Alert archive / Texas / Flash Flood Warnings in 2002

Flash Flood Warning 15, NWS Houston/Galveston, TX

August 15, 2002Harris County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Aug 15, 2002, 10:26 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
Aug 15, 2002, 10:26 AM CDT (15:26 UTC)
Expired
Aug 15, 2002, 1:15 PM CDT
In force
3 hr
Issued by
NWS Houston/Galveston, TX
Area
Counties, with a storm outline in the text

County Harris County, TX

The radar

The Houston radar (KHGX), 25 km from the middle of the area, began a volume at 15:30 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 3.4 hours before the alert went out and 197 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 2002-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 248 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2002-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 41 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
248 J/kg
Mixed-layer CIN
-45 J/kg
Mixed-layer LCL
765 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
41 m²/s²
0-3 km storm-relative helicity
88 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WGUS54 KHGX 151526
FFWHOU
TXC201-151815-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1022 AM CDT THU AUG 15 2002

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  HARRIS COUNTY IN SOUTHEAST TEXAS

* UNTIL 115 PM CDT

* AT 1020 AM CDT...DOPPLER RADAR INDICATED VERY HEAVY RAINFALL 
REDEVELOPING OVER SOUTHEAST HARRIS COUNTY SOUTHWARD INTO BRAZORIA 
COUNTY. THE STORMS WERE MOVING NORTH AT 20 MPH AND WILL TRAIN OVER 
AREAS THAT HAVE RECEIVED 2 TO 3 INCHES OF RAIN ALREADY THIS MORNING. 
AN ADDITIONAL 2 TO 4 INCHES OF RAINFALL IS EXPECTED BY 1 PM OVER 
SOUTH AND SOUTHEAST HARRIS COUNTY. 

* SIGNIFICANT FLOODING OF ROADWAYS AND SMALL STREAMS IS EXPECTED 
OVER MUCH OF THE AREA EAST OF U.S. HIGHWAY 59. IF HEAVIER RAINFALL 
DEVELOPS SIGNIFICANT RISES MAY ALSO OCCUR ON SOME OF THE BAYOUS.

DO NOT CROSS ANY LOCATION WHERE WATER COVERS THE ROAD

SMALL CREEKS...STREAMS...BAYOUS...UNDERPASSES...AND FEEDER ROADS MAY
FLOOD QUICKLY. AVOID LOCATIONS WATER COVERS THE GROUND

PLEASE REPORT FLOODING TO THE COUNTY SHERIFF...LOCAL POLICE...OR
DEPARTMENT OF PUBLIC SAFETY. THEY WILL RELAY YOUR REPORT TO THE
NATIONAL WEATHER SERVICE.

LAT...LON 2967 9496 2955 9514 2961 9524 2963 9546
          2996 9529

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Houston/Galveston, TX wrote its last area forecast discussion before this flash flood warning went out at Aug 15, 9:55 AM CDT, 31 minutes earlier.

Area forecast discussion, Aug 15, 9:55 AM CDT, 31 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
955 AM CDT THU AUG 15 2002

STARTING TO SEE ADDITIONAL DEVELOPMENT SW OF AREA THAT GOT HAMMERED
LATE LAST NIGHT AND EARLY THIS MORNING. HVY RAIN AREAS AS FAR N AS
CLL ATTM. HAVE OPTED TO GO WITH FFA FOR ALL BUT SW CORNER OF CWA
THIS AFTN. WONT TAKE MUCH TO CAUSE MORE FLD PROBLEMS GIVEN
SATURATED GROUND.

SFC ANALYSIS SHOWS MESO BOUNDARY JUST W OF A BRENHAM TO ANGLETON
LN. AREA ALONG AND EAST OF THIS LINE OF MOST CONCERN.

MODELS INDC ENHANCED LIFT AND MOISTURE EXITING THE REGION DRG THE
AFTN. AM NOT ANTICIPATING ANY PROBS TNGT.

FFA ALREADY OUT. NEW ZFP SHORTLY.

46/37/30/WT

.HGX....SCA OFFSHORE...SCEC NEARSHORE.

PRELIMS...
CLL EB 090/076 094/075 095 623
IAH TB 087/076 092/076 094 734
GLS TB 086/080 088/080 089 744
SW COAST                   534

In the hours before

Special weather statement, Aug 15, 5:00 AM CDT, 5 hours 26 minutes before
TXZ178-179-199-200-210>214-226-227-235>238-152100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
500 AM CDT THU AUG 15 2002

...LOCALLY HEAVY RAINFALL THREAT CONTINUES TODAY PRIMARILY
ALONG AND SOUTHEAST OF AN EL CAMPO TO HOUSTON TO CLEVELAND LINE...

