935
FXUS64 KLIX 140533
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1233 AM CDT Tue May 14 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 1224 AM CDT Tue May 14 2024

Convection slowly winding down, and remaining portions of the
Flood Watch will likely be cancelled with the 4 AM CDT forecast
package, if not sooner.

&&

.UPDATE...
Issued at 534 PM CDT Mon May 13 2024

Developing squall line over southwest LA has already had a
history of producing a few tornadoes and widespread wind damage.
This line is expected to accelerate some moving into the CWA
between 6 and 7 and then across most of the area before midnight.
It will also likely remain severe and thus SPC has issued Severe
Thunderstorm Watch 239 until midnight tonight for the entire area.
Main concern is damaging winds possibly greater than hurricane
force force along with large hail and even a few tornadoes. /CAB/

&&

.SHORT TERM...
(This evening through Tuesday night)
Issued at 342 PM CDT Mon May 13 2024

Key Messages:
1. A flood watch remains in effect for areas along and south of
the I-10/12 corridor due to the threat for heavy rainfall that
could result in localized flash flooding primarily in urban and
poor drainage areas.

2. An enhanced risk for severe weather remains primarily along and
south of the I-10/12 corridor for the threat of a secondary round
of storms moving into the area this evening with damaging winds
and hail being the primary threat, but a tornado cannot be ruled
out.

The morning convection has surged southeast into the coastal
waters putting down a decent cold pool that has moderated
temperatures and stabilized the air mass overhead for now. SPC
mesoanalysis and LCH 18z special sounding have indicated that
ample instability (CAPE >5000 j/kg and ML lapse rates >7.5 C/km)
and sufficient 0-6km bulk shear (~45-50kt) lay just to our
southwest which has initiated the second round of deep convection
over coastal Texas. This second round is anticipated to continue
to deepen and organized as it traverses southwest LA and surges
east into our area. Timing of this MCS has sped up to the earliest
arrival into the Atchafalaya Basin to be by 6-7PM CDT. Given the
strength of the developing cold pool with this MCS, 12z HREF
guidance, and latest CAMs the expectation is for this system to
be more progressive though will pack a punch with damaging winds
and hail being the primary severe threat. Locally heavy rainfall
(rainfall rates of 2-3"/hr) will be another concern for urban and
poor drainage areas along and south of the I-10/12 corridor.

Once this squall line pushes through over the course of 4-6 hours,
we`ll be monitoring the progression of the cold pool boundary to
ensure it clears coastal LA and diminishes the flooding threat.
The current thinking is all severe and flooding threat should be
over by sunrise on Tuesday.

Clearing skies by Tuesday afternoon will allow us to rapidly warm
up back into the upper 80s, and we should see temps follow strong
diurnal curves through midweek thereafter. Warmest day of the week
appears to be Wednesday which is collocated best with an
amplifying shortwave ridge and as well as mostly fair skies.

&&

.LONG TERM...
(Wednesday through Sunday night)
Issued at 342 PM CDT Mon May 13 2024

The next upper troughing will then move out into the plains by
mid week with sfc return flow forcing this boundary back to the
north moving back over the area possibly as early as Thu and this
whole thing looks to play out again similar to this event. The
first disturbance moves through mid day Thu and may hug the coast.
This should be associated with the warm front. The next main
system will move along the cold frontal interface as it stalls
across the area with an abundance of deep moisture Fri. This is at
least one solution, but as one can clearly see with the current
system, this will almost surely change several times before we get
there. The general synoptic structure looks valid, but we will
definitely need to get closer to even think of resolving the
smaller scale features. TE

&&

.AVIATION...
(06Z TAFS)
Issued at 1224 AM CDT Tue May 14 2024

Although convective threat is winding down, thunder continues to
be heard well behind the convective line, and will need to carry
mention for at least a few more hours. Most terminals currently
with VFR conditions, but expect at least a brief period of MVFR
ceilings around sunrise before conditions improve to VFR by late
morning. Could be a brief period of low visibilities as well
right along the cold front over the next few hours, especially at
KMCB.

&&

.MARINE...
Issued at 342 PM CDT Mon May 13 2024

Higher winds (15-25 knots) and seas (3-7 feet) are expected through
the overnight hours tonight. Strong thunderstorms moving through the
area could result in locally higher winds and seas which will be
dangerous for small crafts. Winds become more west to southwesterly
and decrease to less than 10 knots through the afternoon on Tuesday
where hazards to small crafts will decrease. Southerly component to
light winds remains intact through midweek but becomes more easterly
with time by later in the week.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  61  86  62  85 /   0   0   0  20
BTR  65  91  67  88 /   0   0   0  30
ASD  66  91  66  88 /   0   0   0  20
MSY  71  89  72  87 /   0   0   0  20
GPT  67  89  67  86 /   0   0   0  10
PQL  66  91  64  89 /   0   0   0  10

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Flood Watch until 6 AM CDT early this morning for LAZ056>060-
     064>070-076>080-087>090.

GM...Gale Warning until 5 AM CDT early this morning for GMZ530-532-
     534-536-538-550-552-555-557-570-572-575-577.

     Small Craft Advisory from 5 AM to 10 AM CDT this morning for
     GMZ530-532-534-536-538-555-557-575-577.

MS...Flood Watch until 6 AM CDT early this morning for MSZ083>088.

GM...Gale Warning until 5 AM CDT early this morning for GMZ532-534-
     536-538-550-552-555-557-570-572-575-577.

     Small Craft Advisory from 5 AM to 10 AM CDT this morning for
     GMZ532-534-536-538-555-557-575-577.

&&

$$

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