Alert archive / Louisiana / Special Marine Warnings in 2021

Special Marine Warning 504, NWS New Orleans, LA

August 30, 2021

NWS New Orleans, LA issued this special marine warning at Aug 30, 2021, 9:01 AM CDT. It was in force for 89 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 30, 2021, 9:01 AM CDT (14:01 UTC)
Expired
Aug 30, 2021, 10:30 AM CDT
In force
89 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Hail
0.0 in
Wind
50.0 mph

What forecasters said that day

The local office's own words before this special marine warning 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 marine warning went out at Aug 30, 8:09 AM CDT, 52 minutes earlier.

Area forecast discussion, Aug 30, 8:09 AM CDT, 52 minutes before
Area Forecast Discussion
National Weather Service New Orleans LA
809 AM CDT Mon Aug 30 2021

.AVIATION...

Low ceilings and numerous showers and possibly embedded storms
will continue across most of the TAFs this morning as Tropical
Cyclone Ida continues to slowly pull away to the north. MVFR
prevails and expect IFR to continue at times especially around
KMCB to KASD and KGPT. Lower rain chances expected in the
afternoon but still looks like scattered to numerous showers and
possible storms. Lowest chances expected around KBTR and KHUM.
Trailing bands of showers appear tonight but should shift off to
the east overnight. Winds will trend to south and southwest
during the day while gradually decreasing.

PREV DISCUSSION... /issued by National Weather Service Jacksonville
FL/

LONG TERM (Wednesday through Saturday)...

The convergence boundary and resultant showers and thunderstorms
will continue to develop over the area on Wednesday and keep likely
POP values in place through the day. By Thursday, deep layer
northerly flow will take hold of the region and this will usher in a
much drier and much more stable airmass. Precipitable water
values will decrease to between 1.5 and 2 inches, and rain chances
will diminish to 20 percent or less from Thursday through
Saturday as strong upper level subsidence warms the mid-levels and
reduces instability. Some weak cool air advection will also
occur, and this should help with recovery and restoration efforts.
Temperatures are projected to dip into the 60s and lower 70s at
night and highs are only expected to rise into the upper 80s.
Humidity values will also be a bit lower than normal for early
September.

MARINE...Hazardous conditions for maritime interests continue
today as what is now Tropical Storm Ida moves inland across
Mississippi. Winds will start to ease today, but a tight pressure
gradient over the coastal waters will keep winds in the Small
Craft Advisory range (20-30 kts) through tonight. The pressure
gradient should continue to weaken on Tuesday and Wednesday as
winds should decrease to 10 to 15 knots by Wednesday night. Seas
will correspondingly decrease to 3 to 5 feet by this time. A weak
front will slip through on Thursday and winds will shift to the
north at 5 to 10 knots for the end of the week. Seas of 2 feet or
less are expected with these lighter winds.

HYDROLOGY...Surge will slowly pull back through today along
the coastal and river parishes today. However, coastal flooding will
likely continue. Moderate to Major river flooding is expected to
begin today or tonight a last through at least Wednesday on
Natalbany, Tchefuncte, Tangipahoa, Bougue Falaya Rivers. Creeks and
tributaries of the Pearl River are also expected to reach moderate
to major flood stages as well over the next 12 to 24 hours if they
haven't already.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  79  72  89  72 / 100  60  40  20
BTR  82  72  89  74 /  80  60  40  40
ASD  86  75  90  75 /  90  80  60  40
MSY  89  77  92  78 /  70  60  60  50
GPT  84  76  89  75 / 100  70  60  50
PQL  83  75  88  73 / 100  80  70  50

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Tropical Storm Warning for LAZ035>037-039-048-050-058-060-061-
     063-064-068>072-075>078.

     Flash Flood Watch through late tonight for LAZ037-039-049-050-
     057>061-063>072-075>078.

     Coastal Flood Advisory until 9 PM CDT this evening for LAZ056-
     059-065>067.

     Storm Surge Warning for LAZ049-050-057-058-060-061-063-064-
     068>070-072-075-076-078.

GM...Tropical Storm Warning for GMZ530-532-534-536-538-552-555-557-
     572-575-577.

     Small Craft Advisory until 5 AM CDT Tuesday for GMZ550-570.

MS...Tropical Storm Warning for MSZ068>071-077-080>082.

     Flash Flood Watch through late tonight for MSZ069>071-077-
     080>082.

     Storm Surge Warning for MSZ080>082.

GM...Tropical Storm Warning for GMZ532-534-536-538-552-555-557-572-
     575-577.

     Small Craft Advisory until 5 AM CDT Tuesday for GMZ570.

&&

In the hours before

Local storm report, Aug 30, 3:53 AM CDT, 5 hours 8 minutes before
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Local storm report, Aug 30, 4:25 AM CDT, 4 hours 36 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
425 AM CDT MON AUG 30 2021

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

0409 AM     TROPICAL STORM   3 NNW MAGNOLIA          31.19N 90.48W
08/30/2021                   PIKE               MS   MESONET

            MESONET STATION MPAM6 PIKE. WIND GUSTS TO 52
            MPH.

&&

GP
Local storm report, Aug 30, 4:27 AM CDT, 4 hours 34 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
427 AM CDT MON AUG 30 2021

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

0410 AM     NON-TSTM WND GST 3 SSE PORT ALLEN        30.41N 91.18W
08/30/2021  M45 MPH          EAST BATON ROUGE   LA   MESONET

            MESONET STATION 1311W LSU TIGER STADIUM.
            WIND GUST TO 45 MPH.

&&

GP
Local storm report, Aug 30, 4:33 AM CDT, 4 hours 28 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
433 AM CDT MON AUG 30 2021

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

0415 AM     TROPICAL STORM   30 E VENICE             29.30N 88.85W
08/30/2021                   GMZ555             LA   AWOS

            AWOS STATION KMIS MAIN PASS 140B. WIND GUSTS
            TO 54 KNOTS.

