894
FXUS64 KLIX 092027
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
327 PM CDT Sun Mar 9 2025

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

.SHORT TERM...
(This evening through Tuesday night)
Issued at 242 PM CDT Sun Mar 9 2025

A broad positively tilted trough axis and an attendant surface low
and cold front will continue to push east across the forecast
area through the overnight hours. Although moisture is rather
limited above 850mb per the 12z sounding, there is enough moisture
beneath an elevated temperature inversion to keep lingering low
stratus in place through the overnight hours. Several of the high
resolution short term models are also indicating that some
isolated shower activity will develop across portions of coastal
and southwest Mississippi late this afternoon into early this
evening. These showers will develop beneath a region of broad and
weak upper level forcing associated with a difluent flow pattern
aloft. As this difluent flow regime pushes further to the east
in the late evening and overnight hours, any rain chances will
quickly drop to zero. Weak cold air advection will also occur
after the front and trough axis push to the east and overnight
lows should fall closer to average in the upper 40s and lower 50s.

The rest of the short term period will be very benign as a deep
layer ridge axis builds over the area and lingers into Tuesday
night. Strong subsidence throughout the atmospheric column will
keep skies clear and also allow for a quick warm up. Temperatures
will be near average tomorrow as the lingering effects of a 925mb
thermal trough axis continue to be felt and the dry air will
combine with clear skies to push overnight lows Monday night below
average by a few degrees. As the thermal trough moves to the
east, temperatures will continue to warm on Tuesday with readings
easily climbing into the mid 70s and even into the upper 70s in a
few locations.

&&

.LONG TERM...
(Wednesday through Saturday night)
Issued at 242 PM CDT Sun Mar 9 2025

Wednesday into Wednesday night will see a fast moving upper level
low pass through the Lower Mississippi Valley, but a lack of
sufficient moisture will greatly limit rain chances with this
system. At most, a few showers could develop over the northern
portion of the forecast area for a few hours. Weak lapse rates
aloft will keep instability at a minimum, so thunderstorm activity
is not anticipated as this fast moving feature moves through. No
real surface reflection of this system is also expected, so
temperatures will continue to warm as a largely zonal regime
dominates aloft. Highs will climb into the upper 70s Wednesday
afternoon, and this may be conservative as ensemble spreads show
some potential for even warmer readings in the lower 80s. By
Thursday, another shortwave ridge and the associated subsidence
with it will help highs easily climb into the low to mid 80s
across the area. Only the Mississippi Coast will stay in the 70s
as a seabreeze modifies temperatures.  Southerly flow in the low
levels will also push Gulf moisture into the area, and these
rising dewpoints will limit overnight cooling. Lows will only fall
into the upper 50s and lower 60s both Wednesday and Thursday
night. Advection fog should be a concern both nights over portions
of the area. Further refinement of this fog threat will occur in
the following days.

Friday will be a transitional day as the deep layer ridge axis
shifts to the east in response to a strong shortwave trough
ejecting out of the Four Corners and into the Plains states. The
model guidance is in good agreement on the timing and depth of the
system, and it looks like the greatest threat for any severe
storms will be displaced well to the north of the forecast area.
The biggest impact from this system on Friday will be gusty
southerly winds developing as the pressure gradient tightens.
Temperatures will also remain very mild with highs easily climbing
back into the low to mid 80s away from the coast and the mid to
upper 70s along the coast. These breezy conditions will continue
into Friday night and this should limit fog development. However,
overcast skies are expected to develop as stratus forms offshore
and moves inland. Lows will remain mild with readings only falling
into the 60s.

Saturday is the most concerning day of the entire forecast. All of
the medium range guidance is in decent agreement on the timing and
placement of this system, and this leads to a higher confidence
forecast than would typically be seen 7 days out. Although it is
very far out, current indications are that a significant severe
weather episode will impact much of the Gulf South including the
forecast area on Saturday. A review of model sounding data from
the GFS and ECMWF indicate that ample instability and shear will
be in place as a strong low level jet forms over the area. Given
the orientation of the trough ejecting out of Texas, forcing
should also not be a concern and deep, long-lasting updrafts are
expected with any convection that develops. Speed and directional
shear values are extremely high and instability values are on the
moderate side. These values also support the development of long-
lasting updrafts and severe thunderstorm activity. At this point
in time, all convective impacts are on the table (hail, damaging
winds, tornadoes), but this is a day 7 forecast and parameters
could change dramatically over the coming days. We will keep you
apprised of the latest forecast changes as we move through the
week.

 &&

.AVIATION...
(18Z TAFS)
Issued at 242 PM CDT Sun Mar 9 2025

A low level thermal trough moving through the area will continue
to keep low stratus in place at all of the terminals through
around 12z tomorrow. Ceilings will range from 1000 to 2000 feet at
nearly all of the terminals through this period, but MCB and GPT
are expected to see ceilings fall into IFR range around 800 feet
for several hours tonight. The peak time for IFR conditions at
these terminals is between 02z and 08z and is related to a low
probability of light rain development over the same time period.
The rain threat is too low to include in the forecast and no
visibility impacts are expected. After 12z, a surge of drier air
will advect into the area and clouds will rapidly lift into VFR
range at all of the terminals. Winds will also be gusty tonight
from the northwest at MSY and NEW with gusts of up to 25 knots
expected as colder air moves over the warmer lake waters. PG

&&

.MARINE...
Issued at 242 PM CDT Sun Mar 9 2025

Cold air advection behind a passing cold front tonight into
tomorrow will push winds into small craft range of 20 to 25 knots.
Seas will also be rough with offshore seas of 5 to 8 feet
expected. Given these conditions, a small craft advisory is in
effect through tomorrow morning for all of the waters. High
pressure will quickly build in tomorrow night and Tuesday and this
will allow winds to fall back below 10 knots and seas to drop
below 3 feet by Tuesday morning. These benign conditions will
persist through Wednesday morning as high pressure passes directly
over the region. A series of fast moving low pressure systems
passing north of the area on Wednesday and again on Friday will
increase the pressure gradient over the waters. The result will be
increasing southerly winds that will eventually climb into small
craft advisory range on Friday. The southerly flow could also
support some fog development over the waters on Wednesday and
Thursday nights.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  46  69  42  75 /  20   0   0   0
BTR  47  69  44  75 /   0   0   0   0
ASD  49  70  43  73 /  10   0   0   0
MSY  50  69  49  73 /   0   0   0   0
GPT  50  70  46  70 /  20   0   0   0
PQL  51  70  42  71 /  30   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Small Craft Advisory from 6 PM this evening to noon CDT Monday
     for GMZ530-532-534-536-538-555-557-575-577.

     Small Craft Advisory until noon CDT Monday for GMZ550-552-570-
     572.

MS...None.
GM...Small Craft Advisory from 6 PM this evening to noon CDT Monday
     for GMZ532-534-536-538-555-557-575-577.

     Small Craft Advisory until noon CDT Monday for GMZ552-570-572.

&&

$$

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