NUMEROUS SHOWERS AND THUNDERSTORMS ARE OCCURRING ALONG THE SOUTHEAST
TEXAS COAST EARLY THIS MORNING. PORTIONS OF GALVESTON ISLAND HAVE
RECEIVED OVER 5 INCHES OF RAIN SINCE MIDNIGHT. ADDITIONAL RAINFALL
AMOUNTS OF 1 TO 3 INCHES ARE POSSIBLE WITH LOCALIZED AMOUNTS TO 4
OR 5 INCHES OVER THE NEXT 12 HOURS.

BE ALERT FOR HIGH STANDING WATER ON ROADWAYS AND IN LOW LYING AREAS.
MOTORISTS SHOULD REMEMBER NOT TO DRIVE INTO AREAS WHERE WATER COVERS
THE ROADWAY.

A STRONG UPPER LEVEL DISTURBANCE IN CONJUNCTION WITH ABUNDANT GULF
MOISTURE IS PRODUCING THE RAIN. THE DISTURBANCE IS EXPECTED TO
GRADUALLY WEAKEN LATER TONIGHT.
Local storm report, Aug 15, 6:07 AM CDT, 4 hours 19 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
507 AM CST THU AUG 15 2002

TIME(CST)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0455 AM    CRYSTAL BEACH             TX   WIND DAMAGE
08/15/02   GALVESTON                      ROOF BLOWN OFF A HOUSE
                                          AND POWERLINES BLOWN
                                          DOWN. OTHER STRUCTURAL
                                          DAMAGE IN THE AREA.
                                          REPORTED BY EMERGENCY
                                          MANAGEMENT.
Local storm report, Aug 15, 6:10 AM CDT, 4 hours 16 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
610 AM CDT THU AUG 15 2002

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0455 AM    CRYSTAL BEACH             TX   WIND DAMAGE
08/15/02   GALVESTON                      ROOF BLOWN OFF A HOUSE
                                          AND POWERLINES BLOWN
                                          DOWN. OTHER STRUCTURAL
                                          DAMAGE IN THE AREA.
                                          REPORTED BY EMERGENCY
                                          MANAGEMENT.

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 15, 1:55 AM CDTSpecial Marine WarningHGX2 hr
Aug 15, 3:47 AM CDTFlash Flood WarningHGXBrazoria, Galveston118 min
Aug 15, 4:00 AM CDTSpecial Marine WarningHGX2 hr
Aug 15, 4:33 AM CDTSevere Thunderstorm WarningHGXGalveston5 hr
Aug 15, 5:48 AM CDTFlash Flood WarningHGXBrazoria, Galveston2 hr
Aug 15, 7:28 AM CDTSpecial Marine WarningHGX62 min
Aug 15, 7:43 AM CDTFlash Flood WarningHGXGalveston107 min
Aug 15, 8:22 AM CDTSpecial Marine WarningHGX53 min
Aug 15, 8:47 AM CDTSevere Thunderstorm WarningHGXHarris34 hr
Aug 15, 9:13 AM CDTSpecial Marine WarningHGX2 hr
Aug 15, 10:34 AM CDTFlash Flood WarningHGXGrimes, Waller, Washington3 hr
Aug 15, 11:10 AM CDTFlash Flood WarningHGXBrazoria, Galveston3 hr
Aug 15, 11:13 AM CDTSpecial Marine WarningHGX2 hr
Aug 15, 11:37 AM CDTTornado WarningHGXGalveston23 min
Aug 15, 11:59 AM CDTTornado WarningHGXGalveston31 min
Aug 15, 1:14 PM CDTFlash Flood WarningHGXGrimes, Waller, Washington3 hr
Aug 15, 1:19 PM CDTSpecial Marine WarningHGX116 min
Aug 15, 1:45 PM CDTFlash Flood WarningHGXBrazoria, Galveston, Harris3 hr
Aug 15, 3:47 PM CDTFlash Flood WarningHGXWaller, Washington2 hr
Aug 15, 3:55 PM CDTFlash Flood WarningHGXHarris3 hr
Aug 15, 4:51 PM CDTFlash Flood WarningHGXBrazoria, Galveston3 hr
Aug 15, 6:10 PM CDTSpecial Marine WarningHGX2 hr
Aug 15, 6:10 PM CDTSpecial Marine WarningHGX2 hr

Nearby

Flash Flood Warnings in Texas, 2002Every flash flood warning in 2002

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.