Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 690

May 2, 20115 states

The Storm Prediction Center issued this mesoscale discussion at May 2, 2011, 1:51 PM CDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: May 2, 2011, 1:51 PM CDT (18:51 UTC)
Expired: May 2, 2011, 4:15 PM CDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 117 counties

Fayette County, AL, Franklin County, AL, Lamar County, AL, Marion County, AL, Pickens County, AL, Ashley County, AR, Chicot County, AR, Desha County, AR, Drew County, AR, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Bienville Parish, LA, Calcasieu Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, East Baton Rouge Parish, LA, East Carroll Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Franklin Parish, LA, Grant Parish, LA, Iberville Parish, LA, Jackson Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Livingston Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Saint Helena Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Tangipahoa Parish, LA, Tensas Parish, LA, Union Parish, LA, Vernon Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Carroll Parish, LA, West Feliciana Parish, LA, Winn Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Copiah County, MS, Covington County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Kemper County, MS, Lafayette County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lincoln County, MS, Lowndes County, MS, Madison County, MS, Marion County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pike County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Sunflower County, MS, Tallahatchie County, MS, Union County, MS, Walthall County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Wilkinson County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS, Newton County, TX, Sabine County, TX

The radar

The Jackson/Brandon,MS radar (KDGX), 50 km from the middle of the area, began a volume at 18:52 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, 6.9 hours before the alert went out and 42 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: 747 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 647 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 166 m²/s²
0-3 km storm-relative helicity: 167 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 3.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

966 
ACUS11 KWNS 021852
SWOMCD
SPC MCD 021851
ALZ000-MSZ000-LAZ000-ARZ000-TXZ000-022115-

MESOSCALE DISCUSSION 0690
NWS STORM PREDICTION CENTER NORMAN OK
0151 PM CDT MON MAY 02 2011

AREAS AFFECTED...SERN AR/MUCH OF MS AND LA/NWRN AL

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 021851Z - 022115Z

SHOWERS AND SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP IN --
AND WEST OF -- THE MOIST/UNSTABLE WARM SECTOR ACROSS THIS REGION.
WHILE A COUPLE OF STRONGER CELLS MAY BE CAPABLE OF LOCALLY
STRONG/GUSTY WINDS AND MARGINAL HAIL...IT APPEARS ATTM THAT LIMITED
POTENTIAL SHOULD NEGATE THE NEED FOR WW ISSUANCE.

RADAR IMAGERY SHOWS CONTINUED DEVELOPMENT OF CONVECTION ACROSS THE
DISCUSSION AREA...NEAR -- AND JUST WEST OF -- THE SURFACE COLD
FRONT...AS WELL AS WITHIN THE WEAKLY CONFLUENT WARM-SECTOR AIRMASS
FARTHER E.  WHILE 1000 TO 1500 J/KG MIXED-LAYER CAPE WHICH HAS
RESULTED FROM THE COMBINATION OF AFTERNOON HEATING AND SURFACE
DEWPOINTS AROUND 70 WILL CONTINUE TO SUPPORT ADDITIONAL CONVECTIVE
DEVELOPMENT...WEAK LAPSE RATES/WARM AIR IN THE 850 TO 650 MB LAYER
WILL HINDER TO SOME DEGREE THE UPDRAFT STRENGTH.  IN
ADDITION...STRONGER FLOW ALOFT REMAINS WELL W IN THE COOLER
POST-FRONTAL AIRMASS...FURTHER LIMITING OVERALL STORM INTENSITY
IN/NEAR THE WARM SECTOR.  WHILE A FEW STRONGER CELLS MAY BRIEFLY
STRENGTHEN ABOVE SEVERE LEVELS...DEGREE OF THREAT ANTICIPATED ATTM
SUGGESTS THAT WW WILL NOT BE NEEDED.

..GOSS.. 05/02/2011

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

ATTN...WFO...BMX...HUN...MEG...JAN...LIX...LZK...LCH...SHV...

LAT...LON   34718782 33758739 30538990 29949131 30059382 31639386
            33909143 34688923 34718782

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 2, 5:00 PM CDT	Mesoscale Discussion	SPC	Lauderdale	60 min
May 1, 7:31 PM CDT	Mesoscale Discussion	SPC	Clay, Cleburne, Conway, Craighead, Faulkner, Garland and 20 more	59 min
May 1, 8:10 PM CDT	Mesoscale Discussion	SPC	Arkansas, Bradley, Calhoun, Clark, Cleveland, Columbia and 24 more	35 min
May 2, 1:28 AM CDT	Mesoscale Discussion	SPC	Howard, Little River, Miller, Sevier	3 hr
May 2, 12:55 AM CDT	Mesoscale Discussion	SPC	Bosque, Brown, Callahan, Coleman, Collin, Comanche and 43 more	3 hr

Nearby

Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Louisiana, 2011 Mesoscale Discussions in Alabama, 2011 Every mesoscale discussion in 2011

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.