Alert archive / Louisiana / Tornado Watches in 2013

Tornado Watch 92

April 10, 2013Ashley County, Chicot County, Union County, Arkansas; 17 parishes in Louisiana; 16 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Apr 10, 2013, 5:42 PM CDT for Ashley County, Chicot County, Union County, Arkansas; 17 parishes in Louisiana; 16 counties in Mississippi. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Apr 10, 2013, 5:42 PM CDT (22:42 UTC)
Expired: Apr 11, 2013, 1:00 AM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 60 kt

All 36 counties

Ashley County, AR, Chicot County, AR, Union County, AR, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Bolivar County, MS, Carroll County, MS, Claiborne County, MS, Franklin County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Leflore County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 148 km from the middle of the area, began a volume at 22:42 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: 20%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 20%
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

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

Issued	Product	Office	Counties	Lasted
Apr 10, 5:46 PM CDT	Severe Thunderstorm Warning	JAN	Ashley, Chicot	59 min
Apr 10, 6:04 PM CDT	Severe Thunderstorm Warning	SHV	Union	41 min
Apr 10, 6:31 PM CDT	Severe Thunderstorm Warning	SHV	Columbia, Nevada, Union	44 min
Apr 10, 8:14 PM CDT	Severe Thunderstorm Warning	JAN	Ashley	46 min
Apr 10, 10:01 PM CDT	Severe Thunderstorm Warning	JAN	Bolivar	29 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

Jackson, MS (KJAN), launched 12:00Z, 10.7 hours before the alert went out and 139 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: 1156 J/kg
Mixed-layer CIN: -226 J/kg
Mixed-layer LCL: 504 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 108 m²/s²
0-3 km storm-relative helicity: 132 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

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

163 
WWUS20 KWNS 102244
SEL2  
SPC WW 102244
ARZ000-LAZ000-MSZ000-110600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 92
NWS STORM PREDICTION CENTER NORMAN OK
545 PM CDT WED APR 10 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       SOUTHEAST ARKANSAS
       NORTHEAST LOUISIANA
       WESTERN MISSISSIPPI

EFFECTIVE THIS WEDNESDAY AFTERNOON AND THURSDAY MORNING FROM 545
PM UNTIL 100 AM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 25 MILES SOUTHWEST OF NATCHEZ
MISSISSIPPI TO 35 MILES NORTH OF GREENVILLE MISSISSIPPI.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU2).

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 88...WW 89...WW 90...WW
91...

DISCUSSION...TSTMS ARE FORMING ATTM IN NE LA AND SW MS...ALONG LINE
OF CONFLUENCE AHEAD OF SW AR/NW LA COLD FRONT. REGION APPEARS TO
BEING GLANCED BY ASCENT WITH JET STREAK/AREA OF UPR DIFFLUENCE
ROUNDING SE QUADRANT OF SRN PLNS UPR TROUGH. RICH LOW-LVL MOISTURE
AND STRENGTH OF LOW TO MID-LVL FLOW PER AREA VWP DATA SUGGEST
POTENTIAL FOR SUPERCELLS WITH SVR HAIL..HIGH WIND...AND POSSIBLY A
COUPLE TORNADOES.

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 21035.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 9, 9:01 PM CDT	Mesoscale Discussion	SPC	Benton, Carroll, Crawford, Madison, Sebastian, Washington	89 min
Apr 10, 1:03 PM CDT	Mesoscale Discussion	SPC	Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 50 more	117 min
Apr 10, 1:20 PM CDT	Tornado Watch	SPC	Arkansas, Ashley, Baxter, Bradley, Calhoun, Chicot and 56 more	10 hr
Apr 10, 3:01 PM CDT	Mesoscale Discussion	SPC	Arkansas, Ashley, Baxter, Bradley, Calhoun, Clark and 47 more	119 min
Apr 10, 6:09 PM CDT	Mesoscale Discussion	SPC	Arkansas, Baxter, Bradley, Calhoun, Clay, Cleburne and 33 more	96 min
Apr 10, 4:46 PM CDT	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 18 more	119 min

Nearby

Tornado Watches in Louisiana, 2013 Tornado Watches in Mississippi, 2013 Tornado Watches in Arkansas, 2013 Every tornado watch in 2013

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.