Alert archive / Texas / Special Weather Statements in 2017

Special Weather Statement, NWS Austin/San Antonio, TX

July 23, 2017Llano County, Texas

NWS Austin/San Antonio, TX issued this special weather statement at Jul 23, 2017, 2:21 PM CDT for Llano County, Texas. It was in force for 24 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
Jul 23, 2017, 2:21 PM CDT (19:21 UTC)
Expired
Jul 23, 2017, 2:45 PM CDT
In force
24 min
Issued by
NWS Austin/San Antonio, TX

County Llano County, TX

The radar

The Ft Hood radar (KGRK), 136 km from the middle of the area, began a volume at 19:22 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

Del Rio, TX (KDLF), launched 12:00Z, 7.4 hours before the alert went out and 248 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 12:00Z on 2017-07-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 501 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Del Rio, TX at 12:00Z on 2017-07-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.1939Sfc1 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
501 J/kg
Mixed-layer CIN
-233 J/kg
Mixed-layer LCL
1356 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
9 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

622 
WWUS84 KEWX 231921
SPSEWX

Special Weather Statement
National Weather Service Austin/San Antonio TX
221 PM CDT SUN JUL 23 2017
 
TXZ171-231945-
Llano TX-
221 PM CDT SUN JUL 23 2017

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL LLANO COUNTY UNTIL
245 PM CDT...

At 220 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from 6 miles southwest of Valley Spring to near
Llano. Movement was southwest at 15 mph.

Pea to dime size hail and winds in excess of 40 mph will be possible 
with these storms.

Locations impacted include...
Llano and Castell. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3081 9862 3061 9871 3061 9896 3076 9897
      3080 9896
TIME...MOT...LOC 1920Z 059DEG 13KT 3078 9888 3076 9872 

$$

RUNYEN

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 2:02 PM CDTSpecial Weather StatementEWXWilliamson28 min
Jul 23, 2:04 PM CDTSpecial Weather StatementEWXBurnet26 min
Jul 23, 2:51 PM CDTSpecial Weather StatementEWXLlano39 min
Jul 23, 3:01 PM CDTSpecial Weather StatementEWXTravis29 min
Jul 23, 3:17 PM CDTSpecial Weather StatementEWXGillespie28 min
Jul 23, 3:27 PM CDTSpecial Weather StatementEWXHays33 min
Jul 23, 3:36 PM CDTSevere Thunderstorm WarningEWXBlanco, Hays38 min
Jul 23, 3:42 PM CDTSpecial Weather StatementEWXGillespie48 min

Nearby

Special Weather Statements in Texas, 2017Every special weather statement in 2017

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.