Special Marine Warning 511, NWS New Orleans, LA

444 
FZUS74 KLIX 070946
MWSLIX

Marine Weather Statement
National Weather Service New Orleans LA
Issued by National Weather Service Lake Charles LA
446 AM CDT Tue Sep 7 2021

GMZ536-071115-
/O.CON.KLIX.MA.W.0511.000000T0000Z-210907T1115Z/
446 AM CDT Tue Sep 7 2021

...A SPECIAL MARINE WARNING REMAINS IN EFFECT UNTIL 615 AM CDT...

For the following areas...
Chandeleur Sound...

At 445 AM CDT, strong thunderstorms were located along a line
extending from near Ship Island to 6 nm south of Chandeleur Sound to
15 nm north of Breton Sound, moving northwest at 15 knots.

HAZARD...Wind gusts 34 knots or greater.

SOURCE...Radar indicated.

IMPACT...Expect wind gusts in excess of 34 knots and suddenly higher 
         waves. Boats could sustain damage or capsize. Make sure all 
         on board are wearing life jackets. Return to safe harbor if 
         possible.

Locations impacted include...
Chandeleur Sound.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Frequent lightning is occurring with these storms. If caught on the
open water stay below deck if possible, keep away from ungrounded
metal objects.

&&

LAT...LON 3013 8884 3005 8888 2995 8886 2986 8888
      2976 8896 2972 8921 2986 8936 2986 8935
      2985 8934 2985 8933 2988 8934 2989 8938
      2990 8937 2994 8938 3008 8908 3020 8897
      3022 8886
TIME...MOT...LOC 0945Z 120DEG 14KT 3017 8887 3002 8897 2983 8904 2984
8926

HAIL...0.00IN
WIND...>34KTS

$$

Landreneau

506 
FZUS74 KLIX 071020
MWSLIX

Marine Weather Statement
National Weather Service New Orleans LA
Issued by National Weather Service Lake Charles LA
520 AM CDT Tue Sep 7 2021

GMZ536-071030-
/O.CAN.KLIX.MA.W.0511.000000T0000Z-210907T1115Z/
520 AM CDT Tue Sep 7 2021

...THE SPECIAL MARINE WARNING IS CANCELLED...

The affected areas were... 
Chandeleur Sound...

The thunderstorms have weakened and no longer pose a significant
threat to boaters.

LAT...LON 3013 8884 3005 8888 2995 8886 2986 8888
      2976 8896 2972 8921 2986 8936 2986 8935
      2985 8934 2985 8933 2988 8934 2989 8938
      2990 8937 2994 8938 3008 8908 3020 8897
      3022 8886
TIME...MOT...LOC 1015Z 153DEG 9KT 3024 8891 3009 8901 2990 8908 2991
8930

$$

Landreneau

Area Forecast Discussion
National Weather Service New Orleans LA
Issued by National Weather Service Mobile AL
349 AM CDT Tue Sep 7 2021

.NEAR TERM (Now through Wednesday)...A frontal boundary will
remain nearly stationary across the forecast area through the
period, while gradually dissipating. The potential for pockets of
more heavy rainfall will exist today, but as the front slides
slightly further southeast, this should be confined to
southeastern parishes and along the Mississippi coast (again), and
WPC has issued a Mesoscale Precipitation Discussion for these
areas. WPC also continues to outlook most of the forecast area
with a Marginal risk of excessive rainfall today, but overall QPF
values look to be less than one-half inch (although pockets where
several inches of rainfall occurs will be possible). Convective
Allowing Models remain in somewhat of a disagreement as to where
and how much heavy rainfall occurs today, but it would appear at
this time that the best potential would be over southeastern
zones. The NAM, GFS, and ECMWF models are not very impressive,
showing quite a bit lower widespread amounts, making for a very
low confidence Flash Flood Watch (FFA) decision. Therefore, we
will hold off on issuing a FFA for today.

An upper level trough will continue to move slowly east across
LA/MS through most of the forecast period and then be just east of
the area by late Wednesday. With this, drier air will gradually
work into the region from the northwest, with the deeper moisture
and rain chances slowly sliding to the south and east. The surface
front will meanwhile continue to extend across far southern and
southeastern LA and into southeast MS through the period while
gradually becoming more diffuse. With this setup, a plume of
deeper moisture will continue across the forecast area through the
period with PWATs remaining around 2 inches. Slightly lower PWATs
may push into northwestern zones by Wednesday. Additional
scattered to locally numerous showers and storms are expected
across the forecast area today, especially over the southeastern
half of the area where available moisture will be greatest. As we
mentioned above, locally heavy rainfall and localized flooding
concerns could be an issue and we will monitor. On Wednesday, the
higher PoPs get pushed even further east across the area as the
upper trough axis begins to slip east of our area.

