Alert archive / Louisiana / Special Weather Statements in 2021

Special Weather Statement, NWS New Orleans, LA

June 21, 2021Orleans Parish, Louisiana

NWS New Orleans, LA issued this special weather statement at Jun 21, 2021, 8:18 PM CDT for Orleans 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: Jun 21, 2021, 8:18 PM CDT (01:18 UTC)
Expired: Jun 21, 2021, 8:45 PM CDT
In force: 27 min
Issued by: NWS New Orleans, LA

County Orleans Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 1.3 hours before the alert went out and 22 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: 55 J/kg
Mixed-layer CIN: -129 J/kg
Mixed-layer LCL: 1096 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: -47 m²/s²
0-3 km storm-relative helicity: -57 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

405 
WWUS84 KLIX 220118
SPSLIX

Special Weather Statement
National Weather Service New Orleans LA
818 PM CDT Mon Jun 21 2021

LAZ061-064-070-075>078-MSZ080-220145-
Southeast St. Tammany-Western Orleans-Upper St. Bernard-Eastern
Orleans-Northwest St. Tammany-Lower St. Bernard-Upper
Jefferson-Hancock-
818 PM CDT Mon Jun 21 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL ST. BERNARD...
ORLEANS...SOUTHEASTERN ST. TAMMANY...NORTHERN JEFFERSON PARISHES IN
SOUTHEASTERN LOUISIANA AND SOUTHWESTERN HANCOCK COUNTIES...

At 818 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Metairie to near Meraux to near
Shell Beach. Movement was northeast at 35 mph.

Winds in excess of 40 mph are possible with these storms.

Locations impacted include...
New Orleans, Slidell, Metairie, East New Orleans, Chalmette, Lake
Catherine, Pearlington, Lacombe, Shell Beach, Arabi, Meraux, Violet,
Slidell Airport and Lakefront Airport.

If outdoors, consider seeking shelter inside a building.

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

LAT...LON 2977 8972 2994 8993 3000 9021 3018 8968
      3026 8998 3039 8995 3031 8959 3019 8944
      3016 8966 3015 8963 3002 8972 3002 8984
      2994 8984 2996 8973 2987 8968 2987 8961
      3008 8949 3005 8938
TIME...MOT...LOC 0118Z 218DEG 32KT 3003 9009 2999 8990 2987 8974 

$$

PG

What forecasters said that day

The local office's own words before this special weather statement 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 special weather statement went out at Jun 21, 3:53 PM CDT, 4 hours 25 minutes earlier.

Area forecast discussion, Jun 21, 3:53 PM CDT, 4 hours 25 minutes before

Area Forecast Discussion
National Weather Service New Orleans LA
353 PM CDT Mon Jun 21 2021

.SHORT TERM...
Tonight through Thursday...
Tonight into Tuesday morning, a frontal system is expected to move
through our area, increasing rain chances. Southerly surface winds
will help to enhance the lifting and moisture advection into the
area. Upper level divergence will help to enhance buoyancy and
help with efficiency. PW values will remain above the 75th
percentile for the SPC sounding climatology for the next few days.
These storms will have the potential for locally heavy rainfall
overnight, especially in the vulnerable areas. Lightning will also
be a concern overnight as well.

Tuesday through Thursday, the frontal boundary will linger over
the area. Wednesday and Thursday, the boundary refires
convection, mainly during the afternoon hours. Southerly surface
winds will help to enhance lifting and moisture advection over the
area Tuesday through Thursday. PW values will remain over the
75th percentile for the next few days. Heavy rainfall inside of
thunderstorm development will be a concern with this frontal
system moving through, particularly Tuesday. Lightning will also
be a concern as well. MSW

.LONG TERM...
Friday through Monday...
Friday through Monday, more of a normal summertime pattern will
begin to dominate the area. Rain chances will be enhanced, mainly
during the afternoon hours. Southerly surface winds will help to
enhance moisture advection in the atmosphere. PW values will
remain high through this time period. Scattered thunderstorms and
showers will be possible daily during the peak daytime heating
hours. Lightning will be a concern inside thunderstorm development
as well. MSW

