Alert archive / Mississippi / Mesoscale Discussions in 2011

Mesoscale Discussion 616

April 27, 201121 counties in Arkansas; 39 counties in Mississippi; 4 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Apr 27, 2011, 6:25 AM CDT for 21 counties in Arkansas; 39 counties in Mississippi; 4 counties in Tennessee. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
Apr 27, 2011, 6:25 AM CDT (11:25 UTC)
Expired
Apr 27, 2011, 7:30 AM CDT
In force
65 min
Issued by
the Storm Prediction Center
All 64 counties

Arkansas County, AR, Cleburne County, AR, Crittenden County, AR, Cross County, AR, Desha County, AR, Faulkner County, AR, Grant County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, St. Francis County, AR, White County, AR, Woodruff County, AR, Alcorn County, MS, Attala County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Itawamba County, MS, Lafayette County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tunica County, MS, Union County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Fayette County, TN, Hardeman County, TN, Shelby County, TN, Tipton County, TN

The radar

The Memphis radar (KNQA), 133 km from the middle of the area, began a volume at 11:25 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Little Rock, AR (KLZK), launched 00:00Z, 11.4 hours before the alert went out and 76 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, Little Rock, AR at 00:00Z on 2011-04-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 468 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, Little Rock, AR at 00:00Z on 2011-04-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 334 square meters per square second.1939587897117Sfc1 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
468 J/kg
Mixed-layer CIN
-130 J/kg
Mixed-layer LCL
966 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
334 m²/s²
0-3 km storm-relative helicity
505 m²/s²
Significant tornado parameter
0.7
Supercell composite
17.7

Open this sounding in Storm Lab

The text

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

303 
ACUS11 KWNS 271126
SWOMCD
SPC MCD 271125
MSZ000-TNZ000-ARZ000-271230-

MESOSCALE DISCUSSION 0616
NWS STORM PREDICTION CENTER NORMAN OK
0625 AM CDT WED APR 27 2011

AREAS AFFECTED...CNTRL AR...NRN/CNTRL MS...SWRN TN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 271125Z - 271230Z

THE THREAT FOR SVR STORMS WILL SHIFT E-NEWD FROM CNTRL AR AND NRN
LA...AND A SVR TSTM WATCH MAY BE NEEDED TO THE EAST OF WW226.

ELEVATED CONVECTION CAPABLE OF PRODUCING LARGE HAIL WILL SHIFT
E-NEWD OUT OF WW226 OVER THE NEXT COUPLE OF HOURS. STEEP MID-LEVEL
LAPSE RATES AND CONTINUED STRONG ASCENT WILL RESULT IN A CONTINUING
THREAT FOR SVR STORMS WITH LARGE HAIL AS THIS ACTIVITY APPROACHES
THE MID-SOUTH. A SVR TSTM WATCH MAY BE NEEDED SHORTLY TO THE EAST OF
WW226. FARTHER TO THE SOUTHEAST ACROSS CNTRL MS NORTH OF TORNADO
WATCH 225...STORMS WILL INITIALLY BE ELEVATED POSING A LARGE HAIL
THREAT. HOWEVER...AS SFC-BASED CONVECTIVE INHIBITION DECREASES WITH
TIME AFTER SUNRISE...THE THREAT WILL EVENTUALLY TRANSITION TO A
TORNADO THREAT BY LATE MORNING.

..COHEN.. 04/27/2011

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

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

LAT...LON   34498834 33758838 32818845 32688948 32799027 33039077
            33509104 33849175 34219249 34899275 35639230 35859098
            35728981 35228859 34498834

