Alert archive / Texas / Flash Flood Warnings in 2016

Flash Flood Warning 17, NWS Houston/Galveston, TX

April 18, 20165 counties in Texas

NWS Houston/Galveston, TX issued this flash flood warning at Apr 18, 2016, 6:30 AM CDT for 5 counties in Texas. It was in force for 3 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: Apr 18, 2016, 6:30 AM CDT (11:30 UTC)
Expired: Apr 18, 2016, 9:00 AM CDT
In force: 3 hr
Issued by: NWS Houston/Galveston, TX
Area: Storm-based polygon
Emergency: Flash flood emergency
Flood severity: None

Counties Austin County, TX, Colorado County, TX, Fort Bend County, TX, Harris County, TX, Waller County, TX

The radar

The Houston radar (KHGX), 89 km from the middle of the area, began a volume at 11:31 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

Corpus Christi, TX (KCRP), launched 00:00Z, 11.5 hours before the alert went out and 261 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: 1949 J/kg
Mixed-layer CIN: -53 J/kg
Mixed-layer LCL: 558 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 104 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 3.5

Open this sounding in Storm Lab

The text

As transmitted.

768 
WGUS54 KHGX 181130
FFWHGX
TXC015-089-157-201-473-181400-
/O.NEW.KHGX.FF.W.0017.160418T1130Z-160418T1400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
630 AM CDT MON APR 18 2016

...FLASH FLOOD EMERGENCY EXPANDED SOUTH...

THE NATIONAL WEATHER SERVICE IN LEAGUE CITY HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL COLORADO COUNTY IN SOUTHEASTERN TEXAS...
  SOUTHEASTERN WALLER COUNTY IN SOUTHEASTERN TEXAS...
  WEST CENTRAL HARRIS COUNTY IN SOUTHEASTERN TEXAS...
  SOUTHEASTERN AUSTIN COUNTY IN SOUTHEASTERN TEXAS...
  NORTHWESTERN FORT BEND COUNTY IN SOUTHEASTERN TEXAS...

* UNTIL 900 AM CDT

* AT 624 AM CDT...DOPPLER RADAR CONTINUED TO INDICATE A BAND OF THUNDERSTORMS PRODUCING
  VERY HEAVY RAIN ACROSS THE WARNED AREA. RAINFALL RATES ARE RANGING FROM 2 TO 4 
  INCHES AN HOUR. FLASH FLOODING IS OCCURRING. 

  THIS IS A FLASH FLOOD EMERGENCY. THIS IS A PARTICULARLY DANGEROUS SITUATION.   

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  NORTHEASTERN SUGAR LAND...KATY...SEALY...BROOKSHIRE...COLUMBUS...BUNKER
  HILL VILLAGE...PINEY POINT VILLAGE...MISSION BEND...TOWN WEST...SPRING
  BRANCH WEST...SPRING BRANCH NORTH...SPRING VALLEY...SOUTHERN ELDRIDGE
  / WEST OAKS...PECAN GROVE...MEADOWS PLACE...HEDWIG VILLAGE...FULSHEAR...
  SIMONTON...SAN FELIPE AND ALIEF.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS AN EXTREMELY DANGEROUS AND LIFE-THREATENING SITUATION. STAY OFF ROADS 
IN THE EMERGENCY AREA. 

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING.

&&

LAT...LON 2965 9559 2963 9585 2966 9611 2966 9636
      2969 9647 2973 9668 2977 9666 2973 9632
      2978 9623 2981 9612 2979 9581 2973 9567
      2975 9560 2984 9553 2986 9549 2977 9552
      2970 9554

$$

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 Apr 18, 3:56 AM CDT, 2 hours 34 minutes earlier.

