Alert archive / Mississippi / Mesoscale Discussions in 2016

Mesoscale Discussion 174

March 3, 201611 counties in Arkansas; 6 parishes in Louisiana; 15 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 3, 2016, 2:29 PM CST for 11 counties in Arkansas; 6 parishes in Louisiana; 15 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Mar 3, 2016, 2:29 PM CST (20:29 UTC)
Expired
Mar 3, 2016, 5:00 PM CST
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 32 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Cleveland County, AR, Desha County, AR, Drew County, AR, Lincoln County, AR, Ouachita County, AR, Union County, AR, East Carroll Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Richland Parish, LA, Union Parish, LA, West Carroll Parish, LA, Attala County, MS, Bolivar County, MS, Carroll County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Leake County, MS, Leflore County, MS, Madison County, MS, Montgomery County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 179 km from the middle of the area, began a volume at 20:29 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, 8.5 hours before the alert went out and 169 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, Jackson, MS at 12:00Z on 2016-03-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Jackson, MS at 12:00Z on 2016-03-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 420 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1734 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
420 m²/s²
0-3 km storm-relative helicity
497 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted.

258 
ACUS11 KWNS 032030
SWOMCD
SPC MCD 032029 
MSZ000-ARZ000-LAZ000-032300-

MESOSCALE DISCUSSION 0174
NWS STORM PREDICTION CENTER NORMAN OK
0229 PM CST THU MAR 03 2016

AREAS AFFECTED...THE ARKLAMISS REGION

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 032029Z - 032300Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...HAIL WILL BE A CONCERN WITH ISOLATED TO SCATTERED
CONVECTION CROSSING THE ARKLAMISS REGION THIS AFTERNOON. AN INSTANCE
OR TWO OF QUARTER-SIZE HAIL CANNOT BE RULED OUT...THOUGH WW ISSUANCE
WILL NOT BE NEEDED.

DISCUSSION...INTENSE FORCING FOR ASCENT IN ADVANCE OF A COMPACT
MID-LEVEL VORT MAX -- ENHANCED WITHIN THE LEFT-EXIT REGION OF AN
ASSOCIATED CYCLONICALLY CURVED JET STREAK -- IS SUPPORTING AN
INCREASE IN CONVECTIVE DEVELOPMENT ACROSS PARTS OF ERN/SRN AR. THIS
ACTIVITY IS BEING AIDED BY POCKETS OF SFC DIABATIC HEATING
FACILITATING THE STEEPENING OF LOW-LEVEL LAPSE RATES. TSTMS WILL
SPREAD EWD/SEWD ACROSS THE ARKLAMISS REGION THROUGH LATE AFTERNOON.
HYDRODYNAMIC PERTURBATION-PRESSURE GRADIENT FORCES ATTENDANT TO
ROTATING UPDRAFTS IN THE MODERATELY TO STRONGLY SHEARED ENVIRONMENT
WILL OFFSET MEAGER BUOYANCY RELATED TO THE PAUCITY OF LOW-LEVEL
MOISTURE -- E.G. SFC DEWPOINTS IN THE MIDDLE 40S TO THE MIDDLE 
50S -- TO SUPPORT STRONG-TSTM POTENTIAL. GIVEN THE VERTICALLY
SHEARED ENVIRONMENT...AND COLD MID-LEVEL TEMPERATURES /H5 TEMPS
AROUND -25C TO -18C IN MANY AREAS/ WITH LOW FREEZING-LEVEL
HEIGHTS...HAIL WILL BE A CONCERN WITH THIS ACTIVITY. IN ADDITION TO
POTENTIALLY COPIOUS AMOUNTS OF SMALL HAIL OCCURRING WITH SOME
TSTMS...A COUPLE OF INSTANCES OF QUARTER-SIZE HAIL MAY OCCUR.
HOWEVER...THE OVERALL DEARTH OF MLCAPE SHOULD PRECLUDE A MORE
SUBSTANTIAL SVR RISK FROM EVOLVING. LOCALLY STRONG WIND GUSTS COULD
ALSO OCCUR WITH A DEEPER BOUNDARY LAYER IN NERN LA...SERN AR...AND
ADJACENT W-CNTRL MS.

..COHEN/HART.. 03/03/2016

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

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

LAT...LON   33409310 33949267 34339173 34249068 33518954 32908929
            32298998 32249173 32869272 33409310

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 3, 1:13 PM CSTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 11 more3 hr
Mar 3, 5:07 PM CSTMesoscale DiscussionSPCClarke, Covington, Forrest, George, Greene, Jasper and 9 more2 hr

Nearby

Mesoscale Discussions in Mississippi, 2016Mesoscale Discussions in Arkansas, 2016Mesoscale Discussions in Louisiana, 2016Every 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.