Alert archive / Louisiana / Mesoscale Discussions in 2018

Mesoscale Discussion 230

April 7, 20186 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Apr 7, 2018, 4:31 AM CDT for 6 parishes in Louisiana. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Apr 7, 2018, 4:31 AM CDT (09:31 UTC)
Expired
Apr 7, 2018, 5:30 AM CDT
In force
59 min
Issued by
the Storm Prediction Center

Counties Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint John the Baptist Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 9.5 hours before the alert went out and 42 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, Slidell Radar S, LA at 00:00Z on 2018-04-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 933 joules per kilogram.LCLLFCEL10008507005003002001001 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, Slidell Radar S, LA at 00:00Z on 2018-04-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 144 square meters per square second.19395878Sfc1 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
933 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
780 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
144 m²/s²
0-3 km storm-relative helicity
257 m²/s²
Significant tornado parameter
0.5
Supercell composite
5.7

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 6, 8:12 PM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Avoyelles, Beauregard, Calcasieu and 21 more63 min
Apr 6, 8:53 PM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 33 more10 hr
Apr 6, 10:57 PM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 28 more93 min
Apr 7, 1:37 AM CDTMesoscale DiscussionSPCAcadia, Allen, Calcasieu, Cameron, Iberia, Jefferson Davis and 4 more83 min

Nearby

Mesoscale Discussions in Louisiana, 2018Every mesoscale discussion in 2018

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.