Alert archive / Texas / Mesoscale Discussions in 2017
Mesoscale Discussion 402
The Storm Prediction Center issued this mesoscale discussion at Apr 2, 2017, 12:22 PM CDT for Sabine Parish, Louisiana; 6 counties in Texas. It was in force for 83 min.
The area
The outline as issued.
The facts
- Issued
- Apr 2, 2017, 12:22 PM CDT (17:22 UTC)
- Expired
- Apr 2, 2017, 1:45 PM CDT
- In force
- 83 min
- Issued by
- the Storm Prediction Center
Counties Sabine Parish, LA, Angelina County, TX, Nacogdoches County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Trinity County, TX
The radar
The Shreveport radar (KSHV), 124 km from the middle of the area, began a volume at 17:22 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
Shreveport, LA (KBAD), launched 12:00Z, 5.4 hours before the alert went out and 130 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
- 25 J/kg
- Mixed-layer CIN
- -354 J/kg
- Mixed-layer LCL
- 1030 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 141 m²/s²
- 0-3 km storm-relative helicity
- 206 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
275
ACUS11 KWNS 021723
SWOMCD
SPC MCD 021722
LAZ000-TXZ000-021845-
Mesoscale Discussion 0402
NWS Storm Prediction Center Norman OK
1222 PM CDT Sun Apr 02 2017
Areas affected...Portions of far east TX and far western LA
Concerning...Tornado Watch 109...
Valid 021722Z - 021845Z
The severe weather threat for Tornado Watch 109 continues.
SUMMARY...Through 1830Z, the greatest tornado potential will exist
for locations near and surrounding the Lufkin area northeastward
toward areas around Shreveport and Natchitoches.
DISCUSSION...Surface pressure falls on the cooler side of an
outflow-reinforced warm front analyzed from Nacogdoches County TX to
Natchitoches Parish LA are associated with open-warm-sector
confluence from the Upper TX Coast northward to the warm front.
Convection continues developing along related convergence bands in
the weakly capped and strongly unstable warm sector, and will
continue spreading toward the warm frontal zone. As this activity
matures ahead of a remnant squall line crossing eastern portions of
central TX, tornado potential should increase given effective SRH
around 400 m2/s2 near the warm front. Significant tornadoes will be
possible.
..Cohen.. 04/02/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...LCH...SHV...HGX...
LAT...LON 30869505 31209526 31749469 32019389 31979353 31719342
31339358 31009424 30869505SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 2, 9:04 AM CDT | Mesoscale Discussion | SPC | Beauregard, Sabine, Vernon | 2 hr |
| Apr 2, 9:05 AM CDT | Mesoscale Discussion | SPC | Acadia, Ascension, East Baton Rouge, Iberville, Lafayette, Livingston and 5 more | 85 min |
| Apr 2, 10:39 AM CDT | Tornado Watch | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 13 more | 5 hr |
| Apr 2, 12:49 PM CDT | Mesoscale Discussion | SPC | Avoyelles, Concordia, East Baton Rouge, East Carroll, East Feliciana, Franklin and 7 more | 116 min |
| Apr 2, 1:34 PM CDT | Tornado Watch | SPC | Acadia, Allen, Avoyelles, Beauregard, Bienville, Calcasieu and 28 more | 7 hr |
| Apr 2, 2:06 PM CDT | Mesoscale Discussion | SPC | Grant, LaSalle, Natchitoches, Rapides, Sabine, Vernon and 1 more | 54 min |
| Apr 2, 3:08 PM CDT | Mesoscale Discussion | SPC | Ascension, East Baton Rouge, East Feliciana, Livingston, Saint Charles, Saint Helena and 6 more | 3 hr |
| Apr 2, 3:13 PM CDT | Mesoscale Discussion | SPC | Allen, Avoyelles, Beauregard, Caldwell, Catahoula, Concordia and 13 more | 92 min |
| Apr 2, 4:52 PM CDT | Tornado Watch | SPC | Ascension, Concordia, East Baton Rouge, East Feliciana, Iberville, Livingston and 8 more | 9 hr |
| Apr 2, 5:54 PM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Avoyelles, Beauregard, Calcasieu, Catahoula and 7 more | 96 min |
| Apr 1, 7:20 PM CDT | Mesoscale Discussion | SPC | Val Verde | 85 min |
| Apr 1, 8:44 PM CDT | Mesoscale Discussion | SPC | Brown, Callahan, Coleman, Comanche, Concho, Eastland and 5 more | 61 min |
| Apr 1, 10:06 PM CDT | Mesoscale Discussion | SPC | Bandera, Bexar, Blanco, Comal, Edwards, Gillespie and 9 more | 114 min |
| Apr 1, 10:28 PM CDT | Tornado Watch | SPC | Bandera, Edwards, Gillespie, Kerr, Kimble, Kinney and 6 more | 8 hr |
| Apr 2, 2:53 AM CDT | Mesoscale Discussion | SPC | Bandera, Edwards, Gillespie, Kerr, Kimble, Kinney and 6 more | 82 min |
| Apr 2, 5:16 AM CDT | Mesoscale Discussion | SPC | Anderson, Angelina, Bandera, Bastrop, Bell, Bexar and 51 more | 119 min |
| Apr 2, 6:00 AM CDT | Tornado Watch | SPC | Anderson, Atascosa, Bandera, Bastrop, Bell, Bexar and 51 more | 7 hr |
| Apr 2, 9:44 AM CDT | Mesoscale Discussion | SPC | Austin, Bastrop, Brazos, Burleson, Caldwell, Cherokee and 19 more | 2 hr |
| Apr 2, 4:23 PM CDT | Mesoscale Discussion | SPC | Aransas, Brazoria, Calhoun, Cameron, Jackson, Kenedy and 5 more | 3 hr |
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.