Alert archive / Louisiana / Mesoscale Discussions in 2017

Mesoscale Discussion 635

May 3, 201719 parishes in Louisiana; 18 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 3, 2017, 7:04 AM CDT for 19 parishes in Louisiana; 18 counties in Texas. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
May 3, 2017, 7:04 AM CDT (12:04 UTC)
Expired
May 3, 2017, 8:30 AM CDT
In force
86 min
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 37 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Grant Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Natchitoches Parish, LA, Pointe Coupee Parish, LA, Rapides Parish, LA, Sabine Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Angelina County, TX, Chambers County, TX, Hardin County, TX, Houston County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Montgomery County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX

The radar

The Lake Charles radar (KLCH), 26 km from the middle of the area, began a volume at 12:06 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 0.1 hours before the alert went out and 27 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 2017-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2161 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 2017-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 154 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
2161 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
549 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
154 m²/s²
0-3 km storm-relative helicity
197 m²/s²
Significant tornado parameter
2.2
Supercell composite
12.3

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
May 3, 7:32 AM CDTTornado WatchSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 24 more9 hr
May 3, 10:07 AM CDTMesoscale DiscussionSPCAcadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 21 more83 min
May 3, 12:34 PM CDTSevere Thunderstorm WatchSPCBossier, Caddo5 hr
May 3, 1:58 PM CDTMesoscale DiscussionSPCAcadia, Allen, Assumption, Beauregard, Calcasieu, Cameron and 11 more62 min
May 3, 3:48 PM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Jefferson Davis87 min
May 3, 3:59 PM CDTMesoscale DiscussionSPCBossier, Caddo91 min
May 3, 5:00 PM CDTSevere Thunderstorm WatchSPCAcadia, Allen, Beauregard, Bienville, Calcasieu, Cameron and 10 more7 hr
May 3, 6:54 PM CDTMesoscale DiscussionSPCAscension, Assumption, East Baton Rouge, Iberville, Livingston, Saint James and 3 more96 min
May 3, 1:30 AM CDTMesoscale DiscussionSPCCollingsworth, Donley, Gray, Hemphill, Wheeler2 hr
May 3, 7:48 AM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Delta, Fannin, Franklin and 11 more117 min
May 3, 11:23 AM CDTMesoscale DiscussionSPCCoryell, Dallas, Ellis, Falls, Freestone, Henderson and 9 more2 hr
May 3, 1:48 PM CDTMesoscale DiscussionSPCAnderson, Bowie, Camp, Cass, Cherokee, Coryell and 31 more87 min

Nearby

Mesoscale Discussions in Louisiana, 2017Mesoscale Discussions in Texas, 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.