Alert archive / Louisiana / Tornado Warnings in 2012

Tornado Warning 10, NWS Shreveport, LA

March 20, 2012De Soto Parish, Natchitoches Parish, Sabine Parish, Louisiana

NWS Shreveport, LA issued this tornado warning at Mar 20, 2012, 11:31 AM CDT for De Soto Parish, Natchitoches Parish, Sabine Parish, Louisiana. It was in force for 29 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Mar 20, 2012, 11:31 AM CDT (16:31 UTC)
Expired: Mar 20, 2012, 12:00 PM CDT
In force: 29 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon

Counties De Soto Parish, LA, Natchitoches Parish, LA, Sabine Parish, LA

The radar

The Shreveport radar (KSHV), 83 km from the middle of the area, began a volume at 16:31 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.

What was reported inside it

Time	Report	Where	Remark
Mar 20, 11:35 AM CDT	TORNADO	2 Ne Zwolle, LA	POSSIBLE TORNADO. MULTIPLE TREES AND POWERLINES DOWN ALONG HWY 1215 AND 120 NEAR THE BELMONT AREA.
Mar 20, 11:41 AM CDT	TORNADO	5 E Zwolle, LA	AN EF0 TORNADO TOUCHED DOWN ALONG HWY. 1215. SEVERAL TREES WERE SNAPPED AND UPROOTED AND A FEW POWERLINES WERE DOWNED. THE TORNADO CONTINUED NORTHEAST CROSSING HWY. 120 NEAR BELMONT SNAPPING A FEW TREES AND DOWNING A FEW POWERLINES BEFORE LIFTING. PATH LENGTH

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Mar 20, 9:46 AM CDT	Tornado Watch	SPC	7 hr

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 4.5 hours before the alert went out and 84 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 395 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 754 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 221 m²/s²
0-3 km storm-relative helicity: 306 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

788 
WFUS54 KSHV 201631
TORSHV
LAC031-069-085-201700-
/O.NEW.KSHV.TO.W.0010.120320T1631Z-120320T1700Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE SHREVEPORT LA
1131 AM CDT TUE MAR 20 2012

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A

* TORNADO WARNING FOR...
  SOUTHEASTERN DE SOTO PARISH IN NORTHWEST LOUISIANA...
  EXTREME WEST CENTRAL NATCHITOCHES PARISH IN NORTHWEST LOUISIANA...
  NORTH CENTRAL SABINE PARISH IN NORTHWEST LOUISIANA...

* UNTIL NOON CDT

* AT 1126 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO JUST TO THE     
  EAST OF ZWOLLE...OR 29 MILES NORTHWEST OF ANACOCO...MOVING         
  NORTHEAST AT 35 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  BELMONT...MARTHAVILLE AND PLEASANT HILL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WARNING MEANS THAT STRONG ROTATION HAS BEEN DETECTED IN THE
STORM. A TORNADO MAY ALREADY BE ON THE GROUND...OR IS EXPECTED TO
DEVELOP SHORTLY. IF YOU ARE IN THE PATH OF THIS DANGEROUS STORM...
MOVE INDOORS AND TO THE LOWEST LEVEL OF THE BUILDING. STAY AWAY FROM
WINDOWS. IF DRIVING...DO NOT SEEK SHELTER UNDER A HIGHWAY OVERPASS.

&&

LAT...LON 3189 9353 3181 9327 3157 9354 3163 9366
TIME...MOT...LOC 1630Z 211DEG 29KT 3165 9355

$$

24

1 follow-up statement

181 
WWUS54 KSHV 201648
SVSSHV

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
1148 AM CDT TUE MAR 20 2012

LAC031-069-085-201700-
/O.CON.KSHV.TO.W.0010.000000T0000Z-120320T1700Z/
SABINE LA-NATCHITOCHES LA-DE SOTO LA-
1148 AM CDT TUE MAR 20 2012

...A TORNADO WARNING REMAINS IN EFFECT UNTIL NOON CDT FOR DE SOTO...
NATCHITOCHES AND SABINE PARISHES...

AT 1146 AM CDT...USING DOPPLER RADAR...NATIONAL WEATHER SERVICE
METEOROLOGISTS CONTINUED TO DETECT A TORNADO.  THIS TORNADO WAS 
LOCATED 5 MILES NORTH OF BELMONT OR 22 MILES WEST OF 
NATCHITOCHES...MOVING NORTHEAST AT 35 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
PLEASANT HILL

LAT...LON 3168 9351 3177 9357 3189 9353 3181 9327
      3170 9339
TIME...MOT...LOC 1648Z 211DEG 29KT 3177 9346

$$

24

The office that day

Everything else NWS Shreveport, LA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 19, 8:36 PM CDT	River Flood Warning	SHV	Caddo	6 days
Mar 20, 10:55 AM CDT	Tornado Warning	SHV	De Soto, Sabine	35 min
Mar 20, 11:06 AM CDT	River Flood Warning	SHV	Bossier, Webster	32 days
Mar 20, 11:16 AM CDT	River Flood Warning	SHV	Bienville, Bossier, Webster	12 days
Mar 20, 11:17 AM CDT	River Flood Warning	SHV	Lincoln, Ouachita, Union	7 days
Mar 20, 11:35 AM CDT	Severe Thunderstorm Warning	SHV	Natchitoches, Sabine	55 min
Mar 20, 12:10 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, De Soto, Natchitoches, Red River, Sabine	65 min
Mar 20, 12:30 PM CDT	Severe Thunderstorm Warning	SHV	Grant, Natchitoches, Sabine, Winn	60 min
Mar 20, 12:54 PM CDT	Tornado Warning	SHV	Natchitoches, Winn	36 min
Mar 20, 1:04 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, Jackson, Lincoln, Natchitoches, Red River, Winn	41 min
Mar 20, 1:34 PM CDT	Severe Thunderstorm Warning	SHV	Bienville, Grant, Jackson, Natchitoches, Winn	56 min
Mar 20, 3:03 PM CDT	Flash Flood Warning	SHV	Grant, Natchitoches, Winn	6 hr
Mar 20, 6:24 PM CDT	Flash Flood Warning	SHV	Natchitoches, Sabine	3 hr

Nearby

Tornado Warnings in Louisiana, 2012 Every tornado warning in 2012 Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.