Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 1597

August 29, 201719 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Aug 29, 2017, 2:09 PM CDT for 19 parishes in Louisiana. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Aug 29, 2017, 2:09 PM CDT (19:09 UTC)
Expired
Aug 29, 2017, 4:45 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Plaquemines Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 7.2 hours before the alert went out and 174 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, Lake Charles Mun, LA at 12:00Z on 2017-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 294 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, Lake Charles Mun, LA at 12:00Z on 2017-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 363 square meters per square second.193958Sfc1 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
294 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
539 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
363 m²/s²
0-3 km storm-relative helicity
449 m²/s²
Significant tornado parameter
0.4
Supercell composite
6.7

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
Aug 28, 11:32 PM CDTMesoscale DiscussionSPCAcadia, Ascension, Assumption, Calcasieu, Cameron, Iberia and 16 more118 min
Aug 29, 6:20 AM CDTMesoscale DiscussionSPCAssumption, Iberia, Jefferson, Lafourche, Plaquemines, Saint Charles and 3 more115 min

Nearby

Mesoscale Discussions in Louisiana, 2017Every mesoscale discussion in 2017

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.