Alert archive / Texas / Flash Flood Warnings in 2021
Flash Flood Warning 10, NWS Houston/Galveston, TX
NWS Houston/Galveston, TX issued this flash flood warning at May 17, 2021, 3:21 PM CDT for Chambers County, Harris County, Liberty County, Texas. It was in force for 3 hr. 2 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 17, 2021, 3:21 PM CDT (20:21 UTC)
- Expired
- May 17, 2021, 6:30 PM CDT
- In force
- 3 hr
- Issued by
- NWS Houston/Galveston, TX
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chambers County, TX, Harris County, TX, Liberty County, TX
The radar
The Houston radar (KHGX), 58 km from the middle of the area, began a volume at 20:25 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
| Time | Report | Where | Remark |
|---|---|---|---|
| May 17, 4:00 PM CDT | FLASH FLOOD | Dayton, TX | HIGHWAY 321 UNDERPASS IN DAYTON WAS FLOODED AND IMPASSABLE. |
| May 17, 4:37 PM CDT | FLASH FLOOD | 1 Nnw Humble, TX | UNDERPASS NEAR IH-69 AND FM 1960 IS FLOODED ACCORDING TO HOUSTON TRANSTAR AND LOCAL MEDIA. |
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, 8.4 hours before the alert went out and 184 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.
- Mixed-layer CAPE
- 626 J/kg
- Mixed-layer CIN
- -14 J/kg
- Mixed-layer LCL
- 699 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 207 m²/s²
- 0-3 km storm-relative helicity
- 314 m²/s²
- Significant tornado parameter
- 0.7
- Supercell composite
- 10.3
The text
As transmitted.
262
WGUS54 KHGX 172021
FFWHGX
TXC071-201-291-172330-
/O.NEW.KHGX.FF.W.0010.210517T2021Z-210517T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
321 PM CDT Mon May 17 2021
The National Weather Service in League City has issued a
* Flash Flood Warning for...
Northwestern Chambers County in southeastern Texas...
Harris County in southeastern Texas...
Southwestern Liberty County in southeastern Texas...
* Until 630 PM CDT.
* At 321 PM CDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 2 and 4 inches of rain
have fallen. Flash flooding is ongoing or expected to begin
shortly.
The gauge at Cedar Bayou and FM 1960 received 4.08 inches in the
last hour.
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...
Northern Baytown, Humble, Liberty, Dayton, Barrett, Highlands,
Channelview, Cloverleaf, Kingwood, Spring, Crosby, Mont Belvieu,
Anahuac, Old River-Winfree, Ames, Cove, Lake Houston Dam, Sheldon,
Lake Houston and Atascocita.
Additional rainfall amounts of 1 to 2 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.
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.
&&
LAT...LON 3006 9523 3012 9497 3004 9470 2977 9453
2978 9517 3002 9542 3004 9531 3003 9529
3003 9526
FLASH FLOOD...RADAR INDICATED
$$2 follow-up statements
039
WGUS74 KHGX 172238
FFSHGX
Flash Flood Statement
National Weather Service Houston/Galveston TX
538 PM CDT Mon May 17 2021
TXC071-201-291-172330-
/O.CON.KHGX.FF.W.0010.000000T0000Z-210517T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chambers TX-Harris TX-Liberty TX-
538 PM CDT Mon May 17 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM CDT THIS
EVENING FOR NORTHWESTERN CHAMBERS, HARRIS AND SOUTHWESTERN LIBERTY
COUNTIES...
At 538 PM CDT, Emergency management reported road closures in the
warned area due to heavy rain: Highway 321 underpass in Dayton was
flooded and impassable, and underpass near IH-69 and FM 1960 was
flooded. Between 4 and 8 inches of rain have fallen. Flash flooding
is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Emergency management.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other
drainage and low lying areas.
Some locations that will experience flash flooding include...
Northern Baytown, Humble, Liberty, Dayton, Barrett, Highlands,
Channelview, Cloverleaf, Kingwood, Spring, Crosby, Mont Belvieu,
Anahuac, Old River-Winfree, Ames, Cove, Lake Houston Dam, Sheldon,
Lake Houston and Atascocita.
Additional rainfall amounts of up to 1 inch are possible in the
warned area.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses
as well as other drainage areas and low lying spots.
