Alert archive / Louisiana / Mesoscale Discussions in 2012
Mesoscale Discussion 2067
The Storm Prediction Center issued this mesoscale discussion at Oct 17, 2012, 6:29 PM CDT for 4 states. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Oct 17, 2012, 6:29 PM CDT (23:29 UTC)
- Expired
- Oct 17, 2012, 8:00 PM CDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 58 counties
Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Columbia County, AR, Drew 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, Caldwell Parish, LA, Catahoula Parish, LA, Claiborne Parish, LA, Concordia Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Franklin Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Tensas Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Adams County, MS, Bolivar County, MS, Claiborne County, MS, Franklin County, MS, Hinds County, MS, Humphreys County, MS, Issaquena County, MS, Jefferson County, MS, Leflore County, MS, Sharkey County, MS, Sunflower County, MS, Warren County, MS, Washington County, MS, Yazoo County, MS, Cass County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Panola County, TX, Rusk County, TX, Shelby County, TX
The radar
The Shreveport radar (KSHV), 44 km from the middle of the area, began a volume at 23:30 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, 11.5 hours before the alert went out and 36 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 810 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 152 m²/s²
- 0-3 km storm-relative helicity
- 140 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
568 ACUS11 KWNS 172330 SWOMCD SPC MCD 172329 MSZ000-ARZ000-LAZ000-TXZ000-180100- MESOSCALE DISCUSSION 2067 NWS STORM PREDICTION CENTER NORMAN OK 0629 PM CDT WED OCT 17 2012 AREAS AFFECTED...NERN TX/SRN AR/NRN LA/W CENTRAL MS CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 172329Z - 180100Z PROBABILITY OF WATCH ISSUANCE...60 PERCENT SUMMARY...A SLOW INCREASE IN CONVECTION IS ONGOING ACROSS THE DISCUSSION AREA...WHICH MAY REQUIRE WW ISSUANCE IN THE NEXT 1-2 HOURS. DISCUSSION...LATEST VISIBLE SATELLITE IMAGERY SHOW CU/CB DEVELOPMENT SWWD ACROSS SWRN AR INTO NWRN LA/E TX INVOF THE ADVANCING COLD FRONT. AS THE MID-LEVEL JET STREAK CONTINUES DIVING SEWD TOWARD THIS AREA...INCREASING LARGE-SCALE ASCENT WITHIN THE MOIST/MODERATELY UNSTABLE WARM SECTOR SUGGESTS THAT DEVELOPMENT WILL CONTINUE TO INCREASE WITH TIME. THIS FORECAST IS ALSO CONFIRMED BY HI-RES MODEL RUNS...EACH SHOWING SWWD DEVELOPMENT OF STORMS ALONG THE BOUNDARY THIS EVENING. ATTM...IT APPEARS THAT STORM MODE MAY BE AT LEAST TEMPORARILY OF A CELLULAR NATURE...WHICH -- GIVEN FAIRLY STRONG/WEAKLY VEERING FLOW IN LOWER LEVELS -- SUGGESTS SOME POTENTIAL FOR ISOLATED TORNADOES ALONG WITH HAIL/WIND POTENTIAL. ..GOSS/CORFIDI.. 10/17/2012 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...MEG...JAN...LZK...SHV... LAT...LON 31729527 32299526 33709386 33839001 31379057 31729527
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 17, 12:55 PM CDT | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Marion | 95 min |
| Oct 17, 3:44 PM CDT | Mesoscale Discussion | SPC | Arkansas, Ashley, Bradley, Calhoun, Chicot, Clay and 29 more | 61 min |
| Oct 17, 5:21 PM CDT | Tornado Watch | SPC | Arkansas, Baxter, Boone, Bradley, Calhoun, Carroll and 57 more | 7 hr |
Nearby
Mesoscale Discussions in Louisiana, 2012Mesoscale Discussions in Mississippi, 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.