Alert archive / Texas / Flash Flood Warnings in 2001

Flash Flood Warning 80, NWS Houston/Galveston, TX

September 9, 2001Montgomery County, Waller County, Texas

NWS Houston/Galveston, TX issued this flash flood warning at Sep 9, 2001, 8:49 AM CDT for Montgomery County, Waller 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 the Iowa Environmental Mesonet reconstructed for it; the warning itself named whole counties.

The facts

Issued
Sep 9, 2001, 8:49 AM CDT (13:49 UTC)
Expired
Sep 9, 2001, 11:15 AM CDT
In force
2 hr
Issued by
NWS Houston/Galveston, TX
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Montgomery County, TX, Waller County, TX

The radar

The Houston radar (KHGX), 111 km from the middle of the area, began a volume at 13:52 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, 1.8 hours before the alert went out and 251 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 2001-09-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3304 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 2001-09-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 151 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
3304 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
530 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
151 m²/s²
0-3 km storm-relative helicity
171 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 091348
FFWHOU
TXC339-473-091615-

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
849 AM CDT SUN SEP 9 2001

THE NATIONAL WEATHER SERVICE HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WALLER COUNTY IN SOUTHEAST TEXAS
  MONTGOMERY COUNTY IN SOUTHEAST TEXAS

* UNTIL 1115 AM CDT

* AT 842 AM CDT...DOPPLER RADAR INDICATED VERY HEAVY RAINFALL        
  CONTINUING OVER NORTHERN WALLER AND WESTERN MONTGOMERY COUNTIES.   
  RAINFALL RATES OF 2 TO 4 INCHES PER HOUR WERE OCCURRING 
  BETWEEN HEMPSTEAD AND MAGNOLIA.

* FLOODING IS EXPECTED IN OR NEAR...
  CONROE...HEMPSTEAD...MAGNOLIA...PANORAMA VILLAGE...PINEHURST...
  PRAIRIE VIEW...MONAVILLE...MONTGOMERY

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 3060 9581 3047 9541 3017 9534 3013 9586
          3017 9599 2998 9592 2992 9606 3020 9611
          3026 9576

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 Sep 9, 6:56 AM CDT, 1 hour 53 minutes earlier.

Area forecast discussion, Sep 9, 6:56 AM CDT, 1 hour 53 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
655 AM CDT SUN SEP 8 2001

...UPDATE...

IR IMAGERY SHOWS CLOUD TOPS COOLING ACROSS CWA. OUTFLOW BOUNDARY
FROM MCS AND SEABREEZE FRONT TO PROVIDE STRONG CONVERGENCE ACROSS SE
TX TODAY. RAINFALL OF 3 TO 4 INCHES HAS ALREADY FALLEN ACROSS
BRAZOS/MADISON COUNTIES. WILL ISSUE FFA FOR ALL BUT COASTAL COUNTIES
FOR TODAY. ALSO WILL LOWER TEMPS AND RAISE POPS EVERYWHERE.

...PREVIOUS DISCUSSION...

ANALYSIS SHOWS TROPICAL AIRMASS IN PLACE ACROSS SE TX WITH 850 MB
DEWPOINTS OF 16C TO 18C...AND SURFACE DEWPOINTS IN THE UPPER 70S.
PWS PROGGED BY BOTH AVN/ETA TO HOVER AROUND 2 INCHES TODAY. 300 MB
DIFLUENCE WILL INCREASE ACROSS AREA THIS MORNING AS SE TX GOES INTO
RRQ OF JET MOVING ACROSS NW TX/OK. BOTH AVN/ETA SHOW STRONG LIFT
FROM SFC TO 500 MB THROUGH LATE THIS AFTN. REMNANTS OF MCS SHOULD
REACH NRN ZONES AFTER 10Z. OUTFLOW BOUNDARIES FROM THIS MCS WILL ACT
AS A FOCUS FOR CONVECTION THIS MORNING. SEABREEZE WILL ALSO SERVE AS
CONVECTIVE FOCUS TODAY AS PRESSURE GRADIENT RELAXES. EXPECT ISOLATED
RAINFALL AMOUNTS OF 2+ INCHES. WILL MENTION LOCALLY HEAVY RAIN IN
ZONES AND PUT OUT HWO FOR HEAVY RAINFALL. SEVERE WEATHER THREAT IS
MINIMAL AS SOUNDINGS WILL RUN NEARLY MOIST ADIABATIC TODAY AND MID
LEVEL WINDS WILL BE VERY WEAK...AROUND 10 KNOTS AT 500 MB.

