Alert archive / Texas / Severe Thunderstorm Watches in 2015

Severe Thunderstorm Watch 310

June 18, 20154 states

The Storm Prediction Center issued this severe thunderstorm watch at Jun 18, 2015, 2:10 PM CDT for 4 states. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued: Jun 18, 2015, 2:10 PM CDT (19:10 UTC)
Expired: Jun 18, 2015, 10:00 PM CDT
In force: 8 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

All 30 counties

Morton County, KS, Stevens County, KS, Curry County, NM, Harding County, NM, Quay County, NM, Roosevelt County, NM, Union County, NM, Beaver County, OK, Cimarron County, OK, Texas County, OK, Armstrong County, TX, Carson County, TX, Castro County, TX, Dallam County, TX, Deaf Smith County, TX, Gray County, TX, Hansford County, TX, Hartley County, TX, Hemphill County, TX, Hutchinson County, TX, Lipscomb County, TX, Moore County, TX, Ochiltree County, TX, Oldham County, TX, Parmer County, TX, Potter County, TX, Randall County, TX, Roberts County, TX, Sherman County, TX, Swisher County, TX

The radar

The Amarillo radar (KAMA), 112 km from the middle of the area, began a volume at 19:11 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: 20%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 60%
One or more gusts of 65 knots or more: 20%
Ten or more severe hail reports: 30%
One or more hailstones of 2 inches or more: 10%
Six or more combined severe hail and wind reports: 80%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jun 18, 4:04 PM CDT	Severe Thunderstorm Warning	AMA	Moore, Sherman	26 min

Discussions around it

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

The nearest sounding before it

Amarillo Airport, TX (KAMA), launched 12:00Z, 7.2 hours before the alert went out and 113 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: 807 J/kg
Mixed-layer CIN: -135 J/kg
Mixed-layer LCL: 1228 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 116 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

351 
WWUS20 KWNS 181908
SEL0  
SPC WW 181908
COZ000-KSZ000-NMZ000-OKZ000-TXZ000-190300-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 310
NWS STORM PREDICTION CENTER NORMAN OK
205 PM CDT THU JUN 18 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 
  SOUTHEAST COLORADO
  SOUTHWEST KANSAS
  NORTHEAST NEW MEXICO
  OKLAHOMA PANHANDLE
  TEXAS PANHANDLE

* EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 205 PM UNTIL
  1000 PM CDT.

* PRIMARY THREATS INCLUDE...
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY
  ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE
  A TORNADO OR TWO POSSIBLE

SUMMARY...INTENSE THUNDERSTORMS ARE EXPECTED TO DEVELOP AND SPREAD
SOUTH SOUTHWESTWARD ACROSS THE PANHANDLE REGION AND ADJACENT
PORTIONS OF THE SOUTHERN HIGH PLAINS THROUGH THE REMAINDER OF THE
AFTERNOON.  SOME OF THIS ACTIVITY MAY CONGEAL INTO A GROWING CLUSTER
OF STORMS WITH AN INCREASED RISK FOR POTENTIALLY DAMAGING WIND
GUSTS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 85
STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTH
NORTHEAST OF LIBERAL KANSAS TO 55 MILES SOUTH SOUTHEAST OF
TUCUMCARI NEW MEXICO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE
THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

&&

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 36015.


...KERR

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 18, 1:26 PM CDT	Mesoscale Discussion	SPC	Finney, Grant, Gray, Greeley, Hamilton, Haskell and 7 more	2 hr
Jun 18, 3:37 PM CDT	Mesoscale Discussion	SPC	Morton	113 min
Jun 18, 5:31 AM CDT	Mesoscale Discussion	SPC	Nacogdoches, Sabine, San Augustine, Shelby	89 min

Nearby

Severe Thunderstorm Watches in Texas, 2015 Severe Thunderstorm Watches in New Mexico, 2015 Severe Thunderstorm Watches in Oklahoma, 2015 Every severe thunderstorm 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.