&&
LAT...LON 3006 9523 3012 9497 3004 9470 2977 9453
2978 9517 3002 9542 3004 9531 3003 9529
3003 9526
FLASH FLOOD...OBSERVED
EXPECTED RAINFALL...1 INCH IN 1 HOUR
$$037
WGUS74 KHGX 172326
FFSHGX
Flash Flood Statement
National Weather Service Houston/Galveston TX
626 PM CDT Mon May 17 2021
TXC071-201-291-172336-
/O.EXP.KHGX.FF.W.0010.000000T0000Z-210517T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chambers TX-Harris TX-Liberty TX-
626 PM CDT Mon May 17 2021
...FLASH FLOOD WARNING WILL EXPIRE AT 630 PM CDT THIS EVENING FOR
NORTHWESTERN CHAMBERS, HARRIS AND SOUTHWESTERN LIBERTY COUNTIES...
The heavy rain has ended as the heavy rain has ended. Light to
moderate rainfall will continue for the next couple of hours. 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 3006 9523 3012 9497 3004 9470 2977 9453
2978 9517 3002 9542 3004 9531 3003 9529
3003 9526
$$The office that day
Everything else NWS Houston/Galveston, TX issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 7:56 PM CDT | Special Marine Warning | HGX | 34 min | |
| May 16, 8:27 PM CDT | River Flood Warning | HGX | Jackson | 11 hr |
| May 16, 8:42 PM CDT | Special Marine Warning | HGX | 48 min | |
| May 16, 10:16 PM CDT | Special Marine Warning | HGX | 44 min | |
| May 16, 11:11 PM CDT | Special Marine Warning | HGX | 64 min | |
| May 17, 1:16 AM CDT | Special Marine Warning | HGX | 89 min | |
| May 17, 2:45 AM CDT | Special Marine Warning | HGX | 45 min | |
| May 17, 12:57 PM CDT | Areal Flood Advisory | HGX | Liberty | 2 hr |
| May 17, 1:41 PM CDT | Flash Flood Watch | HGX | Austin, Brazoria, Brazos, Burleson, Chambers, Colorado and 17 more | 68 hr |
| May 17, 2:06 PM CDT | Flash Flood Warning | HGX | Liberty | 3 hr |
| May 17, 2:08 PM CDT | Special Weather Statement | HGX | San Jacinto | 52 min |
| May 17, 2:09 PM CDT | Areal Flood Advisory | HGX | Grimes, Montgomery, San Jacinto, Walker, Waller, Washington | 3 hr |
| May 17, 2:44 PM CDT | Special Weather Statement | HGX | Liberty, Montgomery | 46 min |
| May 17, 2:59 PM CDT | Areal Flood Advisory | HGX | Austin, Colorado, Harris, Liberty, Montgomery, San Jacinto and 2 more | 3 hr |
| May 17, 3:13 PM CDT | Areal Flood Advisory | HGX | Chambers, Harris, Liberty, Montgomery | 2 hr |
| May 17, 3:19 PM CDT | Special Weather Statement | HGX | Austin, Colorado | 56 min |
| May 17, 3:23 PM CDT | Special Weather Statement | HGX | Chambers, Harris | 67 min |
| May 17, 3:46 PM CDT | Special Marine Warning | HGX | 89 min | |
| May 17, 4:08 PM CDT | Areal Flood Advisory | HGX | Harris | 112 min |
| May 17, 4:25 PM CDT | Special Weather Statement | HGX | Austin, Brazoria, Colorado, Fort Bend, Galveston, Harris and 1 more | 65 min |
| May 17, 5:02 PM CDT | Areal Flood Advisory | HGX | Brazoria, Fort Bend, Galveston, Harris | 118 min |
| May 17, 5:07 PM CDT | River Flood Warning | HGX | Liberty | 36 days |
| May 17, 5:15 PM CDT | Special Marine Warning | HGX | 45 min | |
| May 17, 5:30 PM CDT | Special Marine Warning | HGX | 90 min | |
| May 17, 5:37 PM CDT | Areal Flood Advisory | HGX | Austin, Colorado, Fort Bend, Harris, Waller, Wharton | 113 min |
| May 17, 5:44 PM CDT | Special Weather Statement | HGX | Fort Bend | 61 min |
| May 17, 6:14 PM CDT | Areal Flood Advisory | HGX | Brazoria, Fort Bend, Galveston, Harris, Matagorda, Wharton | 2 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.