LIX issues Area Forecast Discussion (AFD) at Jan 2, 11:19 PM CST ...New AVIATION...938
FXUS64 KLIX 030519
AFDLIX
Area Forecast Discussion
National Weather Service New Orleans LA
1119 PM CST Thu Jan 2 2025
...New AVIATION...
.SHORT TERM...
(This evening through Friday night)
Issued at 225 PM CST Thu Jan 2 2025
We've got plenty of weather to discuss over the next 5-7 days,
lets start things off with what's going on outside the front door
this afternoon/evening and continue into early Saturday with the
short-range.
Another beautiful day today to start off the year. GOES-16
satellite is illustrating cloudless skies, but will continue to
see increasing clouds from the west over SE TX/ SW MS. This is in
response to isentropic lift with a weak surface low over coastal S
TX, helping to pump moisture north and ascending/spreading east
along progressive WNW/NW flow across our area. Guidance is in good
agreement that we'll see mid-level clouds at around 6-10,000ft
AGL spread east throughout the night. Now, how this impacts
temperatures may need to be watched. Current thinking is there
will likely not be enough insolation (at this level especially)
to counteract small-scale radiative cooling processes. Because of
this, did decide to go slightly lower than guidance for I-10/12
north from BTR to coastal MS north, where cloud cover percentages
will be less and did emphasize drainage ditches. It's possible we
could see a few showers/weak elevated returns on radar later
tonight for coastal areas, but with a dry tropospheric profile, it
may take more lift/evaporative cooling to get any light showers
down to the ground. Better chances for this to occur will
generally be for Gulf marine areas south of SE LA, but can't rule
out some isolated drizzle making it to parts of southern SE LA.
Not seeing strong signals in regards to fog tonight, thanks to the
increasing cloud cover and lack of decent southerly return flow.
What's left of this system departs south/east Friday as a weak,
secondary cold front swings through (with the remnant low likely
parked over the stationary front just south of our marine waters).
This will reveal clear skies once again. No modifications to highs
as we will likely top out in the upper 60's to a few isolated low
70's. Performed generally the same attention to detail for lows
Saturday morning hitting slightly colder for I-10/12 north, with
the drainage ditches emphasized given even stronger radiational
cooling at work (with no counteraction from insolation), which
does bring areas like Pascagoula into the mid 30's. Not seeing
freezing temperatures in the short-range forecast through Saturday
morning. KLG
&&
.LONG TERM...
(Saturday through Wednesday night)
Issued at 225 PM CST Thu Jan 2 2025
With the reinforcing surge of CAA/cooler air parked over the
northern Gulf, we'll see a slightly cooler day overall Saturday.
Cooler highs are additionally supported by increasing cloud cover
from the remnant low and attendant stationary boundary drifting
north. Should sunshine dominate more, highs could be too chilly so
was reluctant to make any target of opportunity here. Even in a
dry, continental airmass parked in place, this low will allow for
subtle ascent to drift over the local area that could wetbulb
enough to bring isolated to scattered showers. Coverage/timing is
best mainly southern areas in the afternoon, becoming better with
coverage into the evening and overnight hours. Not anything that
will bring widespread heavy rain, moreso isolated/scattered areas
of light rain or drizzle at times.
By Sunday, we enter into a large-scale return flow regime and
warm sector ahead of the next developing low across the central
US. Going to spend some time here, as it's our next focused
potential threatening weather system. 500mb height cluster
differences utilizing the 00Z THU guidance overall similarities in
CMC and EPS ensemble trends, with the GEFS being the outlier.
That being said, spread/differences in long-range ensemble
guidance is not that different, with all in good agreement on
trough position and amplitude. Caution is advised as we get closer
into the day 3 period on ensemble differences with deterministic
runs, as it is likely the deterministic runs identifying the
amplitude and strength of the trough transition from neutral to
negative tilt likely resulting in a strong, potentially sub-1000mb
low drifting E to perhaps even ESE across the Mid-MS valley
region. Something else to note is the eventual "opening up" of the
shortwave trough as it interacts with a subtle kicker shortwave
driving southeast over the Great Lakes, which does weaken the
trough (some) enough to become positive tilt eventually stretching
out from the central US to the mid-Atlantic. Regardless, what
does all of this mean for us? Surface reflection will take on a
strong-surface low as mentioned before, surging a cold front
quickly east. Warm sector destabilization will take shape during
the day on Saturday across the south-central US, with amplifying
LLJ dynamics and attendant downstream divergence to aid in storms
breaking out along the cold front. For us, we'll still be
welcoming scattered/isolated showers around during the day on
Sunday given strong WAA owing in enough subtle lift for these, but
likely nothing becoming more than that so displaced from greater
large-scale lift. It's later in the evening/overnight when the
cold front approaches, with a likely QLCS or strong squall line
entering our far western areas. Few things to take note of here:
1) surface low position/trajectory is a bit worrisome, with the
aforementioned transitory nature of the shortwave trough allowing
for the surface low, collocated with best downstream divergence
from the evolving trough axis to keep the surface low moving more
E to even ESE over the mid MS valley region. Meaning, LLJ dynamics
will not "quickly eject out of here" as we typically see being on
the southern fringe of greatest dynamic ascent. 850mb jet on the
order of 50-60kts will be draping the northern areas as this line
continues east, supporting the risk for organized updrafts and
producing a notable tornado risk. SPC has us in a 15% area
highlighted for now, but strongly feel this will be pulled east
and south with introductions into categorically greater risks to
come, especially for the I-10/12 corridor north. 2) While
supportive instability wanes overnight, research has shown
supportive dynamics and greater shear to still thrive in a low-
instability environment to produce a distinct tornado risk (more
so, brief/weak tornadoes but in larger quantity - common in a
strongly forced QLCS). This risk will extend east all the way to
coastal MS overnight, then quickly exit the area. More specifics
in regards to timing/threats will be forthcoming, so check back.
