Alert archive / Texas / Tornado Watches in 2015

Tornado Watch 306

June 16, 201521 counties in Texas

The Storm Prediction Center issued this tornado watch at Jun 16, 2015, 11:41 PM CDT for 21 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jun 16, 2015, 11:41 PM CDT (04:41 UTC)
Expired: Jun 17, 2015, 7:00 AM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

All 21 counties

Austin County, TX, Brazoria County, TX, Brazos County, TX, Burleson County, TX, Colorado County, TX, Fayette County, TX, Fort Bend County, TX, Grimes County, TX, Harris County, TX, Jackson County, TX, Lavaca County, TX, Lee County, TX, Leon County, TX, Madison County, TX, Matagorda County, TX, Montgomery County, TX, Robertson County, TX, Walker County, TX, Waller County, TX, Washington County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 104 km from the middle of the area, began a volume at 04:42 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 40%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 5%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 50%

Warnings issued inside it

7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 17, 12:52 AM CDT	Flash Flood Warning	HGX	Austin, Colorado, Waller, Washington, Wharton	113 min
Jun 17, 1:26 AM CDT	Flash Flood Warning	HGX	Brazos, Burleson, Grimes, Waller, Washington	2 hr
Jun 17, 2:50 AM CDT	Flash Flood Warning	HGX	Austin, Colorado, Fort Bend, Harris, Waller, Washington and 1 more	3 hr
Jun 17, 3:08 AM CDT	Flash Flood Warning	HGX	Brazos, Grimes, Harris, Madison, Waller, Washington	3 hr
Jun 17, 4:32 AM CDT	Flash Flood Warning	HGX	Jackson, Matagorda, Wharton	118 min
Jun 17, 6:04 AM CDT	Flash Flood Warning	HGX	Austin, Colorado, Grimes, Walker, Waller, Washington and 1 more	86 min
Jun 17, 6:29 AM CDT	Flash Flood Warning	HGX	Jackson, Matagorda, Wharton	2 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 4.7 hours before the alert went out and 246 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: 418 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 1213 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 89 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.

585 
WWUS20 KWNS 170439
SEL6  
SPC WW 170439
TXZ000-171200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 306
NWS STORM PREDICTION CENTER NORMAN OK
1140 PM CDT TUE JUN 16 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  CENTRAL AND SOUTHEAST TEXAS

* EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 1140 PM
  UNTIL 700 AM CDT.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...THE RISK FOR A COUPLE OF TORNADOES WILL PERSIST OVERNIGHT
IN ASSOCIATION WITH TROPICAL STORM BILL MOVING NORTH THROUGH CENTRAL
TX.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES EAST SOUTHEAST OF
PALACIOS TEXAS TO 50 MILES NORTH NORTHEAST OF COLLEGE STATION
TEXAS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 302...WW 305...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 18030.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 16, 10:50 PM CDT	Mesoscale Discussion	SPC	Anderson, Austin, Bastrop, Bell, Brazoria, Brazos and 47 more	85 min
Jun 17, 3:01 AM CDT	Mesoscale Discussion	SPC	Austin, Brazoria, Brazos, Burleson, Colorado, Fort Bend and 11 more	119 min
Jun 17, 5:31 AM CDT	Mesoscale Discussion	SPC	Anderson, Angelina, Austin, Bowie, Brazoria, Brazos and 49 more	89 min
Jun 17, 7:47 AM CDT	Mesoscale Discussion	SPC	Anderson, Angelina, Austin, Brazoria, Brazos, Burleson and 50 more	2 hr
Jun 17, 12:08 PM CDT	Mesoscale Discussion	SPC	Bowie, Cass, Marion	2 hr
Jun 17, 5:14 PM CDT	Mesoscale Discussion	SPC	Delta, Franklin, Hopkins, Hunt, Lamar, Rains and 4 more	2 hr

Nearby

Tornado Watches in Texas, 2015 Every tornado watch in 2015

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.