397
FXUS64 KLIX 172023
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
323 PM CDT Tue Sep 17 2024

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

.SHORT TERM...
(This evening through Thursday night)
Issued at 256 PM CDT Tue Sep 17 2024

Ongoing convective activity will begin to decrease in coverage
through the evening hours with the loss of daytime heating. This
convective activity is directly related to both a moderate degree
of surface based instability and weak omega on the southwest
periphery of a broad upper level low pressure system over the
Southeastern CONUS. Some mid-level moisture is also still
lingering over the area and this has allowed PWATS to rise to near
2 inches today. Fortunately, the forcing and instability remain
weak enough that only low-topped thunderstorms and showers have
developed this afternoon as temperatures warmed into the mid to
upper 80s.

Later tonight, conditions once again look favorable for boundary
layer decoupling to occur as temperatures cool into the upper 60s
and lower 70s, and fully expect to see widespread low stratus and
areas of light to moderate fog form shortly before daybreak
across inland portions of the CWA. This stratus and fog will
linger into the mid-morning hours tomorrow before lifting as
temperatures warm and boundary layer mixing increases. By tomorrow
afternoon, highs will once again climb back into the mid to upper
80s. Although the upper level low will be pulling out of the
region, enough residual moisture and forcing should be in place to
support the development of isolated convection in the afternoon
hours. Have included a 20 percent POP for much of the area
tomorrow afternoon. By tomorrow evening, the loss of daytime
heating will allow any convection to quickly dissipate.

Increasing subsidence and dry air advection will take hold of the
area on Thursday as a strong deep layer ridge axis moves in from
the west. This will lead to mostly clear skies, much lower PWATS
of around 1.5 inches, and a strong mid-level capping inversion.
The result will be limited cloud development and zero chance of
convective development. Temperatures will also warm a bit more
beneath the subsident airmass with highs in the upper 80s and
lower 90s expected. Fortunately, some recovery is expected at
night given the clear skies, light winds, and lower dewpoints in
place. Lows are projected to fall into the mid to upper 60s over
inland areas and the lower 70s along the coast.

&&

.LONG TERM...
(Friday through Monday night)
Issued at 256 PM CDT Tue Sep 17 2024

The deep layer ridge axis will continue to build over the area
this weekend into early next week, and the result will be a very
dry forecast with near zero percent rain chances and clear skies
in place each day. This is reinforced by anomalously low PWATS of
1.25 inches or less across the area from Friday through Sunday.
Some recovery to around 1.5 inches is expected on Monday, but this
is still below average and will greatly limit any convective
potential with a strong mid-level capping inversion in place.
With strong subsidence in place, temperatures will continue to run
slightly above average each day with highs climbing into the
upper 80s and lower 90s. Fortunately, overnight lows will dip into
the 60s and lower 70s each night due to the dry airmass, light
winds, and clear skies expected. The dry air will also help to
keep apparent temperatures manageable in the upper 90s.

&&

.AVIATION...
(18Z TAFS)
Issued at 256 PM CDT Tue Sep 17 2024

Through 20z, scattered thunderstorm activity will impact MSY and
NEW with periods of gusty winds, lightning strikes, IFR
visibilities and MVFR ceilings. The convective threat should
decrease at these terminals after 20z as the atmosphere becomes a
bit more stabilized, but have opted to include VCSH wording
through the evening hours at not only MSY and NEW, but also the
remainder of the terminals. Around 10z, boundary layer decoupling
is expected to take hold at several of the terminals, and this
will lead to another round of IFR or lower stratus and fog
development. MCB, ASD, HDC, BTR, and GPT will be most impacted by
these IFR conditions as the low level temperature inversion
allowing for the boundary layer decoupling will be most pronounced
at these locations. These low ceilings and reduced visibilities
will linger through 15z before gradually improving. PG

&&

.MARINE...
Issued at 256 PM CDT Tue Sep 17 2024

Through Friday, very benign conditions are expected across all
of the waters as a broad area of high pressure dominates the
northern Gulf of Mexico. Winds will be 5 knots or less and seas
will be nearly calm over this period. By Saturday, a slight
increase in the pressure gradient over the Gulf as the broad high
pressure system moves inland and becomes more centered over
Mississippi and Alabama. The result will be more sustained
easterly wind of 10 to 15 knots developing in the open Gulf waters
and seas increasing to 2 to 4 feet over the weekend. The sounds
and tidal lakes will see winds in the 5 to 10 knot range and seas
of 1 to 2 feet are expected. Overall, despite the slightly uptick
in winds and seas, no significant maritime impacts are expected
through the weekend.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  69  88  68  89 /  10  20  10  10
BTR  72  89  73  91 /  10  20  10  10
ASD  72  87  71  89 /  20  20   0  10
MSY  75  87  75  88 /  20  10   0  10
GPT  73  85  72  87 /  20  20   0  10
PQL  71  87  71  89 /  20  10   0   0

&&

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

$$

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