378
FXUS64 KLIX 271145
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
545 AM CST Thu Nov 27 2025

...New AVIATION...

.KEY MESSAGES...
Updated at 517 AM CST Thu Nov 27 2025

- A substantial cool down Thursday and Friday nights with
  temperatures in the 30s and 40s. A few places could briefly
  touch freezing across SW MS, and within the Pearl and Pascagoula
  River drainage areas.

- Hazardous conditions for small craft through Thursday, possibly
  through the entire weekend.

- Rain threat increases for the weekend and early next week. The
  rain could be locally heavy at times.

&&

.SHORT TERM...
(Tonight through Saturday night)
Issued at 1052 PM CST Wed Nov 26 2025

Initially, the area will remain under the influence of deep layer
northwest flow through Friday morning on the southwest periphery
of a strong longwave trough axis dominating the eastern half of
the CONUS. The core of a 925mb thermal trough axis will also be
passing through the Lower Mississippi Valley today and tomorrow,
and this will keep temperatures a good 10 degrees cooler than
average through tomorrow afternoon. Model sounding analysis
supports daytime highs only rising into the upper 50s and lower
60s today and tomorrow, and strong radiational cooling tonight
will allow overnight lows to fall into the 30s and lower 40s both
this morning and again Thursday night. The coldest night will be
Thursday night as lows fall into the low to mid 30s to the north
of the I-10/12 corridor. Temperatures are highly likely to touch
freezing in the Pearl and Pascagoula River drainages, but the
duration of the freeze will be short enough to not damage
vegetation. As a result, a freeze warning will not be necessary
for the drainages Thursday night into Friday morning. Overall,
have opted to go with NBM 50th percentile temperatures for the
overnight lows given the degree of radiational cooling expected
both this morning and again on Friday morning.

Conditions will begin to shift Friday and Saturday as the longwave
trough axis and associated thermal trough axis begins to lift out
of the region and a more zonal flow regime takes hold.
Temperatures will remain cool Friday night into Saturday morning
due to the very dry airmass in place, but the overnight lows may
occur earlier in the night as high level clouds begin to feed in
by daybreak on Saturday. In the low levels, winds will begin to
veer to a more easterly and eventually southeasterly direction on
Saturday, and temperatures will warm back to more average readings
for this time of year with highs in the upper 60s and lower 70s.
These southeasterly winds will also allow for a surge of deeper
Gulf moisture to quickly feed into the region on Saturday. PWATS
will rise from the 25th percentile in the morning to the 75th
percentile by late evening. Although a weak shortwave through
embedded within the zonal flow will pass through the region on
Saturday, moisture in the mid-levels will remain limited enough to
keep rainfall at bay. However, a northern stream shortwave trough
will merge with the southern stream energy over the Mississippi
Valley Saturday night. The combination of increasing omega and
PWATS further climbing toward the 90th percentile or around 1.25
inches will support rain development over the region. The highest
PoP values will be west of I-55 where the deeper moisture and
stronger forcing is expected. Most of the rainfall will be in the
form of showers, but a few elevated thunderstorms with bases
around 5000 feet or higher could form by late Saturday night as
mid-level lapse rates approach 6.0 C/km. The rainfall could also
turn locally heavy at times late Saturday night over the western
half of the CWA.

&&

.LONG TERM...
(Sunday through Wednesday night)
Issued at 1052 PM CST Wed Nov 26 2025

A very unsettled stretch of weather will impact the forecast area
from Sunday through Tuesday as a series of fast moving southern
stream vorticity maxima slide through the region. As the initial
system impacting the area Saturday night shifts to the east,
another weak shortwave and jet streak will slide in from the west
on Sunday. At the same time, a frontal boundary will slide further
south in response to both the passing shortwave and general
airmass density differentials. Ample deep layer forcing in the
region will tap into the extremely moist airmass as noted by
PWATS over 1.25 inches to produce fairly widespread rainfall.
This rainfall will be heavy at times, especially from any elevated
thunderstorms embedded within the broader moderate rain shield.
Given the high moisture content in place, 1 to 2 inches of
rainfall with locally higher amounts approaching 3 inches cannot
be ruled from late Saturday night through Sunday evening. This
beneficial rain will greatly help the ongoing drought conditions
in the region. With the region still experiencing an onshore wind,
temperatures will remain near average. However, highs may occur a
bit earlier in the day as the frontal boundary slowly sinks
southward and pushes offshore by the late afternoon hours.

