Alert archive / Texas / Mesoscale Discussions in 2017

Mesoscale Discussion 642

May 3, 2017Lafayette County, Miller County, Arkansas; Bossier Parish, Caddo Parish, Louisiana; 23 counties in Texas

The Storm Prediction Center issued this mesoscale discussion at May 3, 2017, 3:59 PM CDT for Lafayette County, Miller County, Arkansas; Bossier Parish, Caddo Parish, Louisiana; 23 counties in Texas. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued
May 3, 2017, 3:59 PM CDT (20:59 UTC)
Expired
May 3, 2017, 5:30 PM CDT
In force
91 min
Issued by
the Storm Prediction Center
All 27 counties

Lafayette County, AR, Miller County, AR, Bossier Parish, LA, Caddo Parish, LA, Anderson County, TX, Bell County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Falls County, TX, Freestone County, TX, Gregg County, TX, Harrison County, TX, Houston County, TX, Leon County, TX, Limestone County, TX, Madison County, TX, Marion County, TX, Milam County, TX, Morris County, TX, Panola County, TX, Robertson County, TX, Rusk County, TX, Smith County, TX, Titus County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 156 km from the middle of the area, began a volume at 20:58 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, 9.0 hours before the alert went out and 165 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 2017-05-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 614 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 2017-05-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 186 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
614 J/kg
Mixed-layer CIN
-325 J/kg
Mixed-layer LCL
1001 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

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, 4:54 AM CDTMesoscale DiscussionSPCBenton, Washington96 min
May 3, 7:48 AM CDTMesoscale DiscussionSPCHempstead, Howard, Lafayette, Little River, Miller, Pike and 2 more117 min
May 3, 12:34 PM CDTSevere Thunderstorm WatchSPCColumbia, Hempstead, Lafayette, Miller, Nevada5 hr
May 3, 1:48 PM CDTMesoscale DiscussionSPCHempstead, Little River, Miller87 min
May 3, 7:04 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 13 more86 min
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, 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, 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, 11:23 AM CDTMesoscale DiscussionSPCCoryell, Dallas, Ellis, Falls, Freestone, Henderson and 9 more2 hr

Nearby

Mesoscale Discussions in Texas, 2017Mesoscale Discussions in Arkansas, 2017Mesoscale 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.