Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 286

March 26, 20118 counties in Arkansas; 11 parishes in Louisiana; 33 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 26, 2011, 8:32 PM CDT for 8 counties in Arkansas; 11 parishes in Louisiana; 33 counties in Mississippi. It was in force for 58 min.

The area

The outline as issued.

The facts

Issued: Mar 26, 2011, 8:32 PM CDT (01:32 UTC)
Expired: Mar 26, 2011, 9:30 PM CDT
In force: 58 min
Issued by: the Storm Prediction Center

All 52 counties

Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Desha County, AR, Drew County, AR, Ouachita County, AR, Union County, AR, Caldwell Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Ouachita Parish, LA, Richland Parish, LA, Union Parish, LA, West Carroll Parish, LA, Attala County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Kemper County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Pontotoc County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 115 km from the middle of the area, began a volume at 01:33 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, 1.5 hours before the alert went out and 106 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: 931 J/kg
Mixed-layer CIN: -52 J/kg
Mixed-layer LCL: 1807 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 147 m²/s²
0-3 km storm-relative helicity: 240 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 5.8

Open this sounding in Storm Lab

The text

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

544 
ACUS11 KWNS 270133
SWOMCD
SPC MCD 270132
MSZ000-ARZ000-LAZ000-270230-

MESOSCALE DISCUSSION 0286
NWS STORM PREDICTION CENTER NORMAN OK
0832 PM CDT SAT MAR 26 2011

AREAS AFFECTED...NRN/CENTRAL MS...SRN AR AND NRN LA

CONCERNING...TORNADO WATCH 63...

VALID 270132Z - 270230Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 63 CONTINUES.

A NEW WW IS BEING CONSIDERED TO REPLACE PARTS OF WW 63...GIVEN THE
UPCOMING 03Z EXPIRATION.

AT 01Z...REGIONAL RADAR IMAGERY SHOWED TSTMS CONTINUING TO INCREASE
IN COVERAGE AND INTENSITY FROM NWRN MS INTO FAR SERN AR WITH
ADDITIONAL UPDRAFTS FARTHER WSW NEAR TO JUST N OF A COLD FRONT INVOF
THE AR/LA BORDER.  THIS LATTER ACTIVITY IS BECOMING UNDERCUT AS THE
COLD FRONT MOVES SWD.  EARLY EVENING SURFACE ANALYSIS SHOWED AN AREA
OF LOW PRESSURE LOCATED OVER NWRN AL WITH A SWD MOVING COLD FRONT
EXTENDING THROUGH ERN MS /JUST S OF CBM/ TO WEST CENTRAL MS AND THEN
WWD INVOF THE LA/AR BORDER.

THE INITIAL ONGOING ACTIVITY SHOULD POSE PRIMARILY A HAIL
THREAT...AS IT IS DEVELOPING IN THE POST-FRONTAL AIR MASS WHERE
MLCAPE IS GENERALLY LESS THAN 1000 J/KG.  IF STORMS CAN DEVELOP AND
REMAIN ALONG THE COLD FRONT OR WITHIN THE WARM SECTOR...THEN THERE
EXISTS A POTENTIAL FOR A TORNADO.  THIS THREAT APPEARS TO BE
GREATEST OVER THE MS AND NERN LA PORTIONS OF WW 63...WHERE LOW LEVEL
SHEAR IS GREATER /I.E. LOW LEVEL WINDS ARE MORE BACKED TO
SWLY/...THAN COMPARED TO FARTHER W ACROSS E TX/WRN LA WHERE WINDS
HAVE BEGUN TO VEER.

FORCING FOR ASCENT WITHIN THE ENTRANCE REGION OF A WLY 70-75 KT
MIDLEVEL JET ACROSS THE TN VALLEY AND LOW LEVEL WAA WILL CONTINUE TO
SUPPORT ELEVATED TSTMS.  HOWEVER...GIVEN RECENT RADAR
TRENDS...SURFACE BASED STORMS SHOULD CONTINUE TO DEVELOP NEAR THE
COLD FRONT IN FAR NRN LA/SRN AR...AND EVENTUALLY INTO MS.

..PETERS.. 03/27/2011

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

ATTN...WFO...MEG...JAN...LZK...SHV...

LAT...LON   34398816 32588840 32488990 32389021 32519052 32169086
            32099111 32189143 31959148 31959242 32159286 32979285
            33449300 33759305 33729192 33949091 34198984 34508861
            34398816

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 26, 9:33 PM CDT	Mesoscale Discussion	SPC	Ashley, Chicot, Union	27 min
Mar 27, 1:41 PM CDT	Mesoscale Discussion	SPC	Ashley, Bradley, Calhoun, Chicot, Clark, Cleveland and 11 more	64 min

Nearby

Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Louisiana, 2011 Mesoscale Discussions in Arkansas, 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.