&&

.AVIATION...
VFR conditions prevail at all area airports. Some vicinity showers
will be possible through the afternoon hours. Temporary periods of
showers and storms will be possible at all area airports which
will cause lower visibilities and ceilings, and TEMPO groups are
in place during the best timing for these showers and storms.
Overnight tonight through the end of the forecast period, MVFR
conditions will be possible due to low ceilings and vicinity
showers. MCB may get to IFR conditions around daybreak tomorrow
briefing due to fog and vicinity showers before returning to MVFR
conditions for the end of the forecast period. MSW

&&

.MARINE...
Tonight through Friday, winds will be southerly and moderate (<15
knots). Friday afternoon through Monday, winds will be easterly to
southeasterly and moderate (<15 knots). Wave heights will
correspond to the wind speeds. MSW

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  71  83  70  89 /  80  80  20  50
BTR  73  86  73  90 /  80  90  30  60
ASD  73  86  72  89 /  80  80  40  70
MSY  76  87  76  89 /  80  80  40  70
GPT  74  85  74  87 /  90  80  40  70
PQL  72  84  72  87 /  90  90  50  70

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

In the hours before

Local storm report, Jun 21, 6:38 PM CDT, 1 hour 40 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
638 PM CDT MON JUN 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0637 PM     FLASH FLOOD      1 WNW SLIDELL           30.29N 89.80W
06/21/2021                   ST. TAMMANY        LA   PUBLIC

            4-6 IN OF STANDING WATER ON THE BACK PATIO.

&&

KO

Local storm report, Jun 21, 6:42 PM CDT, 1 hour 36 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
642 PM CDT MON JUN 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0641 PM     FLASH FLOOD      SLIDELL                 30.28N 89.78W
06/21/2021                   ST. TAMMANY        LA   PUBLIC

            SCATTERED REPORTS OF STREETS FLOODING.

&&

KO

Local storm report, Jun 21, 7:07 PM CDT, 1 hour 11 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
707 PM CDT MON JUN 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0415 PM     FLASH FLOOD      2 NE HARAHAN            29.96N 90.18W
06/21/2021                   JEFFERSON          LA   PUBLIC

            ROADS FLOODED.

&&

KO

Local storm report, Jun 21, 7:12 PM CDT, 1 hour 6 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
712 PM CDT MON JUN 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0430 PM     FLASH FLOOD      2 NW NEW ORLEANS        29.99N 90.11W
06/21/2021                   ORLEANS            LA   PUBLIC

            CANAL BLVD. UNDERPASS FLOODED.

&&

KO

Local storm report, Jun 21, 7:49 PM CDT, 29 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
749 PM CDT MON JUN 21 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0430 PM     FLASH FLOOD      2 ESE METAIRIE          29.99N 90.14W
06/21/2021                   JEFFERSON          LA   PUBLIC

            ESTIMATED 6-8 IN OF WATER OVER THE ROAD
            WAYS.

&&

KO

Special weather statement, Jun 21, 8:18 PM CDT, 0 minutes before

Special Weather Statement
National Weather Service New Orleans LA
818 PM CDT Mon Jun 21 2021

LAZ061-064-070-075>078-MSZ080-220145-
Southeast St. Tammany-Western Orleans-Upper St. Bernard-Eastern
Orleans-Northwest St. Tammany-Lower St. Bernard-Upper
Jefferson-Hancock-
818 PM CDT Mon Jun 21 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL ST. BERNARD...
ORLEANS...SOUTHEASTERN ST. TAMMANY...NORTHERN JEFFERSON PARISHES IN
SOUTHEASTERN LOUISIANA AND SOUTHWESTERN HANCOCK COUNTIES...

