Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 2070

October 17, 20125 states

The Storm Prediction Center issued this mesoscale discussion at Oct 17, 2012, 9:28 PM CDT for 5 states. It was in force for 92 min.

The area

The outline as issued.

The facts

Issued
Oct 17, 2012, 9:28 PM CDT (02:28 UTC)
Expired
Oct 17, 2012, 11:00 PM CDT
In force
92 min
Issued by
the Storm Prediction Center
All 88 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Desha County, AR, Drew County, AR, Lincoln County, AR, Phillips County, AR, Union County, AR, Bienville Parish, LA, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Tensas Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Alcorn County, MS, Attala County, MS, Benton County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Coahoma County, MS, Copiah County, MS, DeSoto County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Lafayette County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Madison County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Quitman County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tippah County, MS, Tunica County, MS, Union County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS, Fayette County, TN, Hardeman County, TN, Shelby County, TN, Sabine County, TX, San Augustine County, TX, Shelby County, TX

The radar

The Jackson/Brandon,MS radar (KDGX), 172 km from the middle of the area, began a volume at 02:31 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

Little Rock, AR (KLZK), launched 00:00Z, 2.5 hours before the alert went out and 139 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 2012-10-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 947 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 2012-10-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 228 square meters per square second.1939587897Sfc1 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
947 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
1045 m above ground
0-6 km bulk shear
63 kt
0-1 km storm-relative helicity
228 m²/s²
0-3 km storm-relative helicity
236 m²/s²
Significant tornado parameter
1.0
Supercell composite
4.8

Open this sounding in Storm Lab

The text

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

243 
ACUS11 KWNS 180229
SWOMCD
SPC MCD 180228
TNZ000-MSZ000-ARZ000-LAZ000-TXZ000-180400-

MESOSCALE DISCUSSION 2070
NWS STORM PREDICTION CENTER NORMAN OK
0928 PM CDT WED OCT 17 2012

AREAS AFFECTED...SERN AR/SWRN TN/NRN AND WRN MS/NRN LA

CONCERNING...TORNADO WATCH 667...668...670...

VALID 180228Z - 180400Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH
667...668...670...CONTINUES.

SUMMARY...THREAT FOR A FEW TORNADOES ALONG WITH LOCALLY DAMAGING
WINDS AND HAIL CONTINUES...

DISCUSSION...LATEST RADAR LOOP REVEALS CONTINUED EWD PROGRESSION OF
A BAND OF STORMS ALONG AND AHEAD OF THE ADVANCING COLD FRONT...WITH
SEVERAL STORMS CONTINUING TO EXHIBIT LOW-LEVEL ROTATION.  WHILE
STORMS MOVING EWD ACROSS WRN TN HAVE SHOWN A TENDENCY TO WEAKEN A
BIT...ISOLATED SEVERE/TORNADO POTENTIAL REMAINS.  FARTHER S...WHERE
A MORE FAVORABLY MOIST/UNSTABLE ENVIRONMENT EXISTS...GREATER TORNADO
POTENTIAL PERSISTS -- AND WILL LIKELY CONTINUE OVER THE NEXT COUPLE
OF HOURS.

..GOSS/CORFIDI.. 10/18/2012

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

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

LAT...LON   35468905 34948828 33658852 31628993 31199457 31899446
            33809232 35488965 35468905

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 17, 7:01 PM CDTTornado WatchSPCAshley, Chicot, Columbia, Hempstead, Howard, Lafayette and 5 more8 hr
Oct 17, 7:35 PM CDTMesoscale DiscussionSPCArkansas, Clark, Clay, Cleburne, Cleveland, Conway and 37 more85 min
Oct 17, 11:49 PM CDTMesoscale DiscussionSPCCaldwell, Catahoula, East Carroll, Franklin, Grant, LaSalle and 6 more86 min
Oct 18, 1:16 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Calcasieu, East Baton Rouge and 12 more59 min
Oct 18, 2:40 AM CDTMesoscale DiscussionSPCAscension, East Baton Rouge, East Feliciana, Iberville, Livingston, Pointe Coupee and 8 more65 min
Oct 17, 8:07 PM CDTMesoscale DiscussionSPCAlcorn53 min
Oct 17, 8:23 PM CDTTornado WatchSPCAlcorn, Benton, Calhoun, Chickasaw, Itawamba, Lafayette and 8 more5 hr
Oct 18, 1:09 AM CDTMesoscale DiscussionSPCGeorge, Greene, Perry, Stone96 min
Oct 17, 8:43 PM CDTSevere Thunderstorm WatchSPCBenton, Carroll, Cheatham, Chester, Decatur, Dickson and 14 more4 hr
Oct 18, 3:27 PM CDTMesoscale DiscussionSPCCameron, Hidalgo, Willacy93 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.