Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 244

March 11, 2012Chicot County, Arkansas; 13 parishes in Louisiana; 19 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 11, 2012, 8:44 PM CDT for Chicot County, Arkansas; 13 parishes in Louisiana; 19 counties in Mississippi. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Mar 11, 2012, 8:44 PM CDT (01:44 UTC)
Expired: Mar 11, 2012, 10:15 PM CDT
In force: 91 min
Issued by: the Storm Prediction Center

All 33 counties

Chicot County, AR, Acadia Parish, LA, Avoyelles Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Carroll Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Madison Parish, LA, Pointe Coupee Parish, LA, Saint Landry Parish, LA, Tensas Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Adams County, MS, Carroll 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, Leflore County, MS, Madison County, MS, Rankin County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Wilkinson County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 129 km from the middle of the area, began a volume at 01:48 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 00:00Z, 1.7 hours before the alert went out and 122 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: 10 J/kg
Mixed-layer CIN: -23 J/kg
Mixed-layer LCL: 960 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 221 m²/s²
0-3 km storm-relative helicity: 261 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.

599 
ACUS11 KWNS 120144
SWOMCD
SPC MCD 120144 
MSZ000-ARZ000-LAZ000-120315-

MESOSCALE DISCUSSION 0244
NWS STORM PREDICTION CENTER NORMAN OK
0844 PM CDT SUN MAR 11 2012

AREAS AFFECTED...SWRN THRU NE LA INTO WRN/NRN MS

CONCERNING...TORNADO WATCH 72...

VALID 120144Z - 120315Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 72 CONTINUES.

AN ADDITIONAL WW IS NOT ANTICIPATED...BUT A FEW WEST CENTRAL
MISSISSIPPI COUNTIES MAY BE ADDED LOCALLY.

AS THE SIGNIFICANT CLOSED LOW/UPPER TROUGH CONTINUES TO LIFT THROUGH
THE CENTRAL PLAINS...AND AWAY FROM THE LOWER MISSISSIPPI VALLEY
REGION...THIS EVENING...LATEST RUC GUIDANCE CONTINUES TO SUGGEST
THAT FORCING FOR UPWARD VERTICAL MOTION SUPPORTING ONGOING
CONVECTIVE DEVELOPMENT WILL WEAKEN DURING THE 03-06Z TIME FRAME.  AT
THE SAME TIME...THE STRONGER SOUTHERLY LOW-LEVEL JET LIKELY WILL
SHIFT NORTHWARD THROUGH THE MIDDLE MISSISSIPPI VALLEY REGION...WITH
A CORRESPONDING GRADUAL WEAKENING OFF THE WESTERN GULF OF MEXICO
THROUGH LOUISIANA AND MISSISSIPPI.  THIS PROBABLY WILL CONTRIBUTE TO
DIMINISHING SEVERE THUNDERSTORM POTENTIAL WITHIN THE NEXT COUPLE OF
HOURS.

THROUGH 03-04Z...HOWEVER...CONDITIONS MAY STILL REMAIN AT LEAST
MARGINALLY CONDUCIVE TO THE PRODUCTION OF POTENTIAL DAMAGING WIND
GUSTS...AND PERHAPS AN ISOLATED TORNADO...WITH THE LINE OF STORMS
SPREADING OUT OF CENTRAL/NORTHEAST LOUISIANA TOWARD THE INTERSTATE
55 CORRIDOR OF MISSISSIPPI...NEAR/NORTH OF JACKSON INTO THE
GREENWOOD VICINITY.  THIS POTENTIAL SEEMS LIKELY TO DIMINISH IN A
MORE STABLE ENVIRONMENT TO THE NORTH AND EAST.

..KERR.. 03/12/2012

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

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

LAT...LON   32309165 33089163 33729111 33588990 32458972 31699036
            31139108 30589166 29619286 30859259 32309165

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 12, 4:02 PM CDT	Mesoscale Discussion	SPC	Chicot	58 min
Mar 11, 11:17 PM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, East Baton Rouge, Iberia, Iberville and 11 more	88 min
Mar 12, 1:23 AM CDT	Mesoscale Discussion	SPC	Ascension, Assumption, Iberia, Iberville, Livingston, Saint Charles and 5 more	2 hr
Mar 12, 8:55 AM CDT	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Iberville, Jefferson Davis, Lafayette and 5 more	65 min

Nearby

Mesoscale Discussions in Mississippi, 2012 Mesoscale Discussions in Louisiana, 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; radar from the NEXRAD Level II archive.