With the upper trough in the area and continued scattered to
locally numerous showers and storms in the afternoons, temps
should trend down slightly in the near term. High temperatures
today will be in the mid to upper 80s. Surface dewpoints remain
elevated just enough across the southwestern portion of the
forecast area, where the highest heat indices will reach the upper
90s to lower 100s, so issued a Heat Advisory for these zones
today from 11 am through 5 pm. Lows tonight in the upper 60s to
around 70 north of I-10, then in the middle 70s most locations to
the south (except upper 70s very near the Gulf). High temperatures
Wednesday will again be in the mid to upper 80s, with slightly
lower heat indices in the mid to upper 90s, so additional Heat
Advisories do not appear to be necessary for Wednesday. /12 /22

&&

.SHORT TERM /Wednesday Night Through Thursday Night/...A tropical
wave, slated to progress northeast from the central Gulf towards
the northeastern Gulf coast Wednesday into Thursday, will
eventually be ingested into the upper level trough over the
eastern CONUS. This trough will also begin to slowly lift north
through the short term period as an upper ridge over the Desert
Southwest begins to build eastward. Meanwhile, a surface cold
front will continue its southward progression over the northern
Gulf coast through Thursday, stalling offshore over the northern
Gulf waters into early Friday. Model PWATs range between 1.3-1.6
inches over southeast Louisiana and up into coastal Mississippi
Thursday afternoon. Meanwhile, guidance indicates much drier air
behind the cold front over areas generally north of I-10 Thursday
afternoon (PWATs around an inch or less). This dry air will
eventually filter down into the southern portions of the local
area Thursday night.

Therefore, with modest deep layer moisture in place over SE LA and
coastal MS, anticipating isolated showers and storms Wednesday
night and through the day on Thursday for these locations with
little to no rain chances for the remaining areas north. By
Thursday night, rain chances will dwindle for the entire local
area. High temperatures Thursday afternoon will be in the upper
80s for most areas, but a few spots in the west may see highs
around 90 degrees. With incoming dry air, lows will decrease
through the period. Expecting lows Wednesday night in the upper
60s to lower 70s; although, some locations near the immediate
coast could see lows around the mid 70s. By Thursday night, lows
will decrease to be in the 60s for most inland areas with lower
70s at the coast. /26

&&

.EXTENDED TERM /Friday Through Monday/...The eastern CONUS upper
trough will continue to lift northward and the Desert Southwest
upper ridge will build eastward for the beginning of the long
term. By late in the weekend, model guidance begins to diverge in
solution. The GFS shows a shortwave trough moving over the Upper
Mississippi Valley/Great Lakes region, with the Deep South in sort
of a col. The ECMWF on the other hand shows the upper ridge
expanding eastward with no indications of this shortwave trough.
Either way, by Saturday night into Sunday, there will be a return
of southerly flow to the region, resulting in increased moisture
once again. Therefore, after isolated chances of showers and
storms Friday and Saturday over southeast LA and coastal MS,
chances are likely to increase a bit area-wide by late weekend and
into early next week, with the pattern shifting to more of a
diurnal, summertime trend. This will be monitored with future
model runs to see if models come into better agreement.

High temperatures will increase somewhat from the upper 80s Friday
afternoon to the upper 80s and lower 90s by Sunday and Monday. Low
temperatures will also follow a warming trend, starting out in
the 60s over inland areas and lower 70s at the immediate coast
Friday night. By Sunday night, lows will rebound to be in the
upper 60s to lower 70s along and north of I-10 and in the lower to
mid 70s south of I-10. /26

&&

.MARINE...Winds variable less than 10 knots this morning will
become mainly light southerly to southwesterly during the day and
evening hours. Winds become northerly Wednesday night as a front
moves through the marine area, then gradually switches to a
northeasterly direction by Friday. Scattered to numerous showers
and thunderstorms can be expected through midweek. /22

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  87  70  89  68 /  40  10  30   0
BTR  87  70  89  69 /  40  10  30   0
ASD  88  72  89  71 /  70  30  60  10
MSY  89  76  90  75 /  70  30  60  10
GPT  87  73  88  72 /  70  40  70  20
PQL  88  72  87  71 /  60  40  70  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from 11 AM this morning to 5 PM CDT this afternoon
     for LAZ046-049-050-056>061-065>068-072-075-077.

GM...None.
MS...None.
GM...None.
&&