Alert archive / Texas / Areal Flood Advisories in 2021

Areal Flood Advisory 22, NWS Austin/San Antonio, TX

May 1, 2021Bexar County, Texas

NWS Austin/San Antonio, TX issued this areal flood advisory at May 1, 2021, 4:14 PM CDT for Bexar County, Texas. It was in force for 2 hr.

The area

The counties it named.

The facts

Issued: May 1, 2021, 4:14 PM CDT (21:14 UTC)
Expired: May 1, 2021, 6:15 PM CDT
In force: 2 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon

County Bexar County, TX

The radar

The Austin/San Antonio radar (KEWX), 55 km from the middle of the area, began a volume at 21:14 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

Corpus Christi, TX (KCRP), launched 12:00Z, 9.2 hours before the alert went out and 223 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: 214 J/kg
Mixed-layer CIN: -33 J/kg
Mixed-layer LCL: 629 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 74 m²/s²
0-3 km storm-relative helicity: 196 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.4

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 May 1, 3:15 PM CDT, 59 minutes earlier.

Area forecast discussion, May 1, 3:15 PM CDT, 59 minutes before

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
315 PM CDT Sat May 1 2021

.SHORT TERM (Tonight through Sunday Night)...
A band of showers and thunderstorms is rapidly pushing away from the
I-37/I-35 corridors with areas of rain over the eastern Hill Country
and Central Texas. The band has and continues to produced excessive
rainfall and renewed flooding. As a result, will keep the Flash Flood
Watch going through 7 PM when the rain, showers, and thunderstorms
move east of our area. Weak instability and lapse rates continue a
possibility of a strong storm or two with gusty winds.

There are scattered showers and isolated thunderstorms over the
Edwards Plateau to near Big Bend associated with an upper level low
over the Serranias del Burro of Mexico. The upper level low will
accelerate moving over the Edwards Plateau later this afternoon,
Hill Country this evening, and Central Texas overnight. The showers
and thunderstorms will accompany the low as it moves across those
areas. With the faster movement, the flood threat is lower. However,
ongoing flooding will be slower to recede in areas that get this
additional rain. A strong storm or two is possible due to weak
instability and lapse rates. The upper level low takes the showers
and thunderstorms with it as moves off to the east by Sunday morning.

As a surface low also moves away on Sunday, southwesterly lower to
mid level flow takes hold drying the airmass somewhat. This allows
for much warmer temperatures. However, high temperatures will be
slightly lower than blended guidance due to moist soils from recent
and ongoing rains.

&&

.LONG TERM (Monday through Saturday)...
A dryline moves toward the I-35 corridor Monday afternoon allowing
temperatures to soar to well above normal across our area. Forecast
soundings show a weak capping inversion at time of peak heating that
may be able to be broken by the dryline and strong heating. Have
maintained slight chances of showers and thunderstorms across the far
eastern Hill Country to along the I-35 corridor late Monday
afternoon into early evening. Forecast soundings show MUCAPEs of
2,000 to 3,000 J/kg along the dryline indicating a potential for
isolated strong to severe storms. A cold front and upper level trough
move across our area Monday night into Tuesday generating isolated
to widely scattered showers and thunderstorms over the eastern half
of our area where moisture will be deepest. Cannot rule out a strong
storm. Breezy conditions are expected late Monday night into Tuesday
as high pressure builds into our area along with cooler temperatures.
Dry northwesterly flow aloft and reinforcing surges of high pressure
result in fair skies and near to slightly above normal temperatures
for mid week into next weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              63  87  68  91  65 /  70  -    0  20  20
Austin Bergstrom Intl Airport  63  87  68  91  65 /  70  -    0  20  20
New Braunfels Muni Airport     63  90  69  93  67 /  50   0   0  20  20
Burnet Muni Airport            61  86  67  91  62 /  70  -    0  20  20
Del Rio Intl Airport           60  95  66  96  65 /  20   0   0   0  -
Georgetown Muni Airport        63  86  68  91  64 /  70  -    0  20  30
Hondo Muni Airport             59  91  65  95  66 /  20   0   0  10  20
San Marcos Muni Airport        62  88  68  91  65 /  60  -    0  20  20
La Grange - Fayette Regional   66  87  70  89  69 /  70  -    0  10  20
San Antonio Intl Airport       63  88  68  92  67 /  30   0   0  20  20
Stinson Muni Airport           63  91  68  93  69 /  20   0   0  10  20

