Alert archive / Texas / Flash Flood Warnings in 2012

Flash Flood Warning 44, NWS Houston/Galveston, TX

July 12, 20125 counties in Texas

NWS Houston/Galveston, TX issued this flash flood warning at Jul 12, 2012, 10:04 AM CDT for 5 counties in Texas. It was in force for 116 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: Jul 12, 2012, 10:04 AM CDT (15:04 UTC)
Expired: Jul 12, 2012, 12:00 PM CDT
In force: 116 min
Issued by: NWS Houston/Galveston, TX
Area: Storm-based polygon
Flood severity: None

Counties Austin County, TX, Harris County, TX, Montgomery County, TX, Waller County, TX, Washington County, TX

The radar

The Houston radar (KHGX), 104 km from the middle of the area, began a volume at 15:04 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, 3.1 hours before the alert went out and 260 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: 2309 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 713 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 64 m²/s²
0-3 km storm-relative helicity: 103 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.

022 
WGUS54 KHGX 121504
FFWHGX
TXC015-201-339-473-477-121700-
/O.NEW.KHGX.FF.W.0044.120712T1504Z-120712T1700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
1004 AM CDT THU JUL 12 2012

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EXTREME SOUTHEASTERN WASHINGTON COUNTY IN SOUTHEAST TEXAS...
  NORTHWESTERN HARRIS COUNTY IN SOUTHEAST TEXAS...
  EXTREME SOUTHWESTERN MONTGOMERY COUNTY IN SOUTHEAST TEXAS...
  CENTRAL WALLER COUNTY IN SOUTHEAST TEXAS...
  EXTREME NORTHEASTERN AUSTIN COUNTY IN SOUTHEAST TEXAS...

* UNTIL 1200 PM CDT

* AT 954 AM CDT...DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA. RAINFALL RATES OF 1 TO 2 
  INCES PER HOUR WERE COMMON WITH THE STORMS FORMING OVER THE 
  WARNED AREA. FLASH FLOODING IS ONGOING AND WILL LIKELY CONTINUE 
  THROUGH THE PERIOD. AREAS IN AND AROUND THE UPPER END OF SPRING 
  CREEK AND ALONG CYPRESS CREEK HAVE RECIEVED HEAVY RAINFALL DURING 
  THE LAST 12 HOURS AND WITH THE ADDITIONAL HEAVY RAINFALL 
  AND RUNOFF FURTHER RISES ON THE SMALL FEEDER STREAMS INTO THESE 
  DRAINAGES WILL AGGRAVATE THE FLOODING. STREET FLOODING IN THE 
  WARNED AREA WILL CONTINUE AND MAY WORSEN AS ADDITIONAL STORMS MOVE 
  INTO THE AREA.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  THE WOODLANDS...TOMBALL...HEMPSTEAD...PRAIRIE VIEW...OAK RIDGE
  NORTH...WALLER...CHATEAU WOODS...PINE ISLAND AND STAGECOACH.

LAT...LON 3018 9599 3018 9532 2991 9557 2990 9600
      3004 9621 3014 9623

$$

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 Jul 12, 7:06 AM CDT, 2 hours 58 minutes earlier.

Area forecast discussion, Jul 12, 7:06 AM CDT, 2 hours 58 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
706 AM CDT THU JUL 12 2012

.DISCUSSION...
SEE AVIATION SECTION FOR 12Z TAF DISCUSSION.

&&

.AVIATION...
A SLOW MOVING LINE OF SHOWERS AND THUNDERSTORMS IS MOVING IN TO
THE WESTERN HOUSTON METRO AREA. IAH COULD SEE 2 TO 3 HOURS OF
MVFR/IFR CONDITIONS FOR LOW CIGS AND VSBY. THIS LINE IS COLLIDING WITH
A SMALL CLUSTER OF FAST MOVING THUNDERSTORMS MOVING INLAND FROM
THE COAST NEAR MATAGORDA BAY. THIS SECOND CLUSTER WILL IMPACT SGR
AND HOU AND PRODUCE 1 TO 2 HOURS OF MVFR/IFR CONDITIONS FOR THE
TWO SOUTHERN AIRPORTS. THE BIGGEST AVIATION IMPACT WILL BE TO
TERMINALS IN THE HOUSTON METRO AREA.