&&

GP

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 29, 7:48 PM CDTFlash Flood Warning Considerable damage threatLIXSaint Charles, Saint John the Baptist2 hr
Aug 29, 8:00 PM CDTSpecial Marine WarningLIX30 min
Aug 29, 8:22 PM CDTTornado WarningLIXSaint Tammany38 min
Aug 29, 8:35 PM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXSaint Charles, Saint John the Baptist6 hr
Aug 29, 8:55 PM CDTFlash Flood Warning EmergencyConsiderable damage threatLIXLivingston, Tangipahoa3 hr
Aug 29, 9:05 PM CDTRiver Flood WarningLIXSaint Tammany12 days
Aug 29, 9:05 PM CDTRiver Flood WarningLIXSaint Tammany21 days
Aug 29, 9:05 PM CDTRiver Flood WarningLIXWashington63 hr
Aug 29, 9:05 PM CDTRiver Flood WarningLIXSaint Tammany, Washington11 days
Aug 29, 10:39 PM CDTSpecial Marine WarningLIX51 min
Aug 29, 10:48 PM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXJefferson15 hr
Aug 29, 10:55 PM CDTSpecial Marine WarningLIX20 min
Aug 29, 11:45 PM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXPlaquemines10 hr
Aug 29, 11:50 PM CDTFlash Flood Warning Considerable damage threatLIXLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington3 hr
Aug 30, 12:05 AM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXLivingston, Tangipahoa12 hr
Aug 30, 1:24 AM CDTFlash Flood WarningLIXLivingston, Saint Helena8 hr
Aug 30, 2:24 AM CDTFlash Flood Warning EmergencyCatastrophic damage threatLIXSaint Charles, Saint John the Baptist8 hr
Aug 30, 2:39 AM CDTFlash Flood Warning Considerable damage threatLIXSaint Tammany9 hr
Aug 30, 2:55 AM CDTFlash Flood Warning Considerable damage threatLIXLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington5 hr
Aug 30, 3:55 AM CDTFlash Flood WarningLIXEast Feliciana, Saint Helena, Tangipahoa, Washington5 hr
Aug 30, 4:19 AM CDTSmall Craft AdvisoryLIX39 hr
Aug 30, 4:51 AM CDTCoastal Flood AdvisoryLIXAssumption15 hr
Aug 30, 7:15 AM CDTSpecial Marine WarningLIX30 min
Aug 30, 7:18 AM CDTSpecial Marine WarningLIX27 min
Aug 30, 7:45 AM CDTFlash Flood WarningLIXLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington3 hr
Aug 30, 9:58 AM CDTAreal Flood WarningLIXJefferson, Lafourche, Livingston, Plaquemines, Saint Charles, Saint James and 1 more60 hr
Aug 30, 10:53 AM CDTAreal Flood WarningLIXSaint Tammany, Tangipahoa, Washington35 hr
Aug 30, 11:04 AM CDTAreal Flood WarningLIXSaint Helena, Saint Tammany, Tangipahoa, Washington35 hr
Aug 30, 11:34 AM CDTAreal Flood WarningLIXSaint Tammany, Washington34 hr
Aug 30, 12:24 PM CDTAreal Flood WarningLIXAscension, Livingston, Saint John the Baptist, Saint Tammany, Tangipahoa33 hr
Aug 30, 2:57 PM CDTHeat AdvisoryLIXAssumption, East Baton Rouge, Iberville, Orleans, Saint Bernard, Saint James and 2 more26 hr
Aug 30, 6:10 PM CDTSpecial Marine WarningLIX95 min
Aug 29, 9:04 PM CDTTornado WarningLIXHancock, Harrison, Pearl River26 min
Aug 29, 9:05 PM CDTRiver Flood WarningLIXPike, Walthall38 hr
Aug 29, 9:06 PM CDTRiver Flood WarningLIXJackson9 days
Aug 29, 9:32 PM CDTTornado WarningLIXHancock, Pearl River13 min
Aug 29, 9:36 PM CDTTornado WarningLIXHancock, Harrison, Pearl River24 min
Aug 29, 10:01 PM CDTTornado WarningLIXHancock, Harrison, Pearl River14 min
Aug 29, 10:34 PM CDTTornado WarningLIXHancock, Harrison, Pearl River41 min
Aug 29, 11:45 PM CDTTornado WarningLIXHancock, Harrison31 min
Aug 30, 12:41 AM CDTTornado WarningLIXHarrison, Jackson49 min
Aug 30, 2:47 AM CDTTornado WarningLIXHarrison, Jackson47 min
Aug 30, 2:55 AM CDTTornado WarningLIXJackson65 min
Aug 30, 4:11 AM CDTFlash Flood WarningLIXHarrison, Jackson8 hr
Aug 30, 5:43 AM CDTFlash Flood WarningLIXPearl River5 hr
Aug 30, 7:28 AM CDTTornado WarningLIXJackson22 min
Aug 30, 7:37 AM CDTTornado WarningLIXHarrison23 min
Aug 30, 8:02 AM CDTTornado WarningLIXHarrison, Jackson28 min
Aug 30, 9:30 AM CDTTornado WarningLIXJackson60 min
Aug 30, 11:17 AM CDTTornado WarningLIXJackson28 min
Aug 30, 12:33 PM CDTFlash Flood Warning EmergencyConsiderable damage threatLIXHarrison, Jackson3 hr
Aug 30, 3:51 PM CDTAreal Flood WarningLIXHarrison, Jackson30 hr

Nearby

Special Marine Warnings in Louisiana, 2021Every special marine warning 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.