10 PM CDT	Areal Flood Advisory	EWX	Atascosa, Bexar, Karnes, Wilson	4 hr
May 20, 5:10 PM CDT	Special Weather Statement	EWX	Atascosa	50 min
May 20, 5:31 PM CDT	Special Weather Statement	EWX	Bexar	44 min
May 20, 5:56 PM CDT	Special Weather Statement	EWX	Atascosa, Wilson	49 min

Nearby

Tornado Warnings in Texas, 2018 Every tornado warning in 2018 Tornadoes in 2018

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.