623
FXUS64 KLIX 040543
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1143 PM CST Wed Dec 3 2025

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

.KEY MESSAGES...
Updated at 1036 PM CST Wed Dec 3 2025

1. An area of low pressure near the coast will bring widespread rain
and embedded thunderstorms to the area Thursday morning through
Saturday morning. 3-day rainfall totals will generally be 1.5" to 3"
along the I-10/12 corridor with locally higher amounts as high as 6"
especially west of I-55.

2. There is a marginal threat of excessive rainfall with this system
particularly on Thursday where locally higher rain totals of 2" to
4" in a approximately 6 hour period could result in flash flooding
of urban and poor drainage areas. Locally higher amounts upwards of
5" cannot be ruled out. Exact location of heaviest rainfall axis
will be tied to the progress of the surface low and associated
convection, but the Baton Rouge metro area appears to be the primary
area of concern as it pertains to flooding of urban and poor
drainage areas with this rainfall.

3. The slow-moving frontal boundary associated with this low will
clear land areas Thursday night. Drier air filtering in will lower
rainfall rates and reduce the risk for excessive rainfall and flash
flooding. Additional rainfall of up to 3" could occur mainly along
and east of the I-55 corridor. However, most areas are likely (>50%)
to see between 0.5" and 1.5" with scattered shower activity Friday
through Saturday.

&&

.SHORT TERM...
(Tonight through Saturday)
Issued at 1036 PM CST Wed Dec 3 2025

Warm front convection in association with a trough of low pressure
near Corpus Christ, TX (as of 0300 UTC) has created a large area of
showers and storms across SW LA and Vermillion Bay. Stratiform from
this deepening convection continues to spread northeast and light
rain will begin across western areas within the next couple of
hours. Dew point temperatures remain in the 40s across most of the
CWA, but the atmosphere is expected to moisten rapidly as the warm
front encroaches on the LA coast early Thursday. The discrepancy in
moistening between LIX (PWAT 0.81") and LCH (PWAT 1.45") 00 UTC
soundings illustrates where each location was in this moistening
process earlier tonight. Dew points will rise into the 50s to low
60s on the immediate coast and PWAT values will exceed the 90th
percentile (1.52") and may approach daily maximum (1.92") as dry
layers aloft mix out and yield a much more conducive environment for
efficient rainfall rates exceeding 2" per hour.

Latest CAM guidance has overall trended faster with onset of
rainfall, but remains in some disagreement regarding where the axis
of heaviest rainfall will occur. HREF guidance is heavily skewed
toward the aggressive NAM 3KM solution of a heavy band of rainfall
stretching from Lake Charles through Donaldsonville later this
morning while other guidance such as the RAP and HRRR suggest that
heavier rainfall could be in the form of a band north of Baton Rouge
and one closer to the Louisiana coast in association with the
surface convergence of the surface trough. The latest forecast
attempts to blend these solutions and focuses on heaviest rainfall
occurring along the I-10/12 corridor in Louisiana on Thursday though
additional revisions could be made as the event gets going later
this morning. Gist is locally heavier rainfall with this convection
could cause flash flooding of urban and poor drainage areas.

The surface trough will continue to push eastward across the coastal
waters during the day Thursday and gradually take away additional
surface forcing needed to sustain new convective development.
Additionally, slightly drier air aloft will bring PWATs down closer
to the 90th percentile and yield less efficient rainfall rates. This
should gradually reduce the excessive rainfall risk from west to
east across the area on Thursday evening into Friday morning. While
the surface forcing mechanism will scoot off to the east, forcing
aloft associated with persistent southwesterly flow of the longwave
trough over the central CONUS will continue to provide enough lift
to squeeze out showers and a couple of elevated storms on Friday
into Saturday.

&&

.LONG TERM...
(Saturday night through Wednesday night)
Issued at 1036 PM CST Wed Dec 3 2025

The fire hose of rainfall will gradually taper off into Saturday
night as a final shortwave trough lifts out with the broader
longwave trough into the eastern CONUS and mid-upper flow pivots
from southwest to northwest. This will allow for a more proper
frontal passage on Sunday night and bring colder temperatures
surface high pressure back across the area to start next week.

Model uncertainty remains regarding the next shot of cold air
early next week, but the average forecast calls for temperatures
near freezing for SW MS at this time. Additional attention will be
brought to this if confidence increases in freezing conditions
across more of the area in future forecast packages.

&&

.AVIATION...
(06Z TAFS)
Issued at 1036 PM CST Wed Dec 3 2025

-SHRA beginning to spread from west to east across terminals with
 VFR VIS/CIGs still prevailing for now. Winds remain light out of
 the east, but will intensify at MSY/NEW namely with wind off the
 lake with gusts upwards of 15 to 20 knots at times during the day
 Thursday. Widespread MVFR-IFR ceilings across all terminals
 starting roughly around 0900-1200 UTC Thursday and last through
 most of the day, potentially through the end of the forecast
 cycle. An area of low pressure will move across the northern Gulf
 Coast bringing periods of light to moderate rainfall from 10z
 through the end of this forecast cycle. There may be a few
 periods of heavier precipitation and reduced VIS/CIGs in which
 TSRA conditions are present. Highest chance of that occurring
 will be at BTR, MSY, HUM, and NEW. -SHRA will prevail through the
 end of the period and additional rounds of light to moderate
 rain will continue into Friday.

&&

.MARINE...
Issued at 1036 PM CST Wed Dec 3 2025

A weak area of low pressure will gradually drift east across the
Louisiana Coast on Thursday. This will tighten the pressure gradient
especially east of the Mississippi River delta. Winds will increase
with moderate to strong east-southeast to easterly winds. This will
have multiple impacts with Small Craft Advisory conditions expected
Thursday into Friday. Winds will relax and return to offshore late
Friday and then more variable on Saturday with the passage of
another weak sfc low. A frontal passage on Sunday night will bring
another push of strong offshore winds on Monday which could prompt
small craft headlines for much of the coastal waters.

In addition to the small craft impacts, the increase in onshore
winds will combine with the increasing tidal cycle at the end of
the week and lead to some minor coastal flooding. Main concern
will be east facing shores of Orleans, St Bernard, Plaquemines,
and far southeastern St Tammany. In addition coastal Hancock
around Waveland will also deal with some minor coastal flooding
Thursday night through Friday morning. The tide cycle will remain
elevated into the weekend and additional minor coastal flooding
cannot be ruled out. Additional headlines may be needed if the
forecast high tide increases any further above 1 foot MHHW.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  55  42  49  44 /   0  90 100 100
BTR  59  46  55  47 /   0  90 100  90
ASD  58  43  57  47 /   0  80  90  90
MSY  60  51  62  53 /   0  80  90  90
GPT  57  45  57  49 /   0  60  90  90
PQL  57  41  56  47 /   0  50  90  90

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Coastal Flood Advisory from 6 PM Thursday to 6 AM CST Friday for
     LAZ070-076-078.

GM...Small Craft Advisory from 6 AM Thursday to 6 AM CST Friday for
     GMZ530-532-534-536-538-555-557-577.

MS...Coastal Flood Advisory from 6 PM Thursday to 6 AM CST Friday for
     MSZ086-087.

GM...Small Craft Advisory from 6 AM Thursday to 6 AM CST Friday for
     GMZ532-534-536-538-555-557-577.

&&

$$

SHORT TERM...TJS
LONG TERM....TJS
AVIATION...TJS
MARINE...TJS