Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 595

April 29, 201715 parishes in Louisiana

The Storm Prediction Center issued this mesoscale discussion at Apr 29, 2017, 2:45 PM CDT for 15 parishes in Louisiana. It was in force for 60 min.

The area

The outline as issued.

The facts

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

Counties Bienville Parish, LA, Caldwell Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, West Carroll Parish, LA, Winn Parish, LA

The radar

The Shreveport radar (KSHV), 131 km from the middle of the area, began a volume at 19:44 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 nearest sounding before it

Shreveport, LA (KBAD), launched 12:00Z, 7.8 hours before the alert went out and 123 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, Shreveport, LA at 12:00Z on 2017-04-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1913 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, Shreveport, LA at 12:00Z on 2017-04-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 6 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
1913 J/kg
Mixed-layer CIN
-190 J/kg
Mixed-layer LCL
840 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
6 m²/s²
0-3 km storm-relative helicity
121 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 29, 9:19 AM CDTMesoscale DiscussionSPCBeauregard, Calcasieu, Sabine, Vernon116 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; radar from the NEXRAD Level II archive.