Alert archive / Texas / Tornado Watches in 2015

Tornado Watch 556

December 23, 20154 states

The Storm Prediction Center issued this tornado watch at Dec 23, 2015, 12:06 AM CST for 4 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Dec 23, 2015, 12:06 AM CST (06:06 UTC)
Expired
Dec 23, 2015, 7:00 AM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 60 counties

Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Hempstead County, AR, Howard County, AR, Lafayette County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Sevier County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, McCurtain County, OK, Anderson County, TX, Angelina County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Henderson County, TX, Hopkins County, TX, Houston County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Rains County, TX, Red River County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Trinity County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 79 km from the middle of the area, began a volume at 06:09 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
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
20%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Dec 23, 5:13 AM CSTSevere Thunderstorm WarningSHVMcCurtain62 min
Dec 23, 6:37 AM CSTSevere Thunderstorm WarningSHVSevier38 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

Shreveport, LA (KBAD), launched 00:00Z, 6.1 hours before the alert went out and 80 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-pSkew-T log-p diagram, Shreveport, LA at 00:00Z on 2015-12-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Shreveport, LA at 00:00Z on 2015-12-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 105 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
948 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
105 m²/s²
0-3 km storm-relative helicity
177 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.

886 
WWUS20 KWNS 230603
SEL6  
SPC WW 230603
ARZ000-LAZ000-OKZ000-TXZ000-231300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 556
NWS STORM PREDICTION CENTER NORMAN OK
1205 AM CST WED DEC 23 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHWEST ARKANSAS
  NORTHWEST LOUISIANA
  SOUTHEAST OKLAHOMA
  EAST TEXAS

* EFFECTIVE THIS WEDNESDAY MORNING FROM 1205 AM UNTIL 700 AM CST.

* PRIMARY THREATS INCLUDE...
  A COUPLE TORNADOES POSSIBLE
  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2
    INCHES IN DIAMETER POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...THUNDERSTORMS...SOME WITH HAIL AND...WITH TIME...POSSIBLY
A COUPLE TORNADOES...EXPECTED TO DEVELOP / INCREASE OVER EAST TEXAS
AND ADJACENT PARTS OF ARKANSAS AND LOUISIANA AS WARM ADVECTION /
MOISTURE TRANSPORT STRENGTHEN DOWNSTREAM FROM AMPLIFYING NORTHWEST
TEXAS UPPER TROUGH.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 90 STATUTE
MILES EAST AND WEST OF A LINE FROM 65 MILES EAST NORTHEAST OF DE
QUEEN ARKANSAS TO 10 MILES SOUTHEAST OF LUFKIN 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.

&&

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 23040.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 22, 10:17 PM CSTMesoscale DiscussionSPCClark, Columbia, Dallas, Garland, Hempstead, Hot Spring and 9 more2 hr
Dec 23, 4:39 AM CSTMesoscale DiscussionSPCBradley, Calhoun, Clark, Cleburne, Cleveland, Columbia and 37 more2 hr
Dec 23, 6:13 AM CSTMesoscale DiscussionSPCClay, Greene, Randolph2 hr
Dec 23, 6:20 AM CSTTornado WatchSPCArkansas, Baxter, Boone, Bradley, Calhoun, Clark and 50 more7 hr
Dec 23, 9:05 AM CSTMesoscale DiscussionSPCArkansas, Clark, Clay, Cleburne, Cleveland, Craighead and 28 more85 min
Dec 23, 9:13 AM CSTTornado WatchSPCClay, Craighead, Greene, Lawrence, Mississippi, Poinsett and 1 more8 hr
Dec 23, 10:12 AM CSTMesoscale DiscussionSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 10 more93 min
Dec 23, 10:29 AM CSTMesoscale DiscussionSPCClay91 min
Dec 23, 10:58 AM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Chicot, Cleveland, Crittenden and 11 more2 hr
Dec 23, 11:57 AM CSTTornado Watch PDSSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 12 more9 hr
Dec 23, 12:48 PM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 16 more57 min
Dec 23, 2:49 PM CSTMesoscale DiscussionSPCChicot, Crittenden, Cross, Desha, Lee, Mississippi and 2 more86 min
Dec 22, 11:20 PM CSTMesoscale DiscussionSPCJefferson, Lafourche, Plaquemines, St. Mary, Terrebonne115 min
Dec 23, 2:34 AM CSTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Caldwell and 38 more86 min
Dec 23, 1:33 PM CSTMesoscale DiscussionSPCEast Baton Rouge, East Feliciana, Saint Helena, Washington57 min

Nearby

Tornado Watches in Texas, 2015Tornado Watches in Arkansas, 2015Tornado Watches in Louisiana, 2015Every 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.