Alert archive / Mississippi / Tornado Watches in 2013

Tornado Watch 552

October 31, 201318 parishes in Louisiana; 41 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Oct 31, 2013, 12:27 PM CDT for 18 parishes in Louisiana; 41 counties in Mississippi. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Oct 31, 2013, 12:27 PM CDT (17:27 UTC)
Expired: Oct 31, 2013, 7:00 PM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

All 59 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Jefferson Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Pointe Coupee Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hancock County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Warren County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 26 km from the middle of the area, began a volume at 17:27 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: 10%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 5%
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

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

Issued	Product	Office	Counties	Lasted
Oct 31, 1:07 PM CDT	Severe Thunderstorm Warning	LIX	Iberville, Pointe Coupee, West Baton Rouge	53 min
Oct 31, 2:10 PM CDT	Flash Flood Warning	JAN	Warren	2 hr
Oct 31, 5:42 PM CDT	Tornado Warning	JAN	Smith	33 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, 5.5 hours before the alert went out and 31 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: 26 J/kg
Mixed-layer CIN: -4 J/kg
Mixed-layer LCL: 535 m above ground
0-6 km bulk shear: 54 kt
0-1 km storm-relative helicity: 364 m²/s²
0-3 km storm-relative helicity: 399 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.

552 
WWUS20 KWNS 311733
SEL2  
SPC WW 311733
LAZ000-MSZ000-CWZ000-010000-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 552
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT THU OCT 31 2013

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  SOUTHEAST LOUISIANA
  CENTRAL ASND SOUTHERN MISSISSIPPI
  COASTAL WATERS

* EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 1230 PM
  UNTIL 700 PM CDT.

* PRIMARY THREATS INCLUDE...
  SEVERAL TORNADOES POSSIBLE
  SEVERAL DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 75 MILES NORTH NORTHWEST OF
MERIDIAN MISSISSIPPI TO 40 MILES SOUTHEAST OF BATON ROUGE
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

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 551...

DISCUSSION...ERN LA SQLN EXPECTED TO CONTINUE EWD AT ABOUT 30 KTS
WHILE EMBEDDED STORMS MOVE MORE RAPIDLY ENE ALONG IT. AREA VWP DATA
SHOW VERY STRONG LOW TO MID-LVL SHEAR PERSISTING ACROSS WW
REGION...DESPITE THE FACT THAT THE BELT OF STRONGEST SSWLY 1 KM FLOW
IS BEGINNING TO SHIFT NWD INTO THE TN/OH VLYS. GIVEN RICH MOISTURE
IN PLACE AHEAD OF LINE...AND EXPECTED MODEST DIURNAL INCREASE IN SFC
TEMPS...A CONDITIONAL RISK FOR ISOLD TORNADOES/LOCALLY DMGG WIND
WILL CONTINUE...ESPECIALLY WITH ANY MORE SUSTAINED LEWPS AND
SMALL-SCALE BOWS.

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 24030.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Oct 31, 6:56 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 30 more	2 hr
Oct 31, 7:32 AM CDT	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 19 more	6 hr
Oct 31, 10:37 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Avoyelles, Calcasieu, Caldwell, Cameron and 20 more	83 min
Oct 31, 12:12 PM CDT	Mesoscale Discussion	SPC	Ascension, Livingston, Saint Helena, Saint Tammany, Tangipahoa, Washington	93 min
Oct 31, 3:11 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint Charles, Saint James, Saint John the Baptist, Saint Tammany, Tangipahoa and 1 more	94 min

Nearby

Tornado Watches in Mississippi, 2013 Tornado Watches in Louisiana, 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.