Alert archive / Texas / Flash Flood Warnings in 2021

Flash Flood Warning 12, NWS Houston/Galveston, TX

May 18, 20218 counties in Texas

NWS Houston/Galveston, TX issued this flash flood warning at May 18, 2021, 9:43 PM CDT for 8 counties in Texas. It was in force for 3 hr. 5 reports 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
May 18, 2021, 9:43 PM CDT (02:43 UTC)
Expired
May 19, 2021, 12:33 AM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Flood severity
None

Counties Austin County, TX, Brazoria County, TX, Fort Bend County, TX, Galveston County, TX, Harris County, TX, Montgomery County, TX, Waller County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 75 km from the middle of the area, began a volume at 02:41 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
May 18, 11:06 PM CDTFLASH FLOOD4 Ese Aldine, TXPUBLIC REPORTS ON SOCIAL MEDIA A FLOODED UNDERPASS NEAR I-69 SOUTHBOUND AND EAST MOUNT HOUSTON ROAD WITH AT LEAST ONE STALLED VEHICLE AT AROUND 11:06 PM CDT.
May 19, 12:28 AM CDTFLASH FLOOD4 E Aldine, TXHARRIS COUNTY SHERRIFF OFFICE REPORTS FLOODED ROADWAY AT INTERSECTION OF EASTEX FREEWAY AND ALDINE MAIL ROUTE ROAD AT APPROXIMATELY 12:28 AM CDT IN NORTHEAST HOUSTON.
May 19, 12:28 AM CDTFLASH FLOOD4 Ne Katy, TXHARRIS COUNTY SHERRIFF OFFICE REPORTS A FLOODED ROADWAY AT 12:28AM CDT NEAR PEEK ROAD AND STOCKDICK SCHOOL ROAD.
May 19, 12:28 AM CDTFLASH FLOOD5 Ne Jersey Village, TXHARRIS COUNTY SHERRIFF OFFICE REPORTS FLOODED ROADWAY AT WEST SAM HOUSTON PARKWAY ONRAMP BY TOMBALL PARKWAY AT APPROXIMATELY 12:28 AM CDT.
May 19, 12:28 AM CDTFLASH FLOOD5 Wsw Jersey Village, TXHARRIS COUNTY SHERRIFF OFFICE REPORTS HIGH WATER NEAR KIETH HARROW BLVD AND HIGHWAY 6 AT APPROXIMATELY 12:28 AM CDT.

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 00:00Z, 2.7 hours before the alert went out and 251 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 00:00Z on 2021-05-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 37 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 00:00Z on 2021-05-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -36 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
37 J/kg
Mixed-layer CIN
-296 J/kg
Mixed-layer LCL
1094 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
-36 m²/s²
0-3 km storm-relative helicity
60 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

370 
WGUS54 KHGX 190243
FFWHGX
TXC015-039-157-167-201-339-473-481-190545-
/O.NEW.KHGX.FF.W.0012.210519T0243Z-210519T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
943 PM CDT Tue May 18 2021

The National Weather Service in League City has issued a

* Flash Flood Warning for...
  Southeastern Austin County in southeastern Texas...
  Northern Brazoria County in southeastern Texas...
  Fort Bend County in southeastern Texas...
  Western Galveston County in southeastern Texas...
  Harris County in southeastern Texas...
  Southern Montgomery County in southeastern Texas...
  Eastern Waller County in southeastern Texas...
  Northeastern Wharton County in southeastern Texas...

* Until 1245 AM CDT.

* At 943 PM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly. Brookshire Creek at US Highway 90 reported 2.00 inches of 
  rain in 30 minutes.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Doppler radar.

  IMPACT...Flooding of small creeks and streams, urban areas,
           highways, streets and underpasses as well as other
           drainage and low lying areas.

* Some locations that will experience flash flooding include...
  Pasadena, Pearland, southwestern League City, Sugar Land, 
  northwestern Baytown, Missouri City, southern Conroe, Friendswood, 
  Deer Park, Rosenberg, Alvin, Stafford, South Houston, Bellaire, 
  Humble, West University Place, Katy, Richmond, Galena Park and 
  Tomball.

Additional rainfall amounts of 1 to 3 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Excessive runoff from heavy rainfall will cause flooding of small 
creeks and streams, urban areas, highways, streets and underpasses 
as well as other drainage areas and low lying spots.

