Alert archive / Texas / Flash Flood Warnings in 2003

Flash Flood Warning 6, NWS Houston/Galveston, TX

February 20, 2003Washington County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Feb 20, 2003, 8:21 PM CST for Washington County, Texas. It was in force for 114 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
Feb 20, 2003, 8:21 PM CST (02:21 UTC)
Expired
Feb 20, 2003, 10:15 PM CST
In force
114 min
Issued by
NWS Houston/Galveston, TX
Area
Counties, with a storm outline in the text

County Washington County, TX

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

Corpus Christi, TX (KCRP), launched 00:00Z, 2.4 hours before the alert went out and 295 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, Corpus Christi, TX at 00:00Z on 2003-02-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 962 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, Corpus Christi, TX at 00:00Z on 2003-02-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 98 square meters per square second.1939587897Sfc1 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
962 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
623 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
98 m²/s²
0-3 km storm-relative helicity
140 m²/s²
Significant tornado parameter
0.5
Supercell composite
2.7

Open this sounding in Storm Lab

The text

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

000 
WGUS54 KHGX 210221
FFWHOU
TXC477-210415-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
821 PM CST THU FEB 20 2003

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

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

* UNTIL 1015 PM CST

* AT 820 PM CST...DOPPLER RADAR INDICATED VERY HEAVY RAINFALL ACROSS 
MUCH OF WASHINGTON COUNTY. ADDITIONAL STORMS CONTINUE TO DEVELOP TO 
THE SOUTHWEST IN FAYETTE COUNTY AND ARE EXPECTED TO MOVE ACROSS 
WASHINGTON COUNTY THROUGH 1015 PM. RAINFALL AMOUNTS OF 1 TO 2 INCHES 
WILL LIKELY LEAD TO FLOODING. 

* FLOODING IS EXPECTED IN OR NEAR...
  LAKE SOMERVILLE DAM...BURTON...BRENHAM...INDEPENDENCE

DO NOT CROSS ANY LOCATION WHERE WATER COVERS THE ROAD

USE EXTRA CAUTION AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE DEPTH
AND SPEED OF FLASH FLOOD WATERS.

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 3040 9618 3027 9612 3012 9622 3007 9661
          3020 9676 3031 9665

$$

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 Feb 20, 1:35 PM CST, 6 hours 46 minutes earlier.

Area forecast discussion, Feb 20, 1:35 PM CST, 6 hours 46 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
135 PM CST THU FEB 20 2003

THE FRONT HAS DRIFTED SLIGHTLY NORTH AND IS NOW ALONG THE INTERSTATE
10 CORRIDOR FROM BPT TO COLUMBUS. TEMPERATURES NORTH OF THE BOUNDARY
HOLDING IN THE MID-UPPER 50S. NEAR THE COAST 60S THE RULE. CONVECTION
HAS BEEN FOCUSED FROM NEAR LAKE SOMERVILLE TO CROCKETT. HEAVIEST
RAINFALL HAS BEEN OVER BURLESON COUNTY ESTIMATING 5 TO 6 INCHES.
RAINFALL AT CLL MIDNIGHT TO 130 PM 2.76. UPPER LOW OVER NORTHERN GULF
OF CALIFORNIA MOVING NEARLY DUE EAST. THE MAIN TROUGH AXIS SHOULD PUSH
THROUGH THE REGION BY LATE FRIDAY NIGHT (MODELS IN GOOD CONSENSUS.) IN
THE MEANTIME SOUTHEAST TEXAS WILL BE UNDER THE FAUCET. FRONT SHOULD
LIFT SLOWLY NORTH THIS EVENING AND WILL PLACE SOUTHERN FA IN FAVORABLE
REGION FOR SEVERE THUNDERSTORMS THOUGH PRECIP WILL BE SCATTERED IN
NATURE NOT AS WIDESPREAD AS NORTH OF THE FRONT. DEWPOINTS 62-66 WILL
BE PRESENT IN THE WARM SECTOR AND LL SHEAR WILL BE ON THE INCREASE
OVERNIGHT AS LLJ DEVELOPS. STRONG DIFFLUENCE ALOFT AND THE APPROACH OF
THE LEFT EXIT REGION WILL WARRANT HIGH POPS WITH HEAVY RAIN AND SEVERE
THREAT. EXPECTING STORM RAINFALL ACCUMULATIONS OF 1-2 BEING FAIRLY
COMMON...ISOLATED TOTALS OF 8 TO 10 INCHES. THE GREATER AMOUNTS SHOULD
BE OVER THE NORTHERN FA. WILL EXPAND THE FLASH FLOOD WATCH TO INCLUDE
THE ENTIRE AREA AND UP ACCUMULATIONS. PREFRONTAL TROUGH AND ASSOCIATED
SQUALL LINE SHOULD DEVELOP TO THE SW AND MOVE INTO THE GULF AND
ASSOCIATED MCV SWEEPS LATE FRIDAY AFTERNOON/EARLY EVENING ENDING THE
PRECIPITATION. MILD PACIFIC AIRMASS FOLLOWS BUT WILL BE QUICKLY
MODIFIED AS NEXT SYSTEM STARTS TO DEVELOP OVER THE SOUTHERN PLAINS
SUNDAY. WILL CARRY SLIGHT CHANCE POPS SOUTH SUNDAY AFTERNOON. THIS
NEXT PACIFIC FRONT GETS JUST OFFSHORE AGAIN AND ON MONDAY AND MOISTURE
INCREASES QUICKLY WITH RAIN CHANCES GOING UP ON MONDAY. CLOUDS SHOULD
BE PERSISTING OVER THE REGION WELL INTO TUESDAY.

