Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 41, NWS Houston/Galveston, TX

October 2, 2021Brazoria County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Oct 2, 2021, 8:27 AM CDT for Brazoria County, Texas. It was in force for 38 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Oct 2, 2021, 8:27 AM CDT (13:27 UTC)
Expired
Oct 2, 2021, 9:05 AM CDT
In force
38 min
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Flood severity
None

County Brazoria County, TX

The radar

The Houston radar (KHGX), 57 km from the middle of the area, began a volume at 13:31 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

Lake Charles Mun, LA (KLCH), launched 12:00Z, 1.5 hours before the alert went out and 237 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, Lake Charles Mun, LA at 12:00Z on 2021-10-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1519 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lake Charles Mun, LA at 12:00Z on 2021-10-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 59 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
1519 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
558 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
59 m²/s²
0-3 km storm-relative helicity
71 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.8

Open this sounding in Storm Lab

The text

As transmitted.

545 
WGUS54 KHGX 021327
FFWHGX
TXC039-021630-
/O.NEW.KHGX.FF.W.0041.211002T1327Z-211002T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
827 AM CDT Sat Oct 2 2021

The National Weather Service in League City has issued a

* Flash Flood Warning for...
  South Central Brazoria County in southeastern Texas...

* Until 1130 AM CDT.

* At 827 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 2 and 4 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  mainly rural areas of South Central Brazoria County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 2897 9529 2898 9529 2901 9529 2902 9526
      2898 9526

FLASH FLOOD...RADAR INDICATED

$$
1 follow-up statement
474 
WGUS74 KHGX 021405
FFSHGX

Flash Flood Statement
National Weather Service Houston/Galveston TX
905 AM CDT Sat Oct 2 2021

TXC039-021415-
/O.CAN.KHGX.FF.W.0041.000000T0000Z-211002T1630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Brazoria TX-
905 AM CDT Sat Oct 2 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL BRAZORIA 
COUNTY...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 2897 9529 2898 9529 2901 9529 2902 9526
      2898 9526

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 2, 10:47 AM CDTAreal Flood AdvisoryHGXFort Bend, Harris118 min
Oct 2, 11:49 AM CDTAreal Flood AdvisoryHGXHarris87 min
Oct 2, 12:00 PM CDTAreal Flood AdvisoryHGXHarris93 min
Oct 2, 12:21 PM CDTFlash Flood WarningHGXHarris74 min

Nearby

Flash Flood Warnings in Texas, 2021Every flash 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.