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 7 PM CDT this evening for Atascosa-Bandera-
Bastrop-Bexar-Blanco-Caldwell-Comal-De Witt-Fayette-Gillespie-
Gonzales-Guadalupe-Hays-Karnes-Kendall-Kerr-Lavaca-Lee-Medina-
Travis-Wilson.

&&

Short-Term/Aviation...04
Long-Term...Runyen
Decision Support...Brady

Hazardous weather outlook, May 1, 11:33 AM CDT, 4 hours 41 minutes before

Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
1133 AM CDT Sat May 1 2021

TXZ171>173-183>194-202>209-217>225-228-021045-
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-
1133 AM CDT Sat May 1 2021

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

.DAY ONE...This Afternoon And Tonight.

Numerous showers and scattered thunderstorms are forecast to
continue this afternoon into evening. Up to 3 inches of additional
rainfall can be expected. This could lead to additional flash
flooding. In addition, a strong storm is possible with gusty winds
and hail the main threats.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to submit storm or flooding reports to
the National Weather Service.

In the hours before

Local storm report, May 1, 3:08 PM CDT, 1 hour 6 minutes before

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Local storm report, May 1, 3:20 PM CDT, 54 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
320 PM CDT SAT MAY 1 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0310 PM     FLASH FLOOD      1 WNW ONION CREEK       30.14N 97.80W
05/01/2021                   TRAVIS             TX   EMERGENCY MNGR

            FLOODING AT LOW WATER CROSSING ON OLD SAN
            ANTONIO ROAD IN TRAVIS COUNTY.

&&

MB

Local storm report, May 1, 3:22 PM CDT, 52 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
322 PM CDT SAT MAY 1 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0315 PM     FLASH FLOOD      4 W SUNSET VALLEY       30.23N 97.87W
05/01/2021                   TRAVIS             TX   DEPT OF HIGHWAYS

            ROAD CLOSED DUE TO FLOODING ACROSS LOW WATER
            CROSSING FROM WILLIAMSON CREEK.

&&

MB

Local storm report, May 1, 3:40 PM CDT, 34 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
340 PM CDT SAT MAY 1 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0330 PM     FLASH FLOOD      3 SSE ANDERSON MILL     30.41N 97.79W
05/01/2021                   TRAVIS             TX   DEPT OF HIGHWAYS

            SEVERAL LOW WATER CROSSINGS CLOSED ALONG
            SPICEWOOD SPRINGS ROAD.

&&

MB

Local storm report, May 1, 3:54 PM CDT, 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
354 PM CDT SAT MAY 1 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0312 PM     FLOOD            FREDERICKSBURG          30.27N 98.87W
05/01/2021                   GILLESPIE          TX   EMERGENCY MNGR

            FLOODING ON STREETS AROUND FREDERICKSBURG
            AND ACROSS GILLESPIE COUNTY. SOME WATER
            COLLECTING ACROSS LOW WATER CROSSINGS WITHIN
            GILLESPIE COUNTY AS WELL.

&&

MB

Local storm report, May 1, 4:01 PM CDT, 13 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
401 PM CDT SAT MAY 1 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0350 PM     FLASH FLOOD      3 W SUNSET VALLEY       30.23N 97.86W
05/01/2021                   TRAVIS             TX   DEPT OF HIGHWAYS

            ROAD CLOSED DUE TO FLOODING FROM WILLIAMSON
            CREEK AT LOW-LEVEL WATER CROSSING NEAR JOE
            TANNER LN AND MCCARTY LN.

