Alert archive / Louisiana / Mesoscale Discussions in 2020

Mesoscale Discussion 488

April 28, 20206 parishes in Louisiana; Hancock County, Pearl River County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2020, 5:38 PM CDT for 6 parishes in Louisiana; Hancock County, Pearl River County, Mississippi. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 28, 2020, 5:38 PM CDT (22:38 UTC)
Expired
Apr 28, 2020, 7:45 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Orleans Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Washington Parish, LA, Hancock County, MS, Pearl River County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 10.6 hours before the alert went out and 57 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 12:00Z on 2020-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2020-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 47 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2051 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
47 m²/s²
0-3 km storm-relative helicity
198 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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 28, 10:09 AM CDTMesoscale DiscussionSPCAllen, Avoyelles, Beauregard, Bienville, Caldwell, Catahoula and 11 more3 hr
Apr 28, 12:47 PM CDTMesoscale DiscussionSPCAllen, Beauregard, Calcasieu, Cameron, Jefferson Davis118 min

Nearby

Mesoscale Discussions in Louisiana, 2020Mesoscale Discussions in Mississippi, 2020Every mesoscale discussion in 2020

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.