Alert archive / Texas / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 146, NWS Houston/Galveston, TX

July 15, 20174 counties in Texas

NWS Houston/Galveston, TX issued this severe thunderstorm warning at Jul 15, 2017, 4:39 PM CDT for 4 counties in Texas. It was in force for 22 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 15, 2017, 4:39 PM CDT (21:39 UTC)
Expired: Jul 15, 2017, 5:01 PM CDT
In force: 22 min
Issued by: NWS Houston/Galveston, TX
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Austin County, TX, Colorado County, TX, Waller County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 116 km from the middle of the area, began a volume at 21:41 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

Corpus Christi, TX (KCRP), launched 12:00Z, 9.7 hours before the alert went out and 243 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: 733 J/kg
Mixed-layer CIN: -120 J/kg
Mixed-layer LCL: 1053 m above ground
0-6 km bulk shear: 12 kt
0-1 km storm-relative helicity: -49 m²/s²
0-3 km storm-relative helicity: -30 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm 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 severe thunderstorm warning went out at Jul 15, 4:12 PM CDT, 27 minutes earlier.

Area forecast discussion, Jul 15, 4:12 PM CDT, 27 minutes before

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Hazardous weather outlook, Jul 15, 4:34 PM CDT, 5 minutes before

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In the hours before

Special weather statement, Jul 15, 3:35 PM CDT, 1 hour 4 minutes before

Special Weather Statement
National Weather Service Houston/Galveston TX
335 PM CDT SAT JUL 15 2017

TXZ178-199-152100-
San Jacinto TX-Montgomery TX-
335 PM CDT SAT JUL 15 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN MONTGOMERY...
SOUTHWESTERN SAN JACINTO AND SOUTHEASTERN WALKER COUNTIES UNTIL 400
PM CDT...

At 335 PM CDT, Doppler radar was tracking a strong thunderstorm 10
miles southwest of Coldspring, or 13 miles east of Willis, moving
southwest at 20 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Northeastern Conroe, Willis, Panorama Village, Cut And Shoot and
Evergreen.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3035 9515 3034 9516 3032 9516 3024 9518
      3037 9554 3051 9541 3051 9536 3057 9535
      3061 9531 3053 9509
TIME...MOT...LOC 2035Z 027DEG 16KT 3049 9526

11

Special weather statement, Jul 15, 3:46 PM CDT, 53 minutes before

Special Weather Statement
National Weather Service Houston/Galveston TX
346 PM CDT SAT JUL 15 2017

TXZ195>198-211-212-152130-
Brazos TX-Washington TX-Grimes TX-Waller TX-Burleson TX-Austin TX-
346 PM CDT SAT JUL 15 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN AUSTIN...
SOUTHEASTERN BURLESON...SOUTHWESTERN GRIMES...WASHINGTON...
SOUTHEASTERN BRAZOS AND NORTHWESTERN WALLER COUNTIES UNTIL 430 PM
CDT...

At 345 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Snook to near Washington. Movement was
south at 10 mph.

Winds in excess of 40 mph will be possible with these storms.

Locations impacted include...
Southwestern College Station, Brenham, Navasota, Hempstead, Prairie
View, Washington, Somerville, Pine Island, Snook, Burton, Millican,
Lake Somerville Dam, Monaville, Independence, Quarry and Wellborn.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3015 9666 2988 9599 3041 9595 3061 9644
TIME...MOT...LOC 2045Z 350DEG 10KT 3049 9639 3029 9608

11

Special weather statement, Jul 15, 3:49 PM CDT, 50 minutes before

Special Weather Statement
National Weather Service Houston/Galveston TX
349 PM CDT SAT JUL 15 2017

TXZ237-152130-
Brazoria TX-
349 PM CDT SAT JUL 15 2017

...SIGNIFICANT WEATHER ADVISORY FOR WESTERN GALVESTON AND CENTRAL
BRAZORIA COUNTIES UNTIL 430 PM CDT...

