Alert archive / Texas / Areal Flood Advisories in 2021

Areal Flood Advisory 9, NWS Austin/San Antonio, TX

April 30, 2021Comal County, Texas

NWS Austin/San Antonio, TX issued this areal flood advisory at Apr 30, 2021, 6:52 PM CDT for Comal County, Texas. It was in force for 69 min.

The area

The counties it named.

The facts

Issued
Apr 30, 2021, 6:52 PM CDT (23:52 UTC)
Expired
Apr 30, 2021, 8:01 PM CDT
In force
69 min
Issued by
NWS Austin/San Antonio, TX
Area
Storm-based polygon

County Comal County, TX

The radar

The Austin/San Antonio radar (KEWX), 27 km from the middle of the area, began a volume at 23:54 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, 11.9 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, Corpus Christi, TX at 12:00Z on 2021-04-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 63 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, Corpus Christi, TX at 12:00Z on 2021-04-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 square meters per square second.193958Sfc1 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
63 J/kg
Mixed-layer CIN
-200 J/kg
Mixed-layer LCL
566 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
84 m²/s²
Significant tornado parameter
0.0
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 Apr 30, 4:16 PM CDT, 2 hours 36 minutes earlier.

Area forecast discussion, Apr 30, 4:16 PM CDT, 2 hours 36 minutes before
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Hazardous weather outlook, Apr 30, 3:36 AM CDT, 15 hours 16 minutes before
Hazardous Weather Outlook
National Weather Service Austin/San Antonio TX
336 AM CDT Fri Apr 30 2021

TXZ171>173-183>194-202>209-217>225-228-011200-
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-
336 AM CDT Fri Apr 30 2021

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

.DAY ONE...Today And Tonight.

Numerous showers and scattered thunderstorms are forecast to
continue today and tonight. The heaviest rainfall is expected
across the Coastal Plains where accumulations could reach 2-4
inches with isolated totals in excess of 6 inches. A Flash Flood
Watch is in effect for locations south and east of a Pleasanton
to New Braunfels to Fayetteville line.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

Numerous showers and scattered thunderstorms are forecast to
continue into Saturday night. The Flash Flood Watch will remain
in effect for locations south and east of a Pleasanton to New
Braunfels to Fayetteville line through Saturday evening. A strong
to marginally severe storm is also possible Saturday.

.SPOTTER INFORMATION STATEMENT...

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

In the hours before

Local storm report, Apr 30, 3:26 PM CDT, 3 hours 26 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
326 PM CDT FRI APR 30 2021

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

0733 PM     TORNADO          4 SSE HONDO             29.30N 99.10W
04/28/2021                   MEDINA             TX   NWS STORM SURVEY

            AN NWS STORM SURVEY TEAM FOUND EVIDENCE OF
            AN EF1 TORNADO WITH MAX WINDS OF 110 MPH
            THAT WAS ON THE GROUND FOR ALMOST 2 MILES.
            PLEASE VIEW THE PUBLIC INFORMATION STATEMENT
            FOR DETAILS.

&&

AAT
Local storm report, Apr 30, 4:26 PM CDT, 2 hours 26 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
426 PM CDT FRI APR 30 2021

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

0712 PM     TSTM WND DMG     D'HANIS                 29.33N 99.29W
04/28/2021                   MEDINA             TX   NWS STORM SURVEY

            MULTIPLE TREES FROM WEST OF TOWN ALONG OLD
            HWY 90 INTO TOWN WITH LARGE LIMBS DOWN OR
            TRUNKS SNAPPED. OTHER DAMAGE INCLUDED
            DESTRUCTION OF A SMALL METAL CAR PORT AND A
            CENTER PIVOT IRRIGATION SYSTEM SLIPPED. WIND
            DRIVEN HAIL ALSO CAUSED DAMAGE. WINDS WERE
            ESTIMATED BETWEEN 75 AND 105 MPH ACROSS THIS
            AREA.

&&

AAT
Local storm report, Apr 30, 4:34 PM CDT, 2 hours 18 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
434 PM CDT FRI APR 30 2021

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

0727 PM     TSTM WND DMG     1 WNW HONDO             29.35N 99.16W
04/28/2021                   MEDINA             TX   NWS STORM SURVEY

            IN AND AROUND HONDO...IN ADDITION TO WIDE
            SPREAD TREE DAMAGE AND MULTIPLE CENTER PIVOT
            IRRIGATION SYSTEMS TOPPLED THERE WERE TWO
            INSTANCES OF METAL BUILDINGS HAVE THEIR
            LARGE DOORS BLOWN IN OR OUT...AND PARTS OF
            THE METAL ROOFING BLOWN OFF A BUILDING NEAR
            THE AIRPORT AMONG OTHER DAMAGE. WINDS HERE
            WERE ALSO ESTIMATED AT 75-110 MPH.

&&

AAT
Local storm report, Apr 30, 4:39 PM CDT, 2 hours 13 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
439 PM CDT FRI APR 30 2021

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

0750 PM     TSTM WND DMG     9 SW CASTROVILLE        29.28N 99.00W
04/28/2021                   MEDINA             TX   NWS STORM SURVEY

            EAST OF THE EF-1 TORNADO AND SOUTH OF DUNLEY
            ADDITIONAL SUBSTANTIAL DAMAGE WAS FOUND. TWO
            DIFFERENT SECTIONS OF POWER LINES WERE
            KNOCKED DOWN...PARTIAL ROOF DAMAGE TO TWO
            RESIDENCE WERE OBSERVED...AND MORE TREES HAD
            LARGE LIMBS MISSING WITH CONTINUED DAMAGE TO
            CENTER PIVOT IRRIGATION SYSTEMS. WIND
            ESTIMATES WERE BETWEEN 80 AND 105 MPH.

&&

AAT

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 30, 3:34 AM CDTFlash Flood WatchEWXAtascosa, Bandera, Bastrop, Bexar, Blanco, Caldwell and 15 more39 hr
Apr 30, 11:25 AM CDTAreal Flood AdvisoryEWXAtascosa3 hr
Apr 30, 4:53 PM CDTAreal Flood AdvisoryEWXBexar112 min
Apr 30, 5:48 PM CDTFlash Flood Warning Considerable damage threatEWXBexar6 hr

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; radar from the NEXRAD Level II archive.