231
FXUS64 KLIX 081745
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1145 AM CST Wed Jan 8 2025

...New AVIATION...

.SHORT TERM...
(Today through Thursday)
Issued at 436 AM CST Wed Jan 8 2025

Chilly night again however even though winds were not expected to
completely decouple we are still seeing slightly stronger winds
than anticipated. Combine that with a good bit of cloud cover
impacting the region and we just haven`t been capable of cooling
efficiently. That said we are still dropping slowly and most
locations in the CWA have seen the wind chills range between 18
and 25. For areas along and south of I-10 in SELA most locations
were still abv freezing at 9z but numerous were close and if winds
can weaken just a touch more before sunrise we should see
scattered to numerous sites at or below freezing.

Today through Thursday will continue to be chilly and tonight has
the potential to be the coldest night in a few locations as long as
the expected radiation cooling conditions that are expected setup.
High pressure quickly slides east-southeast across the Plains and
into the TN Valley by tonight. With the center of it over the TN
Valley it will wedge southwest into the Lower MS Valley and winds
will finally begin to break down from the sfc to abv h85. There will
still be no recovery taking place so dewpoints will remain in the
20s. The only real issue is going to be clouds and looking at
current satellite it is hard to see how we aren`t dealing with at
least some cloud cover. Now it doesn`t appear that it would be low
clouds and mainly mid upper lvl clouds but then again low clouds
sliding in from the northwest this morning weren`t really
anticipated either. Given the sfc high finally pushing east there is
a better chance that those low clouds shouldn`t be a problem. As for
the high clouds I can`t shake the idea that they will be streaming
in through the night and could be thick at times. However, with the
h5 trough finally beginning to amplify as the system currently just
digging into the Baja continues to deepen and slide south The jet
should begin to buckle more and could finally slide far enough north
to keep a majority of the thicker high clouds out. Overall a decent
radiational cooling night should be in store for much of the area.
especially the northeastern half. This will finally set the stage
for our typical cold drainage locations to maximize their potential
and drop. This would be Pearl River and Pascagoula drainage areas and
the West Bank.

Much of the I-12 corridor and then across coastal MS should have no
problem dropping below freezing and most of that area should fall
into the upper 20s, possibly even mid 20s. With lows not just barely
getting below freezing we did opt to issue a Freeze Warning for that
area for tonight. Winds will be much lighter if not light and vrb so
wind chill values will likely be near the actual temp.

North of that area obviously freezing temperatures are expected but
lows will likely only drop into the mid possibly lower 20s and with
light winds the wind chill values likely remain abv 20 as well so
there will be no headlines for the northern FL parishes or southwest
MS but again lows will likely range from 22/23 to 29.

The more difficult forecast is along and south of I-10 in SELA.
Winds should shut down and as long as clouds don`t interfere temps
will drop like a rock tonight. As we mentioned early the setup could
be quite favorable for areas along the west side of the MS river to
bottom out and even portions of the River Parishes to drop nicely
overnight. That said temperatures will likely range even in those
areas from 29 to 33. Because confidence is not as high in these
areas dropping to or below freezing we have opted to issue a Freeze
Watch for tonight. This includes most of the area along and south of
I-10 with the exception of the coastal sections of those parishes.
Yes Orleans parish is in the freeze warning but that is to account
for the portions of the parish that are on the West Bank. Most of
the metro area that is between the River and the Lake will not get
below freezing.

Heading into the Thursday the area will likely remain fairly quiet
for most of the day. Our amplifying L/W trough to the west will want
to start to push east with the closed low at the base opening up and
beginning to lift out. However, another strong disturbance on the
backside will be shooting south west of the Rockies anchoring the
trough. As the first piece of energy in the trough starts to pull
out to the northeast Thursday  it will help to induce cyclogenesis
over the western Gulf. But with the trough being held back to the
west the sfc low will be very slow to move remaining over the
western Gulf all day and into the overnight hours. That said with
all of the energy moving across TX and into the Lower MS Valley the
sfc low and LL winds will rapidly respond. The sfc low will deepen
as it move into the northwestern Gulf and LL winds will ramp up and
this begins to set the stage for the overnight hours and Friday for
our area. It is also going to ramp up the impacts across much of the
ARKLATEX and ARKLAMISS. /CAB/

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 436 AM CST Wed Jan 8 2025

The extended portion of the forecast is mainly focusing on
Thursday night through Friday night. After that the forecast is
expected to be dry and cool through the remainder of this forecast
package. Medium range models and even the last few hours of the
latest CAMs that are just starting to get into this time range are
in decent agreement with the evolution of our system as a whole.
It is just some details that aren`t quite in agreement and
typically that isn`t a huge thing but in this case when trying to
figure out the impacts and having to discern whether there may be
any frozen precipitation and then if there is will it be snow or
ice the details are extremely important. Lucky for us that threat
doesn`t appear to be an issue for us however the details are very
important for us because it could mean the difference between you
seeing 1-2 inches of rain over a 24 to 36 hours time frame or
falling under a band of heavy rain that could lead to 3 to 5
inches with isolated higher amounts. It is where that band
eventually sets up that will be key.