At 349 PM CDT, Doppler radar was tracking a strong thunderstorm near
Iowa Colony, or near Manvel, moving south at 15 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Alvin, northern Angleton, southern Manvel, Danbury, Iowa Colony,
Holiday Lakes, Hillcrest, Liverpool, Bonney, Chocolate Bayou and
Rosharon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2923 9562 2947 9542 2945 9522 2938 9518
      2913 9521
TIME...MOT...LOC 2049Z 020DEG 12KT 2941 9534

11

Local storm report, Jul 15, 4:32 PM CDT, 7 minutes before

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Special weather statement, Jul 15, 4:32 PM CDT, 7 minutes before

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Special weather statement, Jul 15, 4:34 PM CDT, 5 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 14, 10:42 PM CDT	Special Weather Statement	HGX	Trinity	63 min
Jul 15, 12:09 PM CDT	Areal Flood Advisory	HGX	Chambers, Galveston	66 min
Jul 15, 1:05 PM CDT	Special Weather Statement	HGX	Chambers	40 min
Jul 15, 1:17 PM CDT	Special Weather Statement	HGX	Houston	43 min
Jul 15, 1:19 PM CDT	Special Marine Warning	HGX		56 min
Jul 15, 1:34 PM CDT	Special Weather Statement	HGX	Chambers	41 min
Jul 15, 1:44 PM CDT	Areal Flood Advisory	HGX	Harris	2 hr
Jul 15, 1:46 PM CDT	Special Weather Statement	HGX	Liberty	44 min
Jul 15, 1:52 PM CDT	Special Weather Statement	HGX	Harris	38 min
Jul 15, 2:03 PM CDT	Special Weather Statement	HGX	Madison, Walker	42 min
Jul 15, 2:05 PM CDT	Severe Thunderstorm Warning	HGX	Harris	25 min
Jul 15, 2:08 PM CDT	Special Weather Statement	HGX	Montgomery	52 min
Jul 15, 2:21 PM CDT	Areal Flood Advisory	HGX	Chambers, Harris, Liberty	114 min
Jul 15, 2:24 PM CDT	Severe Thunderstorm Warning	HGX	Grimes, Madison, Walker	36 min
Jul 15, 2:29 PM CDT	Severe Thunderstorm Warning	HGX	Harris	31 min
Jul 15, 2:33 PM CDT	Special Weather Statement	HGX	Polk, Trinity	42 min
Jul 15, 2:45 PM CDT	Areal Flood Advisory	HGX	Grimes, Montgomery, Walker	2 hr
Jul 15, 2:49 PM CDT	Special Weather Statement	HGX	San Jacinto	41 min
Jul 15, 2:52 PM CDT	Special Weather Statement	HGX	Harris	38 min
Jul 15, 2:59 PM CDT	Special Weather Statement	HGX	Brazos	46 min
Jul 15, 3:01 PM CDT	Areal Flood Advisory	HGX	Brazoria, Fort Bend, Galveston, Harris	119 min
Jul 15, 3:03 PM CDT	Special Weather Statement	HGX	Brazoria	42 min
Jul 15, 3:16 PM CDT	Special Weather Statement	HGX	Polk, San Jacinto	44 min
Jul 15, 3:26 PM CDT	Special Weather Statement	HGX	Waller	49 min
Jul 15, 3:35 PM CDT	Special Weather Statement	HGX	San Jacinto	25 min
Jul 15, 3:42 PM CDT	Areal Flood Advisory	HGX	Polk, San Jacinto, Trinity	2 hr
Jul 15, 3:46 PM CDT	Special Weather Statement	HGX	Waller, Washington	44 min
Jul 15, 3:49 PM CDT	Special Weather Statement	HGX	Brazoria	41 min
Jul 15, 3:54 PM CDT	Tornado Warning	HGX	Liberty, Polk, San Jacinto	36 min
Jul 15, 3:57 PM CDT	Tornado Warning	HGX	Grimes, Harris, Waller	33 min
Jul 15, 4:32 PM CDT	Special Weather Statement	HGX	San Jacinto	43 min
Jul 15, 4:34 PM CDT	Special Weather Statement	HGX	Wharton	41 min
Jul 15, 4:52 PM CDT	Special Weather Statement	HGX	Wharton	23 min
Jul 15, 5:07 PM CDT	Special Weather Statement	HGX	Wharton	38 min
Jul 15, 5:19 PM CDT	Special Marine Warning	HGX		26 min
Jul 15, 5:33 PM CDT	Special Weather Statement	HGX	Jackson	27 min
Jul 15, 5:44 PM CDT	Special Marine Warning	HGX		61 min
Jul 15, 6:11 PM CDT	Special Marine Warning	HGX		64 min
Jul 15, 6:41 PM CDT	Special Weather Statement	HGX	Matagorda	49 min

Nearby

Severe Thunderstorm Warnings in Texas, 2017 Every severe thunderstorm warning in 2017

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.