Area forecast discussion, Apr 18, 3:56 AM CDT, 2 hours 34 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
356 AM CDT MON APR 18 2016

.DISCUSSION...
SEVERE...HISTORIC FLOOD EVENT ONGOING. SEVERAL FLASH FLOOD
WARNINGS AND FLASH FLOOD EMERGENCIES IN EFFECT FROM SLOW MOVING
BAND OF THUNDERSTORMS. MULTIPLE HIGH WATER RESCUES REPORTED AND
STRUCTURES BEING FLOODED. UNFORTUNATELY BAND OF THUNDERSTORMS TO
IMPACT AREAS ALREADY HAVING RECEIVED HEAVY RAIN FOR POTENTIALLY SEVERAL
MORE HOURS.

WORST CASE SCENARIO AS DEEP MOISTURE ADVECTING IN OFF THE GULF
AND BEING FOCUSSED ALONG E TO W BAND OF THUNDERSTORMS WITH VERY
LITTLE MOVEMENT. MODELS HAVE STRUGGLED TO CAPTURE PLACEMENT AND
TIMING OF CONVECTION AND DIFFICULT GOING FORWARD AS WELL. NOT MUCH
CHANGE IN THE PATTERN IS EXPECTED THROUGH TUESDAY. THROUGH TUESDAY
EXPECT ADDITIONAL ROUNDS OF HEAVY RAIN WHICH WILL ONLY EXACERBATE
FLOODING ALREADY ONGOING. DIFFICULT TO TIME THINGS BUT
THUNDERSTORM COMPLEXES WILL GENERALLY BE SLOW MOVING. CONCERN IS
THEY WILL OCCUR IN SIMILAR AREAS. HAVE HAD TO RAISE POPS WEDNESDAY
AS WELL AS MODELS SHOWING ANOTHER VORT LOBE PIVOTING AROUND UPPER
LOW LIKELY BRINGING MORE SHOWERS AND THUNDERSTORMS. REALLY DONT
DRY OUT UNTIL POSSIBLY FRIDAY AS MODELS SUGGEST RIDGING AT SURFACE
AND ALOFT. 46

&&

.MARINE...
A COASTAL FLOOD WARNING REMAINS IN EFFECT FOR THE UPPER COASTAL
AREAS...GALVESTON...HARRIS...CHAMBERS. FURTHER SOUTH ACROSS BRAZORIA
AND MATAGORDA WILL HAVE A COASTAL FLOOD ADVISORY. WATER LEVELS ARE
PEAKING AROUND 4 FEET AT HIGH TIDES IN THE WARNING AREA AND AROUND
3.5 FEET IN THE ADVISORY AREA. AFTER THE AFTERNOON HIGHT TIDE
PEAKING 2-3 PM WE WILL LIKELY SEE WATER LEVELS BEGIN TO SUBSIDE
SOME...ALTHOUGH STILL WELL ABOVE NORMAL.

THE SMALL CRAFT ADVISORY WILL CONTINUE TODAY AS WELL. SHOULD SEE
WINDS/SEAS SUBSIDE SOME DURING THE DAY TODAY. 33

&&

.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL)      75  66  78  66  81 / 100  90  60  20  40
HOUSTON (IAH)              77  67  77  67  82 /  90  90  70  30  50
GALVESTON (GLS)            75  70  75  70  77 /  70  80  80  30  30

&&

.HGX WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH THROUGH TUESDAY MORNING FOR THE FOLLOWING
     ZONES: AUSTIN...BRAZORIA...BRAZOS...BURLESON...CHAMBERS...
     COLORADO...FORT BEND...GALVESTON...GRIMES...HARRIS...
     HOUSTON...JACKSON...LIBERTY...MADISON...MATAGORDA...
     MONTGOMERY...POLK...SAN JACINTO...TRINITY...WALKER...
     WALLER...WASHINGTON...WHARTON.

     COASTAL FLOOD WARNING UNTIL 1 PM CDT THIS AFTERNOON FOR THE
     FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...HARRIS...
     MATAGORDA.

GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THIS MORNING FOR THE
     FOLLOWING ZONES: GALVESTON BAY...MATAGORDA BAY.

     SMALL CRAFT ADVISORY UNTIL 11 AM CDT THIS MORNING FOR THE
     FOLLOWING ZONES: 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.

