Alert archive / Louisiana / Areal Flood Advisories in 2021

Areal Flood Advisory 113, NWS New Orleans, LA

July 15, 2021Jefferson Parish, Louisiana

NWS New Orleans, LA issued this areal flood advisory at Jul 15, 2021, 12:31 PM CDT for Jefferson Parish, Louisiana. It was in force for 65 min.

The area

The counties it named.

The facts

Issued
Jul 15, 2021, 12:31 PM CDT (17:31 UTC)
Expired
Jul 15, 2021, 1:36 PM CDT
In force
65 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon

County Jefferson Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 5.5 hours before the alert went out and 74 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-pSkew-T log-p diagram, Slidell Radar S, LA at 12:00Z on 2021-07-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2331 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Slidell Radar S, LA at 12:00Z on 2021-07-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -23 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
2331 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
619 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
-23 m²/s²
0-3 km storm-relative helicity
-34 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this areal flood advisory went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS New Orleans, LA wrote its last area forecast discussion before this areal flood advisory went out at Jul 15, 10:08 AM CDT, 2 hours 23 minutes earlier.

Area forecast discussion, Jul 15, 10:08 AM CDT, 2 hours 23 minutes before
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In the hours before

Special weather statement, Jul 15, 10:23 AM CDT, 2 hours 8 minutes before
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Special weather statement, Jul 15, 11:40 AM CDT, 51 minutes before
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Special weather statement, Jul 15, 11:42 AM CDT, 49 minutes before
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Special weather statement, Jul 15, 11:48 AM CDT, 43 minutes before
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Special weather statement, Jul 15, 12:21 PM CDT, 10 minutes before
Special Weather Statement
National Weather Service New Orleans LA
1221 PM CDT Thu Jul 15 2021

LAZ061-077-151815-
Western Orleans-Upper Jefferson-
1221 PM CDT Thu Jul 15 2021

...A STRONG THUNDERSTORM WILL AFFECT WEST CENTRAL ORLEANS AND
NORTHWESTERN JEFFERSON PARISHES...

At 1215 PM CDT, a strong thunderstorm was located over Bridge City,
or near Avondale, moving north at 10 mph.

Winds in excess of 30 mph are possible with this storm.

Locations impacted include...
New Orleans, Metairie, Marrero, Avondale, Harvey, Jefferson, Harahan,
Westwego, Elmwood, Bridge City, River Ridge, Waggaman and Estelle.

This includes the following Interstates...
 Interstate 10 in Louisiana between mile markers 224 and 236.
 Interstate 610 between mile markers 1 and 3.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

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 2985 9021 3005 9026 3002 9018 3002 9011
      3003 9009 3004 9005 2985 9010
TIME...MOT...LOC 1715Z 183DEG 8KT 2992 9015

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 15, 10:23 AM CDTSpecial Weather StatementLIXTerrebonne37 min
Jul 15, 11:40 AM CDTSpecial Weather StatementLIXIberville35 min
Jul 15, 11:42 AM CDTSpecial Weather StatementLIXJefferson63 min
Jul 15, 11:48 AM CDTSpecial Weather StatementLIXSaint James57 min
Jul 15, 12:21 PM CDTSpecial Weather StatementLIXSaint Charles54 min
Jul 15, 12:45 PM CDTSpecial Weather StatementLIXWashington75 min
Jul 15, 12:48 PM CDTFlash Flood WarningLIXJefferson49 min
Jul 15, 12:53 PM CDTSpecial Weather StatementLIXSaint John the Baptist82 min
Jul 15, 1:11 PM CDTSpecial Weather StatementLIXOrleans79 min
Jul 15, 1:33 PM CDTSpecial Weather StatementLIXWest Feliciana57 min
Jul 15, 1:50 PM CDTSpecial Weather StatementLIXSaint Tammany55 min
Jul 15, 1:58 PM CDTSpecial Weather StatementLIXEast Baton Rouge62 min
Jul 15, 2:35 PM CDTSpecial Weather StatementLIXTangipahoa55 min
Jul 15, 2:47 PM CDTSpecial Weather StatementLIXSaint James58 min
Jul 15, 3:31 PM CDTSpecial Weather StatementLIXEast Feliciana29 min

Nearby

Areal Flood Advisories in Louisiana, 2021Every areal flood advisory 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.