Say hello again to old man winter come Monday of next week!
Strong CAA will make us struggle to reach the upper 40's for
highs, with a good (but cold) northwest wind making it feel
colder. For now, minimum Apparent T's touch into the mid to upper
20's along/near and north of a line from the Atchafalaya Basin to
the I-59 corridor. Lows tap freezing for SW MS and the northern
Florida Parishes regardless of strong winds, revealing the
strength of the arctic airmass connection in place. It'll be
Tuesday and Wednesday morning when the core of the arctic air
settles in. Be advised, winds could remain elevated enough Tuesday
and Wednesday mornings to provide very cold windchills into the
teens each morning, with a high likelihood of cold weather
headlines to be issued during this time frame.
And ofcourse, what many have been talking about is what, if any,
risk of winter weather brings to the local area later next week.
We'll see our next shortwave impulse crossing the PacNW, diving
deep into the SW US, with our local area becoming more quasi-zonal
as east-coast troughing relaxes some. Going back into the Cluster
Analysis world reveals noticeably larger spread in guidance with
the CMC, EPS and GEFS solutions, namely trough strength and
amplification, which has everything to do with position and
eventual downstream reflection of a surface low. Not going to
pick/choose solutions this far out, but does require watching at
the likelihood of low-genesis in the western Gulf, aiding in
enough isentropic upglide across the southeastern US to produce
precipitation, potentially wintry depending on location. Remember,
everything is interconnected, trough position/strength will
reveal where and how strong a surface gulf low forms, and tracks,
resulting in how much precipitation overspreads a primed cold
airmass in place. Will mention, this is a pretty typical setup for
some type of winter weather in the southeast, but is very
difficult to narrow down specifics yet. Given the isentropic
upglide effect of the surface low, ice/wintry mix would likely be
associated with this system wherever temperatures match up.
Again, timing would be primarily Thursday into Thursday night but
ANY shift in low position farther south (which would likely lead
to a weaker low) would reduce QPF potential leading to a drier
forecast. A low too far north, would keep us too warm for winter
weather concerns. Any threat to the local area would need a "zone"
of best low path/position, attendant dynamic isentropic ascent
and timing with the primed cold airmass at the surface. That is
like threading a needle like a cat trying to fit through a closed
door. We will be keeping a close eye on it and expect
changes/updates as we roll along. KLG
&&
.AVIATION...
(06Z TAFS)
Issued at 1117 PM CST Thu Jan 2 2025
A mid-level cloud deck rangning between 6000 and 8000 feet will
remain over the terminals through 12 to 15z. Skies will then
clear at all of the terminals by 15z and light north-northeast
flow of around 5 knots will develop. Overall, VFR conditions will
prevail and no significant impacts to aviation operations are
anticipated.
&&
.AVIATION...
(00Z TAFS)
Issued at 514 PM CST Thu Jan 2 2025
A scattered to broken mid-level cloud deck rangning between 6000
and 8000 feet will overspread BTR, HUM, MSY, HDC, NEW, and ASD
this evening, but no impacts to aviation operations are expected
from this cloud deck. Overall, prevailing VFR conditions can be
expected at all of the terminals over the next 24 hours.
&&
.MARINE...
Issued at 225 PM CST Thu Jan 2 2025
A weak low pressure system will bring isolated showers to coastal
areas tonight into Friday, with a frontal boundary drifting
north. Shower chances increase Saturday into Sunday, with a strong
cold front and strong/severe storms expected late Sunday into
Monday. Strong onshore fetch ahead of this system Sunday will
likely bring Small Craft Advisory conditions with hazardous seas
and strong winds, followed by a stronger surge of greater winds
and attendant response in wave/seas after this front passes
early/mid-week next week, with additional headlines likely. KLG
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 40 62 36 55 / 0 0 0 10
BTR 49 69 45 62 / 10 0 0 20
ASD 45 67 39 62 / 10 0 0 10
MSY 53 66 49 63 / 10 0 0 20
GPT 44 65 38 61 / 0 0 0 0
PQL 40 68 35 63 / 0 0 0 0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
SHORT TERM...KLG
LONG TERM....KLG
AVIATION...PG
MARINE...KLG
Source:
LIX issues Area Forecast Discussion (AFD) at Jan 2, 11:19 PM CST ...New AVIATION...---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
