Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 413

April 2, 20125 states

The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2012, 12:15 PM CDT for 5 states. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued: Apr 2, 2012, 12:15 PM CDT (17:15 UTC)
Expired: Apr 2, 2012, 1:45 PM CDT
In force: 90 min
Issued by: the Storm Prediction Center

All 135 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Lafayette County, AR, Lincoln County, AR, Little River County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Sevier County, AR, Union County, AR, Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Avoyelles Parish, LA, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jackson Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Orleans Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Union Parish, LA, Vermilion Parish, LA, Washington Parish, LA, Webster Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Bolivar County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Pearl River County, MS, Pike County, MS, Rankin County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Sunflower County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Yazoo County, MS, Choctaw County, OK, McCurtain County, OK, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Delta County, TX, Fannin County, TX, Franklin County, TX, Gregg County, TX, Harrison County, TX, Hopkins County, TX, Hunt County, TX, Lamar County, TX, Marion County, TX, Morris County, TX, Panola County, TX, Rains County, TX, Red River County, TX, Rusk County, TX, Shelby County, TX, Smith County, TX, Titus County, TX, Upshur County, TX, Van Zandt County, TX, Wood County, TX

The radar

The Shreveport radar (KSHV), 66 km from the middle of the area, began a volume at 17:17 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 5.3 hours before the alert went out and 59 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: 1679 J/kg
Mixed-layer CIN: -73 J/kg
Mixed-layer LCL: 558 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: -91 m²/s²
0-3 km storm-relative helicity: 4 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.

886 
ACUS11 KWNS 021715
SWOMCD
SPC MCD 021715 
LAZ000-MSZ000-ARZ000-TXZ000-OKZ000-021845-

MESOSCALE DISCUSSION 0413
NWS STORM PREDICTION CENTER NORMAN OK
1215 PM CDT MON APR 02 2012

AREAS AFFECTED...ARKLATEX REGION EWD/SEWD INTO THE LOWER MS VALLEY

CONCERNING...SEVERE THUNDERSTORM WATCH 126...

VALID 021715Z - 021845Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 126
CONTINUES.

BOWING MCS CONTINUES MOVING GENERALLY NEWD ACROSS E TX/SWRN LA.  AS
THE BOW SHIFTS BOTH NEWD AND EWD ACROSS WW 126 WITH TIME...ISSUANCE
OF ONE OR MORE ADDITIONAL WATCHES IS EXPECTED.

LATEST RADAR IMAGERY SHOWS THE BOWING MCS EXPANDING AND INTENSIFYING
AS IT MOVES ACROSS E TX AND WRN LA...AS DIURNAL HEATING OF THE MOIST
BOUNDARY LAYER IS RESULTING IN ADDITIONAL AIRMASS DESTABILIZATION. 
WHILE DEEP-LAYER WIND FIELD REMAINS SOMEWHAT MODEST...THE ALREADY
WELL-ORGANIZED SYSTEM -- WITH 50 KT REAR INFLOW JET OBSERVED AT 1 KM
VIA KLCH /LAKE CHARLES LA/ WSR-88D VWP -- SHOULD REMAIN INTACT THIS
AFTERNOON.  GIVEN THIS LEVEL OF ORGANIZATION AND AN INCREASINGLY
UNSTABLE ENVIRONMENT...DEGREE OF WIND/HAIL POTENTIAL WILL LIKELY
JUSTIFY ADDITIONAL WW ISSUANCE.  AS STORMS ON THE NRN FRINGE OF THE
BOW CONTINUE NWD...A WW N OF THE CURRENT WW IS ANTICIPATED...AND
SIMILAR NEW WATCH REQUIREMENT IS ENVISIONED INTO MS AS STORMS MOVE
ENEWD TOWARD THE MS RIVER VALLEY.

..GOSS.. 04/02/2012

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

ATTN...WFO...MOB...JAN...LIX...LZK...LCH...SHV...TSA...FWD...
OUN...

LAT...LON   31769501 32169576 33239650 33839650 34499481 34469256
            33699049 32868973 31228916 29408999 29429233 31179287
            31749402 31769501

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 2, 12:41 PM CDT	Severe Thunderstorm Watch	SPC	Bradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 11 more	6 hr
Apr 2, 12:50 PM CDT	Severe Thunderstorm Watch	SPC	Ashley, Chicot	7 hr
Apr 2, 3:18 PM CDT	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Clark, Cleveland, Columbia and 28 more	117 min
Apr 2, 3:23 PM CDT	Mesoscale Discussion	SPC	Ashley, Chicot	2 hr
Apr 2, 3:49 PM CDT	Severe Thunderstorm Watch	SPC	Arkansas, Conway, Crawford, Desha, Faulkner, Franklin and 19 more	4 hr
Apr 2, 5:58 PM CDT	Mesoscale Discussion	SPC	Arkansas, Clark, Cleveland, Conway, Dallas, Desha and 23 more	62 min
Apr 2, 9:57 AM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 27 more	63 min
Apr 2, 10:10 AM CDT	Severe Thunderstorm Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 31 more	7 hr
Apr 2, 5:36 PM CDT	Mesoscale Discussion	SPC	Orleans, Saint Bernard, Saint Tammany	54 min
Apr 2, 3:00 PM CDT	Mesoscale Discussion	SPC	Alfalfa, Beaver, Beckham, Blaine, Caddo, Canadian and 16 more	2 hr
Apr 2, 3:37 PM CDT	Severe Thunderstorm Watch	SPC	Alfalfa, Beaver, Beckham, Blaine, Caddo, Comanche and 16 more	7 hr
Apr 2, 5:16 AM CDT	Mesoscale Discussion	SPC	Austin, Brazoria, Chambers, Colorado, Fayette, Fort Bend and 13 more	2 hr
Apr 2, 6:51 PM CDT	Mesoscale Discussion	SPC	Archer, Baylor, Brown, Callahan, Clay, Coleman and 17 more	54 min

Nearby

Mesoscale Discussions in Louisiana, 2012 Mesoscale Discussions in Mississippi, 2012 Mesoscale Discussions in Texas, 2012 Every mesoscale discussion 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.