Alert archive / Mississippi / Mesoscale Discussions in 2016

Mesoscale Discussion 309

March 31, 201612 parishes in Louisiana; 19 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 31, 2016, 3:30 PM CDT for 12 parishes in Louisiana; 19 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 31, 2016, 3:30 PM CDT (20:30 UTC)
Expired: Mar 31, 2016, 5:30 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 31 counties

Ascension Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Pointe Coupee Parish, LA, Saint Helena Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS, Wilkinson County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 8.5 hours before the alert went out and 66 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: 596 J/kg
Mixed-layer CIN: -54 J/kg
Mixed-layer LCL: 597 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 466 m²/s²
0-3 km storm-relative helicity: 554 m²/s²
Significant tornado parameter: 1.5
Supercell composite: 8.6

Open this sounding in Storm Lab

The text

As transmitted.

011 
ACUS11 KWNS 312030
SWOMCD
SPC MCD 312030 
ALZ000-MSZ000-LAZ000-312230-

MESOSCALE DISCUSSION 0309
NWS STORM PREDICTION CENTER NORMAN OK
0330 PM CDT THU MAR 31 2016

AREAS AFFECTED...SE LA...SRN MS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 312030Z - 312230Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...A SEVERE THREAT MAY INCREASE ACROSS SE LA AND SRN MS OVER
THE NEXT FEW HOURS. ISOLATED LARGE HAIL AND WIND DAMAGE MAY OCCUR
WITH THE STRONGER THUNDERSTORMS. THE SEVERE THREAT SHOULD REMAIN
ISOLATED AND WW ISSUANCE CAN NOT BE RULED OUT.

DISCUSSION...LATEST SFC ANALYSIS SHOWS SLY FLOW ACROSS SE LA AND SRN
MS WITH SFC DEWPOINTS GENERALLY IN THE LOWER TO MID 70S. THE MOIST
AIRMASS IS CONTRIBUTING TO MLCAPE VALUES BETWEEN 1000 AND 1500 J/KG
AS IS ESTIMATED BY MESOCALE ANALYSIS DATA. SCATTERED THUNDERSTORMS
HAVE DEVELOPED IN THIS MODERATELY UNSTABLE AIRMASS FROM NORTH OF
LAKE PONTCHARTRAIN NWD TO NEAR JACKSON MS ALONG THE AXIS OF THE
STRONGEST LOW-LEVEL FLOW. IN ADDITION TO THE INSTABILITY...MODERATE
DEEP-LAYER SHEAR IS PRESENT ACROSS THE MCD AREA ACCORDING TO
REGIONAL WSR-88D VWPS. 0-6 KM SHEAR OF 40 TO 50 KT ALONG WITH THE
INSTABILITY AND STEEP MID-LEVEL LAPSE RATES WILL MAKE SUPERCELLS
WITH LARGE HAIL POSSIBLE. HOWEVER...WEAK LARGE-SCALE ASCENT WILL
HELP KEEP MOST OF THE STORMS MULTICELLULAR. DUE TO THE MOIST
AIRMASS...CELLS COULD ALSO PRODUCE WET DOWNBURSTS. SHORT-TERM MODEL
FORECASTS SUGGEST THAT THE STRONGER THUNDERSTORMS WILL MOVE NEWD
INTO WW 70.

..BROYLES/THOMPSON.. 03/31/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MOB...JAN...LIX...LCH...

LAT...LON   30788859 30558913 30309008 30059120 30269168 30869163
            31709084 31848866 31148840 30788859

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 30, 8:39 PM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 13 more	96 min
Mar 30, 10:00 PM CDT	Tornado Watch	SPC	Bienville, Caldwell, Catahoula, Claiborne, Concordia, East Carroll and 16 more	6 hr
Mar 30, 11:30 PM CDT	Mesoscale Discussion	SPC	Catahoula, Concordia, East Carroll, Franklin, Madison, Morehouse and 3 more	60 min
Mar 31, 3:04 AM CDT	Mesoscale Discussion	SPC	East Feliciana, Pointe Coupee, Saint Helena, Tangipahoa, Washington, West Feliciana	86 min
Mar 31, 3:20 AM CDT	Tornado Watch	SPC	East Baton Rouge, East Feliciana, Livingston, Pointe Coupee, Saint Helena, Saint Tammany and 4 more	6 hr
Mar 31, 1:30 PM CDT	Mesoscale Discussion	SPC	Avoyelles, Caldwell, Catahoula, Concordia, East Carroll, Franklin and 12 more	2 hr
Mar 31, 2:05 PM CDT	Severe Thunderstorm Watch	SPC	Avoyelles, Bienville, Caldwell, Catahoula, Claiborne, Concordia and 20 more	8 hr
Mar 31, 5:22 PM CDT	Mesoscale Discussion	SPC	Caldwell, Catahoula, East Carroll, Franklin, Grant, Jackson and 9 more	53 min
Mar 31, 7:47 AM CDT	Mesoscale Discussion	SPC	Covington, Forrest, Greene, Jefferson Davis, Jones, Lamar and 3 more	58 min
Mar 31, 8:43 AM CDT	Tornado Watch	SPC	George, Greene, Perry, Stone	5 hr
Mar 31, 10:26 AM CDT	Mesoscale Discussion	SPC	Coahoma, DeSoto, Tate, Tunica	3 hr
Mar 31, 2:35 PM CDT	Tornado Watch	SPC	Adams, Alcorn, Attala, Benton, Bolivar, Calhoun and 60 more	7 hr
Mar 31, 4:47 PM CDT	Mesoscale Discussion	SPC	Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 55 more	58 min
Mar 31, 5:58 PM CDT	Tornado Watch	SPC	Wayne	7 hr
Mar 31, 6:52 PM CDT	Mesoscale Discussion	SPC	Alcorn, Calhoun, Chickasaw, Choctaw, Clarke, Clay and 29 more	53 min

Nearby

Mesoscale Discussions in Mississippi, 2016 Mesoscale Discussions in Louisiana, 2016 Every mesoscale discussion in 2016

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.