At 818 PM CDT, radar indicated strong thunderstorms were located
along a line extending from near Metairie to near Meraux to near
Shell Beach. Movement was northeast at 35 mph.

Winds in excess of 40 mph are possible with these storms.

Locations impacted include...
New Orleans, Slidell, Metairie, East New Orleans, Chalmette, Lake
Catherine, Pearlington, Lacombe, Shell Beach, Arabi, Meraux, Violet,
Slidell Airport and Lakefront Airport.

If outdoors, consider seeking shelter inside a building.

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

LAT...LON 2977 8972 2994 8993 3000 9021 3018 8968
      3026 8998 3039 8995 3031 8959 3019 8944
      3016 8966 3015 8963 3002 8972 3002 8984
      2994 8984 2996 8973 2987 8968 2987 8961
      3008 8949 3005 8938
TIME...MOT...LOC 0118Z 218DEG 32KT 3003 9009 2999 8990 2987 8974

PG

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 7:56 PM CDT	Flood Watch	LIX	Assumption, Orleans, Saint Bernard, Saint James, Saint John the Baptist, Saint Tammany	6 min
Jun 21, 8:05 PM CDT	Flash Flood Watch	LIX	Assumption, Orleans, Saint Bernard, Saint James, Saint John the Baptist, Saint Tammany	23 hr
Jun 21, 8:19 PM CDT	Special Marine Warning	LIX		41 min
Jun 21, 8:24 PM CDT	Special Marine Warning	LIX		66 min
Jun 21, 8:36 PM CDT	Special Weather Statement	LIX	West Feliciana	54 min
Jun 21, 9:01 PM CDT	Severe Thunderstorm Warning	LIX	East Feliciana, Saint Helena, West Feliciana	29 min
Jun 21, 9:31 PM CDT	Severe Thunderstorm Warning	LIX	East Feliciana, Saint Helena, Tangipahoa	44 min
Jun 21, 9:49 PM CDT	Special Marine Warning	LIX		26 min
Jun 21, 10:11 PM CDT	Special Weather Statement	LIX	Tangipahoa, Washington	34 min
Jun 21, 10:14 PM CDT	Special Marine Warning	LIX		61 min
Jun 22, 5:18 AM CDT	Special Marine Warning	LIX		57 min
Jun 22, 6:16 AM CDT	Special Marine Warning	LIX		59 min
Jun 22, 8:10 AM CDT	Special Marine Warning	LIX		25 min
Jun 22, 12:38 PM CDT	Special Marine Warning	LIX		67 min
Jun 22, 4:02 PM CDT	Special Weather Statement	LIX	Saint John the Baptist	28 min
Jun 22, 4:54 PM CDT	Areal Flood Advisory	LIX	Ascension, East Baton Rouge, Livingston	111 min
Jun 21, 8:48 PM CDT	Special Weather Statement	LIX	Hancock	42 min
Jun 21, 9:33 PM CDT	Special Weather Statement	LIX	Harrison	42 min
Jun 21, 9:44 PM CDT	Flash Flood Warning	LIX	Hancock, Harrison	2 hr
Jun 21, 10:09 PM CDT	Special Weather Statement	LIX	Jackson	36 min
Jun 21, 10:27 PM CDT	Flash Flood Warning	LIX	Jackson	93 min
Jun 22, 6:00 AM CDT	River Flood Warning	LIX	Harrison	69 hr
Jun 22, 6:02 AM CDT	River Flood Warning	LIX	Harrison	47 hr
Jun 22, 9:39 AM CDT	River Flood Warning	LIX	Jackson	4 days
Jun 22, 5:10 PM CDT	Areal Flood Advisory	LIX	Harrison, Jackson	2 hr
Jun 22, 6:14 PM CDT	Flash Flood Warning	LIX	Harrison, Jackson	108 min
Jun 22, 6:32 PM CDT	Special Weather Statement	LIX	Harrison	28 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.