Alert archive / Texas / Flash Flood Warnings in 2002

Flash Flood Warning 23, NWS Houston/Galveston, TX

August 15, 2002Brazoria County, Galveston County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Aug 15, 2002, 7:49 PM CDT for Brazoria County, Galveston County, Texas. It was in force for 71 min. 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, 7:49 PM CDT (00:49 UTC)
Expired
Aug 15, 2002, 9:00 PM CDT
In force
71 min
Issued by
NWS Houston/Galveston, TX
Area
Counties, with a storm outline in the text

Counties Brazoria County, TX, Galveston County, TX

The radar

The Houston radar (KHGX), 23 km from the middle of the area, began a volume at 00:48 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 00:00Z, 0.8 hours before the alert went out and 206 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 2002-08-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 355 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 00:00Z on 2002-08-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 94 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
355 J/kg
Mixed-layer CIN
-61 J/kg
Mixed-layer LCL
927 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
178 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

000 
WGUS54 KHGX 160049
FFWHOU
TXC039-167-160200-

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

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  BRAZORIA COUNTY IN SOUTHEAST TEXAS
  GALVESTON COUNTY IN SOUTHEAST TEXAS

* UNTIL 900 PM CDT

* AT 745 PM CDT...DOPPLER RADAR INDICATED LIGHT RAIN OVER PARTS OF 
BRAZORIA AND GALVESTON COUNTIES. RUNOFF FROM TODAYS HEAVY RAINS WILL 
CONTINUE TO KEEP STREAMS AND CREEKS NEAR BANKFULL. PERSONS WHO LIVE 
NEAR WATERSHEDS SHOULD REMAIN ALERT FOR RISING WATER IF HEAVY RAIN 
REDEVELOPS LATER TONIGHT.  

IN ADDITION...LOCAL LAW ENFORCEMENT AGENCIES INDICATE THAT MANY 
ROADS THROUGH THESE COUNTIES REMAIN WATER COVERED. MOTORISTS SHOULD 
REMAIN ALERT FOR HIGH WATER IF DRIVING TONIGHT. MOST FLOODING 
DEATHS OCCUR AT NIGHT WHEN DRIVERS MISJUDGE THE DEPTH OF WATER 
COVERING A ROAD. 

SOME RAINFALL TOTALS FROM THESE COUNTIES

ALVIN          7.00 INCHES
SEAWOLF PARK  13.90 INCHES  
LA MARQUE      9.70 INCHES
GALVESTON     11.32 INCHES
 
DO NOT CROSS ANY LOCATION WHERE WATER COVERS THE ROAD

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 2936 9485 2923 9481 2911 9550 2929 9549

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, 2:05 PM CDT, 5 hours 44 minutes earlier.

Area forecast discussion, Aug 15, 2:05 PM CDT, 5 hours 44 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
205 PM CDT THU AUG 15 2002

FAIRLY SIGNIFICANT FLOOD EVENT UNDERWAY OVR THE CWA. RAINFALL UP TO
11+ INCHES AT GLS. WIDESPREAD STREET FLOODING RESULTING IN SOME
ROAD CLOSURES. ALSO EARLIER REPORTS OF WATER IN HOUSES AND
BUSINESSES IN HOUSTON AND GALVESTON.

MODELS HAVE BEEN OVERLY AGGRESSIVE TRYING TO PULL THE MOISTURE AND
LIFT OUT OF THE AREA. WILL SLOW DOWN THE HEAVY RAIN EXITING TONIGHT.
WILL KEEP FFA UP UNTIL MIDNIGHT. BEST ACTIVITY SHOULD BE OUT BY
THEN. ONLY PROBLEM IS...ANY REDEVELOPMENT OVERNIGHT...EVEN MODERATE
...COULD BE ENOUGH TO AGGRAVATE ONGOING FLOODING. BACK EDGE OF HVY
RAIN HAS ACTUALLY SHIFTED SW DRG THE DAY. LOW CONFIDENCE IN SHORT
TERM MODEL OUTPUT AS A RESULT.

TEMPS SHOULD HOLD ABT WHERE THEY ARE E OF THE BACK EDGE OF THE
PRECIP. WILL FEATURE STEADY TEMPS MOST ZONES TNGT EXCEPT SW.

H5 TROF AXIS REMAINS IN PLACE TNGT INTO FRI...THO IT WEAKENS. PW
VALUES STILL PROGGED AOA 2 ERN ZONES BY LATE TMRW...AND ONLY LOWERS
SLIGHTLY SATURDAY. WILL USE CHC POPS ALL ZONES FRI AND CHC IN THE E
SATURDAY. WILL CONT SLGT CHC ALL ZONES SUN THRU THU...BUT MAY HAVE TO
INCR IN SPOTS IF PRESENT TRENDS CONT IN THE AVN MODEL.

WINDS AND SEAS WARRANT FLAGS ON THE MARINE SIDE. NOT A GREAT DAY FOR
BOATING.

46/37/30/43/WT

.HGX....SCA GULF WATERS...SCEC BAYS.
        FLASH FLOOD WATCH UNTIL 05Z E OF COLORADO RVR.

PRELIMS...
CLL EB 071/090 075/094 075 542
IAH TB 071/089 075/092 075 552
GLS TB 075/087 079/088 079 552

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 16, 6:45 AM CDTSpecial Marine WarningHGX60 min
Aug 16, 7:41 AM CDTFlash Flood WarningHGXChambers, Liberty3 hr
Aug 16, 6:05 PM CDTSevere Thunderstorm WarningHGXHouston3 days

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.