Alert archive / Mississippi / Mesoscale Discussions in 2016

Mesoscale Discussion 98

February 15, 201617 parishes in Louisiana; 20 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 15, 2016, 5:27 AM CST for 17 parishes in Louisiana; 20 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Feb 15, 2016, 5:27 AM CST (11:27 UTC)
Expired: Feb 15, 2016, 8:00 AM CST
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

All 37 counties

Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Amite County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Walthall County, MS, Wayne County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 11.5 hours before the alert went out and 79 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 885 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 238 m²/s²
0-3 km storm-relative helicity: 244 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

286 
ACUS11 KWNS 151128
SWOMCD
SPC MCD 151127 
MSZ000-LAZ000-151400-

MESOSCALE DISCUSSION 0098
NWS STORM PREDICTION CENTER NORMAN OK
0527 AM CST MON FEB 15 2016

AREAS AFFECTED...PORTIONS SERN LA...CENTRAL/SRN MS.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 151127Z - 151400Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...ISOLATED HAIL NEAR SVR LIMITS IS POSSIBLE ACROSS
DISCUSSION AREA...HOWEVER THREAT APPEARS ISOLATED/MRGL ENOUGH DURING
NEXT COUPLE HOURS THAT WW ISSUANCE APPEARS UNLIKELY.

DISCUSSION...TSTMS CONTINUE TO DEVELOP AND MOVE NEWD APPROXIMATELY
20 KT...WITHIN SLOWLY EWD-SHIFTING PLUME OF LOW-LEVEL LIFT ABOVE
SFC.   THAT CORRIDOR EXTENDS ATTM FROM CENTRAL MS SSWWD ACROSS MCB
AREA AND SERN LA TO GULF S OF ARA.  CONVECTION IS MOST CONCENTRATED
IN MS PORTION OF THIS UVV ZONE...THOUGH ISOLATED CELLS FARTHER S
ALSO MAY POSE SOME MRGL SVR RISK.  SOMEWHAT ELEVATED SUPERCELLS WITH
ISOLATED HAIL AND STG GUSTS ARE POSSIBLE.  TORNADO THREAT APPEARS
VERY CONDITIONAL/LOW ATTM DUE TO LACK OF MORE INSTABILITY AT
SFC...THOUGH THAT RISK MAY INCREASE THROUGH MID-LATE MORNING AS
BOUNDARY LAYER DESTABILIZES FROM BOTH THETAE ADVECTION AND POCKETS
OF SUSTAINED INSOLATION.

SUBTLE CONFLUENCE OF 850-MB STREAMLINES IS APPARENT ACROSS THIS
REGION IN COMBINATION OF PLANAR VWP PLOTS AND RAP ANALYSES AT THAT
LEVEL...COLLOCATED WITH AXIS OF 35-40-KT LLJ.  THAT CONFLUENCE ZONE
SHOULD SHARPEN THROUGH REMAINDER MORNING AS IT MOVES EWD ACROSS SRN
MS AND SERN LA THROUGH ABOUT 14Z PRIOR TO AFOREMENTIONED
DESTABILIZATION.  LATTER WILL SUPPORT ADDITIONAL CONVECTIVE
DEVELOPMENT AMIDST WEAK MUCINH AND MUCAPE GENERALLY 500-1000 J/KG
INVOF LA/MS BORDER AND SERN LA...DECREASING WITH NWD EXTENT. 
MODIFIED FCST SOUNDINGS USED TO DERIVE THOSE VALUES TO NOT INCLUDE
BAD THERMODYNAMIC OBSERVATIONS AT STATION 1R7 IN LINCOLN
COUNTY...WHICH HAS ERRONEOUSLY REPORTED 71-73 F DEW POINTS IN PAST 2
HOURS.  LOW-LEVEL HODOGRAPHS APPEAR SOMEWHAT FAVORABLE WITH SRH
AROUND 100-200 J/KG IN 0-1-KM LAYER AND 200-300 J/KG IN 0-3-KM
LAYER...PER MODIFIED LIX VWP.  35-40 KT EFFECTIVE-SHEAR MAGNITUDES
SHOULD PREVAIL OVER MOST OF THIS AREA THROUGH ABOUT 14Z.  

THOUGH SVR THREAT IN NEAR TERM IS LIMITED...RISK SHOULD RAMP UP 
LATER THIS MORNING INTO AFTERNOON.  MORE DETAILS WILL BE OFFERED ON
THAT SCENARIO IN 13Z SPC CONVECTIVE DAY-1 OUTLOOK.

..EDWARDS.. 02/15/2016

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

ATTN...WFO...MOB...JAN...LIX...LCH...

LAT...LON   29469182 30919138 31429093 32269015 32458953 32288919
            31868868 31438863 30988888 30548943 29959025 29119091
            29369140 29389121 29529138 29739157 29469182

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 15, 7:41 AM CST	Mesoscale Discussion	SPC	Allen, Avoyelles, Beauregard, Calcasieu, Catahoula, Concordia and 8 more	3 hr
Feb 15, 9:30 AM CST	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 27 more	8 hr
Feb 15, 11:50 AM CST	Mesoscale Discussion	SPC	East Baton Rouge, East Feliciana, Livingston, Saint Helena, Saint Tammany, Tangipahoa and 1 more	115 min
Feb 15, 1:51 PM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 11 more	114 min
Feb 15, 4:24 PM CST	Mesoscale Discussion	SPC	George, Jackson	2 hr

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.