Alert archive / Mississippi / Mesoscale Discussions in 2012

Mesoscale Discussion 981

May 30, 201235 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at May 30, 2012, 2:34 PM CDT for 35 counties in Mississippi. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued: May 30, 2012, 2:34 PM CDT (19:34 UTC)
Expired: May 30, 2012, 3:30 PM CDT
In force: 56 min
Issued by: the Storm Prediction Center

All 35 counties

Attala County, MS, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Clay County, MS, Coahoma County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Lafayette County, MS, Leake County, MS, Leflore County, MS, Madison County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Oktibbeha County, MS, Panola County, MS, Quitman County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica 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), 137 km from the middle of the area, began a volume at 19:34 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, 7.6 hours before the alert went out and 134 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: 1192 J/kg
Mixed-layer CIN: -72 J/kg
Mixed-layer LCL: 1334 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 14 m²/s²
0-3 km storm-relative helicity: -4 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.

260 
ACUS11 KWNS 301934
SWOMCD
SPC MCD 301934 
MSZ000-ARZ000-LAZ000-302030-

MESOSCALE DISCUSSION 0981
NWS STORM PREDICTION CENTER NORMAN OK
0234 PM CDT WED MAY 30 2012

AREAS AFFECTED...NRN/CNTRL MS

CONCERNING...SEVERE THUNDERSTORM WATCH 321...

VALID 301934Z - 302030Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 321
CONTINUES.

SUMMARY...DMGG WIND AND HAIL THREAT WILL CONTINUE TO PROGRESS EWD
THROUGH NRN/CNTRL MS. AREAS IN THE WAKE OF THE THUNDERSTORM COMPLEX
MAY BE CLEARED FROM WW321.

DISCUSSION...19Z SURFACE ANALYSIS IS INDICATING A WEAK LOW/MCV OVER
NWRN MS...WHICH CONTINUES TO INFLUENCE A SEMI-ORGANIZED CLUSTER OF
THUNDERSTORMS. AMPLE SURFACE HEATING IN ADVANCE OF THIS FEATURE HAS
LED TO STEEPENING LOW-LEVEL LAPSE RATES /8.5-9 C/KM PER
MESOANALYSIS/ AND LARGE T/TD SPREADS NEAR 20-25 DEGREES F...WHICH
WILL FAVOR SUSTENANCE OF THE ONGOING COLD POOL AND A SUBSEQUENT DMGG
WIND THREAT. HAIL MAY BE POSSIBLE WITH THE STRONGER CORES THAT CAN
DEVELOP ALONG THE LEADING EDGE. 19Z VISIBLE IMAGERY AND SURFACE
OBSERVATIONS SUGGEST A SUBTLE MOISTURE GRADIENT FROM APPROXIMATELY
MEMPHIS SEWD TO DOTHAN AL. THE ONGOING CLUSTER OF THUNDERSTORMS WILL
LIKELY CONTINUE TO PROGRESS SEWD WITHIN THE MOIST WARM
SECTOR...THOUGH WEAK DEEP LAYER FLOW SUGGESTS A SLOW FORWARD
PROPAGATION OF ABOUT 20-25 KTS...WITH THE COMPLEX REACHING THE EDGE
OF THE WW AROUND 22Z. HOWEVER...THE NRN MOST PORTION OF THE MCS MAY
BEGIN TO WEAKEN AS IT PROGRESSES INTO THE DRY SIDE OF THE
BOUNDARY...AND ANVILS BEGIN TO HINDER SURFACE HEATING/INSTABILITY
DOWNSTREAM.

..HURLBUT.. 05/30/2012

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

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

LAT...LON   34849038 34808967 33628860 32618872 32278896 31969001
            32659105 34009112 34849038

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 30, 12:07 PM CDT	Mesoscale Discussion	SPC	Attala, Bolivar, Carroll, Claiborne, Coahoma, Copiah and 21 more	83 min
May 30, 12:27 PM CDT	Severe Thunderstorm Watch	SPC	Attala, Benton, Bolivar, Calhoun, Carroll, Chickasaw and 36 more	7 hr
May 30, 4:56 PM CDT	Mesoscale Discussion	SPC	Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 39 more	94 min

Nearby

Mesoscale Discussions in Mississippi, 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.