Alert archive / Texas / Areal Flood Warnings in 2021

Areal Flood Warning 4, NWS Houston/Galveston, TX

May 1, 2021Brazoria County, Matagorda County, Texas

NWS Houston/Galveston, TX issued this areal flood warning at May 1, 2021, 12:00 PM CDT for Brazoria County, Matagorda County, Texas. It was in force for 3 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 1, 2021, 12:00 PM CDT (17:00 UTC)
Expired: May 1, 2021, 3:00 PM CDT
In force: 3 hr
Issued by: NWS Houston/Galveston, TX
Area: Storm-based polygon
Flood severity: None

Counties Brazoria County, TX, Matagorda County, TX

The radar

The Houston radar (KHGX), 83 km from the middle of the area, began a volume at 17:04 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

Corpus Christi, TX (KCRP), launched 12:00Z, 5.0 hours before the alert went out and 211 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 warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Houston/Galveston, TX wrote its last area forecast discussion before this areal flood warning went out at May 1, 10:56 AM CDT, 1 hour 4 minutes earlier.

Area forecast discussion, May 1, 10:56 AM CDT, 1 hour 4 minutes before

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In the hours before

Local storm report, May 1, 11:23 AM CDT, 37 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1123 AM CDT SAT MAY 1 2021

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

1007 AM     FLASH FLOOD      SWEENY                  29.05N 95.70W
05/01/2021                   BRAZORIA           TX   BROADCAST MEDIA

            FLOODED VEHICLES IN SWEENY.

&&

The office that day

Everything else NWS Houston/Galveston, TX issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 30, 8:36 PM CDT	River Flood Warning	HGX	Matagorda, Wharton	65 hr
May 1, 3:44 AM CDT	Areal Flood Advisory	HGX	Austin, Brazoria, Colorado, Fort Bend, Jackson, Matagorda and 1 more	3 hr
May 1, 4:43 AM CDT	Rip Current Statement	HGX	Brazoria, Galveston, Matagorda	17 hr
May 1, 4:50 AM CDT	Small Craft Advisory	HGX		17 hr
May 1, 5:06 AM CDT	Flash Flood Warning	HGX	Brazoria, Fort Bend, Matagorda, Wharton	3 hr
May 1, 6:01 AM CDT	Special Marine Warning	HGX		59 min
May 1, 6:08 AM CDT	Areal Flood Warning	HGX	Austin, Brazoria, Fort Bend, Matagorda, Wharton	3 hr
May 1, 7:49 AM CDT	Areal Flood Advisory	HGX	Brazoria, Fort Bend, Harris, Matagorda	3 hr
May 1, 7:59 AM CDT	Areal Flood Advisory	HGX	Austin, Brazoria, Colorado, Fort Bend, Matagorda, Wharton	4 hr
May 1, 8:04 AM CDT	River Flood Warning	HGX	Brazoria, Fort Bend, Wharton	7 days
May 1, 9:09 AM CDT	Areal Flood Warning	HGX	Brazoria, Fort Bend, Matagorda, Wharton	3 hr
May 1, 9:32 AM CDT	River Flood Warning	HGX	Jackson	72 hr
May 1, 9:32 AM CDT	River Flood Warning	HGX	Jackson, Wharton	12 hr
May 1, 9:32 AM CDT	River Flood Warning	HGX	Colorado, Jackson, Wharton	52 hr
May 1, 9:55 AM CDT	River Flood Warning	HGX	Harris, Montgomery	24 hr
May 1, 12:37 PM CDT	Areal Flood Advisory	HGX	Brazoria, Fort Bend, Matagorda, Wharton	2 hr
May 1, 1:53 PM CDT	River Flood Warning	HGX	Brazoria	21 days
May 1, 1:53 PM CDT	River Flood Warning	HGX	Austin, Colorado, Fort Bend, Wharton	3 days
May 1, 2:15 PM CDT	River Flood Warning	HGX	Lavaca	21 days
May 1, 2:25 PM CDT	Areal Flood Advisory	HGX	Waller	8 hr
May 1, 2:29 PM CDT	Areal Flood Advisory	HGX	Waller	8 hr
May 1, 4:13 PM CDT	Areal Flood Advisory	HGX	Montgomery	6 hr

Nearby

Areal Flood Warnings in Texas, 2021 Every areal flood warning 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.