As we head into Thursday night We already mentioned the deepening
sfc low over the northwestern Gulf and the LL winds responding. Most
everything that was brought up 24 hrs ago still looks applicable.
First our L/W trough will not be in a hurry to get out.  With so
much energy on the backside holding the base of the trough back
while it continue to push east into the Great Lakes we will see
southwest flow aloft greatly increase over the area. This is a very
dynamic system and the mid lvl jet which will be increasing
throughout Thursday night and Friday and could be over 100 kt by
late Friday. The LLs respond with a very strong LL jet develop over
our CWA just ahead of the sfc low. H85 winds are still expected to
be around 50 kts (and could be even stronger. This moves right
across the region Friday with the nose of the jet possibly setting
up along the FL parishes and southwest MS. This would lead to very
strong WAA in the h85 to h7 lvls providing a significant amount of
lift. This is also going to help to transport very deep moisture
into the area with PWs probably ranging from near 1.4 in the
northwest to just under 2" near the coast. That is very high for
this time of the year with the median around 0.76 and the 90th
percentile 1.39". The sfc low will finally begin to lift to the ENE
right along the coast and actually may come inland just a touch as
it will want to move towards the strongest WAA in the boundary layer
which should be just south of the max LL WAA. A lot of this is
screaming a heavy rain event is possible if not expected however
there is one things that is missing and that is instability. The
only sfc based instability that we could conceivably have would be
along the coast and in the Gulf however I think the models may be
missing or at least it is not as apparentt and that is could CSI
(Slantwise Convection). This tends to be overlooked or missed as it
is far weaker than convective instability. Given the very strong LL
winds providing more than enough LL convergence and a lot of WAA
leading to a very large area of lift to the north and northeast of
the sfc low I think we could see this lead to some instability as
the parcel gets transported in a slanted but upward trajectory. This
will provide very efficient showers and possibly a few rumbles of
thunder. It could also lead to a more defined band or two of heavier
rain that could provide a localized Flash Flooding concern. Also we
need to take into account how cold the preceding 72 hours will have
been some the ground is cold and hard and will not soak up the rain.
In addition where the heaviest rain is expected the temperatures
have been colder.

At this time it looks like rain should really get going during the
overnight hours with the bulk of the heavier rain occurring from
early Friday possibly into the early afternoon hours. We still have
a Marginal risk for excessive rainfall in place for all of the CWA
Friday but that may be refined later today or tonight as we get a
better idea if and where the heavier rain is expected to fall.

After Friday night we dry out again and rain cool through the rest
of the forecast. /CAB/

&&

.AVIATION...
(18Z TAFS)
Issued at 1143 AM CST Wed Jan 8 2025

VFR conditions will prevail through the period. Northwesterly to
northerly winds during the day today will become light overnight
and shift more to the northeast or east by Thursday morning as
high pressure moves away from the area.

&&

.MARINE...
Issued at 436 AM CST Wed Jan 8 2025

High pressure is pushing into the area and winds continue to
slack off with all headlines finally ending later this morning. We
will see about a 24 hours window of light winds but then winds
will being to ramp back up as a sfc low takes shape over the
western Gulf Thursday. This sfc low will deepen and move across
the coastal waters and possibly even just come inland over SELA
with strong winds both and ahead and behind it. Headlines will
be needed again with this sfc low but winds should begin to back
off once again over the weekend. We will see numerous showers and
even a few thunderstorms with the sfc low as well and that will
impact the coastal waters possibly as early as Thursday afternoon
and through Friday. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  45  25  48  35 /   0   0   0  90
BTR  50  28  51  42 /   0   0  10 100
ASD  50  26  52  41 /   0   0   0  80
MSY  49  35  51  46 /   0   0   0  80
GPT  49  28  51  40 /   0   0   0  70
PQL  53  25  53  39 /   0   0   0  60

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Freeze Watch from late tonight through Thursday morning for
     LAZ046-056>060-065-077-085>090.

     Freeze Warning from midnight tonight to 9 AM CST Thursday for
     LAZ047-048-076-079>084.

GM...None.
MS...Freeze Warning from midnight tonight to 9 AM CST Thursday for
     MSZ083>088.

GM...None.
&&

$$

SHORT TERM...CAB
LONG TERM....CAB
AVIATION...DM
MARINE...CAB