Alert archive / Louisiana / Mesoscale Discussions in 2012

Mesoscale Discussion 439

April 3, 2012Ashley County, Chicot County, Union County, Arkansas; 22 parishes in Louisiana; 19 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 3, 2012, 5:24 PM CDT for Ashley County, Chicot County, Union County, Arkansas; 22 parishes in Louisiana; 19 counties in Mississippi. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued: Apr 3, 2012, 5:24 PM CDT (22:24 UTC)
Expired: Apr 3, 2012, 6:30 PM CDT
In force: 66 min
Issued by: the Storm Prediction Center

All 44 counties

Ashley County, AR, Chicot County, AR, Union County, AR, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Claiborne County, MS, Copiah County, MS, Franklin County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lawrence County, MS, Lincoln County, MS, Madison County, MS, Rankin County, MS, Sharkey County, MS, Simpson County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS

The nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 10.4 hours before the alert went out and 172 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: 159 J/kg
Mixed-layer CIN: -252 J/kg
Mixed-layer LCL: 1092 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: -33 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.

893 
ACUS11 KWNS 032225
SWOMCD
SPC MCD 032224
MSZ000-LAZ000-ARZ000-032330-

MESOSCALE DISCUSSION 0439
NWS STORM PREDICTION CENTER NORMAN OK
0524 PM CDT TUE APR 03 2012

AREAS AFFECTED...N-CNTRL/NERN LA...W-CNTRL MS...FAR SRN AR

CONCERNING...SEVERE THUNDERSTORM WATCH 134...

VALID 032224Z - 032330Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 134
CONTINUES.

MCS CONTINUES TO SLOWLY PROPAGATE SSEWD ACROSS NRN LA/WRN MS.
ACCOMPANYING COLD POOL IS SURGING ACROSS CNTRL MS...QUICKLY
UNDERCUTTING ANY NEW DEVELOPING CONVECTION. GREATEST SHORT-TERM
POTENTIAL FOR DMGG WINDS AND HAIL APPEARS TO BE ALONG WRN FLANK OF
THE MCS...WHERE RADAR REFLECTIVITY INDICATES STRONGEST CORES ARE
CURRENTLY LOCATED. COLD POOL HAS BEEN SLOWER MOVING HERE...IN PART
DUE TO STRONGER LOW-LEVEL SLY WINDS /20-30 KTS IN THE 0-2 KM AGL
LAYER PER POE VWP/ AND RICHER MOISTURE OVER WRN/CNTRL LA.
SLOW-MOVING NATURE OF TSTMS WILL ALSO POSE A THREAT FOR HEAVY
RAINFALL ACROSS N-CNTRL/NERN LA.

..ROGERS.. 04/03/2012

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

ATTN...WFO...JAN...LZK...LCH...SHV...

LAT...LON   31369335 33199335 33388973 31528969 31369335

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 3, 1:42 PM CDT	Mesoscale Discussion	SPC	Chicot	93 min
Apr 3, 2:22 PM CDT	Severe Thunderstorm Watch	SPC	Columbia, Hempstead, Lafayette, Nevada, Union	8 hr
Apr 3, 2:36 PM CDT	Tornado Watch	SPC	Howard, Little River, Miller, Sevier	7 hr
Apr 3, 3:05 PM CDT	Mesoscale Discussion	SPC	Hempstead, Howard, Little River, Montgomery, Nevada, Pike and 2 more	85 min
Apr 3, 3:43 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Bradley, Calhoun, Clark, Crawford, Dallas and 16 more	6 hr
Apr 3, 5:00 PM CDT	Mesoscale Discussion	SPC	Little River, Miller	60 min
Apr 3, 6:53 PM CDT	Mesoscale Discussion	SPC	Columbia, Hempstead, Lafayette, Little River, Miller, Nevada and 1 more	67 min
Apr 2, 10:10 PM CDT	Mesoscale Discussion	SPC	Iberia, St. Mary	3 hr
Apr 3, 1:46 PM CDT	Mesoscale Discussion	SPC	Caddo, De Soto	89 min

Nearby

Mesoscale Discussions in Louisiana, 2012 Mesoscale Discussions in Mississippi, 2012 Mesoscale Discussions in Arkansas, 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.