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 26, 7:59 PM CDTMesoscale DiscussionSPCChicot2 hr
Apr 26, 8:53 PM CDTMesoscale DiscussionSPCCalhoun, Clark, Columbia, Dallas, Grant, Hempstead and 10 more97 min
Apr 26, 9:13 PM CDTMesoscale DiscussionSPCArkansas, Clay, Craighead, Crittenden, Cross, Desha and 21 more62 min
Apr 26, 9:33 PM CDTTornado Watch PDSSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Cleveland and 11 more7 hr
Apr 26, 9:58 PM CDTTornado WatchSPCCraighead, Crittenden, Cross, Greene, Jackson, Lee and 8 more7 hr
Apr 26, 11:33 PM CDTMesoscale DiscussionSPCChicot, Desha, Phillips117 min
Apr 27, 3:29 AM CDTMesoscale DiscussionSPCHempstead, Lafayette, Little River, Miller2 hr
Apr 27, 4:53 AM CDTSevere Thunderstorm WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 19 more5 hr
Apr 27, 8:40 AM CDTMesoscale DiscussionSPCBaxter, Benton, Boone, Carroll, Clay, Cleburne and 28 more65 min
Apr 27, 9:48 AM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Clark, Cleveland and 10 more27 min
Apr 27, 11:02 AM CDTTornado Watch PDSSPCAshley, Chicot8 hr
Apr 27, 12:42 PM CDTSevere Thunderstorm WatchSPCBaxter, Clay, Cleburne, Conway, Craighead, Crittenden and 19 more5 hr
Apr 27, 3:06 PM CDTMesoscale DiscussionSPCClay, Craighead, Greene, Mississippi, Poinsett54 min
Apr 27, 3:29 PM CDTTornado WatchSPCMississippi5 hr
Apr 27, 1:56 AM CDTMesoscale DiscussionSPCClarke, Copiah, Covington, Jasper, Jefferson Davis, Kemper and 11 more64 min
Apr 27, 2:26 AM CDTTornado WatchSPCAdams, Alcorn, Attala, Calhoun, Chickasaw, Choctaw and 38 more6 hr
Apr 27, 8:08 AM CDTTornado WatchSPCAlcorn, Calhoun, Carroll, Chickasaw, Choctaw, Clay and 16 more6 hr
Apr 27, 10:45 AM CDTMesoscale DiscussionSPCAdams, Attala, Benton, Calhoun, Carroll, Chickasaw and 53 more90 min
Apr 27, 1:42 PM CDTTornado Watch PDSSPCGreene, Perry, Wayne8 hr
Apr 27, 2:56 PM CDTMesoscale DiscussionSPCAlcorn, Attala, Calhoun, Chickasaw, Choctaw, Clarke and 35 more2 hr
Apr 27, 5:01 PM CDTMesoscale DiscussionSPCAttala, Chickasaw, Choctaw, Clarke, Clay, Covington and 26 more89 min
Apr 27, 6:27 PM CDTMesoscale DiscussionSPCClarke, Clay, Copiah, Covington, Forrest, Jasper and 22 more33 min
Apr 27, 6:42 PM CDTTornado WatchSPCClarke, Covington, Forrest, Jasper, Jefferson Davis, Jones and 13 more3 hr
Apr 27, 4:33 AM CDTMesoscale DiscussionSPCBedford, Cannon, Clay, Coffee, Cumberland, DeKalb and 15 more57 min
Apr 27, 5:07 AM CDTTornado WatchSPCBedford, Bledsoe, Cannon, Clay, Coffee, Cumberland and 27 more5 hr
Apr 27, 7:34 AM CDTTornado WatchSPCAnderson, Blount, Bradley, Campbell, Claiborne, Grainger and 13 more4 hr
Apr 27, 10:27 AM CDTTornado WatchSPCAnderson, Bedford, Bledsoe, Blount, Bradley, Cannon and 29 more6 hr
Apr 27, 11:39 AM CDTMesoscale DiscussionSPCBledsoe, Blount, Bradley, Cannon, Coffee, DeKalb and 16 more66 min
Apr 27, 12:08 PM CDTMesoscale DiscussionSPCBenton, Carroll, Cheatham, Chester, Crockett, Decatur and 21 more67 min
Apr 27, 1:03 PM CDTMesoscale DiscussionSPCBledsoe, Blount, Bradley, Grundy, Hamilton, Loudon and 10 more57 min
Apr 27, 1:05 PM CDTMesoscale DiscussionSPCFranklin, Giles, Lawrence, Lincoln, Marshall, Maury and 1 more85 min
Apr 27, 2:22 PM CDTMesoscale DiscussionSPCAnderson, Blount, Campbell, Carter, Claiborne, Cocke and 17 more83 min
Apr 27, 3:36 PM CDTTornado Watch PDSSPCAnderson, Bedford, Benton, Bledsoe, Blount, Bradley and 66 more8 hr
Apr 27, 5:38 PM CDTMesoscale DiscussionSPCAnderson, Bedford, Bledsoe, Blount, Bradley, Cannon and 36 more97 min

Nearby

Mesoscale Discussions in Mississippi, 2011Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Tennessee, 2011Every 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.