Alert archive / Texas / Areal Flood Advisories in 2021

Areal Flood Advisory 202, NWS Austin/San Antonio, TX

July 29, 2021Williamson County, Texas

NWS Austin/San Antonio, TX issued this areal flood advisory at Jul 29, 2021, 7:17 PM CDT for Williamson County, Texas. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Jul 29, 2021, 7:17 PM CDT (00:17 UTC)
Expired
Jul 29, 2021, 10:30 PM CDT
In force
3 hr
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon

County Williamson County, TX

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 0.3 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-pSkew-T log-p diagram, Fort Worth, TX at 00:00Z on 2021-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1363 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, Fort Worth, TX at 00:00Z on 2021-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 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
1363 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
1966 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
13 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory 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 areal flood advisory went out at Jul 29, 6:46 PM CDT, 31 minutes earlier.

Area forecast discussion, Jul 29, 6:46 PM CDT, 31 minutes before
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Hazardous weather outlook, Jul 29, 8:40 AM CDT, 10 hours 37 minutes before
Hazardous Weather Outlook...UPDATED
National Weather Service Austin/San Antonio TX
840 AM CDT Thu Jul 29 2021

TXZ171>173-183>194-202>209-217>225-228-301345-
Llano-Burnet-Williamson-Val Verde-Edwards-Real-Kerr-Bandera-
Gillespie-Kendall-Blanco-Hays-Travis-Bastrop-Lee-Kinney-Uvalde-
Medina-Bexar-Comal-Guadalupe-Caldwell-Fayette-Maverick-Zavala-
Frio-Atascosa-Wilson-Karnes-Gonzales-De Witt-Lavaca-Dimmit-
840 AM CDT Thu Jul 29 2021

This Hazardous Weather Outlook is for South-Central Texas..

.DAY ONE...Today And Tonight.

Isolated to scattered thunderstorms are possible this afternoon
through early evening across the Hill Country and along and east
of the I-35 and I-37 corridors. There is a low risk that a few
storms could produce gusty winds in excess of 40 mph.

Elevated heat index values of 105 to 108 degrees are forecast
this afternoon along and east of the I-35 and I-37 corridors.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Elevated heat index values of 105 to 108 degrees are forecast
during the afternoon Friday through Sunday along and east of the
I-35 and I-37 corridors.

No other hazardous weather is forecast at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

In the hours before

Special weather statement, Jul 29, 4:34 PM CDT, 2 hours 43 minutes before
Special Weather Statement
National Weather Service Austin/San Antonio TX
434 PM CDT Thu Jul 29 2021

TXZ206-207-223-292215-
Guadalupe TX-Comal TX-Gonzales TX-
434 PM CDT Thu Jul 29 2021

...SIGNIFICANT WEATHER ADVISORY FOR GUADALUPE...NORTHWESTERN GONZALES
AND SOUTHEASTERN COMAL COUNTIES UNTIL 515 PM CDT...

At 434 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Zorn to near Kingsbury. Movement was
southwest at 10 mph.

Wind gusts up to 50 mph will be possible with these storms.

Locations impacted include...
New Braunfels, Schertz, Seguin, Cibolo, Universal City, Selma,
Luling, Garden Ridge, McQueeney, Marion, Kingsbury, Santa Clara, New
Berlin, Geronimo, Zorn, Zuehl, Nolte, Zipp, Bracken and Freiheit.

LAT...LON 2939 9779 2954 9822 2956 9824 2955 9826
      2956 9830 2960 9831 2961 9834 2980 9804
      2979 9801 2976 9800 2978 9797 2970 9774
      2968 9771 2967 9770 2967 9765 2964 9761
TIME...MOT...LOC 2134Z 044DEG 11KT 2973 9802 2964 9774

HAMPSHIRE
Special weather statement, Jul 29, 4:57 PM CDT, 2 hours 20 minutes before
Special Weather Statement
National Weather Service Austin/San Antonio TX
457 PM CDT Thu Jul 29 2021

TXZ223-292245-
Gonzales TX-
457 PM CDT Thu Jul 29 2021

...SIGNIFICANT WEATHER ADVISORY FOR WEST CENTRAL GONZALES COUNTY
UNTIL 545 PM CDT...

At 457 PM CDT, Doppler radar was tracking a strong thunderstorm over
Palmeto State Park, or near Luling, moving southwest at 25 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Palmeto State Park, Belmont, Leesville, Monthalia, Oak Forest and
Ottine.

