271 
FXUS64 KLIX 102348
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
648 PM CDT Tue Oct 10 2023

...New AVIATION...

.SHORT TERM...
(This evening through Friday night) 
Issued at 442 PM CDT Tue Oct 10 2023

High clouds streaming in all day lead to a mostly cloudy day. 
Temperatures struggled to get into the 80s for much of the area. 
Main focus of the forecast is in the next 48 hours and really 
hours 12 to 36. 

Tonight will be quiet but shortly after sunrise tomorrow things 
should quickly start to deteriorate across the coastal waters and 
rain will begin to move in from the Gulf but how much rain is a big 
question mark. Around midday winds will likely begin to increase 
quickly over land areas especially along the coast. Tides will then 
respond during the afternoon and remain high through the night. 

This will be all from a sfc low that will traverse the north-central 
Gulf tomorrow and into the northeastern Gulf by Thursday morning. 
The remnants of Max has helped to get things going with the sfc low 
still currently in the southwestern Gulf but it will be the energy 
from Lidia that finally starts to kick this low off to the 
northeast early tomorrow morning. The sfc low will continue to 
deepen thanks to its locations with the subtropical jet which will 
provide optimal divergence aloft. The sfc low will follow a weak 
warm front that will move towards the northeast Gulf tomorrow night 
and this track will keep it offshore just off our coast. With that 
we will see no instability and remain in the so called cool sector. 
That will mean any rain we see will be shower and not anticipating 
any thunder over the land areas. That said very deep moisture will 
be pushing into the area and it still looks like the southeast half 
of the CWA will see Pws of 2-2.25". This is well above the 90th 
percentile but the problem could be how much convection occurs 
across the Gulf. It is highly anticipated that a lot convection will 
occur in our coastal waters and into the Gulf and this will likely 
cut off a good portion of the area from the deeper moisture. 

Impacts:

Tides - Luckily we will not have a prolonged period of onshore flow 
that will cause the water to build and pile up along the coast. This 
will be a rather quick hitter and strong onshore flow likely will 
only occur for about 18 to maybe 24 hours and even then these winds 
will be backing during those final 12 hours becoming easterly by 12z 
and then ENE by 18z. Winds will then continue to back around to the 
northeast during the late afternoon and through the evening along 
with increasing significantly from 18z till 00z. Other positive 
aspect helping to keep tides from getting worse is we are once again 
moving towards neap tide which is Thursday and Friday. Tidal ranges 
are by far the smallest during this time and that is working to help 
keep the peak from this event worse. Given the strength of the winds 
and perfect direction down Lake Borgne locations in St Bernard near 
Shell Beach and along the east facing shores of St Bernard and 
Plaquemines will likely see the greatest impact from tides where 
tidal inundation of 1.5 to 3' is expected. The other area of 
greatest concern will be locations outside of the levees around the 
south shore of Lake Pontchartrain. Again the winds will have an 
almost optimum trajectory to push water into the Lake and then to 
the southwest. In these areas 1-2.5' of inundation will be possible. 
On the north side of the Lake there may initially be some coastal 
flooding but once the stronger northeast winds get going late 
afternoon/early evening these locations should quickly improve. Only 
other spot with warnings is the Rigolets and Hancock county. 
Waveland always tends to overachieve and should still see 1.5-2' of 
inundation which is right at the point of adv/warning. Tides will 
slowly back off through the morning hours Thursday as winds quickly 
subside. Coastal Flood warning for much of the tidal lakes, Hancock 
county, and east facing shores of Plaquemines and St Bernard. 
Coastal flood advisory on the north-central and northwest side of 
Lake Pontchartrain. 

Winds - a pressure gradient of 4 to 5 mb across just the 
southeastern half of the CWA is already leading to extremely 
hazardous winds and seas across the coastal waters but this will 
also lead to a rather windy day and evening across much of the area. 
Luckily the strongest winds will be out of the northeast so for much 
of the area winds will be coming from and over the land but easterly 
to ene winds around midday and early afternoon will still cause 
windy conditions across coastal MS. During the afternoon and evening 
hours as the pressure gradient tightens and winds continue to back 
to the northeast very strong winds will then come across southeast 
LA and these winds will come off the Lake and the Gulf. With that 
locations around the New Orleans metro and across St Bernard and 
Plaquemines will see sustained winds of 20 to 30 mph at times with 
gusts likely approaching 45 mph at times. Shell Beach and Lakefront 
both wouldn't be a surprise if they touched 50 mph. Biggest concern 
though is that the strongest winds could occur around evening rush 
hour. It looks like the worst may be between 23z and 3z so it would 
catch the back end of rush hour traffic and with all of the elevated 
roads and high bridges in the area crosswinds will be hazardous for 
high profile vehicles. Coastal MS and southeast of a line from 
LaPlace to Houma has a wind advisory out.

Rain - This is the least likely of the concerns to cause any major 
impacts. WPC did remove the Slight Risk out of all of our area with 
the exception of the mouth of the River, which is basically water 
anyway. The track of the sfc low and the nature of the setup will 
keep the majority of the rain to the north and east of the center of 
the sfc low. This will allow some rain to move in across the CWA 
maybe as early as tomorrow morning but that will push off to the 
east and the heavier rain will remain confined to the coast and 
likely the Gulf. There is one small aspect that keeps popping up on 
many of the models and that is possible band of light to moderate 
rain that appears to be associated with a deformation axis. That 
said even if this did develop at the best we would see moderate rain 
with that feature and that will be welcomed if it happens. In all 
most people will probably be quite upset with the lack of rainfall 
they get. STill looking at widespread 0.5 to 2 inches over much of 
the area but there could be some areas that see even less rain while 
the immediate SELA coast could see near 3". The other aspect for 
rain not being as much a concern will be the sfc low quickly exiting 
the area.