UTS...LBX...AND GLS WILL BE PREVAILING VFR WITH BRIEF PERIODS OF
MVFR CONDITIONS AS STRONGER SHOWERS PASS OVER THE TERMINALS.

CLL WILL LIKELY REMAIN VFR FOR REMAINDER OF THE DAY AS THE
PRECIPITATION APPEARS TO BE CONCENTRATED TO THE EAST OF THE
TERMINAL.

MOST OF THE PRECIPITATION SHOULD MOVE TO THE EAST OF THE HOUSTON
METRO AREA BY EARLY AFTERNOOON. 44

&&

.PREV DISCUSSION... /ISSUED 419 AM CDT THU JUL 12 2012/

UPDATE...
ADDED MARINE AND AVIATION DISCUSSION.

PREV DISCUSSION... /ISSUED 400 AM CDT THU JUL 12 2012/

.LOCALLY HEAVY RAIN POSSIBLE THIS MORNING...

DISCUSSION...
1SHORT TERM MODELS ARE IN EXCELLENT AGREEMENT WITH REGARD TO THE
NEXT HEAVY RAIN EVENT DEVELOPING OVER SOUTHEAST TEXAS. A NEARLY
STATIONARY LINE OF SHRA/TSRA HAS DEVELOPED FROM COLUMBUS TO CONROE
TO LIVINGSTON. RAINFALL RATES WITHIN THIS LINE ARE BETWEEN 1 TO 2
INCHES PER HOUR. 00Z ANALYSIS SHOWS UPPER FLOW REMAINS STRONGLY
DIVERGENT. AT 850 MB...A WEAK LOW PRESSURE SYSTEM WAS OVER
SOUTHEAST TEXAS WITH A WEAK 850-700 MB TROUGH STRETCHED ALONG THE
US HWY 59 CORRIDOR. MOISTURE IS POOLING ALONG AND NORTH OF THIS
FEATURE. WILL MAINTAIN THE FLASH FLOOD WATCH THROUGH 21Z BUT
SEVERAL OF THE SHORT TERM MODELS (WHICH ARE VERIFYING WELL) SHUNT
THE PRECIP EAST OF THE REGION BY 19-20Z. CURRENTLY...AM EXPECTING
1 TO 3 INCHES OF RAIN WITH LOCALLY HIGHER AMOUNTS APPROACHING 5
INCHES IF TRAINING DEVELOPS (AND IT LOOKS LIKE IT HAS IN
MONTGOMERY AND SAN JACINTO COUNTIES). WITH ALL THE HEAVY RAIN OVER
THE PAST COUPLE OF DAYS...IT WILL NOT TAKE MUCH RAIN TO CAUSE
FLOODING.

THE UPPER LEVEL WEAKNESS RESPONSIBLE FOR THE RECENT RAINS WILL
LINGER OVER THE UPPER TEXAS COAST THROUGH EARLY NEXT WEEK. FEEL
DAYTIME HEATING WILL TRIGGER SCATTERED SHRA/TSRA EACH DAY. ECMWF
DRIES THINGS OUT A BIT WHILE THE GFS IS WETTER. UPPER LEVEL
RIDGING WILL TRY TO REASSERT ITSELF BY NEXT WEDNESDAY BUT IT
APPEARS THE RIDGE WILL BE FAR ENOUGH NORTH TO ALLOW WEAK
DISTURBANCES TO UNDERCUT THE RIDGE AND KEEP RAIN CHANCES IN THE
FORECAST THROUGH ALL OF NEXT WEEK. AS FOR TEMPS...BLENDED MET AND
MAV GUIDANCE THROUGH FRIDAY AND BLENDED MEX ECMWF GUIDANCE FOR THE
EXTENDED. 43

&&

MARINE...
NO SIGNIFICANT CHANGES TO CURRENT FCST TRENDS. A WEAK SURFACE TROUGH
WILL KEEP A LIGHT WIND REGIME IN PLACE THROUGH THE WEEKEND. AN UPPER
LEVEL TROUGH INTERACTING WITH THE SURFACE TROUGH WILL ALSO KEEP
SCATTERED STORMS IN THE FCST THROUGH THE END OF THE WEEK.

