Alert archive / Texas / Mesoscale Discussions in 2017
Mesoscale Discussion 641
The Storm Prediction Center issued this mesoscale discussion at May 3, 2017, 3:48 PM CDT for 6 parishes in Louisiana; 18 counties in Texas. It was in force for 87 min.
The area
The outline as issued.
The facts
- Issued
- May 3, 2017, 3:48 PM CDT (20:48 UTC)
- Expired
- May 3, 2017, 5:15 PM CDT
- In force
- 87 min
- Issued by
- the Storm Prediction Center
All 24 counties
Acadia Parish, LA, Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Jefferson Davis Parish, LA, Angelina County, TX, Chambers County, TX, Hardin County, TX, Houston County, TX, Jasper County, TX, Jefferson County, TX, Liberty 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, Shelby County, TX, Trinity County, TX, Tyler County, TX, Walker County, TX
The radar
The Lake Charles radar (KLCH), 117 km from the middle of the area, began a volume at 20:51 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, 8.8 hours before the alert went out and 119 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.
- 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
The text
As transmitted.
042
ACUS11 KWNS 032049
SWOMCD
SPC MCD 032048
LAZ000-TXZ000-032215-
Mesoscale Discussion 0641
NWS Storm Prediction Center Norman OK
0348 PM CDT Wed May 03 2017
Areas affected...southeast Texas through southwest Louisiana
Concerning...Tornado Watch 190...
Valid 032048Z - 032215Z
The severe weather threat for Tornado Watch 190 continues.
SUMMARY...Tornado watch 190 will likely need to be replaced by
another WW before expiration time of 22Z. Isolated large hail and
damaging wind gusts will be the main threats though a couple of
tornadoes cannot be ruled out.
DISCUSSION...Storms continue developing along a southeast-advancing
cold front across a portion central through northeast TX as well as
north of a large convective outflow boundary across southern LA.
Atmosphere is moderately to strongly unstable over southeast TX, and
storms will likely continue developing along the cold front/outflow
boundary intersection and some distance south along the cold front
into southeast TX this evening. Southward extent of development will
be limited by a stronger cap and tendency for deeper forcing
associated with the shortwave trough to remain north of warm sector.
Deep-layer winds and effective bulk shear have increased and are
sufficient for organized structures including supercells, but
low-level hodograph size is limited in warm sector. Primary threats
should be large hail and damaging wind, but a conditional risk for a
couple of tornadoes will exist with storms interacting with
modifying outflow boundary.
..Dial.. 05/03/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LCH...SHV...HGX...
LAT...LON 30899596 31399539 31939421 31009314 30089219 29609256
29839374 29579488 30209535 30899596SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 3, 7:04 AM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 13 more | 86 min |
| May 3, 7:32 AM CDT | Tornado Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 24 more | 9 hr |
| May 3, 10:07 AM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 21 more | 83 min |
| May 3, 12:34 PM CDT | Severe Thunderstorm Watch | SPC | Bossier, Caddo | 5 hr |
| May 3, 1:58 PM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Assumption, Beauregard, Calcasieu, Cameron and 11 more | 62 min |
| May 3, 3:59 PM CDT | Mesoscale Discussion | SPC | Bossier, Caddo | 91 min |
| May 3, 5:00 PM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Beauregard, Bienville, Calcasieu, Cameron and 10 more | 7 hr |
| May 3, 6:54 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, Iberville, Livingston, Saint James and 3 more | 96 min |
| May 3, 1:30 AM CDT | Mesoscale Discussion | SPC | Collingsworth, Donley, Gray, Hemphill, Wheeler | 2 hr |
| May 3, 7:48 AM CDT | Mesoscale Discussion | SPC | Bowie, Camp, Cass, Delta, Fannin, Franklin and 11 more | 117 min |
| May 3, 11:23 AM CDT | Mesoscale Discussion | SPC | Coryell, Dallas, Ellis, Falls, Freestone, Henderson and 9 more | 2 hr |
| May 3, 1:48 PM CDT | Mesoscale Discussion | SPC | Anderson, Bowie, Camp, Cass, Cherokee, Coryell and 31 more | 87 min |
Nearby
Mesoscale Discussions in Texas, 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.