Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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610
FXUS64 KLIX 031142
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
542 AM CST Wed Dec 3 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 538 AM CST Wed Dec 3 2025

 - With rather persistent cloud cover most of the evening and even
   holding on into the overnight hours the potential for freezing
   conditions has decreased precipitously

 - Another storm system will bring widespread rain and embedded
   thunderstorms to the area Thursday through Friday night. There
   will be at least a low-end threat of heavy rain with this
   system and two-day rainfall totals are currently forecast in
   the 2-4 inch range. Please check the forecast for updates in
   the coming days as forecast rainfall totals and associated
   flood threats will continue to be refined.

&&

.SHORT TERM...
(Today through this Evening)
Issued at 1120 PM CST Tue Dec 2 2025

Clouds have plagued the area all night and we are not quite cooling
as much as expected. This is going to have a significant impact on
morning lows and we will likely remain abv freezing over most if not
all of the area.

Forecast focus is on the overnight period through the weekend but
quickly today. Clouds could still be a little stubborn to start the
day but eventually the low clouds should clear out but as soon as
the occurs mid lvl clouds will quickly push in from the southwest
this afternoon. This is the beginning of moisture returning which
will increase much more rapidly overnight. Highs will be warmer
today with upper 50s to mid 60s. /CAB/

&&

.LONG TERM...
(Thursday through Tuesday night)
Issued at 1120 PM CST Tue Dec 2 2025

Main forecast concern is Thursday through the weekend. Models
continue to struggle some with placement of the rain, how much, and
how fast long it lasts at times. The latest trend has been a
renewed 3rd shot of rain over mainly coastal sections of the CWA
Saturday night into Sunday. The biggest problem with the overnight
forecast tonight and through Thursday is how models are handling the
band of rain/convection with 2 distinct scenarios being advertised.
One where the regional and global models have the higher rain across
the northern half of the area and the other advertised by the CAMs
which as one would expect try to surge the convection towards the
higher instability and cut off the moisture for a good chunk of the
northern half of the CWA. Given the highly uncertain and low
confidence in the forecast stuck pretty close to the latest NBM
guidance. It is showing high PoPs for almost the entire area from
overnight tonight till early Sunday and lets be honest it will not
rain over the entire area that entire time. However, trying to
explicitly time things out and focus on specific locations is mostly
futile right now.

So a quick look at the pattern and setup. Overnight tonight with a
rather ugly L/W trough stretching to the southwest from the Hudson
Bay into the Pacific well southwest of southern CA. This is already
putting us under increasing west-southwest to southwest flow aloft
which is easily visible on GOES19 with clouds streaming from the
Pacific across Mexico and now into southern TX and the western Gulf.
That said there are a few keys pieces of energy embedded in the
broad L/W with the one that will have the greatest say over the area
currently moving south over CA. This stronger s/w will begin to
split with part of it heading back to the south-southwest along the
backside of the trough and the rest trying to round out just south
of the 4 corners. This s/w will start to flatten out and eventually
just merge becoming more part of the L/W trough. That said it will
add a lot of energy with the mid lvl flow greatly responding across
the southern Plains, the Lower MS Valley and into the TN Valley
Thursday. Even though it just becomes part of the whole setup and
loses its identity it will provide enough support to see low
pressure start to take shape across the TX coast early Thursday with
an inverted trough axis extending to the northeast across southern
LA. If the s/w can hold onto its identity a little more it may try
to help to draw the broad sfc low and inverted trough a touch more
north however, if it just quickly merges with the main flow we will
likely see a weaker broad sfc low along the TX coast and the
inverted trough and possible warm front along the coast. This will
have implications on rainfall especially amounts and location.

This is where the the two different scenarios emerge. First all
model solutions have a weak sfc low and the bigger issue is how the
handle the evolution of convection and the locations of the inverted
trough and warm front. The global and even regional models draw
things farther north where the CAMs which are just now getting into
the time frame really allow convection to dictate and eventually
surge the convection cold pool style towards the coast and the
better instability. That would make sense but am hesitant given as
this could just be feedback as the CAMs just feed into themselves.
The strong s/w and its impact across the southern Plains make me
initially think it will try to draw things a touch farther north.
The key will be where convection as as we cross midnight tonight and
see it it is continuing to expand ENE or if the eastern edge of the
precip isn`t quickly expanding ENE and actually holding onto a
harder edge and moving more east with a slight southern component
suggesting it trying to be drawn towards the coast. This also would
likely be self fulfilling as convection would try to strengthen the
sfc low over the coast or coastal waters and thus reinforce
convection trying to become more coastal.