Once we get past Sunday, the forecast confidence begins to falter
as model differences increase on the positioning of the frontal
boundary. The GFS stalls the front along the coast while the ECMWF
and Canadian models push the front past the coastal waters and
into the northern Gulf Sunday night. These differences have
resulted in a very large temperature spread of around 20 degrees
on average from Sunday night through Monday night. The main trend
that has been noticed is that the NBM has been placing more weight
toward the EURO/Canadian solution the last couple of runs. Given
this trend and the decent agreement between these two models, have
opted to lean toward a cooler solution to start off the week that
ties in more closely with the NBM 50th percentile for
temperatures. This results in overnight lows ranging from the
upper 30s in southwest Mississippi to the lower 50s along the
Louisiana coast both Sunday and Monday nights. Highs only warm
into the 50s for most locations on Monday and Tuesday.

Additionally, another fast moving southern stream vorticity max
will slide into the region on Monday. A highly difluent pattern
aloft and favorable jet positioning will provide ample lift over a
region of enhanced baroclincity in the northern Gulf. The end
result will be the development of a potent Gulf low Monday into
Tuesday that will bring widespread rainfall to the area. Additional
forcing in the mid-levels will occur as southerly flow ahead of
the system is isentropically forced over the cooler and more
stable airmass to the north of the front, and this will further
support widespread rainfall development across the entire forecast
area. PWATS are projected to surge to the daily max value of
around 1.5 inches over this period, so heavy rainfall will be a
concern Monday into Monday night. Fortunately, convection looks
to be limited as the lapse rates remain weak in the mid- levels,
but an isolated elevated thunderstorm embedded within the broader
rain shield cannot be completely ruled out.

All of the model guidance is good agreement that a northern
stream system will dive southward on Tuesday and merge with the
southern stream energy to produce another longwave trough over the
eastern CONUS. As this system develops, a stronger frontal
boundary will sweep through the region on Tuesday. Strong dry and
cold air advection will take hold and skies will rapidly clear
Tuesday afternoon and evening. Wednesday into Wednesday night will
see northwesterly flow keep skies mainly clear and temperatures
cooler than average as a dry and stable surface high builds in
from the northwest.

&&

.AVIATION...
(12Z TAFS)
Issued at 517 AM CST Thu Nov 27 2025

NE winds will be strongest on the lee side of lakes through this
taf cycle but otherwise all terminals will be VFR.

&&

.MARINE...
Issued at 1052 PM CST Wed Nov 26 2025

A cold and dry high pressure system will build over the waters
through Friday.  As this colder and drier air moves across the
warmer waters, stronger winds aloft will transport down to the
surface. As a result, an extended period of small craft advisory
conditions due to northerly winds of 20 knots or greater and
rough seas of over 7 feet will impact the waters through Friday.
Winds will relax slightly to between 15 and 20 knots and begin to
turn more southeasterly and southerly over the weekend as another
low pressure system pushes through the region. A weak front will
slide offshore and stall over the northern Gulf early next week.
As this occurs, northerly winds will develop. At the same time, a
low pressure system will strengthen over the northern Gulf Monday
night into Tuesday. This will allow the winds to increase back
into small craft advisory range as the low passes through.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  59  32  57  36 /   0   0   0   0
BTR  62  36  60  40 /   0   0   0   0
ASD  63  32  60  35 /   0   0   0   0
MSY  62  44  60  48 /   0   0   0   0
GPT  63  35  60  38 /   0   0   0   0
PQL  63  30  60  33 /   0   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Small Craft Advisory until noon CST Friday for GMZ530-532-534-
     536-538-550-552-555-557-570-572-575-577.

MS...None.
GM...Small Craft Advisory until noon CST Friday for GMZ532-534-536-
     538-550-552-555-557-570-572-575-577.

&&

$$

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