Alert archive / Louisiana / Mesoscale Discussions in 2018

Mesoscale Discussion 65

February 11, 20184 parishes in Louisiana; Harrison County, Jackson County, Mississippi

The Storm Prediction Center issued this mesoscale discussion at Feb 11, 2018, 5:43 AM CST for 4 parishes in Louisiana; Harrison County, Jackson County, Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Feb 11, 2018, 5:43 AM CST (11:43 UTC)
Expired
Feb 11, 2018, 8:15 AM CST
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Jefferson Parish, LA, Lafourche Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Harrison County, MS, Jackson County, MS

The radar

The Mobile radar (KMOB), 136 km from the middle of the area, began a volume at 11:42 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

Jackson, MS (KJAN), launched 00:00Z, 11.7 hours before the alert went out and 297 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, Jackson, MS at 00:00Z on 2018-02-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Jackson, MS at 00:00Z on 2018-02-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
890 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
33 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
Feb 10, 8:29 PM CSTMesoscale DiscussionSPCClarke, George, Greene, Harrison, Jackson, Perry and 2 more3 hr

Nearby

Mesoscale Discussions in Louisiana, 2018Mesoscale Discussions in Mississippi, 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; radar from the NEXRAD Level II archive.