Alert archive / Louisiana / Mesoscale Discussions in 2012
Mesoscale Discussion 49
The Storm Prediction Center issued this mesoscale discussion at Jan 22, 2012, 7:59 PM CST for 5 counties in Arkansas; 12 parishes in Louisiana; 6 counties in Texas. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Jan 22, 2012, 7:59 PM CST (01:59 UTC)
- Expired
- Jan 22, 2012, 9:30 PM CST
- In force
- 91 min
- Issued by
- the Storm Prediction Center
All 23 counties
Bradley County, AR, Calhoun County, AR, Columbia 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, Natchitoches Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Angelina County, TX, Nacogdoches County, TX, Panola County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX
The radar
The Shreveport radar (KSHV), 67 km from the middle of the area, began a volume at 02:02 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 (KSHV), launched 00:00Z, 2.0 hours before the alert went out and 58 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
- 1190 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 1056 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 235 m²/s²
- 0-3 km storm-relative helicity
- 339 m²/s²
- Significant tornado parameter
- 1.8
- Supercell composite
- 6.9
The text
As transmitted, in the capitals the NWS used until 2016.
244
ACUS11 KWNS 230159
SWOMCD
SPC MCD 230159
LAZ000-ARZ000-TXZ000-230330-
MESOSCALE DISCUSSION 0049
NWS STORM PREDICTION CENTER NORMAN OK
0759 PM CST SUN JAN 22 2012
AREAS AFFECTED...NRN LA...NERN TX
CONCERNING...TORNADO WATCH 5...
VALID 230159Z - 230330Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 5 CONTINUES.
SW OF WW 5...MONITORING FOR A POSSIBLE TORNADO WATCH ISSUANCE WITH
CONVECTION FORMING ALONG PRE-FRONTAL CONFLUENCE AXIS INTO NERN TX.
UNCERTAINTY EXISTS OVER THE POTENTIAL MATURITY OF SHOWERS THAT HAVE
FORMED SWWD ACROSS FAR NWRN LA INTO NACOGDOCHES COUNTY TX. THIS
DEVELOPMENT APPEARS TO BE ALONG THE TRAILING INFLUENCE OF THE SHORT
WAVE IMPULSE PIVOTING ACROSS MO/AR. AS THIS FEATURE PROGRESSES
NEWD...ASCENT ALONG THE PRE-FRONTAL CONFLUENCE AXIS SHOULD WANE.
STILL...MODERATE INSTABILITY JUXTAPOSED WITH RATHER STRONG
DEEP-LAYER SHEAR WOULD PROVE FAVORABLE FOR ALL MODES OF SEVERE
THREATS SHOULD CONVECTIVE DEVELOPMENT BE SUSTAINED. LATER THIS
EVENING...THE PACIFIC COLD FRONT WILL LIKELY OVERTAKE THIS
CONFLUENCE AXIS AND MAY REINVIGORATE DEVELOPMENT OVER PARTS OF NERN
LA INTO MS.
..GRAMS.. 01/23/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...JAN...LZK...LCH...SHV...HGX...
LAT...LON 33079361 33479315 33779260 33809228 33619197 33239186
32679200 31509304 31079411 31289494 31579499 33079361SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 22, 6:07 PM CST | Mesoscale Discussion | SPC | Bradley, Calhoun, Clark, Cleveland, Columbia, Dallas and 10 more | 53 min |
| Jan 22, 6:48 PM CST | Mesoscale Discussion | SPC | Arkansas, Bradley, Calhoun, Cleveland, Craighead, Cross and 19 more | 57 min |
| Jan 22, 8:37 PM CST | Mesoscale Discussion | SPC | Arkansas, Bradley, Chicot, Clay, Craighead, Crittenden and 14 more | 83 min |
| Jan 22, 9:47 PM CST | Mesoscale Discussion | SPC | Ashley, Chicot, Crittenden, Desha, Phillips | 58 min |
| Jan 22, 10:59 PM CST | Tornado Watch | SPC | Ashley, Chicot | 7 hr |
| Jan 23, 1:25 AM CST | Mesoscale Discussion | SPC | Madison, Tensas | 2 hr |
| Jan 23, 4:02 AM CST | Mesoscale Discussion | SPC | Ascension, East Baton Rouge, Iberville, Livingston, Saint Helena, Saint John the Baptist and 3 more | 118 min |
| Jan 23, 6:38 AM CST | Mesoscale Discussion | SPC | Jefferson, Lafourche, Orleans, Saint Charles, Saint James, Saint John the Baptist and 2 more | 97 min |
Nearby
Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Arkansas, 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.