Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

Home |  Current Version |  Previous Version |  Text Only |  Print | Product List |  Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
773
FXUS64 KLIX 181147
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
647 AM CDT Sat Oct 18 2025

...New AVIATION...

.UPDATE...
Issued at 638 AM CDT Sat Oct 18 2025

A moisture convergence band has induced some light to moderate
rain shower activity in a north-south orientation stretching from
the Pearl River drainage southward across eastern portions of
metro New Orleans and into coastal Louisiana over the past hour.
These showers will persist for a few more hours before dissipating
as convergent band weakens. Pop, weather, and QPF forecast has
been adjusted through mid-morning to reflect the ongoing
conditions.

&&

.SHORT TERM...
(Today through Sunday)
Issued at 638 AM CDT Sat Oct 18 2025

Upper ridging centered over the Appalachians with an upper trough
from Ontario Canada to the Four Corners region. At the surface, low
pressure over western Ontario had a frontal boundary southward to
the Kansas-Oklahoma border, then southward into west Texas. Onshore
flow during the day definitely added moisture to the airmass with
evening surface dew points mainly in the upper 60s to around 70,
about 5 degrees higher than the same time Thursday evening.
Precipitable water values jumped from about 0.9 inches Thursday
evening to about 1.35 inches 24 hours later.

The upper trough over the Rockies during the evening will move
eastward over the next 48 hours, crossing the local area between
midnight and sunrise Sunday, with the frontal boundary moving across
the area prior to sunrise Sunday as well. The low level onshore flow
will continue to pump moisture into the area, especially during the
afternoon hours, with precipitable water values approaching 2
inches, which would be somewhere around the 95th percentile
climatologically. Airmass will become unstable, but not exceedingly
so, with lifted indices in the -3 to -5 range and mid level lapse
rates in the 6 to 6.5 range. The 0 to 1 km and 0 to 2 km SRH values
are expected to be around 200. While none of these are extreme
values, they also are worthy of at least monitoring the situation.
The primary threat would likely be damaging winds, but considering
the low level helicity values, a few tornadoes certainly can`t be
ruled out.

Wouldn`t be surprised if there is a little patchy fog this morning,
but it should burn off pretty quickly, especially once winds pick up
a little. Isolated convection could occur as early as late
afternoon, but the main line of thunderstorms may not move into our
CWA from the northwest until right around midnight, give or take an
hour or two. Current indications are that most or all precipitation
will be east of the area by sunrise Sunday. With the extremely
progressive trends in the guidance, this doesn`t look to be a major
rain producer on the large scale, with areas seeing less than an
inch, possibly much less.

Skies should clear pretty quickly Sunday with rapid drying expected.
Dew points that will be in the 65 to 70 degree range just ahead of
the cold front will likely be in the mid 40s to mid 50s Sunday
evening. Precipitable water values will similarly fall from around
the 90th to 95th percentile to the 10th or lower (0.4 to 0.5 inches).

High temperatures are likely to be in the mid and upper 80s both
days, but Sunday could actually turn out the warmer of the two,
although with much less humidity, for areas from about the Pearl
River Basin eastward. Quite frequently, behind a cold front with
northwest or north winds, those areas tend to heat up a bit more due
to weak compressional heating. Wouldn`t be a total shock if
somewhere between Hammond and Pascagoula touches 90 Sunday
afternoon.

&&

.LONG TERM...
(Sunday night through Friday)
Issued at 638 AM CDT Sat Oct 18 2025

Cooling behind the frontal passage will be very noticeable. Low
temperatures Monday morning are likely to be 15 to 20 degrees cooler
than Sunday morning. Highs Monday will struggle to reach 80 degrees,
which is actually pretty close to normal. We`ll need to keep an eye
on dew points Monday afternoon, as they could drag minimum RH values
fairly close to critical levels across the north half of the area
(<30 percent). As a shortwave moves through the middle Mississippi
River Valley Tuesday, it will bring a reinforcing cold front across
the area, but might not produce more than a few sprinkles of rain.
High pressure behind that front should keep the remainder of the
workweek dry. Highs are likely to be in the upper 70s to mid 80s for
much of next week with lows primarily in the 50s, although Thursday
morning could see lows in the 40s in normally cooler areas. As a
comparison, normal highs for next week should be in the upper 70s
with lows in the 50s.

&&

.AVIATION...
(12Z TAFS)
Issued at 638 AM CDT Sat Oct 18 2025

Brief periods of rain associated with a moisture convergence band
will impact ASD, NEW, MSY through 14z. The rain is light, so no
significant visibility concerns are expected. The convergence band
will weaken after 14z, and prevailing VFR conditions will take
hold at all of the terminals. After 19z, scattered storms will
start to develop near HUM and BTR, and a threat of MVFR
conditions as these showers move through is reflected with PROB 30
wording from 19z to 01z. The convective activity will spread to
the rest of the terminals after 01z with occasional MVFR ceilings
and visibilities reflected by PROB30 wording. After 06z, a
stronger line of thunderstorms in advance of a passing front will
impact most of the terminals with gusty winds and IFR
visibilities. The line of storms should clear GPT by the end of
the forecast period. MCB, BTR, HDC, ASD, GPT, and NEW are most
likely to affected by the line based on the latest high resolution
model solutions. Given this, MSY and HUM only have a mention of
rain over this period. After the line of storms and associated
front moves through the terminals, a period of post-frontal IFR
stratus will linger at all of the terminals for a few hours. PG

&&

.MARINE...
Issued at 638 AM CDT Sat Oct 18 2025

High pressure has moved east of the area, and winds are now
southeasterly. Winds will remain not much more than 15 knots ahead
of a cold front that is expected to move through the coastal waters
by midday Sunday. May eventually need a Small Craft Exercise Caution
headline for tomorrow night for some of the open waters, but won`t
go with one this package. After the front moves through, winds will
shift to the northwest, but choppy conditions will persist. Winds
and waves should subside on Monday as high pressure moves in.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  85  66  76  47 /  40  70   0   0
BTR  87  69  80  48 /  50  60   0   0
ASD  84  67  82  48 /  20  70  10   0
MSY  87  71  85  59 /  30  70   0   0
GPT  84  70  83  54 /  10  80  50   0
PQL  85  68  85  48 /  20  80  70   0

&&

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

$$

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