051
FXUS64 KLIX 161901
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
201 PM CDT Thu May 16 2024

...New AVIATION, MARINE...

.SHORT TERM...
(Today through Friday)
Issued at 336 AM CDT Thu May 16 2024

The sfc part of the old frontal boundary is stalled near the coast
this morning and drapes inland near Terrebonne Parish westward to
Beuregard Parish. This can be seen with showers developing along
this boundary while the 850mb part of this is stalled over the
central gulf and this part of the front can be easily seen over
the eastern portion of the gulf as storms fire along its boundary.
The 850mb part of this continues through the gulf and comes
ashore near Corpus Christi TX. This will be the main line to watch
later today as it gets brought back to the north and storms start
to fire along it. Rainfall rates will intensify through the day
along this boundary and should be most intense with a corridor of
heaviest rainfall from near a line from Austin to DeRidder then up
to McComb to near Hattiesburg over the next few days. Obviously,
the heavy rain will not just lie along this line but either side
of it as well. WPC has kept a portion of the area near BTR in a
moderate risk which looks warranted. This is also where the
current flood watch has been posted and this will remain for now
but may be changed a bit for Fri depending on how things unfold.
This boundary will also compartmentalize where severe storms will
form. North of this boundary should be all heavy rain but there is
the potential for large hail to the north of this boundary. The
sfc instability will be through the area this morning and sh/ts
are already forming along this sfc instability line, while the
elevated instability will start to move through by 3pm. The entire
area should be unstable throughout the column before midnight
tonight. This deep vertical instability should be evident by where
the rain and storms begin to fire later today. Even though SPC
has a marginal risk level for the area, it still warrants
attention as conditions will be conducive for severe storms, just
not to the degree that Fri is looking. The first wave moves out
Fri morning and fast on its heals will be the next disturbance
that should start developing near the Houston area Fri morning and
quickly move ENE along this same boundary entering our area
around 3pm Fri. The next system will be right behind this one.
This third one should develop somewhere between Houston and Corpus
late Fri and move ENE at a very rapid pace entering the area
around or just after midnight Fri night into Sat morning. This one
looks like the same style of systems we have been having for the
last several weeks, the wake low type scenario with a very fast
moving squall line producing severe wind speeds. We will need to
see exactly where and the time this complex forms to pin down any
discrete placement and timing locally. These Fri systems look
quite volatile and will have a lot of energy to use in the form of
almost every severe wx variable with all modes of severe
possible. Models have been ever so slightly nudging this whole
mess northward, but we are still quite confident that most of the
area will see strong chances of heavy rainfall and severe storms
at some point between today and early Saturday.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 336 AM CDT Thu May 16 2024

Even though the boundary gets left in place across the area
Saturday, the sfc low and upper troughing move east bringing the mid
and upper support with it after the third disturbance exits the
area. This will help alleviate the heavy rain and severe storm
threat for most of the weekend. High pressure builds and moves east
by the new week but ridges over the gulf coast through about mid
week. A new cold front will move to around the Ark/La line before
stalling with our area possibly staying rain free for the most of
the week.

&&

.AVIATION...
(18Z TAFS)
Issued at 103 PM CDT Thu May 16 2024

VFR this afternoon with mid level clouds from upstream convection
overspread the area. CU field eventually building from SW to NE
across the area later this afternoon and early evening as a warm
front progress northward. A complex of showers and storms
currently over C and NE TX will move in from the west this
evening as it interacts with a northward moving warm front.
Attempted to narrow the timing window of storms based on the
current observations and latest model guidance, but there is
still some uncertainty with the onset timing. There is some
indication that storms could arrive a couple of hours earlier than
what`s advertised in the 18Z TAFs (as early as 01Z for BTR/MCB,
03Z for MSY/HDC/NEW/ASD and 04Z for GPT/HUM). The latest TAFs
also show CIGs and VSBYs lowering to MVFR shortly after the onset.
Also added a 2-3 hour TEMPO IFR group late this evening and
overnight for all TAFs except HUM as confidence of storms
making it this far is lower. In reality, conditions will
deteriorate to IFR at the onset with brief/local restrictions near
LIFR in heavy downpours.

Some of the model guidance in indicating the potential for a wake
low to develop late in the day. Easterly winds would strengthen
overnight for at least 2-3 hours as a result. Forecast wind speeds
may be underdone.

A relative lull in the showers and storms are expected Friday
morning and afternoon in wake of the overnight MCS. However, it
may not be entirely convection free with a few showers and storms
lingering near MCB and GPT during the morning. Additional storms
are expected to develop during peak heating hours, especially
during the latter half of the afternoon as it will likely take
some time to recover from the earlier activity.

&&

.MARINE...
Issued at 103 PM CDT Thu May 16 2024

A warm front was located over the coastal waters of LA. A slight
wind shift from easterly to southeasterly is occurring with the
frontal passage. Wind speeds will also increase from around 10 kt
to 15 kt with occasional gusts to 20 kt. This boundary will
continue to lift northeastward through the rest of the waters
through the evening.

Storms have already developed just behind the surface boundary
across our far southwestern zones early this afternoon. Locally
strong wind gusts of 30-40 kt is possible with the strongest
convection.

Additional showers and storms are expected to move in this
evening and continue overnight. The highest coverage will be over
the lakes and MS Sound as convection becomes focused along the
warm front. Will likely need a SCA for tonight owing to the
presence of a wake low behind the storms. There is a potential for
a brief 1-3 hour period of gales depending on where the wake low
tracks and how strong it is as it approaches our area.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  65  83  67  84 /  90  70  70  50
BTR  71  89  70  89 /  80  70  60  50
ASD  71  89  70  87 /  70  60  60  70
MSY  75  89  73  87 /  60  50  70  60
GPT  71  85  70  85 /  70  50  70  70
PQL  70  87  70  85 /  70  50  60  80

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flood Watch from 7 PM CDT this evening through Saturday morning
     for LAZ034>037-039-046>048-057-058-060-064-071-076>087-089.

GM...None.
MS...Flood Watch from 7 PM CDT this evening through Saturday morning
     for MSZ068>071-077-083>088.

GM...None.
&&

$$

SHORT TERM...TE
LONG TERM....TE
AVIATION...JK
MARINE...JK