Alert archive / Mississippi / Tornado Watches in 2015

Tornado Watch 547

November 17, 2015Ashley County, Chicot County, Arkansas; 18 parishes in Louisiana; 26 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Nov 17, 2015, 12:36 PM CST for Ashley County, Chicot County, Arkansas; 18 parishes in Louisiana; 26 counties in Mississippi. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Nov 17, 2015, 12:36 PM CST (18:36 UTC)
Expired
Nov 17, 2015, 8:00 PM CST
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 46 counties

Ashley County, AR, Chicot County, AR, Ascension Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Franklin Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Pointe Coupee Parish, LA, Richland Parish, LA, Saint Helena Parish, LA, Tensas Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Bolivar County, MS, Carroll County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Lawrence County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Pike County, MS, Rankin County, MS, Sharkey County, MS, Simpson County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 114 km from the middle of the area, began a volume at 18:37 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
50%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Nov 17, 2:28 PM CSTSevere Thunderstorm WarningJANAshley62 min
Nov 17, 3:28 PM CSTSevere Thunderstorm WarningJANAshley, Chicot47 min
Nov 17, 4:18 PM CSTSevere Thunderstorm WarningJANBolivar57 min
Nov 17, 4:59 PM CSTFlash Flood WarningJANMorehouse, Richland, West Carroll3 hr
Nov 17, 6:37 PM CSTSevere Thunderstorm WarningJANCatahoula, Concordia68 min
Nov 17, 7:18 PM CSTSevere Thunderstorm WarningJANMadison28 min
Nov 17, 7:40 PM CSTSevere Thunderstorm WarningJANConcordia, Tensas35 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, 6.6 hours before the alert went out and 104 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, Jackson, MS at 12:00Z on 2015-11-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 71 joules per kilogram.LCLLFCEL10008507005003002001001 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, Jackson, MS at 12:00Z on 2015-11-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 200 square meters per square second.19395878Sfc1 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
71 J/kg
Mixed-layer CIN
-150 J/kg
Mixed-layer LCL
709 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
200 m²/s²
0-3 km storm-relative helicity
352 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.

700 
WWUS20 KWNS 171833
SEL7  
SPC WW 171833
ARZ000-LAZ000-MSZ000-180200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 547
NWS STORM PREDICTION CENTER NORMAN OK
1235 PM CST TUE NOV 17 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  EXTREME SOUTHEAST ARKANSAS
  EASTERN LOUISIANA
  WESTERN MISSISSIPPI

* EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 1235 PM UNTIL
  800 PM CST.

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

SUMMARY...A LINE OF THUNDERSTORMS INTENSIFYING TO THE WEST OF THE
REGION IS EXPECTED TO SPREAD EAST ACROSS THE WATCH AREA THIS
AFTERNOON THROUGH THIS EVENING.  OTHER STORMS MAY FORM AHEAD OF THE
SQUALL LINE BEFORE EVENTUALLY MERGING WITH IT.  DAMAGING
STRAIGHT-LINE WINDS AND A FEW TORNADOES ARE POSSIBLE WITH THE
STRONGEST STORMS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES SOUTH OF NATCHEZ
MISSISSIPPI TO 35 MILES NORTHWEST OF GREENWOOD MISSISSIPPI.  FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU7).

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 545...WW 546...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 22035.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Nov 17, 4:35 AM CSTMesoscale DiscussionSPCBenton, Crawford, Franklin, Howard, Johnson, Logan and 9 more115 min
Nov 17, 4:48 AM CSTTornado WatchSPCHoward, Little River, Miller, Sevier4 hr
Nov 17, 6:27 AM CSTSevere Thunderstorm WatchSPCBaxter, Benton, Boone, Carroll, Clark, Conway and 21 more6 hr
Nov 17, 8:24 AM CSTMesoscale DiscussionSPCColumbia, Lafayette66 min
Nov 17, 8:55 AM CSTTornado WatchSPCColumbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more7 hr
Nov 17, 9:59 AM CSTMesoscale DiscussionSPCArkansas, Ashley, Baxter, Boone, Bradley, Calhoun and 58 more2 hr
Nov 17, 11:07 AM CSTTornado WatchSPCArkansas, Bradley, Calhoun, Clark, Cleburne, Cleveland and 21 more6 hr
Nov 17, 12:19 PM CSTMesoscale DiscussionSPCAshley, Chicot116 min
Nov 17, 1:35 PM CSTMesoscale DiscussionSPCArkansas, Cleburne, Cleveland, Craighead, Crittenden, Cross and 25 more115 min
Nov 17, 3:15 PM CSTTornado WatchSPCCraighead, Crittenden, Cross, Lee, Mississippi, Phillips and 2 more4 hr
Nov 17, 3:19 PM CSTMesoscale DiscussionSPCClay, Fulton, Greene, Izard, Lawrence, Randolph and 1 more116 min
Nov 17, 5:36 PM CSTMesoscale DiscussionSPCCrittenden, Cross, Lee, Monroe, Phillips, Poinsett and 1 more84 min
Nov 17, 2:51 PM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 20 more84 min
Nov 17, 3:33 PM CSTTornado WatchSPCAcadia, Allen, Avoyelles, Calcasieu, Cameron, Evangeline and 6 more4 hr
Nov 17, 5:54 PM CSTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Calcasieu, Cameron, Evangeline and 6 more96 min

Nearby

Tornado Watches in Mississippi, 2015Tornado Watches in Louisiana, 2015Tornado Watches in Arkansas, 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.