BRIEF GUSTY WINDS AND ELEVATED SEAS ARE POSSIBLE IN AND NEAR ANY
THUNDERSTORM ACTIVITY. 44

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      88  73  89  73  91 /  60  20  50  30  30
HOUSTON (IAH)              86  74  89  73  91 /  80  30  50  40  40
GALVESTON (GLS)            86  79  88  80  89 /  70  30  50  50  40

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH UNTIL 4 PM CDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...
     CHAMBERS...COLORADO...FORT BEND...GALVESTON...GRIMES...
     HARRIS...JACKSON...LIBERTY...MADISON...MATAGORDA...
     MONTGOMERY...POLK...SAN JACINTO...WALKER...WALLER...
     WASHINGTON...WHARTON.

GM...NONE.
&&

DISCUSSION...43
AVIATION/MARINE...44

Hazardous weather outlook, Jul 12, 4:39 AM CDT, 5 hours 25 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
439 AM CDT THU JUL 12 2012

GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226-
227-235>238-130945-
AUSTIN-BRAZORIA-BRAZOS-BURLESON-CHAMBERS-COLORADO-FORT BEND-
GALVESTON-GALVESTON BAY-GRIMES-HARRIS-HOUSTON-JACKSON-LIBERTY-
MADISON-MATAGORDA-MATAGORDA BAY-MONTGOMERY-POLK-SAN JACINTO-
TRINITY-WALKER-WALLER-WASHINGTON-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL 20 NM TO 60 NM-
WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM-
WATERS FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM-
WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM-WHARTON-
438 AM CDT THU JUL 12 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST TEXAS.

.DAY ONE...TODAY AND TONIGHT

...FLASH FLOOD WATCH IN EFFECT...

SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL PERSIST
THROUGH THE EARLY AFTERNOON BEFORE DIMINISHING BY EVENING.
RAINFALL AMOUNTS WILL AVERAGE BETWEEN 1 AND 3 INCHES ALONG AND
SOUTH OF A LIVINGSTON TO CONROE TO COLUMBUS LINE WITH LOCALLY
HIGHER TOTALS BETWEEN 4 AND 7 INCHES. A FLASH FLOOD WATCH REMAINS
IN EFFECT THROUGH THIS AFTERNOON.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH DAY INTO
EARLY NEXT WEEK. THE GROUND IS INCREASINGLY SATURATED AND HEAVY
RAINS COULD PRODUCE LOCALIZED FLOODING.

.SPOTTER INFORMATION STATEMENT...

EMERGENCY MANAGERS AND STORM SPOTTERS SHOULD PREPARE FOR
ACTIVATION.

In the hours before

Special weather statement, Jul 12, 6:15 AM CDT, 3 hours 49 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
615 AM CDT THU JUL 12 2012

TXZ213-227-121145-
HARRIS TX-FORT BEND TX-
615 AM CDT THU JUL 12 2012

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN HARRIS AND
NORTHEASTERN FORT BEND COUNTIES UNTIL 645 AM CDT...

AT 614 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS
TRACKING A STRONG THUNDERSTORM NEAR TOWN WEST...MOVING NORTHEAST
AT 45 MPH.

WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM. VERY HEAVY
RAINFALL RATES WILL ALSO BE POSSIBLE...UP TO THREE INCHES PER HOUR.

LOCATIONS IMPACTED INCLUDE...
HOUSTON...MISSION BEND...SUGAR LAND...FIRST COLONY...BELLAIRE...
WEST UNIVERSITY PLACE...STAFFORD...JERSEY VILLAGE...TOWN WEST...
MEADOWS...HUNTERS CREEK VILLAGE...BUNKER HILL VILLAGE...SPRING
VALLEY...PINEY POINT VILLAGE...HEDWIG VILLAGE...SOUTHSIDE PLACE
AND HILSHIRE VILLAGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY
LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 2954 9559 2965 9576 3000 9564 2981 9530
TIME...MOT...LOC 1114Z 215DEG 41KT 2966 9564

Special weather statement, Jul 12, 6:49 AM CDT, 3 hours 15 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
649 AM CDT THU JUL 12 2012

TXZ199-213-214-121230-
HARRIS TX-CHAMBERS TX-MONTGOMERY TX-
649 AM CDT THU JUL 12 2012

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN HARRIS...WEST CENTRAL
CHAMBERS AND SOUTHEASTERN MONTGOMERY COUNTIES UNTIL 730 AM CDT...

AT 648 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS
TRACKING A STRONG THUNDERSTORM NEAR HOUSTON...MOVING NORTHEAST AT
35 MPH.

WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM. VERY HEAVY
RAINFALL IS ALSO POSSIBLE WITH HOURLY RAINFALL RATES IN EXCESS OF
TWO INCHES PER HOUR.

LOCATIONS IMPACTED INCLUDE...
HOUSTON...PASADENA...BAYTOWN...KINGWOOD...LA PORTE...CHANNELVIEW...
DEER PARK...CLOVERLEAF...HUMBLE...SOUTH HOUSTON...ALDINE...WEST
UNIVERSITY PLACE...GALENA PARK...JACINTO CITY...HIGHLANDS...
BARRETT...CROSBY...SHELDON...SOUTHSIDE PLACE AND HILSHIRE VILLAGE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY
LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A
SAFE SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 2968 9488 2967 9493 2968 9497 2967 9497
      2968 9498 2966 9500 2961 9540 2986 9554
      3013 9511
TIME...MOT...LOC 1148Z 243DEG 31KT 2975 9539

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 3:47 AM CDT	Areal Flood Advisory	HGX	Montgomery, Polk, San Jacinto, Waller	118 min
Jul 12, 4:08 AM CDT	Areal Flood Advisory	HGX	Jackson, Matagorda	52 min
Jul 12, 4:17 AM CDT	Flash Flood Warning	HGX	Harris, Montgomery, San Jacinto, Waller	3 hr
Jul 12, 4:43 AM CDT	Areal Flood Advisory	HGX	Austin, Colorado, Waller	2 hr
Jul 12, 5:23 AM CDT	Areal Flood Advisory	HGX	Harris, Liberty, Montgomery, Waller	112 min
Jul 12, 5:52 AM CDT	Flash Flood Warning	HGX	Austin, Colorado, Fort Bend, Harris, Montgomery, Waller	113 min
Jul 12, 6:15 AM CDT	Special Weather Statement	HGX	Harris	30 min
Jul 12, 6:35 AM CDT	Areal Flood Advisory	HGX	Fort Bend, Harris, Liberty	3 hr
Jul 12, 6:49 AM CDT	Special Weather Statement	HGX	Harris	41 min
Jul 12, 7:15 AM CDT	Areal Flood Advisory	HGX	Harris, Montgomery, San Jacinto	60 min
Jul 12, 7:22 AM CDT	Special Marine Warning	HGX		38 min
Jul 12, 7:29 AM CDT	River Flood Warning	HGX	Harris	6 days
Jul 12, 7:41 AM CDT	Flash Flood Warning	HGX	Fort Bend, Harris, Montgomery, Waller	2 hr
Jul 12, 7:51 AM CDT	Areal Flood Advisory	HGX	Austin, Colorado, Wharton	114 min
Jul 12, 8:19 AM CDT	Special Marine Warning	HGX		41 min
Jul 12, 8:26 AM CDT	River Flood Warning	HGX	Harris	25 hr
Jul 12, 8:44 AM CDT	Areal Flood Advisory	HGX	Austin, Colorado, Fort Bend, Jackson, Wharton	2 hr
Jul 12, 9:14 AM CDT	Areal Flood Advisory	HGX	Austin, Brazoria, Fort Bend, Harris, Waller, Washington and 1 more	106 min
Jul 12, 9:48 AM CDT	Areal Flood Advisory	HGX	Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty and 1 more	117 min
Jul 12, 10:11 AM CDT	Areal Flood Advisory	HGX	Austin, Brazoria, Fort Bend, Harris, Waller, Washington and 1 more	49 min
Jul 12, 11:18 AM CDT	Areal Flood Advisory	HGX	Austin, Colorado, Fort Bend, Harris, Waller	117 min
Jul 12, 11:55 AM CDT	Areal Flood Advisory	HGX	Brazoria, Galveston	3 hr
Jul 12, 12:01 PM CDT	Flash Flood Warning	HGX	Austin, Grimes, Harris, Montgomery, Waller, Washington	3 hr
Jul 12, 12:46 PM CDT	River Flood Warning	HGX	Harris, Montgomery	21 hr
Jul 12, 2:26 PM CDT	River Flood Warning	HGX	Harris, Montgomery	70 hr
Jul 12, 3:11 PM CDT	Areal Flood Advisory	HGX	Brazos	64 min

Nearby

Flash Flood Warnings in Texas, 2012 Every flash flood warning in 2012

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.