Alert archive / Mississippi / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 356

June 4, 201220 counties in Mississippi

The Storm Prediction Center issued this severe thunderstorm watch at Jun 4, 2012, 8:41 PM CDT for 20 counties in Mississippi. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jun 4, 2012, 8:41 PM CDT (01:41 UTC)
Expired: Jun 5, 2012, 12:23 AM CDT
In force: 4 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1.5 in
Strongest gust expected: 60 kt

Counties Attala County, MS, Carroll County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Leake County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Sharkey County, MS, Webster County, MS, Winston 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 01:42 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: 10%
One or more EF2 to EF5 tornadoes: 2%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 5%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 70%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
Jun 4, 9:18 PM CDT	Severe Thunderstorm Warning	JAN	Humphreys, Sharkey, Sunflower, Washington	57 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 00:00Z, 1.7 hours before the alert went out and 111 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: 1465 J/kg
Mixed-layer CIN: -74 J/kg
Mixed-layer LCL: 1552 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 107 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

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

930 
WWUS20 KWNS 050143
SEL6
SPC WW 050143
LAZ000-MSZ000-050600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 356
NWS STORM PREDICTION CENTER NORMAN OK
840 PM CDT MON JUN 4 2012

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

       FAR NORTHEAST LOUISIANA
       CENTRAL MISSISSIPPI

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 840 PM UNTIL
100 AM CDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 65
STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES EAST
NORTHEAST OF GREENWOOD MISSISSIPPI TO 60 MILES SOUTH OF GREENWOOD
MISSISSIPPI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 352...WW 353...WW
354...WW 355...

DISCUSSION...LONG-LIVED MCV /LEFT OVER FROM EARLY DAY MCS IN NE OK/
EXPECTED TO CONTINUE STEADILY ESEWD.  GIVEN DEGREE OF
INSTABILITY/MOISTURE PRESENT DOWNSTREAM ACROSS CNTRL MS AND MDT
WNWLY DEEP SHEAR.../REF MCD #1060/...CONVECTION MAY CONTINUE TO
PERIODICALLY INCREASE TO SVR LIMITS ON ERN/SRN SIDE OF
SYSTEM...POSING A RISK FOR LOCALLY DMGG WIND/HAIL.  WEAK NW/SE
OUTFLOW BOUNDARY AHEAD OF THE MCV /THROUGH CNTRL AND ERN MS/ ALSO
MAY CONTRIBUTE TO AN INCREASE IN STORMS LATER THIS EVE.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 29025.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 4, 8:03 PM CDT	Mesoscale Discussion	SPC	Attala, Bolivar, Carroll, Choctaw, Claiborne, Copiah and 21 more	87 min
Jun 4, 11:29 PM CDT	Mesoscale Discussion	SPC	Attala, Carroll, Choctaw, Clay, Holmes, Humphreys and 10 more	61 min

Nearby

Severe Thunderstorm Watches in Mississippi, 2012 Every severe thunderstorm watch in 2012

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.