Alert archive / Mississippi / Mesoscale Discussions in 2016

Mesoscale Discussion 99

February 15, 201614 parishes in Louisiana; 16 counties in Mississippi; Jefferson County, Orange County, Texas

The Storm Prediction Center issued this mesoscale discussion at Feb 15, 2016, 7:41 AM CST for 14 parishes in Louisiana; 16 counties in Mississippi; Jefferson County, Orange County, Texas. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Feb 15, 2016, 7:41 AM CST (13:41 UTC)
Expired: Feb 15, 2016, 10:15 AM CST
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 32 counties

Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Catahoula Parish, LA, Concordia Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Jefferson Davis Parish, LA, LaSalle Parish, LA, Rapides Parish, LA, Tensas Parish, LA, Vernon Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Claiborne County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Jefferson County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS, Jefferson County, TX, Orange County, TX

The radar

The Ft Polk radar (KPOE), 105 km from the middle of the area, began a volume at 13:42 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.

Tornado Watch 14Feb 15, 9:30 AM CST

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 1.7 hours before the alert went out and 145 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: 1013 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 765 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 207 m²/s²
0-3 km storm-relative helicity: 283 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 8.5

Open this sounding in Storm Lab

The text

As transmitted.

628 
ACUS11 KWNS 151341
SWOMCD
SPC MCD 151341 
MSZ000-LAZ000-TXZ000-151615-

MESOSCALE DISCUSSION 0099
NWS STORM PREDICTION CENTER NORMAN OK
0741 AM CST MON FEB 15 2016

AREAS AFFECTED...UPPER TX COAST / SWRN INTO CNTRL LA / SWRN MS

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 151341Z - 151615Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...THE POTENTIAL FOR SEVERE STORM DEVELOPMENT WILL LIKELY
INCREASE THIS MORNING.  THE TIMING IS UNCLEAR BUT AN EVENTUAL NEED
FOR A TORNADO WATCH WILL BE COINCIDENT WITH DIURNAL HEATING.

DISCUSSION...RADAR MOSAIC SHOWS A PRE-FRONTAL BAND OF STORMS FROM
THE UPPER TX COAST NEWD INTO CNTRL PORTIONS OF LA.  THIS ACTIVITY
WILL SLOWLY INCREASE IN INTENSITY THIS MORNING AS POCKETS OF HEATING
COUPLED WITH A GRADUAL INCREASE IN LOW-LEVEL MOISTURE CONTRIBUTE TO
MODERATE BUOYANCY AND REDUCED MLCINH BY MID-LATE MORNING. 
FURTHERMORE...SHEAR PROFILES SUPPORTIVE OF ROTATION IN THE STRONGER
UPDRAFTS WILL LEND SOME INCREASING THREAT FOR LARGE HAIL AND DMGG
WINDS.  THE RISK FOR SURFACE-BASED SUPERCELLS /ONCE TEMPS RISE INTO
THE MID-UPPER 60S/ AND INCREASING PROBABILITY FOR ONE OR MORE
TORNADOES WILL LIKELY BE LOW IN THE SHORT TERM BUT INCREASE AS THE
BOUNDARY LAYER DESTABILIZES FURTHER BY LATE THIS MORNING AND INTO
THE AFTERNOON.  GIVEN THE UNCERTAINTY IN THE TIMING OF THE ONSET OF
SEVERAL STORMS POSING AN ISOLD SEVERE THREAT...SHORT-TERM
OBSERVATIONAL TRENDS WILL CONTINUE TO BE MONITORED.

..SMITH/EDWARDS.. 02/15/2016

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

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

LAT...LON   29839425 31149322 32079194 31868969 31218906 31068973
            30749191 29809335 29839425

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 15, 5:27 AM CST	Mesoscale Discussion	SPC	Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 11 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 Mesoscale Discussions in Texas, 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.