477
FXUS64 KLIX 142108
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
408 PM CDT Tue May 14 2024

...New SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
(This evening through Wednesday night)
Issued at 354 PM CDT Tue May 14 2024

KEY MESSAGE: Severe weather and excessive rainfall threats return to
the area by Thursday night through Saturday morning. Exact details
remain uncertain at this range, but we will continue to monitor the
progress of this system over the next few days.

Aside from feathered cirrus from convective blowoff associated with
more MCS activity over the central Gulf of Mexico, we have broken
out into sunny skies areawide. This has allowed temperatures to
climb into the low to mid 80s, right around average for this time of
year. A somewhat more balmy and "cooler" night expected tonight as
radiational cooling will be more efficient and surface high pressure
builds overhead.

Wednesday afternoon will approach the 90F mark at many locations as
a shortwave ridge builds in and high pressure keeps skies largely
clear. Light northwest flow will also assist in some subtle
compressional warming from higher elevations. On Thursday, winds
then flip back southerly and gradually increase along with upper-
level sky cover in association with the next approaching system that
could bring impacts to our area. Return flow will allow moisture to
surge back north during the day on Thursday which will set the stage
for the next round of excessive rainfall and severe weather threats
to end the week.

Pertaining to excessive rainfall and severe weather threat:
A trough within the subtropical jetstream pattern will eject out
of SW CONUS/Northern Mexico on Thursday morning providing ample
lift and open warm sector for widespread convective activity to
initiate across the Southern Great Plains by the
afternoon/evening. The primary area to watch will be a smaller
leading shortwave within this flow which could assist in initiate
warm sector convection across the Sabine River Basin which could
organize and move northeast, clipping northern portions of our
area through the overnight hours and into Friday morning. While we
are outlooked for an excessive rainfall threat during this
period, the extent of impacts further east into our area are more
uncertain at this time.

The more notable risk for severe weather and excessive rainfall
threat will come on Friday as the main trough pushes northeast into
the ArkLaTex region and a trailing shortwave trough positioned
further south provides a more focused area of lift that could
initiate a more robust area of deep convection along the Texas coast
extending northeast into southern Louisiana and beyond Friday night.
Exact placement and timing of these troughs will be crucial. It is
possible that we see multiple waves of convection pass near or
through our area over the course of 36 hours which could drastically
alter the thermodynamic and kinematic environments each successive
wave of convection has to work with. Therefore, the extent of
impacts over our area associated with this event remains highly
uncertain at this time, but it is safe to say that the threat for
severe weather and excessive rainfall has increased for this period.

Once the main trough lifts into Friday night, the primary concern
after that will be lingering excessive rainfall threat as a boundary
stalls in generally west to east orientation along the LA coast.
Exact placement of where this stalls could prolong the potential for
heavy rain into Saturday morning.

&&

.LONG TERM...
(Friday through Monday night)
Issued at 354 PM CDT Tue May 14 2024

Still some significant differences regarding the specific details of
the next system, but most guidance indicates the local area will be
solidly in the warm sector as a shortwave moves through the lower
Mississippi Valley. Looks like instability will be in no short
supply and with dewpoints forecast to be in the low to mid 70s with
PW values nearing 2" moisture will be plentiful as well. In fact, if
the PW values pan out as forecast, we will once again be above the
90th percentile for the day and nearing the daily max in the
sounding climatology for May 17.  What does all this mean?
Unfortunately another round of possible severe weather and heavy
rainfall. As previously mentioned the details are still a bit fuzzy,
but the synoptic scale setup is looking favorable for both and we`ll
need to keep an eye on it.

The "cold" front will move through during the day on Saturday, with
quieter weather currently forecast Sunday and to start the next work
week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1238 PM CDT Tue May 14 2024

CIGs have lifted and VFR are now prevailing areawide. Only
concerns through the forecast period will be VIS at MCB where
some dense fog could develop at sunrise. Some patchy fog will also
be possible elsewhere, primarily near the Atchafalaya Basin.
Otherwise, FEW clouds and southerwestly winds of 5-10 knots.

&&

.MARINE...
Issued at 354 PM CDT Tue May 14 2024

Light winds and calmer seas will prevail through Thursday as high
pressure sets up overhead. Onshore flow increases with winds up to
10-15 knots by Thursday night into Friday ahead of the next
system. Will need to monitor progress of showers and storms by
Friday morning and into the weekend which could cause higher winds
and seas than what is currently forecasted. Cannot rule out wake
low activity in association with strong complexes of thunderstorms
especially Friday night.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  83  60  86  62 /  10   0   0   0
BTR  88  64  90  67 /   0   0   0   0
ASD  88  66  91  67 /  20   0   0   0
MSY  87  69  89  72 /  20   0   0   0
GPT  86  66  89  68 /  30  10   0   0
PQL  86  65  91  65 /  40  10   0   0

&&

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

$$

SHORT TERM...TJS
LONG TERM....TJS
AVIATION...TJS
MARINE...TJS