-- Discussion containing changed information from previous version are highlighted. --
950
FXUS64 KLIX 230841
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
341 AM CDT Mon Sep 23 2024

...NEW SHORT TERM, LONG TERM, MARINE...

.SHORT TERM...
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(Today through Tuesday Night)
Issued at 203 AM CDT Mon Sep 23 2024

Another rather hot day is forecast for today as a H5 ridge roughly
around 592dam resides over the northern Gulf. The higher
thicknesses/heights will allow the region to remain above average
in terms of temperatures and as for any rain chances...slim to
none with plenty of subsidence helping keep things on the dry
side. The ridge will begin to spread east later this afternoon and
especially overnight tonight and an upper level shortwave begins
to weaken the western periphery of the ridge. At the surface, a
weak frontal boundary will begin to move southward through the
Ozarks and into the Mid MS River Valley. This feature looks to
bring at least an uptick in POPs late on Tuesday and there also
could be some morning fog Tuesday morning...especially in the more
fog favored locations as moisture begins to pool out ahead of the
slowly advancing front. Models have been struggling a bit with
fog potential over the last day or so and at this juncture it may
be worth mentioning once probs increase a bit more in subsequent
packages. Otherwise, patchy fog seems appropriate this morning
again in those favored lower spots. (Frye)
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&&

.LONG TERM...
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(Wednesday through Sunday)
Issued at 203 AM CDT Mon Sep 23 2024

Things begin to become a bit more interesting going out into
midweek. First, the synoptic pattern is interesting as the
aforementioned shortwave/weakness takes shape across the northwest
and north Gulf. Within the flow a mid/upper level low begins to
pinch off over the Cornbelt region and drops southward over the
mid MS River Valley. This is important because Invest 97L is
forecast to deepen and move generally northward out of the
western Caribbean and into the southern Gulf of Mexico. Where the
feature goes will really depend on two things. First
timing...both of the upper level low as well as what is forecast
to likely become a tropical cyclone. As well as exact placement of
the upper level low. Any slight adjustment could cause the
forecast to change. Models have come into agreement in terms of
timing with respective ensemble spreads also starting to hone in
on a faster solution with a landfall point somewhere along the
Florida Panhandle Thursday or Thursday night. Again, stressing
here that any slight change in strength of the synoptic features
could cause some changes in the actual path.

So, in terms of the local area, keeping in mind a TC isn`t just a
point on the map and impacts may extend well away from the
center...our local impacts seem to be rather limited since we will
be on the dry side of the TC. In fact, QPF values have mostly
been dropping off with a tight gradient of anticipated rainfall
amounts setting up on the western periphery. Frictional divergence
as well as subsidence aloft could also point to a much drier
forecast, but there again remains uncertainty in the rainfall
amounts depending on the exact track. That said, the globals have
shown a fairly "large" system with a larger wind field. This could
lead to at least higher gradient winds offshore (see marine
section).

As the system moves inland over the southeast US, the TC starts
mingling with the upper level feature and eventually rotates north
and west with the flow around the ULL as the tropical
characteristics decay. The low and the much cooler upper levels
could signal for some convection later this weekend and into the
weekend. Albeit lower end POPs/QPF signal for now with mostly dry
air (dry slot?) over our region...a few hailstones would certainly
be possible in this environment, especially across far southwest
MS in the more robust updrafts. As for temperatures, with the
upper level heights crashing for much of the long term, MaxTs will
be a bit cooler and instead of the lower 90s we will likely
experience lower and middle 80s throughout much of the period with
temperatures being just a skosh warmer by next weekend. (Frye)
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&&

.AVIATION...
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(06Z TAFS)
Issued at 1131 PM CDT Sun Sep 22 2024

VFR conditions across all forecast terminals at 0000CDT (05z). If
there are going to be any impacts in the first 12 hours of the
forecast, it`d be a few patches of fog, but that`s not expected to
be widespread. If there are going to be favored terminals for
that, it`d be KMCB, KHUM and perhaps KBTR and KHDC. Will only
carry a TEMPO for MVFR visibilities at the first two.

As we`ve seen for the last several days, there is a non zero
threat of SHRA during the afternoon hours on Monday, but areal
coverage is expected to be way below the threshold to mention in
the forecast this far out. (RW)
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&&

.MARINE...
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Issued at 203 AM CDT Mon Sep 23 2024

Mostly benign marine conditions expected early this week as the
low level flow remains quite light across the local waters. This
quiet period will quickly end going into late Tuesday and
especially through mid to late week as AL97 is likely to continue
to move into the southern and eventually central or eastern Gulf
of Mexico as a formidable tropical cyclone. Pressure gradient
over the local waters will tighten as the system move northward
toward the Southeast U.S. The increase in winds and seas will
likely lead to hazardous marine conditions, especially over the
local gulf waters. Conditions will be slow to improve through
Friday, but eventually as the TC moves inland conditions will
begin to settle. (Frye)
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&&

.PRELIMINARY POINT TEMPS/POPS...
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MCB  91  68  89  68 /   0   0  10  30
BTR  94  74  94  73 /   0   0  10  20
ASD  91  71  90  72 /   0   0  10  10
MSY  91  74  90  75 /  10   0   0  10
GPT  90  72  88  72 /   0   0   0  10
PQL  94  71  92  73 /   0   0  10  20
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&&

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

$$

SHORT TERM...RDF
LONG TERM....RDF
AVIATION...RW
MARINE...RDF