Again if I had to choose one side over the other I am probably
slightly leaning towards the global and regional models. The forcing
is not overwhelming to really lead to so strong of convection that
cold pooling would take over. In addition the strongest forcing is
still north so convection will likely remain focused on the inverted
trough which will eventually get anchored over the northern half of
the CWA early Thursday through the midday hours.

As for potential of heavy rain. The biggest feature is rapidly
increasing moisture overnight tonight. PWs will be abv the 90th
percentile. So convection will already be efficient and combine that
with some elevated instability to work with and there could be a
band of locally heavy rain. Obviously the other concern would be
training given the band will likely be parallel to the mid lvl flow
so the main issue would be where that sets up. Most of the area had
been rather dry and even with vegetation likely in a more dormant
phase the dry soils and low rivers can handle quite a bit of rain.
The issue would be if this lines up directly over any of our larger
urban areas. Where runoff is always a problem if the rain comes
down hard enough.

That is just round one as the trough starts to buckle a little with
some the closed low in the Pacific finally sliding east with the L/W
trough. This will lead to a break in the rain late Thursday and
possible Thursday night however there will still be spotty showers
out there overnight. The next round of rain be Friday as stronger
forcing spreads out over the area. Even though the forcing will
increase it will be broad with no real focus and still some weak
inverted trough laying up along the southeastern half of the CWA
Friday. Rain will likely be lighter Friday especially over the
northwest.

As that moves to the east we will probably see another break with
spotty light rain overnight Friday and into Saturday but a third
area of low pressure could develop over the southern Plains or even
the western Gulf and as the trough axis gets closer we will see a
3rd round of rain try to impact the region overnight Saturday and
into Sunday.

One last thing to mention and it was brought up in the Marine
section. There is a window for minor coastal flooding Thursday night
into Friday during high tide. 24 to 36 hours of easterly to east-
southeasterly flow increasing in strength and occuring at the same
time as peak tides this month should lead to some minor coastal
flooding across coastal Hancock county and east facing shore of
SELA. /CAB/

&&

.AVIATION...
(12Z TAFS)
Issued at 538 AM CST Wed Dec 3 2025

A low stratus deck ranging between 1000 and 1500 feet has
persisted at most of the terminals through the night. Only BTR has
remained clear, but the stratus deck is now expanding westward and
will be in place at BTR by the top of the hour. As a result, all
of the terminals will continue to experience these MVFR and fuel
alternate ceilings through at least 18z. Some mixing of drier
mid-level air toward the surface after 18z will allow the ceilings
to briefly improve into MVFR range of 3000 to 6000 feet this
afternoon into early this evening. However, increased isentropic
upglide over a cool and stable airmass at the surface will start
to bring rain to the terminals between 04z and 08z. The rain will
turn moderate with IFR visibilities of 2 to 3 miles and a mix of
IFR and MVFR ceilings ranging from 800 to 1500 feet from 08z
through the end of the forecast period.

&&

.MARINE...
Issued at 1120 PM CST Tue Dec 2 2025

High pressure has moved in but will continue to sliding east quickly
leading to light return flow by midday/early afternoon today. Weak
low pressure will begin to develop along the Texas coast tonight and
slowly drift east-northeast Thursday along the coast. This will
tighten the pressure gradient especially east of the Mississippi
River delta. Winds will increase with moderate to strong east-
southeast to easterly winds. This will have multiple impacts with
Small Craft Advisory conditions expected Thursday into Friday but
the increase in onshore winds will combine with the increasing tidal
cycle at the end of the week likely leading to at least some minor
coastal flooding. Main concern will be east facing shores of
Orleans, St Bernard, Plaquemines, and far southeastern St Tammany.
In addition coastal Hancock around Waveland will also deal with some
minor coastal flooding Thursday night through Friday morning. Winds
will relax and return to offshore late Friday and Friday night but
another weak surface low will develop Saturday moving across the
coastal waters late Saturday bringing another brief period of
moderate to strong winds. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  59  42  50  44 /   0  90 100  90
BTR  62  47  55  47 /   0 100 100  90
ASD  60  44  56  47 /   0  80  90  80
MSY  63  52  61  53 /   0  80  90  80
GPT  59  45  56  48 /   0  70  90  80
PQL  60  41  58  46 /   0  60  90  80

&&

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

$$

SHORT TERM...CAB
LONG TERM....CAB
AVIATION...PG
MARINE...CAB