Alert archive / Texas / Areal Flood Advisories in 2021

Areal Flood Advisory 207, NWS Austin/San Antonio, TX

August 1, 2021Kendall County, Texas

NWS Austin/San Antonio, TX issued this areal flood advisory at Aug 1, 2021, 11:02 PM CDT for Kendall County, Texas. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued: Aug 1, 2021, 11:02 PM CDT (04:02 UTC)
Expired: Aug 2, 2021, 2:15 AM CDT
In force: 3 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon

County Kendall County, TX

The radar

The Austin/San Antonio radar (KEWX), 71 km from the middle of the area, began a volume at 04:04 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 (KDRT), launched 00:00Z, 4.0 hours before the alert went out and 215 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: 619 J/kg
Mixed-layer CIN: -185 J/kg
Mixed-layer LCL: 1602 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 105 m²/s²
0-3 km storm-relative helicity: 154 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

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 Aug 1, 8:28 PM CDT, 2 hours 34 minutes earlier.

Area forecast discussion, Aug 1, 8:28 PM CDT, 2 hours 34 minutes before

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Hazardous weather outlook, Aug 1, 8:24 PM CDT, 2 hours 38 minutes before

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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
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        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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In the hours before

Special weather statement, Aug 1, 5:36 PM CDT, 5 hours 26 minutes before

Special Weather Statement
National Weather Service Austin/San Antonio TX
536 PM CDT Sun Aug 1 2021

TXZ206-012315-
Comal TX-
536 PM CDT Sun Aug 1 2021

...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL COMAL COUNTY UNTIL 615 PM
CDT...

At 536 PM CDT, Doppler radar was tracking a strong thunderstorm over
Spring Branch, or 11 miles west of Canyon Lake Dam, moving south at
10 mph.

Half inch hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Canyon Lake, Bulverde, Guadalupe River State Park, Spring Branch,
Smithson Valley, Timberwood Park, Anhalt, Honey Creek State Natural
Area and Specht Store.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 3001 9831 2975 9827 2974 9840 2975 9841
      2974 9842 2973 9848 2975 9853 2987 9850
      3001 9833
TIME...MOT...LOC 2236Z 000DEG 10KT 2989 9839

CP

Special weather statement, Aug 1, 6:01 PM CDT, 5 hours 1 minute before

Special Weather Statement
National Weather Service Austin/San Antonio TX
601 PM CDT Sun Aug 1 2021

TXZ187-189-204>206-020000-
Comal TX-Bexar TX-Medina TX-Bandera TX-Kendall TX-
601 PM CDT Sun Aug 1 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN MEDINA...
SOUTHEASTERN BANDERA...SOUTHERN KENDALL...NORTHWESTERN BEXAR AND
SOUTHWESTERN COMAL COUNTIES UNTIL 700 PM CDT...

At 601 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Hill Country State Natural Area to Pipe
Creek to near Boerne to Bergheim. Movement was southeast at 10 mph.

Half inch hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
San Antonio, Universal City, Live Oak, Boerne, Selma, Hondo, Bandera,
San Antonio Int Airport, Leon Valley, Helotes, Fair Oaks Ranch,
Bulverde, Shavano Park, Hollywood Park, Cross Mountain, Walnut Grove,
Bandera Falls, The Dominion, Mico and Kreutzberg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 2990 9855 2960 9830 2959 9831 2956 9830
      2936 9920 2962 9929 2979 9893 2978 9892
      2980 9891 2987 9877
TIME...MOT...LOC 2301Z 307DEG 7KT 2959 9920 2971 9894 2974 9871 2981
9857

CP

Special weather statement, Aug 1, 6:43 PM CDT, 4 hours 19 minutes before

Special Weather Statement
National Weather Service Austin/San Antonio TX
643 PM CDT Sun Aug 1 2021

TXZ187-204-205-020030-
Bexar TX-Medina TX-Bandera TX-
643 PM CDT Sun Aug 1 2021

...SIGNIFICANT WEATHER ADVISORY FOR EAST CENTRAL MEDINA...
SOUTHEASTERN BANDERA AND BEXAR COUNTIES UNTIL 730 PM CDT...