AVN STILL RUNNING ABOUT 6 HOURS FASTER WITH FROPA ACROSS CWA...BUT
IS TOO HIGH CURRENTLY WITH SFC PRESSURES OVER THE PANHANDLE. WILL
LEAN TOWARD SLOWER MESOETA WITH MOVEMENT OF FRONT...REACHING NW
ZONES LATE TODAY AND COASTAL WATERS LATE TNGT. EXPECT TSRA TO
DIMINISH THIS EVENING WITH LOSS OF DAYTIME HEATING. PWS PROGGED TO
HOVER AROUND 1.8 TO 2 INCHES SRN HALF MONDAY...AND WILL LEAVE IN LOW
POPS FOR THESE AREAS. DRIER AIR WILL DEFINITELY TAKE ITS TIME
FILTERING IN ACROSS SE TX BEHIND FRONT. AVN IS MUCH MORE AGGRESSIVE
WITH DRYING LATE MONDAY/MONDAY NIGHT...BUT LIKELY TOO QUICK. WILL GO
ABOVE MAV GUIDANCE FOR TEMPS MONDAY NIGHT HOUSTON AND COAST.

FOR EXTENDED...500 MB HIGH BUILDS ACROSS TEXAS TUESDAY THROUGH THE
END OF THE WEEK. MUCH DRIER AIR SHOULD SPREAD AREA WIDE ON TUESDAY.
PER AVN...SYSTEM DEVELOPING NEAR FLORIDA WILL CONTINUE TO CIRCULATE
DRY AIR ACROSS SE TX THROUGH THE END OF THE WEEK. MIGHT SEE
DEWPOINTS IN THE UPPER 50S/LOWER 60S FOR ABOUT 3 DAYS
TUESDAY/WEDNESDAY NIGHTS WILL LIKELY BE THE COOLEST NIGHTS.

.HGX...FFA INLAND COUNTIES TODAY.
       SCEC HIGH ISLAND TO MATAGORDA OUT 60 NM THIS MORNING.

35/46/TF

CLL TB 083/068 086/066 090 831
IAH TE 086/071 087/069 090 843
GLS TE 088/077 086/075 086 743

In the hours before

Special weather statement, Sep 9, 3:45 AM CDT, 5 hours 4 minutes before
TXZ163-164-176>179-195>200-210>214-226-227-235>238-092200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
345 AM CDT SUN SEP 9 2001

...HEAVY RAINFALL POSSIBLE ACROSS SOUTHEAST TEXAS TODAY...

A COLD FRONT MOVING ACROSS CENTRAL TEXAS WILL COMBINE WITH AN
UPPER LEVEL DISTURBANCE TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS SOUTHEAST TEXAS TODAY. WITH DEEP TROPICAL
MOISTURE IN PLACE ACROSS THE AREA...SOME OF THE STORMS WILL PRODUCE
HEAVY RAINFALL.

RAINFALL AMOUNTS WILL AVERAGE 1/2 TO 1 INCH ACROSS SOUTHEAST TEXAS
TODAY. RAINFALL AMOUNTS OF 2 TO 3 INCHES WILL BE POSSIBLE IN SOME
AREAS FROM THE HEAVIER STORMS. HEAVY RAINS COULD CAUSE FLOODING OF
FEEDER ROADS AND LOW LYING AREAS AND PONDING OF WATER ON ROADWAYS.
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DIMINISH AFTER SUNSET.

MOTORISTS SHOULD USE CAUTION TODAY. DO NOT DRIVE ACROSS ANY LOCATION
WHERE WATER COVERS THE ROAD IT ONLY TAKES A FEW FEET OF RUNNING WATER
TO SWEEP AWAY MOST VEHICLES.

STAY TUNED TO NOAA WEATHER RADIO OR OTHER NEWS SOURCES FOR THE
LATEST STATEMENTS.

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 9, 6:40 AM CDTFlash Flood WarningHGXBrazos3 hr
Sep 9, 9:12 AM CDTFlash Flood WarningHGXAustin, Colorado3 hr
Sep 9, 9:39 AM CDTFlash Flood WarningHGXBrazos2 hr
Sep 9, 10:55 AM CDTFlash Flood WarningHGXMontgomery, Waller2 hr
Sep 9, 11:55 AM CDTFlash Flood WarningHGXColorado2 hr

Nearby

Flash Flood Warnings in Texas, 2001Every flash flood warning in 2001

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.