Our sfc low will quickly will be push off to the ENE and winds and 
rain will slack off considerably by sunrise if not early on 
Thursday. That said we may see more light rain return Thursday 
evening and into Friday as the remnants of Lidia try to move through. 
However we will likely be cleaned out for the most part and no real 
time to recover prior to it so not anticipating much outside of 
light rain and cloud cover. 

Friday should be quiet before the next cold front moves into the 
region this weekend. /CAB/

&&

.LONG TERM...
(Saturday through Monday night) 
Issued at 442 PM CDT Tue Oct 10 2023

The long term forecast is still looking to be on track as an 
upper level trough slides across the central U.S. This transitions
upper level flow to zonal through Friday and Saturday, before it 
switches again, to northwesterly, following the trough moving off 
to the east and a ridge building to the west. At the surface a 
cold front will sweep through our area late Friday and into 
Saturday, bringing a drier and cooler air mass with it. Some 
offshore showers will remain possible late Friday night into early
Saturday morning as a frontal boundary hangs around the area. 
Beyond this, PoPs are at or near zero through the remainder of the
forecast period.

Following the cold front, it will be fairly windy late Saturday and 
throughout Sunday. Temperatures overnight Saturday will fall into 
the 50s and Sunday night some northern areas will even fall to the 
40s. High temps will sit in the 70s each day through mid week 
starting Sunday. /HL/

&&

.AVIATION...
(00Z TAFS)
Issued at 626 PM CDT Tue Oct 10 2023

Currently VFR conditions, and that should remain the case for
about the next 9-12 hours. Already seeing some radar echoes to the
south and southwest at about FL100-FL150, which goes along with
some of the surface obs we've seen out that way. Expect a gradual
lowering of ceilings overnight, and perhaps some -RA/-SHRA by
sunrise. MVFR flight restrictions should be necessary by mid
morning, especially at the southern terminals of KHUM/KNEW/KMSY.
At least some possibility of IFR ceilings during the afternoon
hours. Expect at least some improvement during Wednesday evening
as the main portion of the system pulls away to the northeast, but
widespread improvement to VFR ceilings may not occur until mid-
morning Thursday. Forecast soundings do not indicate that 
significant instability is available during this event, and TSRA 
has not been included in any of the terminal forecasts. 

Winds will also be an issue from mid morning Wednesday through 
the evening hours with wind gusts out of the northeast, 
potentially gusting to 25 to 35 knots, with the higher speeds 
primarily at KNEW and KMSY. This has the potential to pose some 
crosswind issues, possibly on both east- west and north-south 
oriented runway configurations. Winds should begin to diminish 
from west to east by mid to late evening Wednesday. 

&&

.MARINE...
Issued at 442 PM CDT Tue Oct 10 2023

Quiet for now but conditions will quickly go down hill overnight 
and especially through the day tomorrow. A sfc low will traverse 
across the coastal waters while slightly deepening. This will ramp
the winds up approaching 30-35kts sustained tomorrow afternoon 
and evening with gusts approaching 45-50kts. With that the gale 
Watch was upgraded to a warning earlier today but there is a small
chance that Storm conditions could develop on the backside of the
low as it moves towards the northeastern Gulf. Seas of 10 to as 
high as 14 ft can be expected with locally higher seas possible. 
As strong as the winds will be they should quickly back off during
the early morning hours Thursday. Much lighter winds will be back
in place Thursday afternoon through Friday but we could see winds
pick back up as a cold front approaches Saturday. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  60  70  56  81 /  30  60  30  20 
BTR  63  71  59  83 /  40  70  20  20 
ASD  62  73  58  79 /  20  90  50  30 
MSY  68  74  64  78 /  30  90  50  20 
GPT  65  74  59  79 /  20  90  60  30 
PQL  62  76  58  79 /  20  90  60  30 

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Wind Advisory from 1 PM Wednesday to 6 AM CDT Thursday for 
     LAZ058>060-064>070-076>078-087>090.

     Coastal Flood Warning from 7 PM Wednesday to 4 PM CDT Thursday 
     for LAZ058-060-069-070-076>078-087.

     Coastal Flood Advisory from 7 PM Wednesday to 4 PM CDT Thursday 
     for LAZ080-082-084.

GM...Gale Warning from 10 AM Wednesday to 6 AM CDT Thursday for 
     GMZ530-532-534-536-538-550-552-555-557-570-572-575-577.

MS...Wind Advisory from 1 PM Wednesday to 6 AM CDT Thursday for 
     MSZ086>088.

     Coastal Flood Warning from 7 PM Wednesday to 4 PM CDT Thursday 
     for MSZ086.

GM...Gale Warning from 10 AM Wednesday to 6 AM CDT Thursday for 
     GMZ532-534-536-538-550-552-555-557-570-572-575-577.

&&

$$

SHORT TERM...CAB
LONG TERM....HL
AVIATION...RW
MARINE...CAB