Alert archive / Mississippi / Tornado Watches in 2011

Tornado Watch 243

April 27, 201119 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Apr 27, 2011, 6:42 PM CDT for 19 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Apr 27, 2011, 6:42 PM CDT (23:42 UTC)
Expired
Apr 27, 2011, 10:04 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt

Counties Clarke County, MS, Covington County, MS, Forrest County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Lowndes County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Winston County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 67 km from the middle of the area, began a volume at 23:44 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
30%
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

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

IssuedProductOfficeCountiesLasted
Apr 27, 7:22 PM CDTSevere Thunderstorm WarningJANClarke, Jasper53 min
Apr 27, 7:51 PM CDTSevere Thunderstorm WarningJANKemper, Lauderdale, Newton39 min
Apr 27, 7:59 PM CDTSevere Thunderstorm WarningJANClarke46 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, 11.7 hours before the alert went out and 69 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 2011-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 890 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 2011-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 449 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
890 J/kg
Mixed-layer CIN
-102 J/kg
Mixed-layer LCL
609 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
449 m²/s²
0-3 km storm-relative helicity
786 m²/s²
Significant tornado parameter
0.0
Supercell composite
21.2

Open this sounding in Storm Lab

The text

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

584 
WWUS20 KWNS 272335
SEL3
SPC WW 272335
MSZ000-280400-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 243
NWS STORM PREDICTION CENTER NORMAN OK
640 PM CDT WED APR 27 2011

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

       EASTERN AND SOUTHERN MISSISSIPPI

EFFECTIVE THIS WEDNESDAY EVENING FROM 640 PM UNTIL 1100 PM CDT.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE
MILES EAST AND WEST OF A LINE FROM 35 MILES WEST NORTHWEST OF
COLUMBUS MISSISSIPPI TO 45 MILES WEST SOUTHWEST OF PINE BELT
MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

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 232...WW 235...WW
236...WW 237...WW 238...WW 239...WW 240...WW 241...WW 242...

DISCUSSION...SUPERCELLS NEAR MEI AND NE OF MCB WILL CONTINUE TO
IMPACT THE WW AREA FOR THE NEXT FEW HOURS.  ENVIRONMENT REMAINS
SUPPORTIVE OF TORNADOES...DAMAGING WINDS AND HAIL.

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 24040.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 26, 7:59 PM CDTMesoscale DiscussionSPCAlcorn, Attala, Calhoun, Carroll, Chickasaw, Choctaw and 26 more2 hr
Apr 26, 9:13 PM CDTMesoscale DiscussionSPCBenton, Bolivar, Coahoma, DeSoto, Marshall, Panola and 3 more62 min
Apr 26, 9:33 PM CDTTornado Watch PDSSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 41 more7 hr
Apr 26, 9:58 PM CDTTornado WatchSPCDeSoto, Tunica7 hr
Apr 26, 11:33 PM CDTMesoscale DiscussionSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 42 more117 min
Apr 27, 1:56 AM CDTMesoscale DiscussionSPCClarke, Copiah, Covington, Jasper, Jefferson Davis, Kemper and 11 more64 min
Apr 27, 2:26 AM CDTTornado WatchSPCAdams, Alcorn, Attala, Calhoun, Chickasaw, Choctaw and 38 more6 hr
Apr 27, 4:53 AM CDTSevere Thunderstorm WatchSPCBolivar, Sunflower, Washington5 hr
Apr 27, 6:25 AM CDTMesoscale DiscussionSPCAlcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 33 more65 min
Apr 27, 8:08 AM CDTTornado WatchSPCAlcorn, Calhoun, Carroll, Chickasaw, Choctaw, Clay and 16 more6 hr
Apr 27, 9:48 AM CDTMesoscale DiscussionSPCClaiborne, Issaquena, Washington27 min
Apr 27, 10:45 AM CDTMesoscale DiscussionSPCAdams, Attala, Benton, Calhoun, Carroll, Chickasaw and 53 more90 min
Apr 27, 11:02 AM CDTTornado Watch PDSSPCAdams, Alcorn, Attala, Benton, Bolivar, Calhoun and 63 more8 hr
Apr 27, 1:42 PM CDTTornado Watch PDSSPCGreene, Perry, Wayne8 hr
Apr 27, 2:56 PM CDTMesoscale DiscussionSPCAlcorn, Attala, Calhoun, Chickasaw, Choctaw, Clarke and 35 more2 hr
Apr 27, 5:01 PM CDTMesoscale DiscussionSPCAttala, Chickasaw, Choctaw, Clarke, Clay, Covington and 26 more89 min
Apr 27, 6:27 PM CDTMesoscale DiscussionSPCClarke, Clay, Copiah, Covington, Forrest, Jasper and 22 more33 min

Nearby

Tornado Watches in Mississippi, 2011Every tornado watch in 2011

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.