Alert archive / Texas / Flash Flood Warnings in 2003

Flash Flood Warning 18, NWS Houston/Galveston, TX

August 31, 2003Liberty County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Aug 31, 2003, 12:40 PM CDT for Liberty County, Texas. It was in force for 2 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 31, 2003, 12:40 PM CDT (17:40 UTC)
Expired: Aug 31, 2003, 3:00 PM CDT
In force: 2 hr
Issued by: NWS Houston/Galveston, TX
Area: Counties, with a storm outline in the text

County Liberty County, TX

The radar

The Houston radar (KHGX), 93 km from the middle of the area, began a volume at 17:42 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, 5.7 hours before the alert went out and 139 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 659 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 692 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 141 m²/s²
0-3 km storm-relative helicity: 174 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 4.0

Open this sounding in Storm Lab

The text

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

000 
WGUS54 KHGX 311745
FFWHOU
TXC291-312000-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1240 PM CDT SUN AUG 31 2003

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

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

* UNTIL 300 PM CDT

* AT 1232 PM CDT...DOPPLER RADAR INDICATED A BAND OF HEAVY RAINFALL 
EXTENDING FROM CLEVELAND TO DEVERS AND SOUTHWARD BEYOND 60 MILES 
OFFSHORE. RADAR ESTIMATES 6 TO 8 INCHES OF RAIN HAS FALLEN IN THIS 
AREA ALREADY. THE GROUND IS BECOMING INCRESINGLY SATURATED AND 
ADDITIONAL RAINS WILL RUNOFF AND CAUSE FLASH FLOODING. AS OF 1240 
PM...THERE ARE NO REPORTS OF FLOODING HOWEVER WITH TRAINING STORMS 
WITH RAINFALL RATES OF 2 INCHES PER HOUR...FLASH FLOODING IS 
IMMINENT.

* FLOODING IS EXPECTED IN OR NEAR...
  LIBERTY...DAYTON...DAISETTA...AMES...DEVERS...CLEVELAND

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 3043 9450 2991 9438 2992 9491 3043 9494

$$

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 31, 9:49 AM CDT, 2 hours 51 minutes earlier.

Area forecast discussion, Aug 31, 9:49 AM CDT, 2 hours 51 minutes before

SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
949 AM CDT SUN AUG 31 2003

TROPICAL STORM GRACE DOWNGRADED TO A DEPRESSION. TROPICAL STORM
WARNINGS DROPPED.

LOOSE CIRCULATION AT BEST...BETTER CIRCULATION DEVELOPING INLAND
NEAR ELLINGTON...CLOSE TO THE DEEPER CONVECTION. WINDS ALONG THE COAST
DEPICTING WESTERLY WINDS. RAINFALL REMAINS THE BIG ISSUE. HEAVY RAINS
OVERNIGHT AND THIS MORNING PRODUCED 2+ EAST OF I-45 A FEW SPOTS
IN EASTERN HARRIS COUNTY SHOWING 5-6. THE TROPICAL TAP SQUEEZED
NORTH BETWEEN THE UPPER LOW NEAR BROWNSVILLE AND THE UPPER
ANTICYCLONE NEAR BATON ROUGE. GPS IPWV SHOWING 2.3-2.5 AT 14Z. THIS
TAP SHOULD SLOWLY TRAVERSE THE AREA WESTWARD AS THE HIGH PUSHES WEST
THOUGH THE WINDS SHOULD RELAX AS THE REMAINS MOVES INLAND AWAY FROM
THE FUEL. WILL PROBABLY SEE THE CONVECTION BREATH OUT THIS
AFTERNOON THEN GET A CONTRACTION LATE THIS AFTERNOON/TONIGHT. WILL
KEEP THE FLOOD WATCH UP AND REFRESH IT LATER THIS MORNING TO ADDRESS
CURRENT TRENDS. TIDES SHOULD BE DROPPING OFF WITH THE WESTERLY
COMPONENT TO THE WINDS AND UPCOMING ASTRONOMICAL LOW TIDES.

WILL UPDATE QPF GRIDS AND LOWER AFTERNOON TEMPERATURES A FEW DEGREES.

45/37/31/47/DH

.HGX...FLOOD WATCH ALL OF SE TX THROUGH TONIGHT.

Hazardous weather outlook, Aug 31, 7:00 AM CDT, 5 hours 40 minutes before

GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226-
227-235>238-011100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
700 AM CDT SUN AUG 31 2003

...TROPICAL STORM WARNING IN EFFECT FROM HIGH ISLAND TO MATAGORDA
BAY...
...FLOOD WATCH IN EFFECT FOR ALL OF SOUTHEAST TEXAS THROUGH
TONIGHT...
...LOCALLY HEAVY RAINFALL POSSIBLE THROUGH TONIGHT...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT.
A TROPICAL STORM WARNING REMAINS IN EFFECT THIS MORNING FROM HIGH
ISLAND TO MATAGORDA BAY. WEAK AND POORLY ORGANIZED TROPICAL STORM
GRACE IS EXPECTED TO MOVE INLAND ALONG THE MIDDLE TEXAS COAST LATER
TODAY. WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED TO
PERSIST ACROSS PORTIONS OF SOUTHEAST TEXAS TODAY AND TONIGHT AS
INFLOW OFF THE GULF CONTINUES. RAINFALL TOTALS THROUGH MIDNIGHT
TONIGHT ARE EXPECTED TO AVERAGE AS HIGH AS 6 TO 8 INCHES WITH
ISOLATED 8 TO 12 INCH AMOUNTS POSSIBLE WHERE THE BEST TRAINING
DEVELOPS. PLEASE REFER TO HLSHOU AND FFAHGX FOR MORE DETAILS
REGARDING THIS ONGOING FLOOD THREAT.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.
THE THREAT FOR LOCALLY HEAVY RAINFALL IS EXPECTED TO GRADUALLY SHIFT
TO THE WEST ON MONDAY AFTERNOON. WESTERN PORTIONS OF SOUTHEAST TEXAS
MAY EXPERIENCE THE GREATEST THREAT FOR LOCALLY HEAVY RAINFALL. THESE
SAME WESTERN COUNTIES MAY CONTINUE TO BE UNDER THE GUN FOR HEAVY
RAINFALL ON TUESDAY AND WEDNESDAY AS THE REMNANTS OF GRACE MOVE
SLOWLY IN AND AROUND THE TEXAS HILL COUNTRY. SLIGHTLY DRIER AIR
MIGHT FINALLY ENTER THE FORECAST AREA FROM THE NORTH TOWARD THE END
OF THE WEEK.

.SPOTTER INFORMATION STATEMENT...
EMERGENCY MANAGERS AND STORM SPOTTERS SHOULD BE PREPARED FOR
ACTIVATION. PREPAREDNESS PLANS SHOULD BE IMPLEMENTED.

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 31, 1:20 AM CDT	Flash Flood Warning	HGX	Galveston, Harris	4 hr
Aug 31, 11:52 AM CDT	Flash Flood Warning	HGX	Chambers, Galveston	3 hr

Nearby

Flash Flood Warnings in Texas, 2003 Every 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; radar from the NEXRAD Level II archive.