Alert archive / Mississippi / Mesoscale Discussions in 2016

Mesoscale Discussion 199

March 11, 2016Orleans Parish, Saint Bernard Parish, Saint Tammany Parish, Louisiana; 5 counties in Mississippi

The Storm Prediction Center issued this mesoscale discussion at Mar 11, 2016, 5:42 AM CST for Orleans Parish, Saint Bernard Parish, Saint Tammany Parish, Louisiana; 5 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued: Mar 11, 2016, 5:42 AM CST (11:42 UTC)
Expired: Mar 11, 2016, 8:15 AM CST
In force: 3 hr
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Orleans Parish, LA, Saint Bernard Parish, LA, Saint Tammany Parish, LA, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Stone County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 11.7 hours before the alert went out and 25 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: 687 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 512 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 463 m²/s²
0-3 km storm-relative helicity: 470 m²/s²
Significant tornado parameter: 1.6
Supercell composite: 14.9

Open this sounding in Storm Lab

The text

As transmitted.

617 
ACUS11 KWNS 111142
SWOMCD
SPC MCD 111142 
ALZ000-MSZ000-LAZ000-111415-

MESOSCALE DISCUSSION 0199
NWS STORM PREDICTION CENTER NORMAN OK
0542 AM CST FRI MAR 11 2016

AREAS AFFECTED...SE LA...SRN MS

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 111142Z - 111415Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...AN ISOLATED WIND DAMAGE THREAT ONGOING IN SE LA MAY AFFECT
SRN MS BUT WILL LIKELY REMAIN MARGINAL OVER THE NEXT COUPLE OF
HOURS. WW ISSUANCE IS NOT EXPECTED ACROSS THE LOWER MS VALLEY THIS
MORNING.

DISCUSSION...THE LATEST RADAR IMAGERY SHOWS A LINE OF STRONG
THUNDERSTORMS EXTENDING FROM NEAR LAKE PONTCHARTRAIN SEWD TO THE
MOUTH OF THE MS RIVER WHERE SEVERAL PARTS OF THE LINES HAVE A BOWING
STRUCTURE. AN AXIS OF INSTABILITY IS LOCATED JUST AHEAD OF THE LINE
OF STORMS WHERE MLCAPE IS ESTIMATED IN THE 500 TO 700 J/KG RANGE. IN
ADDITION...A 35 TO 45 KT LOW-LEVEL JET IS ANALYZED OVER SE LA WHICH
IS PROVIDING SUPPORT FOR THE LINE. THE NEW ORLEANS WSR-88D VWP IS
SAMPLING THE LOW-LEVEL JET WELL WITH UNIDIRECTIONAL WINDS OF 40 TO
50 KT ABOVE 1 KM AGL. DOWNDRAFTS ASSOCIATED WITH THE LINE OF STORMS
MAY BE ABLE TO TRANSFER THE STRONGER LOW-LEVEL FLOW TO THE SURFACE
RESULTING IN MARGINALLY SEVERE WIND GUSTS. THE POTENTIAL FOR STRONG
WIND GUSTS MAY CONTINUE FOR ANOTHER HOUR OR TWO BUT SHOULD END AS
THE CONVECTION REACHES THE COOLER AIR ON THE NORTH SIDE OF AN EAST
TO WEST BOUNDARY EXTENDING ACROSS SRN MS.

..BROYLES/THOMPSON.. 03/11/2016

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

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

LAT...LON   30249017 29678970 30138864 30518831 30928909 31068985
            30529020 30249017

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.