Alert archive / Texas / Flash Flood Warnings in 2017

Flash Flood Warning 21, NWS Houston/Galveston, TX

June 24, 2017Harris County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Jun 24, 2017, 8:07 AM CDT for Harris 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 outline as issued.

The facts

Issued
Jun 24, 2017, 8:07 AM CDT (13:07 UTC)
Expired
Jun 24, 2017, 11:00 AM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Storm-based polygon
Flood severity
None

County Harris County, TX

The radar

The Houston radar (KHGX), 51 km from the middle of the area, began a volume at 13:08 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, 1.1 hours before the alert went out and 188 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 2017-06-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2946 joules per kilogram.LCLEL10008507005003002001001 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 2017-06-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -25 square meters per square second.1939Sfc1 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
2946 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
578 m above ground
0-6 km bulk shear
6 kt
0-1 km storm-relative helicity
-25 m²/s²
0-3 km storm-relative helicity
-31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

972 
WGUS54 KHGX 241307
FFWHGX
TXC201-241600-
/O.NEW.KHGX.FF.W.0021.170624T1307Z-170624T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Houston/Galveston TX
807 AM CDT SAT JUN 24 2017

The National Weather Service in League City has issued a

* Flash Flood Warning for...
  East central Harris County in southeastern Texas...

* Until 1100 AM CDT.

* At 806 AM CDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Over 4.3 inches of rain has 
  already fallen over southern parts of the Lake Houston area with 
  continued moderate to heavy rain occurring. Flash flooding is 
  expected to begin shortly.

* Some locations that will experience flooding include...
  Lake Houston Dam, Lake Houston and southern Atascocita. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2996 9512 2989 9509 2987 9516 2994 9519

$$
2 follow-up statements
783 
WGUS74 KHGX 241424
FFSHGX

Flash Flood Statement
National Weather Service Houston/Galveston TX
924 AM CDT SAT JUN 24 2017

TXC201-241600-
/O.CON.KHGX.FF.W.0021.000000T0000Z-170624T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Harris TX-
924 AM CDT SAT JUN 24 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1100 AM CDT FOR
EAST CENTRAL HARRIS COUNTY...

At 920 AM CDT, Doppler radar indicated continued precipitation 
across the warned area. Over 6 inches of rain has already fallen and 
additional thunderstorms and heavy rain is developing to the south. 
Flash flooding is expected...especially in and around neighborhoods 
near the southern tip of Lake Houston.

Some locations that will experience flooding include...
Lake Houston Dam, Lake Houston and southern Atascocita. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2996 9512 2989 9509 2987 9516 2994 9519

$$
997 
WGUS74 KHGX 241605
FFSHGX

Flash Flood Statement
National Weather Service Houston/Galveston TX
1105 AM CDT SAT JUN 24 2017

TXC201-241610-
/O.EXP.KHGX.FF.W.0021.000000T0000Z-170624T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Harris TX-
1105 AM CDT SAT JUN 24 2017

...THE FLASH FLOOD WARNING FOR EAST CENTRAL HARRIS COUNTY HAS
EXPIRED...

Rain rates have dropped substantially for the time being...but we 
will continue to closely monitor the situation. Some roads may still 
be flooded in the area. Please continue to heed any remaining road 
closures.

LAT...LON 2996 9512 2989 9509 2987 9516 2994 9519

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 24, 2:17 AM CDTBeach Hazards StatementHGXBrazoria, Chambers, Galveston22 hr
Jun 24, 7:37 AM CDTAreal Flood AdvisoryHGXHarris113 min
Jun 24, 7:50 AM CDTAreal Flood AdvisoryHGXAustin, Fort Bend, Waller55 min
Jun 24, 8:23 AM CDTAreal Flood AdvisoryHGXGrimes, Liberty, Montgomery, Polk, San Jacinto112 min
Jun 24, 8:45 AM CDTAreal Flood AdvisoryHGXChambers, Harris, Liberty3 hr
Jun 24, 8:56 AM CDTAreal Flood AdvisoryHGXAustin, Brazoria, Fort Bend, Harris, Waller2 hr
Jun 24, 9:20 AM CDTAreal Flood AdvisoryHGXHarris3 hr
Jun 24, 9:38 AM CDTFlash Flood WarningHGXHarris3 hr
Jun 24, 9:48 AM CDTAreal Flood AdvisoryHGXLiberty3 hr
Jun 24, 10:18 AM CDTAreal Flood AdvisoryHGXAustin, Colorado, Waller, Wharton117 min
Jun 24, 10:56 AM CDTAreal Flood AdvisoryHGXAustin, Fort Bend, Harris, Waller, Wharton2 hr
Jun 24, 11:18 AM CDTAreal Flood AdvisoryHGXColorado, Jackson, Wharton57 min
Jun 24, 11:55 AM CDTFlash Flood WarningHGXFort Bend2 hr
Jun 24, 1:01 PM CDTAreal Flood AdvisoryHGXBrazos, Burleson, Grimes, Washington59 min
Jun 24, 2:08 PM CDTSpecial Marine WarningHGX52 min

Nearby

Flash Flood Warnings in Texas, 2017Every flash flood warning in 2017

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.