-- Discussion containing changed information from previous version are highlighted. --
103
FXUS64 KLIX 211701
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1201 PM CDT Sat Sep 21 2024

...New AVIATION...

.SHORT TERM...
(Today through Sunday)
Issued at 256 AM CDT Sat Sep 21 2024

Locally, for the next few days, there`s not a lot happening. Very
little if any in the way of rain and temps will remain warm in the
low to mid 90s. The stacked high to our west is getting flattened by
the upper trough digging and moving east through the Rockies today
and this will continue to be the case Sunday.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 256 AM CDT Sat Sep 21 2024

The interest continues to be in the extended in the tropical
category so lets dive into that. We need to start off with the main
large scale systems at play today then move into the extended to see
how this all plays out.

The stacked high near us will actually move east with time across
the gulf coast into the western Atlantic by late Wed. This will
allow the next trough to create a weakness down the Miss River
Valley during that same time frame which splits the stacked high to
the east and the new stacked high over the SW CONUS. Now we need to
back up to the present again. The current east coast upper trough
extends SSW down the east coast through the FL Keys then SW into the
Yucatan then turns west as it exits Chiapas, MX into the EASTPAC.
This is very important as this trough has a strong mid level
reflection whose axis extends along this same arc. The east coast
upper trough will keep moving east stretching the southern end and
eventually cutting off an upper low from its southern most portion.
It is this trough that will slowly cause the EASTPAC energy to begin
flowing along its mid level boundary. And as we all know how mass
moves along these boundaries in the northern hemisphere, it will
eventually cause the disturbances flowing westeard along the ITCZ to
stall in the eastern most portion of the Pacific which should occur
by late today/evening. We will then see the activity along the ITCZ
actually begin to flow eastward by Sunday. Where this trough axis
bends over southern Mexico, it will cause a lot of this energy to be
trasported NEward into the Caribbean during this time as well. We
already see this flow occurring in the upper levels with help from
IR sat imagery. Eventually, even the disturbances south of Mexico
will turn northward by late Tue into Wed as the upper low begins to
move NNW over the gulf. This flow of disturbances and deep moisture
that has trasported into the Caribbean will then be allowed to start
developing under a more hospitable environment. This "area" could be
over the western Caribbean or southern gulf or both since this
energy transport will also start moving into the southern gulf too
which is the reason for the large area of 60% development probs. By
now, one can now start putting the pieces together. During this same
time frame(Wednesdayish), is when something is trying to get going
near the Yucatan while, if you read the start of this paragraph,
this is the same time that the weakness is located over the Miss
River Valley. Any mass to the south of this CONUS trough will
obviously be transported northward. It is in this time frame that
things become very questionable, mainly because we are quite a ways
out in time and all kinds of things that are not accounted for in
the models could cause things to diverge from what they are trying
to advertise. But a strong short wave is shown to begin moving south
out of central Canada Mon/Tue digging into the base of this upper
trough by Wed which would slow the trough while it does so. This is
what we see bringing this system into the central and northern gulf
with time via each model. Now...let alone the plethera of things not
accounted for, timing will be the biggest question with this short
wave into the base of the Miss River upper trough by mid week. This
timing will be paramount as we move from Wed into the end of next
week. It takes a while for all these things to come together with
these types of scenarios but it looks likely that it will. One thing
that all global models agree on is the transformation of this system
from a barotropic to more baroclinicity as it moves north developing
a frontal arc to its south as it moves toward the northern gulf
coast, wherever that may be. This does not mean much except that
when systems do this, typically their wind field begins to expand
outward. This is very normal as we move into the end of September
into October.

&&

.AVIATION...
-- Changed Discussion --
(18Z TAFS)
Issued at 1158 AM CDT Sat Sep 21 2024

VFR conditions prevail at all area airports and will persist
through the forecast period for most area airports. Some airports,
like BTR and MCB will drop to IFR conditions around daybreak
tomorrow for a couple of hours due to fog and will improve to VFR
by midday. Wind shifts greater than 30 degrees will be possible at
coastal airports throughout the forecast period. MSW
-- End Changed Discussion --

&&

.MARINE...
Issued at 256 AM CDT Sat Sep 21 2024

Winds will remain stable from the east at around 10-15kt into the
new week. A few sh/ts could develop over nearshore waters mainly
during the morning hours and winds and seas will be higher in and
around this activity. The hurricane center has an area outlooked at
60% for tropical development over the next 7 days over the NW
Caribbean and southern gulf. Remain updated with future fcasts
concerning this area over the next several days.

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
MCB  69  91  69  90 /   0   0   0   0
BTR  72  94  72  94 /   0   0   0   0
ASD  71  90  71  90 /   0   0   0   0
MSY  75  90  74  90 /   0   0   0   0
GPT  73  90  72  89 /   0   0   0   0
PQL  72  93  72  93 /   0   0   0   0
-- End Changed Discussion --

&&

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

$$

SHORT TERM...TE
LONG TERM....TE
AVIATION...MSW
MARINE...TE