Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 38, NWS Houston/Galveston, TX

October 1, 2021Fort Bend County, Harris County, Waller County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Oct 1, 2021, 8:29 AM CDT for Fort Bend County, Harris County, Waller County, Texas. It was in force for 3 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Oct 1, 2021, 8:29 AM CDT (13:29 UTC)
Expired
Oct 1, 2021, 11:00 AM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Flood severity
None

Counties Fort Bend County, TX, Harris County, TX, Waller County, TX

The radar

The Houston radar (KHGX), 79 km from the middle of the area, began a volume at 13:33 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.

What was reported inside it

TimeReportWhereRemark
Oct 1, 11:04 AM CDTFLASH FLOOD4 Ne Katy, TXPEEK ROAD BETWEEN STOCKDICK SCHOOL ROAD AND BECKENDORF ROAD CLOSED DUE TO FLOODING.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 1.5 hours before the alert went out and 255 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 2021-10-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1808 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 2021-10-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 30 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
1808 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
585 m above ground
0-6 km bulk shear
10 kt
0-1 km storm-relative helicity
30 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

431 
WGUS54 KHGX 011329
FFWHGX
TXC157-201-473-011600-
/O.NEW.KHGX.FF.W.0038.211001T1329Z-211001T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
829 AM CDT Fri Oct 1 2021

The National Weather Service in League City has issued a

* Flash Flood Warning for...
  North Central Fort Bend County in southeastern Texas...
  Harris County in southeastern Texas...
  Southeastern Waller County in southeastern Texas...

* Until 1100 AM CDT.

* At 829 AM CDT, Emergency management reported high water and some 
  impassable roads due to thunderstorms producing heavy rain across 
  the warned area. Between 2 and 5 inches of rain have fallen. 
  Another storm capable of producing additional rainfall rates of 1 
  to 2 inches per hour is moving towards the warned area. Flash 
  flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Emergency management reported.

  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...
  Katy, Fulshear and Cinco Ranch.

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.

&&

LAT...LON 2977 9588 2980 9587 2985 9585 2988 9583
      2988 9581 2986 9574 2984 9573 2979 9573
      2975 9574 2971 9577 2967 9585 2967 9588
      2969 9592

FLASH FLOOD...OBSERVED

$$
1 follow-up statement
838 
WGUS74 KHGX 011557
FFSHGX

Flash Flood Statement
National Weather Service Houston/Galveston TX
1057 AM CDT Fri Oct 1 2021

TXC157-201-473-011607-
/O.EXP.KHGX.FF.W.0038.000000T0000Z-211001T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Fort Bend TX-Harris TX-Waller TX-
1057 AM CDT Fri Oct 1 2021

...FLASH FLOOD WARNING AT 11 AM CDT THIS MORNING FOR NORTH CENTRAL 
FORT BEND, HARRIS AND SOUTHEASTERN WALLER COUNTIES HAS BEEN REPLACED 
WITH A FLOOD WARNING...

LAT...LON 2977 9588 2980 9587 2985 9585 2988 9583
      2988 9581 2986 9574 2984 9573 2979 9573
      2975 9574 2971 9577 2967 9585 2967 9588
      2969 9592

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 1, 5:37 AM CDTAreal Flood AdvisoryHGXChambers, Harris, Liberty27 min
Oct 1, 5:57 AM CDTAreal Flood AdvisoryHGXAustin, Grimes, Waller, Washington2 hr
Oct 1, 6:04 AM CDTFlash Flood WarningHGXHarris3 hr
Oct 1, 6:52 AM CDTAreal Flood AdvisoryHGXHarris113 min
Oct 1, 7:23 AM CDTAreal Flood AdvisoryHGXFort Bend, Harris, Waller67 min
Oct 1, 7:40 AM CDTAreal Flood AdvisoryHGXAustin, Grimes, Harris, Waller, Washington99 min
Oct 1, 8:34 AM CDTAreal Flood AdvisoryHGXHarris, Montgomery65 min
Oct 1, 8:38 AM CDTFlash Flood WarningHGXPolk, San Jacinto, Trinity3 hr
Oct 1, 9:01 AM CDTAreal Flood WarningHGXChambers, Harris, Liberty5 hr
Oct 1, 9:19 AM CDTFlash Flood WarningHGXGrimes, Waller, Washington3 hr
Oct 1, 9:25 AM CDTAreal Flood AdvisoryHGXFort Bend3 hr
Oct 1, 9:37 AM CDTAreal Flood AdvisoryHGXHarris3 hr
Oct 1, 10:57 AM CDTAreal Flood WarningHGXFort Bend, Harris, Waller3 hr
Oct 1, 11:01 AM CDTAreal Flood AdvisoryHGXLiberty, San Jacinto3 hr
Oct 1, 11:08 AM CDTRiver Flood WarningHGXHarris4 hr
Oct 1, 11:54 AM CDTAreal Flood AdvisoryHGXPolk, San Jacinto, Trinity2 hr
Oct 1, 12:02 PM CDTAreal Flood WarningHGXAustin, Grimes, Harris, Waller, Washington2 hr
Oct 1, 12:42 PM CDTAreal Flood AdvisoryHGXFort Bend, Harris, Montgomery78 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.