FXUS64 KLIX 111722

Area Forecast Discussion
National Weather Service New Orleans LA
1122 AM CST Mon Dec 11 2023

...New AVIATION...

(Today through Wednesday)
Issued at 225 AM CST Mon Dec 11 2023

Pressure gradient continues to breakdown from west to east across
the region this morning. Along with clear skies and calmer winds,
temperatures have dropped well into the 30s north of I10/12 with
some locations at or winding up just a tad below freezing. A
rather cool day is in store, however, with high pressure building
in over the lower MS River Valley, expect plenty of sunshine
today, so overall pleasant.

The high pressure begins to lift north and east later tonight and
into the day on Tuesday. Still with calmer winds and clear skies
temperatures will likely drop into the 30s across the northern
tier again by Tuesday morning...as always the cooler locations
look to be in the typical drainage areas around the Pascagoula
and Pearl River Basins. That said, guidance does have the surface
high pressure moving north and eastward away, which may help allow
pressure gradient to tighten once again, especially for the
southern tier or closer to the immediate coast. These areas may
see overnight lows held up just a bit, especially when compared to
Monday morning. A strong easterly fetch will begin to develop by
late Tuesday, which will help increase boundary layer moisture at
least slightly despite the somewhat unfavorable fetch. The
previous frontal boundary that recently moved through our region
in the last day or two will get stuck over the southern Gulf under
the strong surface high pressure. This will again help increase
surface winds just a bit by Wednesday. That said, the forecast
area should continue to remain dry as the remnant/passive front to
our south will be just out of reach for any type of isentropic
upglide that would be needed for the development of showers.


(Wednesday night through Sunday)
Issued at 225 AM CST Mon Dec 11 2023

The long term begins dry for the most part, but a tad on the
breezy side as pressure gradient between a strong 1040mb+ high
pressure system near the Great Lakes and lower pressures over the
Gulf tighten across the local area. The easterly fetch will bring
in some low level moisture, however, any moist return will be
slow to occur given the direction of the fetch. A passive surface
front will reside to our south over the southern Gulf Wednesday
night into Thursday. Globals show some light QPF signal across the
far Gulf waters, however, the region appears to remain dry at
least going into the start of late week with little in the way of
lift. Temperatures by this time will have started to rebound
again with a slight increase in heights and thicknesses across
the CWFA. That said, this appears to be rather modest again
without much of a return flow to speak of help really bring in the
warmer and moist conditions south of the aforementioned front.

From here things get more...we'll say interesting. Globals
generally start to diverge significantly (so from Thursday beyond
the overall forecast confidence is VERY LOW). The synoptic pattern
starts off in decent agreement we'll say, but the evolution of the
pattern leaves much to be questioned. First, the GFS has an
inverted surface trough sharpen over the Gulf. This feature
begins to lift northward on Thursday and eventually closes off a
surface low late Thursday and into Friday. The ECM shows a weak
surface trough at the same time, but appears to be lagging
slightly. Eyes then focus up stream over the Texas high plains as
surface cyclogenesis takes shape and continues to move south and
eastward toward the northwest Gulf by this weekend. Both GFS and
ECM depict this feature "somewhat" well. However, the ECM doesn't
really develop an initial low in the Gulf instead holds on to a
surface trough or the old frontal boundary through this
timeframe. The GFS takes the initial low and pushes it eastward
over the Florida Peninsula and tends to be a bit more on the
progressive side with the pattern.

As the system over Texas moves into the Gulf, the GFS indicates
that the parent trough will help push the earlier low downstream
generally north and east along the east coast helping strengthen
this system over the Gulf Stream as it lifts quickly north and
east away from our CWFA. However, the ECMWF doesn't agree. In
fact, the ECM actually further develops the surface feature over
the northern and central Gulf and beyond holds the low over the
gulf through the end of the period. The concern here is of course
with a slower moving system more opportunity for rainfall...which
of course is shown in the ECM. However, the GFS is quite a bit
drier with most of the precipitation remaining offshore and the
fact that the solution there is a bit faster. The CMC tends to
take a more middle of the two route adding very little in terms of
helping add long range confidence. EPS and GEFS respectively show
a deepening surface low move across florida, but once again the
respective ensemble means follow the parental deterministic
guidance fairly closely. So, all that said, the bottom line again
is low confidence. We do have POPs respectively for the best
overlap and since the region should remain mostly in the cool
sector think thunder probs will be a bit lower, unless the front
across the Gulf finds its ways closer to our area prior to the
eventual evolution of the system(s). Otherwise, regardless of the
solution, breezy to windy conditions will be possible along with
perhaps coastal flooding concerns, especially if the ECMWF
materializes over the GFS. However, at this juncture it would be
tough to even speculate specifics with such variations in the
solutions in both globals and their ensembles. (Frye)


(18Z TAFS)
Issued at 1121 AM CST Mon Dec 11 2023

A broad surface high centered over the Lower Mississippi Valley
will keep skies clear and VFR conditions in place at all of the
terminals through tomorrow afternoon. Winds will be light from the
north and northeast through the period. PG


(06Z TAFS)
Issued at 1118 PM CST Sun Dec 10 2023

As high pressure settles into the area, very light to calm winds
are expected to prevail through the period with no significant
cloud cover. The only real exception is KNEW where winds will be a
little stronger (but still generally 10 kts or less) due to
proximity to the lake. (DM)


Issued at 225 AM CST Mon Dec 11 2023

Winds and seas will continue to decrease through the morning and
into the afternoon hours as pressure gradient begins to relax
across the local waters. Moderate winds and seas can be
anticipated early this week, however, the break from hazardous
marine conditions will be short-lived as easterly flow strengthens
over the local waters by midweek. From this point on, a
potentially prolonged period of hazardous to even dangerous marine
conditions is forecast from midweek through the next weekend.
Small Craft Advisories are expected and gale products are becoming
increasingly likely, especially over the open waters late week
and into this weekend as the easterly flow around a strong high
pressure centered to our northeast remains strong. (Frye)


MCB  57  33  60  36 /   0   0   0   0
BTR  61  37  64  40 /   0   0   0   0
ASD  59  36  62  39 /   0   0   0   0
MSY  57  45  60  47 /   0   0   0   0
GPT  58  38  60  41 /   0   0   0   0
PQL  59  34  63  38 /   0   0   0   0