A Flash Flood Warning means that flooding is imminent or occurring. 
If you are in the warned area move to higher ground immediately. 
Residents living along streams and creeks should take immediate 
precautions to protect life and property.

&&

LAT...LON 2965 9609 2971 9622 3000 9588 3023 9607
      3027 9514 2977 9502 2928 9527 2927 9620

FLASH FLOOD...RADAR INDICATED

$$
1 follow-up statement
485 
WGUS74 KHGX 190533
FFSHGX

Flash Flood Statement
National Weather Service Houston/Galveston TX
1233 AM CDT Wed May 19 2021

TXC015-039-157-167-201-339-473-481-190543-
/O.CAN.KHGX.FF.W.0012.000000T0000Z-210519T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Austin TX-Brazoria TX-Fort Bend TX-Galveston TX-Harris TX-Montgomery
TX-Waller TX-Wharton TX-
1233 AM CDT Wed May 19 2021

...FLASH FLOOD WARNING FOR SOUTHEASTERN AUSTIN, NORTHERN BRAZORIA, 
FORT BEND, WESTERN GALVESTON, HARRIS, SOUTHERN MONTGOMERY, EASTERN 
WALLER AND NORTHEASTERN WHARTON COUNTIES HAS BEEN REPLACED WITH A 
FLOOD WARNING...

The heavy rain has ended, though light to moderate rainfall will 
prolong the time it takes for any flooding to recede. Please 
continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 700 AM CDT Thursday for 
portions of south central Texas and southeast Texas.

