Alert archive / Mississippi / Mesoscale Discussions in 2016

Mesoscale Discussion 73

February 2, 20164 parishes in Louisiana; 42 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 2, 2016, 10:41 AM CST for 4 parishes in Louisiana; 42 counties in Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Feb 2, 2016, 10:41 AM CST (16:41 UTC)
Expired: Feb 2, 2016, 12:45 PM CST
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 46 counties

East Carroll Parish, LA, Franklin Parish, LA, Madison Parish, LA, Tensas Parish, LA, Adams County, MS, Attala County, MS, Benton County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Copiah County, MS, Franklin 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, Lincoln County, MS, Madison County, MS, Marshall County, MS, Montgomery County, MS, Panola County, MS, Pontotoc 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, Union County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Wilkinson County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 89 km from the middle of the area, began a volume at 16:41 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

Jackson, MS (KJAN), launched 12:00Z, 4.7 hours before the alert went out and 81 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: 550 J/kg
Mixed-layer CIN: -159 J/kg
Mixed-layer LCL: 590 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 329 m²/s²
0-3 km storm-relative helicity: 540 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

As transmitted.

649 
ACUS11 KWNS 021642
SWOMCD
SPC MCD 021641 
MSZ000-TNZ000-LAZ000-ARZ000-021845-

MESOSCALE DISCUSSION 0073
NWS STORM PREDICTION CENTER NORMAN OK
1041 AM CST TUE FEB 02 2016

AREAS AFFECTED...MUCH OF MS AND PORTIONS OF ADJACENT WRN TN...NE LA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 021641Z - 021845Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...A TORNADO WATCH IS LIKELY AT SOME POINT THIS AFTERNOON. 
TIMING REMAINS A BIT UNCERTAIN...BUT IT IS POSSIBLE WITHIN THE NEXT
COUPLE OF HOURS.

DISCUSSION...ALTHOUGH STRONG CAPPING EVIDENT IN THE MORNING RAOB
FROM JACKSON HAS TENDED TO SUPPRESS CONVECTION...PERSISTENT NARROW
BANDS OF CONVECTION HAVE BEEN DEVELOPING ALONG LOW-LEVEL CONFLUENCE
ZONES WITHIN THE WARM SECTOR ACROSS THE LOWER MISSISSIPPI
VALLEY/GULF COAST REGION.  ONE PERSISTENT BAND HAS BEEN SOUTH OF
MEMPHIS TN THROUGH THE GREENVILLE MS AREA.

BREAKS IN CLOUD COVER ARE ALLOWING INSOLATION TO CONTRIBUTE TO
GRADUAL DESTABILIZATION OF THE BOUNDARY LAYER ACROSS THE REGION...AS
LOW-LEVELS CONTINUE TO MOISTEN.  AS MID-LEVEL FLOW CONTINUES TO
TRANSITION TO BROADLY CYCLONIC...AND HEIGHTS BEGIN TO GRADUALLY
FALL...SUFFICIENT WEAKENING OF INHIBITION TO ALLOW FOR DISCRETE
STORM DEVELOPMENT APPEARS AT LEAST POSSIBLE AS EARLY AS 18-21Z.

GUIDANCE APPEARS GENERALLY SUGGESTIVE THAT THE MOST SIGNIFICANT
CONVECTIVE DEVELOPMENT MAY NOT OCCUR UNTIL LATER THIS AFTERNOON INTO
THE EVENING HOURS.  HOWEVER...DEEP LAYER AND LOW-LEVEL SHEAR ARE
ALREADY MORE THAN SUFFICIENT FOR ORGANIZED CONVECTION
DEVELOPMENT...INCLUDING SUPERCELLS CAPABLE OF PRODUCING
TORNADOES...ONCE BOUNDARY LAYER STORM DEVELOPMENT COMMENCES.

..KERR/GOSS.. 02/02/2016

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

ATTN...WFO...MEG...JAN...LIX...

LAT...LON   32039178 34129072 35178938 34528852 32098948 30929147
            32039178

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 2, 12:50 PM CST	Mesoscale Discussion	SPC	Jefferson, Lafourche, Orleans, Saint Bernard, Saint Charles, Saint James and 5 more	55 min
Feb 2, 1:18 PM CST	Tornado Watch	SPC	Acadia, Ascension, Assumption, Avoyelles, Catahoula, Concordia and 25 more	6 hr
Feb 2, 5:18 PM CST	Mesoscale Discussion	SPC	Acadia, Ascension, Assumption, Avoyelles, Catahoula, Concordia and 25 more	117 min
Feb 2, 12:22 PM CST	Tornado Watch	SPC	Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 33 more	9 hr
Feb 2, 1:43 PM CST	Mesoscale Discussion	SPC	Choctaw, Clay, Covington, Jasper, Jefferson Davis, Leake and 9 more	2 hr
Feb 2, 5:31 PM CST	Mesoscale Discussion	SPC	Lowndes	119 min

Nearby

Mesoscale Discussions in Mississippi, 2016 Mesoscale Discussions in Louisiana, 2016 Every mesoscale discussion in 2016

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.