45/41/31/37

.HGX...FFA ALL OF SE TX.
       SCA HIGH ISLAND TO MATAGORDA OUT 20 TO 60 NM.

PRELIMS...
CLL TT 056/063 049/069 047 ++5
IAH TT 061/067 051/068 048 999
GLS TT 062/068 054/065 057 889
Hazardous weather outlook, Feb 20, 4:28 PM CST, 3 hours 53 minutes before
TXZ163-164-176>179-195>200-210>214-226-227-235>238-211300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
428 PM CST THU FEB 20 2003

...THREAT FOR HEAVY RAINFALL AND SEVERE STORMS ACROSS SOUTHEAST
TEXAS THROUGH FRIDAY...
...FLOOD WATCH IN EFFECT THROUGH FRIDAY...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

.DAY ONE...TONIGHT AND FRIDAY.

A STATIONARY FRONT FROM NEAR COLUMBUS TO BEAUMONT WILL MEANDER
SLOWLY NORTH OVERNIGHT. DEEP MOISTURE WILL STREAM INLAND AND WILL
OVER RUN THIS BOUNDARY HELPING TO FOCUS HEAVY RAINS.  A SERIES OF
UPPER LEVEL DISTURBANCES WILL MOVE OVER THE REGION BRINGING BANDS OF
PRECIPITATION. LOCALLY HEAVY RAINFALL WILL BE LIKELY WITH SOME OF THE
STORMS. RAINFALL AMOUNTS WILL AVERAGE 1 TO 2 INCHES WITH ISOLATED
TOTALS OF 7 TO 9 INCHES BY THE TIME THE EVENT COMES TO AN END FRIDAY
EVENING. GIVEN THE HEAVY RAINS THAT HAVE FALLEN A FLASH FLOOD
WATCH WILL BE IN EFFECT THROUGH FRIDAY.

IN ADDITION...THE ATMOSPHERIC WIND PROFILE WILL FAVOR THE POSSIBILITY
OF A FEW STORMS BECOMING SEVERE TONIGHT AND FRIDAY.  LARGE HAIL AND
ISOLATED TORNADOES WILL BE THE PRIMARY SEVERE WEATHER THREATS...WITH
DAMAGING WINDS ALSO POSSIBLE.

REMEMBER...A FLOOD WATCH MEANS RAPIDLY RISING WATER OR FLOODING IS
POSSIBLE WITHIN THE WATCH AREA. CHECK OVER YOUR PREPAREDNESS
REQUIREMENTS...KEEP INFORMED...AND BE READY FOR QUICK ACTION IF
FLOODING IS OBSERVED OR IF A WARNING IS ISSUED.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY.

SATURDAY THROUGH WEDNESDAY...NO HAZARDOUS WEATHER EXPECTED AT THIS
TIME...BUT RIVER FLOODING PROBLEMS COULD BE ONGOING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED TONIGHT AND SHOULD BE EXPECTED
FRIDAY.

The office that day

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

IssuedProductOfficeCountiesLasted
Feb 20, 6:10 PM CSTFlash Flood WarningHGXBrazos, Burleson, Grimes, Houston, Madison, Walker4 hr
Feb 21, 4:53 AM CSTSevere Thunderstorm WarningHGXJackson22 min
Feb 21, 5:15 AM CSTSevere Thunderstorm WarningHGXJackson, Wharton45 min
Feb 21, 6:51 AM CSTSevere Thunderstorm WarningHGXPolk, San Jacinto39 min
Feb 21, 12:20 PM CSTSevere Thunderstorm WarningHGXBrazoria, Galveston40 min
Feb 21, 12:46 PM CSTSpecial Marine WarningHGX59 min
Feb 21, 1:32 PM CSTSevere Thunderstorm WarningHGXFort Bend43 min
Feb 21, 1:45 PM CSTSevere Thunderstorm WarningHGXHarris60 min
Feb 21, 2:20 PM CSTSevere Thunderstorm WarningHGXMontgomery55 min
Feb 21, 2:54 PM CSTSevere Thunderstorm WarningHGXLiberty66 min
Feb 21, 3:15 PM CSTSevere Thunderstorm WarningHGXPolk45 min
Feb 21, 4:16 PM CSTSevere Thunderstorm WarningHGXLiberty44 min

Nearby

Flash Flood Warnings in Texas, 2003Every flash flood warning in 2003

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.