Alert archive / Louisiana / Special Weather Statements in 2021

Special Weather Statement, NWS New Orleans, LA

August 11, 2021Jefferson Parish, Louisiana

NWS New Orleans, LA issued this special weather statement at Aug 11, 2021, 12:21 PM CDT for Jefferson Parish, Louisiana. It was in force for 69 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: Aug 11, 2021, 12:21 PM CDT (17:21 UTC)
Expired: Aug 11, 2021, 1:30 PM CDT
In force: 69 min
Issued by: NWS New Orleans, LA
Hail: 0.00 in
Wind: 30

County Jefferson Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 5.4 hours before the alert went out and 87 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: 3290 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 603 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 11 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

249 
WWUS84 KLIX 111721
SPSLIX

Special Weather Statement
National Weather Service New Orleans LA
1221 PM CDT Wed Aug 11 2021
 
LAZ059-061-063-068-069-111830-
Lower Plaquemines LA-Lower Jefferson LA-Upper Plaquemines LA-
Upper Lafourche LA-Upper Jefferson LA-
1221 PM CDT Wed Aug 11 2021

...A strong thunderstorm will impact portions of east central
Lafourche, central Jefferson and west central Plaquemines Parishes
through 130 PM CDT...

At 1221 PM CDT, Doppler radar was tracking a strong thunderstorm near
Myrtle Grove, or 17 miles south of Belle Chasse, moving northwest at
5 mph.

HAZARD...Winds in excess of 30 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around 
         unsecured objects.

Locations impacted include...
Belle Chasse, Jean Lafitte, Myrtle Grove, Lafitte, Barataria and
Woodmere.

Main concern is frequent cloud to ground lightning.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building. 

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 2942 8981 2943 8981 2941 8987 2945 8982
      2948 8984 2943 8991 2948 8988 2949 8992
      2949 8993 2944 8993 2951 9000 2951 9001
      2949 8999 2948 9000 2963 9029 2983 9007
      2948 8972 2939 8983
TIME...MOT...LOC 1721Z 133DEG 5KT 2959 9001 

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...30 MPH

$$

CAB

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 8:28 AM CDT	Special Marine Warning	LIX		62 min
Aug 11, 10:59 AM CDT	Special Marine Warning	LIX		2 hr
Aug 11, 12:04 PM CDT	Special Weather Statement	LIX	Saint Tammany	56 min
Aug 11, 12:28 PM CDT	Special Weather Statement	LIX	Saint Tammany	62 min
Aug 11, 12:35 PM CDT	Areal Flood Advisory	LIX	Saint Tammany	66 min
Aug 11, 1:40 PM CDT	Special Weather Statement	LIX	Saint Charles, Saint John the Baptist	65 min
Aug 11, 1:54 PM CDT	Special Weather Statement	LIX	Livingston	81 min
Aug 11, 2:28 PM CDT	Special Weather Statement	LIX	Assumption	77 min
Aug 11, 2:31 PM CDT	Special Weather Statement	LIX	Washington	74 min
Aug 11, 2:35 PM CDT	Special Weather Statement	LIX	Saint James	25 min
Aug 11, 2:51 PM CDT	Special Weather Statement	LIX	Plaquemines	54 min
Aug 11, 3:24 PM CDT	Special Weather Statement	LIX	East Baton Rouge	36 min
Aug 11, 3:40 PM CDT	Special Weather Statement	LIX	Iberville	35 min
Aug 11, 3:48 PM CDT	Special Marine Warning	LIX		57 min
Aug 11, 4:20 PM CDT	Special Weather Statement	LIX	Pointe Coupee	40 min
Aug 11, 5:11 PM CDT	Special Weather Statement	LIX	West Feliciana	64 min
Aug 11, 11:44 AM CDT	Special Weather Statement	LIX	Jackson	76 min
Aug 11, 5:48 PM CDT	Special Weather Statement	LIX	Wilkinson	27 min

Nearby

Special Weather Statements in Louisiana, 2021 Every special weather statement in 2021

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.