688
FXUS64 KLIX 310508
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1208 AM CDT Sun Aug 31 2025

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

.SHORT TERM...
(Today through Monday)
Issued at 1203 AM CDT Sun Aug 31 2025

Primary axis of upper trough extended from Maine to Georgia during
the evening hours with shortwaves over Oklahoma and South Dakota
headed toward the base of the trough. Ridging was noted from Arizona
to Idaho. At the surface, high pressure was centered over the
western Great Lakes with frontal boundaries near the Louisiana coast
in the vicinity of Houma and to the north along Interstate 40. South
of the Louisiana boundary, precipitable water values were in excess
of 2.1 inches, as noted in the LCH sounding. North of the boundary,
drier air was in place as noted by the 1.85 inches here at the
office, and even drier on the JAN sounding at 1.45 inches. Most
precipitation across the area had dissipated by 8 PM CDT. Most
evening temperatures ranged from the mid 70s to lower 80s with dew
points in the lower and middle 70s.

With the Oklahoma shortwave weakening and the surface boundary
forecast to drift offshore over the next 24 hours, areal coverage of
convection during the next two days is expected to be considerably
less than recent days. Any convection that does develop over the
next two days is likely to be isolated and limited to areas south of
Interstate 10. It is entirely possible that only the extreme lower
portions of the Louisiana coastal parishes to the south of a Houma
to Port Sulphur line experience any storms. By this time tomorrow
night, precipitable water values are expected to be near 1.5 inches
or lower across essentially the entire CWA. That is around the 25th
percentile climatologically. The NBM PoPs look to be a bit on the
high side, especially on Labor Day, but were at least supported
somewhat by the 12z ECMWF solution.

The drier airmass should support warmer high temperatures as
compared to Saturday, with high temperatures around 90 for much of
the area. What will be just about as noticeable is lower dew points
and relative humidities, especially for Labor Day north of
Interstate 10, where dew points could be in the mid 60s.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 1203 AM CDT Sun Aug 31 2025

Troughing is expected to continue across the eastern half of the
country over the next week as ridging near Bermuda is blocking it
from going much of anywhere. The forecast issue locally is with the
timing of shortwaves moving into the base of the trough. Forecast
soundings from the GFS would indicate that moisture levels should be
well below the 50th percentile climatologically for much of the
week, if not all week. There may be enough forcing with shortwaves
Tuesday or Wednesday to produce at least isolated precipitation,
which was supported by at least some of the ECMWF ensemble members,
and the operational GFS from Saturday`s 12z runs, as well as the
recently received NAM for the 00z Sunday run. A significant
departure (more than 10-15 percent) from the NBM PoPs doesn`t appear
justified for Tuesday and Wednesday at this time, and will leave
current numbers in place this run. Beyond Wednesday, little or no
precipitation is expected through the end of the forecast period.

NBM temperatures more closely resemble the operational GFS solution
for most of the week, and would note that the ECMWF operational
numbers from the 12z Saturday run were on the cooler side of their
ensemble range.


&&

.AVIATION...
(06Z TAFS)
Issued at 1203 AM CDT Sun Aug 31 2025

Terminals were VFR at forecast issuance. May be a few MVFR
ceilings at southern terminals briefly overnight, and perhaps some
MVFR visibilities briefly at KMCB around sunrise, but most should
remain VFR. A frontal boundary was near KHUM, so if there`s a
threat of precipitation during the overnight hours, that is the
one most likely to be impacted.

As cumulus field develops at mid-morning, won`t rule out brief MVFR
ceilings, but cloud bases should lift above FL030 before 18z. The
main question during the day will be the location of the frontal
boundary. Current thinking is that it should drift a little further
southward. Will only carry a mention, PROB30, at KHUM during the
afternoon hours. The threat at the New Orleans terminals, KNEW and
KMSY, is non-zero, but not high enough to justify a mention in the
forecast.

Beyond 00z Monday, all terminals should be VFR.

&&

.MARINE...
Issued at 1203 AM CDT Sun Aug 31 2025

The main concern will be daily thunderstorm activity across the
marine areas today and early in the week, as a stalled front hangs
around the coastal waters.  Locally higher winds and waves will be
expected near any thunderstorm.

The frontal boundary will continue to nudge a bit further offshore
today. The question is whether it makes it far enough offshore today
for winds over the eastern open waters and Breton and Chandeleur
Sounds to justify Small Craft Exercise Caution headlines. At
present, we`re carrying 10 to 15 knots, but if winds become a little
stronger than expected, we`ll need to add headlines. Winds are
expected to be offshore for a couple days, then easterly at midweek.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  88  68  88  67 /  10  10  10  10
BTR  90  71  90  70 /  20  10  20  10
ASD  89  69  88  68 /  20  10  30  10
MSY  91  77  90  76 /  20  10  40  20
GPT  89  71  88  70 /  20  10  30  10
PQL  88  69  89  68 /  20  10  20  10

&&

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

$$

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