&&

MB

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 30, 8:01 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal	2 hr
Apr 30, 8:17 PM CDT	Special Weather Statement	EWX	Terrell	28 min
Apr 30, 8:22 PM CDT	Areal Flood Advisory	EWX	Bexar, Guadalupe, Wilson	50 min
Apr 30, 9:12 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar, Guadalupe, Wilson	3 hr
Apr 30, 11:59 PM CDT	Areal Flood Advisory	EWX	Lavaca	3 hr
May 1, 3:09 AM CDT	Areal Flood Advisory	EWX	Lavaca	51 min
May 1, 3:57 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Lavaca	3 hr
May 1, 8:10 AM CDT	Special Weather Statement	EWX	Maverick	35 min
May 1, 8:23 AM CDT	Special Weather Statement	EWX	Dimmit	52 min
May 1, 9:10 AM CDT	Special Weather Statement	EWX	Dimmit	35 min
May 1, 9:24 AM CDT	Special Weather Statement	EWX	Zavala	36 min
May 1, 9:55 AM CDT	Areal Flood Advisory	EWX	Kinney, Maverick, Uvalde, Val Verde, Zavala	3 hr
May 1, 10:02 AM CDT	Special Weather Statement	EWX	Uvalde, Zavala	43 min
May 1, 10:36 AM CDT	Special Weather Statement	EWX	Frio, Medina, Uvalde	54 min
May 1, 10:49 AM CDT	Areal Flood Advisory	EWX	Bandera, Frio, Medina	3 hr
May 1, 11:15 AM CDT	Flash Flood Warning Considerable damage threat	EWX	Medina, Uvalde	4 hr
May 1, 11:18 AM CDT	Areal Flood Advisory	EWX	Uvalde	3 hr
May 1, 11:31 AM CDT	Special Weather Statement	EWX	Atascosa, Bexar, Medina	59 min
May 1, 11:44 AM CDT	Areal Flood Advisory	EWX	Bandera, Gillespie, Kerr, Medina	4 hr
May 1, 12:01 PM CDT	Areal Flood Advisory	EWX	Atascosa	3 hr
May 1, 12:09 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar	4 hr
May 1, 12:30 PM CDT	Special Weather Statement	EWX	Atascosa, Bexar, Wilson	45 min
May 1, 12:40 PM CDT	River Flood Warning	EWX	Bexar	32 hr
May 1, 1:03 PM CDT	Areal Flood Advisory	EWX	Comal	3 hr
May 1, 1:14 PM CDT	Special Weather Statement	EWX	Comal, Guadalupe, Karnes, Wilson	61 min
May 1, 1:22 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Comal, Guadalupe, Wilson	3 hr
May 1, 1:52 PM CDT	Areal Flood Advisory	EWX	Gillespie, Kendall	3 hr
May 1, 2:07 PM CDT	River Flood Warning	EWX	Bexar, Wilson	41 hr
May 1, 2:07 PM CDT	Special Weather Statement	EWX	Caldwell, Gonzales, Guadalupe	38 min
May 1, 2:27 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Caldwell, Hays	3 hr
May 1, 2:44 PM CDT	Areal Flood Advisory	EWX	Gonzales	3 hr
May 1, 2:58 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Bastrop, Travis	3 hr
May 1, 3:11 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Gonzales	3 hr
May 1, 3:39 PM CDT	Areal Flood Advisory	EWX	Lee, Williamson	3 hr
May 1, 4:11 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Williamson	3 hr
May 1, 4:25 PM CDT	Areal Flood Advisory	EWX	Lavaca	3 hr
May 1, 4:31 PM CDT	Special Weather Statement	EWX	Bandera, Kerr	44 min
May 1, 6:13 PM CDT	Areal Flood Advisory	EWX	Bandera, Gillespie, Kendall, Kerr	3 hr
May 1, 6:53 PM CDT	Areal Flood Advisory	EWX	Gillespie, Kendall	3 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.