At 643 PM CDT, Doppler radar was tracking a strong thunderstorm over
Cross Mountain, or 11 miles southeast of Boerne, moving southeast at
15 mph.

Wind gusts of 50 to 55 mph will be possible with this storm.

Locations impacted include...
San Antonio, Schertz, Universal City, Live Oak, Selma, Castroville,
Stinson Municipal Airport, San Antonio Int Airport, Randolph AFB,
Leon Valley, Helotes, Fair Oaks Ranch, Kirby, Alamo Heights,
Windcrest, Terrell Hills, Shavano Park, Hollywood Park, Cross
Mountain and Olmos Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

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

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

&&

LAT...LON 2931 9900 2973 9885 2974 9881 2972 9878
      2972 9874 2973 9873 2973 9871 2975 9865
      2974 9864 2974 9861 2976 9855 2974 9853
      2974 9848 2946 9821 2920 9852
TIME...MOT...LOC 2343Z 334DEG 15KT 2964 9866

CP

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 1, 7:53 PM CDT	Areal Flood Advisory	EWX	Bandera, Real	3 hr
Aug 2, 12:27 AM CDT	Areal Flood Advisory	EWX	Bastrop, Hays, Travis	3 hr
Aug 2, 3:45 AM CDT	Areal Flood Advisory	EWX	Comal, Guadalupe, Hays	4 hr
Aug 2, 3:53 AM CDT	Areal Flood Advisory	EWX	Edwards, Kinney	4 hr
Aug 2, 4:09 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal, Guadalupe	4 hr
Aug 2, 4:13 AM CDT	Areal Flood Advisory	EWX	Uvalde	4 hr
Aug 2, 5:41 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Guadalupe	4 hr
Aug 2, 5:45 AM CDT	Areal Flood Advisory	EWX	Bexar, Guadalupe, Wilson	3 hr
Aug 2, 5:51 AM CDT	Areal Flood Advisory	EWX	Bandera, Real	3 hr
Aug 2, 5:57 AM CDT	Areal Flood Advisory	EWX	Comal, Hays	4 hr
Aug 2, 6:37 AM CDT	Areal Flood Advisory	EWX	Bandera, Kerr, Medina	4 hr
Aug 2, 6:37 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal	5 hr
Aug 2, 6:52 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Hays	3 hr
Aug 2, 7:15 AM CDT	Areal Flood Advisory	EWX	Bandera, Bexar, Comal, Kendall, Kerr, Medina	5 hr
Aug 2, 7:29 AM CDT	Special Weather Statement	EWX	Bexar	46 min
Aug 2, 7:47 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar, Comal, Kendall	4 hr
Aug 2, 8:13 AM CDT	Areal Flood Advisory	EWX	Kinney	3 hr
Aug 2, 8:15 AM CDT	Areal Flood Advisory	EWX	Bastrop, Lee, Travis, Williamson	5 hr
Aug 2, 8:18 AM CDT	Special Weather Statement	EWX	Bexar, Comal	42 min
Aug 2, 8:26 AM CDT	Areal Flood Advisory	EWX	Bexar, Comal, Kendall	4 hr
Aug 2, 8:36 AM CDT	Areal Flood Advisory	EWX	Bexar	4 hr
Aug 2, 9:16 AM CDT	Areal Flood Advisory	EWX	Blanco, Hays, Travis	3 hr
Aug 2, 10:25 AM CDT	Areal Flood Advisory	EWX	Kinney, Maverick, Uvalde, Zavala	3 hr
Aug 2, 2:45 PM CDT	Areal Flood Advisory	EWX	Bandera, Edwards, Kerr, Real, Val Verde	3 hr
Aug 2, 4:56 PM CDT	Areal Flood Advisory	EWX	Travis, Williamson	3 hr
Aug 2, 5:12 PM CDT	Areal Flood Advisory	EWX	Blanco, Hays	3 hr
Aug 2, 6:19 PM CDT	Areal Flood Advisory	EWX	Caldwell, Hays, Travis	2 hr

Nearby

Areal Flood Advisories in Texas, 2021 Every 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; radar from the NEXRAD Level II archive.