Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 417

April 2, 2012Ashley County, Chicot County, Arkansas; 15 parishes in Louisiana; 49 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2012, 3:23 PM CDT for Ashley County, Chicot County, Arkansas; 15 parishes in Louisiana; 49 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 2, 2012, 3:23 PM CDT (20:23 UTC)
Expired
Apr 2, 2012, 5:30 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 66 counties

Ashley County, AR, Chicot County, AR, East Carroll Parish, LA, East Feliciana Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Carroll Parish, LA, Amite County, MS, Attala County, MS, Bolivar County, MS, Carroll County, MS, Choctaw County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jackson County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Sunflower County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Wayne County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 71 km from the middle of the area, began a volume at 20:25 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 nearest sounding before it

Jackson, MS (KJAN), launched 12:00Z, 8.4 hours before the alert went out and 68 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 2012-04-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1280 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 2012-04-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -68 square meters per square second.193958Sfc1 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
1280 J/kg
Mixed-layer CIN
-71 J/kg
Mixed-layer LCL
566 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
-68 m²/s²
0-3 km storm-relative helicity
29 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.

830 
ACUS11 KWNS 022024
SWOMCD
SPC MCD 022023
MSZ000-LAZ000-ARZ000-022230-

MESOSCALE DISCUSSION 0417
NWS STORM PREDICTION CENTER NORMAN OK
0323 PM CDT MON APR 02 2012

AREAS AFFECTED...SERN AR/SERN LA/SWRN MS

CONCERNING...SEVERE THUNDERSTORM WATCH 128...

VALID 022023Z - 022230Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 128
CONTINUES.

SEVERE THREAT CONTINUES AS STORMS CROSS WW 128.

LATEST RADAR LOOP SHOWS A BAND OF STORMS ADVANCING EWD/NEWD ACROSS
NERN AR/SWRN MS/SERN LA...WITH OTHER STORMS CONTINUING TO EXPAND
ACROSS SRN MS AHEAD OF THE ARCING CONVECTIVE BAND.  AIRMASS AHEAD OF
THE CONVECTION REMAINS VERY UNSTABLE...AND GIVEN WELL-ORGANIZED
NATURE OF THE ACTIVITY...EXPECT THREAT FOR LOCALLY DAMAGING WINDS
AND HAIL TO CONTINUE.

WITH STORMS ADVANCING AT ROUGHLY 35 KT...THE CONVECTION WILL BEGIN
APPROACHING THE EDGES OF THE WATCH IN THE NEXT 1-2 HOURS.
ATTM...NEW WW MAY BECOME NECESSARY TO COVER THE ONGOING THREAT.

..GOSS.. 04/02/2012

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

ATTN...WFO...MOB...MEG...JAN...LIX...LZK...SHV...

LAT...LON   32119126 32579195 33459176 34079067 33418927 31838853
            29618835 29619067 30229091 31289120 32119126

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 2, 12:15 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Clark, Cleveland and 17 more90 min
Apr 2, 12:41 PM CDTSevere Thunderstorm WatchSPCBradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 11 more6 hr
Apr 2, 12:50 PM CDTSevere Thunderstorm WatchSPCAshley, Chicot7 hr
Apr 2, 3:18 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Clark, Cleveland, Columbia and 28 more117 min
Apr 2, 3:49 PM CDTSevere Thunderstorm WatchSPCArkansas, Conway, Crawford, Desha, Faulkner, Franklin and 19 more4 hr
Apr 2, 5:58 PM CDTMesoscale DiscussionSPCArkansas, Clark, Cleveland, Conway, Dallas, Desha and 23 more62 min
Apr 2, 9:57 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 27 more63 min
Apr 2, 10:10 AM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 31 more7 hr
Apr 2, 5:36 PM CDTMesoscale DiscussionSPCOrleans, Saint Bernard, Saint Tammany54 min

Nearby

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