Alert archive / Louisiana / Tornado Warnings in 2015

Tornado Warning 21, NWS New Orleans, LA

May 17, 2015Saint Helena Parish, Tangipahoa Parish, Louisiana

NWS New Orleans, LA issued this tornado warning at May 17, 2015, 4:18 AM CDT for Saint Helena Parish, Tangipahoa Parish, Louisiana. It was in force for 27 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: May 17, 2015, 4:18 AM CDT (09:18 UTC)
Expired: May 17, 2015, 4:45 AM CDT
In force: 27 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon

Counties Saint Helena Parish, LA, Tangipahoa Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 9.3 hours before the alert went out and 92 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: 2431 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 785 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 98 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

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

309 
WFUS54 KLIX 170918
TORLIX
LAC091-105-170945-
/O.NEW.KLIX.TO.W.0021.150517T0918Z-150517T0945Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
418 AM CDT SUN MAY 17 2015

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* TORNADO WARNING FOR...
  WEST CENTRAL TANGIPAHOA PARISH IN SOUTHEASTERN LOUISIANA...
  SOUTHEASTERN ST. HELENA PARISH IN SOUTHEASTERN LOUISIANA...

* UNTIL 445 AM CDT
    
* AT 416 AM CDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING A TORNADO. THIS DANGEROUS STORM WAS LOCATED 
  JUST WEST OF INDEPENDENCE...OR 8 MILES NORTHWEST OF HAMMOND...AND 
  MOVING NORTH AT 5 MPH.

* LOCATIONS IMPACTED INCLUDE...
  AMITE...AMITE CITY...INDEPENDENCE AND ROSELAND. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW. MOVE TO A BASEMENT OR AN INTERIOR ROOM ON THE LOWEST
FLOOR OF A STURDY BUILDING. AVOID WINDOWS. IF YOU ARE IN A MOBILE
HOME OR OUTDOORS...MOVE TO THE CLOSEST SUBSTANTIAL SHELTER AND
PROTECT YOURSELF FROM FLYING DEBRIS.

&&

LAT...LON 3079 9039 3059 9042 3060 9057 3065 9057
      3065 9061 3076 9064
TIME...MOT...LOC 0916Z 174DEG 6KT 3061 9053 

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
May 16, 11:24 PM CDT	Flash Flood Watch	LIX	Washington	16 hr
May 17, 3:42 AM CDT	Tornado Warning	LIX	Livingston, Saint Helena, Tangipahoa	33 min
May 17, 4:34 AM CDT	Tornado Warning	LIX	Tangipahoa	26 min
May 17, 5:35 AM CDT	Special Weather Statement	LIX	Tangipahoa	25 min

Nearby

Tornado Warnings in Louisiana, 2015 Every tornado warning in 2015 Tornadoes in 2015

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.