LAT...LON 2965 9609 2971 9622 3000 9588 3023 9607
      3027 9514 2977 9502 2928 9527 2927 9620

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 18, 7:19 PM CDTSpecial Weather StatementHGXWashington41 min
May 18, 7:33 PM CDTTornado WarningHGXColorado27 min
May 18, 8:01 PM CDTSpecial Weather StatementHGXAustin, Colorado59 min
May 18, 8:21 PM CDTAreal Flood AdvisoryHGXAustin, Colorado, Fort Bend, Washington, Wharton114 min
May 18, 8:24 PM CDTTornado WarningHGXAustin, Colorado, Fort Bend, Waller, Wharton36 min
May 18, 8:28 PM CDTSpecial Weather StatementHGXJackson47 min
May 18, 8:40 PM CDTAreal Flood AdvisoryHGXAustin, Brazos, Burleson, Grimes, Harris, Houston and 5 more3 hr
May 18, 8:41 PM CDTSevere Thunderstorm WarningHGXAustin, Colorado, Fort Bend, Waller, Wharton49 min
May 18, 8:52 PM CDTFlash Flood WarningHGXAustin, Burleson, Colorado, Waller, Washington, Wharton113 min
May 18, 9:10 PM CDTSevere Thunderstorm WarningHGXFort Bend, Harris, Waller35 min
May 18, 9:12 PM CDTTornado WarningHGXFort Bend, Harris, Waller33 min
May 18, 9:25 PM CDTAreal Flood AdvisoryHGXBrazoria, Colorado, Fort Bend, Jackson, Matagorda, Wharton3 hr
May 18, 9:25 PM CDTSevere Thunderstorm WarningHGXGrimes, Harris, Montgomery, Waller35 min
May 18, 9:28 PM CDTAreal Flood AdvisoryHGXAustin, Brazoria, Fort Bend, Harris, Montgomery, Waller3 hr
May 18, 9:44 PM CDTSevere Thunderstorm WarningHGXHarris, Montgomery31 min
May 18, 9:44 PM CDTTornado WarningHGXFort Bend, Harris31 min
May 18, 9:51 PM CDTSevere Thunderstorm WarningHGXBrazoria, Fort Bend, Galveston, Harris39 min
May 18, 10:01 PM CDTSpecial Marine WarningHGX29 min
May 18, 10:11 PM CDTSpecial Weather StatementHGXLiberty, Montgomery49 min
May 18, 10:22 PM CDTSpecial Marine WarningHGX83 min
May 18, 10:31 PM CDTTornado WarningHGXChambers, Harris, Liberty29 min
May 18, 10:37 PM CDTSpecial Weather StatementHGXBrazoria, Matagorda53 min
May 18, 10:43 PM CDTAreal Flood WarningHGXAustin, Brazos, Burleson, Colorado, Grimes, Waller and 2 more2 hr
May 18, 11:12 PM CDTFlash Flood WarningHGXBrazoria, Jackson, Matagorda, Wharton3 hr
May 18, 11:25 PM CDTAreal Flood AdvisoryHGXChambers, Liberty, Polk3 hr
May 18, 11:30 PM CDTAreal Flood AdvisoryHGXBrazoria, Galveston, Harris3 hr
May 18, 11:42 PM CDTAreal Flood AdvisoryHGXMontgomery, San Jacinto3 hr
May 18, 11:43 PM CDTSpecial Marine WarningHGX77 min
May 18, 11:55 PM CDTSpecial Marine WarningHGX65 min
May 18, 11:57 PM CDTRiver Flood WarningHGXJackson, Wharton45 hr
May 19, 12:03 AM CDTRiver Flood WarningHGXBrazoria21 days
May 19, 12:04 AM CDTSpecial Weather StatementHGXPolk41 min
May 19, 12:18 AM CDTAreal Flood WarningHGXJackson, Wharton3 hr
May 19, 12:21 AM CDTFlash Flood WarningHGXJackson, Matagorda3 hr
May 19, 12:25 AM CDTSpecial Marine WarningHGX65 min
May 19, 12:33 AM CDTAreal Flood WarningHGXAustin, Brazoria, Fort Bend, Galveston, Harris, Montgomery and 2 more12 min
May 19, 12:33 AM CDTSevere Thunderstorm WarningHGXBrazoria, Matagorda27 min
May 19, 12:38 AM CDTRiver Flood WarningHGXPolk, San Jacinto, Trinity, Walker32 days
May 19, 12:44 AM CDTSpecial Weather StatementHGXJackson46 min
May 19, 12:56 AM CDTSpecial Marine WarningHGX64 min
May 19, 12:58 AM CDTAreal Flood AdvisoryHGXBrazoria, Galveston3 hr
May 19, 12:58 AM CDTSpecial Marine WarningHGX32 min
May 19, 1:07 AM CDTAreal Flood WarningHGXMontgomery, Waller3 hr
May 19, 1:26 AM CDTSpecial Marine WarningHGX34 min
May 19, 1:53 AM CDTSpecial Marine WarningHGX52 min
May 19, 2:10 AM CDTRiver Flood WarningHGXLavaca43 hr
May 19, 2:10 AM CDTRiver Flood WarningHGXJackson21 days
May 19, 2:10 AM CDTRiver Flood WarningHGXJackson, Lavaca4 days
May 19, 2:39 AM CDTRiver Flood WarningHGXColorado, Jackson, Wharton4 days
May 19, 2:40 AM CDTRiver Flood WarningHGXHarris, Liberty, Montgomery21 days
May 19, 2:57 AM CDTRiver Flood WarningHGXJackson9 days
May 19, 2:57 AM CDTRiver Flood WarningHGXJackson, Wharton68 hr
May 19, 3:12 AM CDTAreal Flood WarningHGXWaller15 hr
May 19, 3:19 AM CDTSpecial Marine WarningHGX116 min
May 19, 3:25 AM CDTSevere Thunderstorm WarningHGXBrazoria, Colorado, Fort Bend, Jackson, Matagorda, Wharton50 min
May 19, 3:26 AM CDTFlash Flood WarningHGXJackson, Matagorda10 hr
May 19, 3:27 AM CDTSmall Craft AdvisoryHGX33 min
May 19, 3:38 AM CDTAreal Flood AdvisoryHGXBrazoria, Matagorda14 hr
May 19, 4:13 AM CDTAreal Flood WarningHGXMontgomery, Waller12 hr
May 19, 6:06 AM CDTRiver Flood WarningHGXPolk, San Jacinto9 hr
May 19, 9:58 AM CDTRiver Flood WarningHGXJackson, Lavaca4 days
May 19, 1:13 PM CDTAreal Flood WarningHGXJackson, Matagorda6 hr
May 19, 1:15 PM CDTAreal Flood AdvisoryHGXJackson, Matagorda6 hr
May 19, 4:04 PM CDTRiver Flood WarningHGXHarris21 days
May 19, 4:16 PM CDTAreal Flood WarningHGXMontgomery, Waller5 hr
May 19, 6:16 PM CDTAreal Flood WarningHGXWaller3 hr

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.