&&

DISCUSSION...99

In the hours before

Local storm report, Apr 18, 4:26 AM CDT, 2 hours 4 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE Houston/Galveston TX
426 AM CDT MON APR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0423 AM     FLASH FLOOD      6 N COLUMBUS            29.79N  96.55W
04/18/2016                   COLORADO           TX   LAW ENFORCEMENT

            NUMEROUS ROADS CLOSED AND WATER RESCUES BEING CONDUCTED
            ACROSS THE NORTHERN PARTS OF THE COUNTY.

&&

CORRECTED REMARKS

EVENT NUMBER HGX1600071

42

Local storm report, Apr 18, 4:51 AM CDT, 1 hour 39 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE Houston/Galveston TX
451 AM CDT MON APR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0450 AM     FLASH FLOOD      HOUSTON                 29.77N  95.39W
04/18/2016                   HARRIS             TX   COUNTY OFFICIAL

            SIXTY HIGH WATER RESCUES IN PROGRESS ACROSS PARTS OF
            HARRIS COUNTY.

&&

EVENT NUMBER HGX1600072

42

Local storm report, Apr 18, 4:57 AM CDT, 1 hour 33 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE Houston/Galveston TX
457 AM CDT MON APR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0454 AM     FLASH FLOOD      6 SSW JERSEY VILLAGE    29.82N  95.62W
04/18/2016                   HARRIS             TX   TRAINED SPOTTER

            NUMEROUS WATER COVERED ROADS. WATER IN HOMES IN AND
            AROUND THE ADDICKS AREA.

&&

EVENT NUMBER HGX1600073

42

Local storm report, Apr 18, 5:08 AM CDT, 1 hour 22 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE Houston/Galveston TX
508 AM CDT MON APR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0505 AM     FLASH FLOOD      7 NW TODD MISSION       30.35N  95.90W
04/18/2016                   GRIMES             TX   BROADCAST MEDIA

            MAJOR FLOODING ALONG COUNTY ROAD 311 WITH WATER HALFWAY
            UP STREET SIGNS.

&&

EVENT NUMBER HGX1600074

42

Local storm report, Apr 18, 5:15 AM CDT, 1 hour 15 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE Houston/Galveston TX
515 AM CDT MON APR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0510 AM     FLASH FLOOD      4 WNW JERSEY VILLAGE    29.91N  95.63W
04/18/2016                   HARRIS             TX   BROADCAST MEDIA

            RAIN GUAGE NEAR THE INTERSECTION OF HUFFMIESTER AND
            HIGHWAY 6 NORTH HAS SURPASSED MORE THAN 20 INCHES. THE
            COPPER GROVE SUBDIVISION HAS HIGH THIGH DEEP WATER IN
            THE ROADS WITH WATER UP TO THE SIDE WINDOWS OF MANY
            VEHICLES.

&&

EVENT NUMBER HGX1600075

42

Local storm report, Apr 18, 5:39 AM CDT, 51 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE Houston/Galveston TX
539 AM CDT MON APR 18 2016

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0532 AM     FLASH FLOOD      HOUSTON                 29.77N  95.39W
04/18/2016                   HARRIS             TX   COUNTY OFFICIAL

            AT LEAST 40 SUBDIVISIONS IN AND AROUND THE HOUSTON AREA
            REPORTING FLOODING.

