Alert archive / Louisiana / Mesoscale Discussions in 2012
Mesoscale Discussion 551
The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2012, 3:44 PM CDT for 9 counties in Arkansas; 10 parishes in Louisiana; Panola County, Shelby County, Texas. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Apr 15, 2012, 3:44 PM CDT (20:44 UTC)
- Expired
- Apr 15, 2012, 5:15 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
All 21 counties
Calhoun County, AR, Clark County, AR, Columbia County, AR, Hempstead County, AR, Lafayette County, AR, Miller County, AR, Nevada County, AR, Ouachita County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Red River Parish, LA, Union Parish, LA, Webster Parish, LA, Panola County, TX, Shelby County, TX
The radar
The Shreveport radar (KSHV), 100 km from the middle of the area, began a volume at 20:47 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 (KSHV), launched 12:00Z, 8.7 hours before the alert went out and 93 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
- 784 J/kg
- Mixed-layer CIN
- -163 J/kg
- Mixed-layer LCL
- 542 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 207 m²/s²
- 0-3 km storm-relative helicity
- 266 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted, in the capitals the NWS used until 2016.
190
ACUS11 KWNS 152045
SWOMCD
SPC MCD 152044
LAZ000-ARZ000-TXZ000-152215-
MESOSCALE DISCUSSION 0551
NWS STORM PREDICTION CENTER NORMAN OK
0344 PM CDT SUN APR 15 2012
AREAS AFFECTED...EXTREME NERN TX...NWRN LA AND SWRN AR
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 152044Z - 152215Z
STORMS COULD INTENSIFY AS THEY DEVELOP THROUGH SWRN AR INTO NWRN LA.
THE PRIMARY THREATS WOULD BE DAMAGING WIND AND HAIL...WITH A
CONDITIONAL THREAT FOR ISOLATED TORNADOES.
STORMS ARE BEGINNING TO DEVELOP CLOSER TO LEADING EDGE OF OUTFLOW
BOUNDARY FROM SWRN AR INTO NERN TX. TEMPERATURES HAVE WARMED INTO
THE LOW 80S SUPPORTING AXIS OF 1000-1500 J/KG MLCAPE DOWNSTREAM FROM
THE LINE. HOWEVER...CHARACTER OF THE CLOUDS WITH EXTENSIVE
STRATOCUMULUS SUGGESTS A CAPPING INVERSION ALOFT REMAINS...AND
STORMS ARE STILL DEVELOPING ABOVE A LOW CLOUD DECK. THE INCREASE IN
STORMS ALONG AND WEST OF THE OUTFLOW BOUNDARY APPEARS TO BE PARTLY
IN RESPONSE TO FORCING AND DEEPER ASCENT WITHIN UPPER JET ENTRANCE
REGION. THIS ZONE OF ASCENT COULD EVENTUALLY OVERTAKE WRN PORTION OF
WARM SECTOR...CONTRIBUTING TO A WEAKER CAP AND SUGGESTING THAT
STORMS COULD INTENSIFY FURTHER AS THEY DEVELOP EWD. VERTICAL WIND
PROFILES REMAIN STRONG WITH LARGE HODOGRAPHS ALONG LLJ EXPECTED TO
PERSIST INTO EARLY EVENING SUPPORTING THE POTENTIAL FOR ORGANIZED
STORMS INCLUDING BOWING SEGMENTS AND SUPERCELLS.
..DIAL.. 04/15/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LZK...SHV...
LAT...LON 34199302 33739235 32139218 31709455 32749420 33909371
34199302SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 15, 6:35 AM CDT | Mesoscale Discussion | SPC | Benton, Crawford, Madison, Sebastian, Washington | 85 min |
| Apr 15, 6:38 AM CDT | Severe Thunderstorm Watch | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 4 hr |
| Apr 15, 9:25 AM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 22 more | 95 min |
| Apr 15, 10:51 AM CDT | Tornado Watch | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 18 more | 7 hr |
| Apr 15, 1:38 PM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Conway, Crawford, Franklin and 18 more | 97 min |
| Apr 15, 4:22 PM CDT | Mesoscale Discussion | SPC | Arkansas, Bradley, Calhoun, Clay, Cleburne, Cleveland and 29 more | 83 min |
| Apr 15, 4:25 PM CDT | Tornado Watch | SPC | Arkansas, Baxter, Bradley, Calhoun, Clark, Clay and 49 more | 6 hr |
| Apr 14, 10:11 PM CDT | Mesoscale Discussion | SPC | Borden, Childress, Collingsworth, Cottle, Crosby, Dawson and 17 more | 34 min |
| Apr 14, 10:29 PM CDT | Severe Thunderstorm Watch | SPC | Andrews, Archer, Baylor, Borden, Briscoe, Callahan and 43 more | 6 hr |
| Apr 15, 6:29 PM CDT | Mesoscale Discussion | SPC | Refugio, San Patricio | 91 min |
Nearby
Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Texas, 2012Every mesoscale discussion in 2012
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.