LAT...LON 2957 9747 2929 9780 2935 9786 2937 9785
      2940 9779 2963 9761 2964 9761
TIME...MOT...LOC 2157Z 050DEG 21KT 2959 9761

HAMPSHIRE
Special weather statement, Jul 29, 5:13 PM CDT, 2 hours 4 minutes before
Special Weather Statement
National Weather Service Austin/San Antonio TX
513 PM CDT Thu Jul 29 2021

TXZ205>207-221-292300-
Guadalupe TX-Comal TX-Bexar TX-Wilson TX-
513 PM CDT Thu Jul 29 2021

...SIGNIFICANT WEATHER ADVISORY FOR GUADALUPE...NORTHEASTERN
WILSON...NORTHEASTERN BEXAR AND EASTERN COMAL COUNTIES UNTIL 600 PM
CDT...

At 513 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from Smithson Valley to Santa Clara to 11 miles
south of Kingsbury. Movement was southwest at 20 mph.

Wind gusts up to 50 mph will be possible with these storms.

Locations impacted include...
San Antonio, New Braunfels, Schertz, Seguin, Cibolo, Universal City,
Live Oak, Selma, Randolph AFB, Canyon Lake, Windcrest, Bulverde,
Garden Ridge, McQueeney, St. Hedwig, La Vernia, Marion, Kingsbury,
Santa Clara and New Berlin.

LAT...LON 2939 9829 2966 9849 2994 9830 2975 9807
      2958 9769 2935 9786 2928 9788
TIME...MOT...LOC 2213Z 023DEG 16KT 2981 9834 2959 9819 2948 9781

HAMPSHIRE
Special weather statement, Jul 29, 5:15 PM CDT, 2 hours 2 minutes before
Special Weather Statement
National Weather Service Austin/San Antonio TX
515 PM CDT Thu Jul 29 2021

TXZ173-292245-
Williamson TX-
515 PM CDT Thu Jul 29 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN WILLIAMSON COUNTY
UNTIL 545 PM CDT...

At 515 PM CDT, Doppler radar was tracking a strong thunderstorm near
Weir, or near Georgetown, moving southwest at 15 mph.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Round Rock, Cedar Park, Georgetown, Taylor, Serenada, Leander, Hutto,
Weir, Georgetown Dam, Brushy Creek, Jonah and Jollyville.

LAT...LON 3061 9749 3049 9762 3048 9764 3048 9768
      3047 9769 3046 9769 3045 9774 3061 9790
      3075 9762
TIME...MOT...LOC 2215Z 050DEG 12KT 3064 9763

HAMPSHIRE
Special weather statement, Jul 29, 5:32 PM CDT, 1 hour 45 minutes before
Special Weather Statement
National Weather Service Austin/San Antonio TX
532 PM CDT Thu Jul 29 2021

TXZ184-202-292315-
Kinney TX-Edwards TX-
532 PM CDT Thu Jul 29 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL KINNEY AND
SOUTHWESTERN EDWARDS COUNTIES UNTIL 615 PM CDT...

At 532 PM CDT, Doppler radar was tracking a strong thunderstorm 10
miles west of Barksdale, or 19 miles south of Rocksprings, moving
southwest at 15 mph.

Half inch hail and wind gusts up to 50 mph will be possible with this
storm.

Locations impacted include...
Kickapoo Cavern State Park.

LAT...LON 2984 10017 2967 10009 2949 10041 2974 10054
TIME...MOT...LOC 2232Z 065DEG 13KT 2973 10021

HAMPSHIRE
Special weather statement, Jul 29, 6:35 PM CDT, 42 minutes before
Special Weather Statement
National Weather Service Austin/San Antonio TX
635 PM CDT Thu Jul 29 2021

TXZ173-300015-
Williamson TX-
635 PM CDT Thu Jul 29 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL WILLIAMSON COUNTY UNTIL
715 PM CDT...

At 635 PM CDT, Doppler radar was tracking a strong thunderstorm near
Weir, or 8 miles northwest of Taylor, moving west at 10 mph.

Wind gusts up to 50 mph will be possible with this storm.

Locations impacted include...
Round Rock, Georgetown, Taylor, Serenada, Hutto, Weir, Georgetown
Dam, Brushy Creek, Jonah and Jollyville.

LAT...LON 3055 9744 3050 9757 3050 9760 3048 9764
      3048 9768 3046 9769 3045 9772 3070 9780
      3072 9749
TIME...MOT...LOC 2335Z 075DEG 8KT 3062 9755

HAMPSHIRE

Nearby

Areal Flood Advisories in Texas, 2021Every areal flood advisory in 2021

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.