&&

EVENT NUMBER HGX1600076

42

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 17, 7:30 PM CDT	Special Weather Statement	HGX	Colorado	45 min
Apr 17, 8:10 PM CDT	Special Weather Statement	HGX	Colorado	65 min
Apr 17, 8:33 PM CDT	Special Weather Statement	HGX	Fort Bend, Waller	57 min
Apr 17, 8:53 PM CDT	Areal Flood Advisory	HGX	Colorado, Wharton	3 hr
Apr 17, 9:28 PM CDT	Areal Flood Advisory	HGX	Austin, Fort Bend, Harris, Waller	2 hr
Apr 17, 9:38 PM CDT	Flash Flood Warning	HGX	Fort Bend, Harris, Waller	112 min
Apr 17, 10:36 PM CDT	Flash Flood Warning	HGX	Austin, Colorado, Harris, Waller	3 hr
Apr 17, 11:11 PM CDT	River Flood Warning	HGX	Harris, Waller	7 days
Apr 17, 11:15 PM CDT	Special Weather Statement	HGX	Harris	45 min
Apr 17, 11:17 PM CDT	Special Weather Statement	HGX	Waller	43 min
Apr 17, 11:22 PM CDT	Flash Flood Warning	HGX	Grimes, Harris, Montgomery, Waller	3 hr
Apr 17, 11:29 PM CDT	Severe Thunderstorm Warning	HGX	Harris, Montgomery	31 min
Apr 17, 11:57 PM CDT	Severe Thunderstorm Warning	HGX	Harris, Montgomery	63 min
Apr 18, 12:04 AM CDT	Flash Flood Warning	HGX	Austin, Fort Bend, Harris, Montgomery, Waller	3 hr
Apr 18, 12:07 AM CDT	Tornado Warning	HGX	Harris, Montgomery	38 min
Apr 18, 12:39 AM CDT	River Flood Warning	HGX	Harris	45 hr
Apr 18, 12:48 AM CDT	River Flood Warning	HGX	Harris	45 hr
Apr 18, 1:04 AM CDT	River Flood Warning	HGX	Harris	69 hr
Apr 18, 1:15 AM CDT	Flash Flood Warning	HGX	Harris, Montgomery	3 hr
Apr 18, 1:23 AM CDT	Hydrologic Statement	HGX	Harris	6 days
Apr 18, 1:37 AM CDT	Flash Flood Warning	HGX	Austin, Colorado, Waller, Washington	3 hr
Apr 18, 1:44 AM CDT	Flash Flood Warning Emergency	HGX	Grimes, Harris, Waller	3 hr
Apr 18, 1:47 AM CDT	Flash Flood Warning	HGX	Grimes, Montgomery, San Jacinto, Walker	3 hr
Apr 18, 2:04 AM CDT	Flash Flood Warning Emergency	HGX	Harris	3 hr
Apr 18, 2:09 AM CDT	River Flood Warning	HGX	Harris, Montgomery	44 hr
Apr 18, 2:09 AM CDT	River Flood Warning	HGX	Harris, Montgomery	4 days
Apr 18, 2:09 AM CDT	Hydrologic Statement	HGX	Harris, Montgomery	6 days
Apr 18, 2:09 AM CDT	Hydrologic Statement	HGX	Harris	6 days
Apr 18, 2:09 AM CDT	Hydrologic Statement	HGX	Harris	6 days
Apr 18, 2:31 AM CDT	Flash Flood Warning	HGX	Grimes, Harris, Montgomery, Waller	2 hr
Apr 18, 3:03 AM CDT	Severe Thunderstorm Warning	HGX	Harris	27 min
Apr 18, 3:13 AM CDT	Tornado Warning	HGX	Harris	32 min
Apr 18, 3:14 AM CDT	River Flood Warning	HGX	Fort Bend, Harris	6 days
Apr 18, 3:14 AM CDT	River Flood Warning	HGX	Harris	6 days
Apr 18, 3:14 AM CDT	River Flood Warning	HGX	Harris	6 days
Apr 18, 3:14 AM CDT	River Flood Warning	HGX	Harris	6 days
Apr 18, 3:14 AM CDT	River Flood Warning	HGX	Harris	4 days
Apr 18, 3:14 AM CDT	River Flood Warning	HGX	Harris, Montgomery	4 days
