Alert archive / Texas / Areal Flood Advisories in 2021

Areal Flood Advisory 7, NWS Austin/San Antonio, TX

April 30, 2021Atascosa County, Texas

NWS Austin/San Antonio, TX issued this areal flood advisory at Apr 30, 2021, 11:25 AM CDT for Atascosa County, Texas. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued: Apr 30, 2021, 11:25 AM CDT (16:25 UTC)
Expired: Apr 30, 2021, 2:30 PM CDT
In force: 3 hr
Issued by: NWS Austin/San Antonio, TX
Area: Storm-based polygon

County Atascosa County, TX

The radar

The Austin/San Antonio radar (KEWX), 102 km from the middle of the area, began a volume at 16:27 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, 4.4 hours before the alert went out and 174 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: 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, 10:10 AM CDT, 1 hour 15 minutes earlier.

Area forecast discussion, Apr 30, 10:10 AM CDT, 1 hour 15 minutes before

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Hazardous weather outlook, Apr 30, 3:36 AM CDT, 7 hours 49 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.

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 30, 3:34 AM CDT	Flash Flood Watch	EWX	Atascosa, Bandera, Bastrop, Bexar, Blanco, Caldwell and 15 more	39 hr
Apr 30, 4:53 PM CDT	Areal Flood Advisory	EWX	Bexar	112 min
Apr 30, 5:48 PM CDT	Flash Flood Warning Considerable damage threat	EWX	Bexar	6 hr
Apr 30, 6:52 PM CDT	Areal Flood Advisory	EWX	Comal	69 min

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.