Apr 18, 3:22 AM CDT	River Flood Warning	HGX	Colorado, Wharton	3 days
Apr 18, 3:23 AM CDT	Flash Flood Warning	HGX	Fort Bend, Harris, Waller	97 min
Apr 18, 3:28 AM CDT	Flash Flood Warning	HGX	Austin, Colorado	92 min
Apr 18, 3:38 AM CDT	Tornado Warning	HGX	Harris	27 min
Apr 18, 3:55 AM CDT	River Flood Warning	HGX	Harris	42 hr
Apr 18, 3:55 AM CDT	River Flood Warning	HGX	Harris	6 days
Apr 18, 3:55 AM CDT	River Flood Warning	HGX	Harris	6 days
Apr 18, 3:55 AM CDT	River Flood Warning	HGX	Harris	12 hr
Apr 18, 3:55 AM CDT	River Flood Warning	HGX	Harris	40 hr
Apr 18, 3:55 AM CDT	River Flood Warning	HGX	Harris	34 hr
Apr 18, 4:39 AM CDT	Flash Flood Warning Emergency	HGX	Austin, Colorado, Grimes, Harris, Montgomery, Waller	4 hr
Apr 18, 4:39 AM CDT	Flash Flood Warning	HGX	Austin, Colorado, Fort Bend, Grimes, Harris, Liberty and 7 more	4 hr
Apr 18, 4:51 AM CDT	River Flood Warning	HGX	Harris	41 hr
Apr 18, 4:51 AM CDT	River Flood Warning	HGX	Harris	41 hr
Apr 18, 4:51 AM CDT	River Flood Warning	HGX	Harris	41 hr
Apr 18, 4:52 AM CDT	Tornado Warning	HGX	Harris	23 min
Apr 18, 5:16 AM CDT	Coastal Flood Advisory	HGX	Brazoria, Matagorda	20 hr
Apr 18, 5:17 AM CDT	Severe Thunderstorm Warning	HGX	Chambers, Harris, Liberty	43 min
Apr 18, 5:39 AM CDT	Tornado Warning	HGX	Liberty	36 min
Apr 18, 5:57 AM CDT	Flash Flood Warning Emergency	HGX	Harris, Montgomery	3 hr
Apr 18, 5:59 AM CDT	River Flood Warning	HGX	Harris	40 hr
Apr 18, 5:59 AM CDT	River Flood Warning	HGX	Harris	40 hr
Apr 18, 5:59 AM CDT	River Flood Warning	HGX	Harris	40 hr
Apr 18, 5:59 AM CDT	River Flood Warning	HGX	Harris	26 hr
Apr 18, 6:12 AM CDT	River Flood Warning	HGX	Fort Bend, Harris	10 days
Apr 18, 6:12 AM CDT	River Flood Warning	HGX	Harris	10 days
Apr 18, 6:12 AM CDT	River Flood Warning	HGX	Harris	10 days
Apr 18, 6:12 AM CDT	River Flood Warning	HGX	Harris	10 days
Apr 18, 6:25 AM CDT	River Flood Warning	HGX	Harris	40 hr
Apr 18, 6:25 AM CDT	River Flood Warning	HGX	Harris	40 hr
Apr 18, 6:25 AM CDT	River Flood Warning	HGX	Harris	28 hr
Apr 18, 6:25 AM CDT	River Flood Warning	HGX	Harris	31 hr
Apr 18, 6:25 AM CDT	River Flood Warning	HGX	Harris	28 hr
Apr 18, 6:42 AM CDT	River Flood Warning	HGX	Harris	39 hr
Apr 18, 6:42 AM CDT	River Flood Warning	HGX	Harris	39 hr
Apr 18, 6:42 AM CDT	River Flood Warning	HGX	Harris	39 hr
Apr 18, 6:42 AM CDT	River Flood Warning	HGX	Harris	39 hr
Apr 18, 6:42 AM CDT	River Flood Warning	HGX	Harris	39 hr
Apr 18, 6:42 AM CDT	River Flood Warning	HGX	Harris	39 hr
Apr 18, 6:51 AM CDT	River Flood Warning	HGX	Harris	39 hr
Apr 18, 7:05 AM CDT	Flash Flood Warning Emergency	HGX	Fort Bend, Harris	115 min
Apr 18, 7:08 AM CDT	River Flood Warning	HGX	Harris	39 hr

Nearby

Flash Flood Warnings in Texas, 2016 Every flash flood warning in 2016

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.