240
FXUS64 KLIX 271145
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
645 AM CDT Thu Jun 27 2024

...New AVIATION...

.SHORT TERM...
(Today through Friday)
Issued at 325 AM CDT Thu Jun 27 2024

Upper ridging centered near El Paso this morning, with a trough
extending from eastern Kentucky to near Lake Charles. A stronger
trough was over the Pacific Northwest. A weak frontal boundary
extended from Tennessee into north Texas. Scattered showers and
thunderstorms were noted on radar with most of the activity south
of Interstate 10. The greatest areal coverage was over the lower
portions of the Louisiana coastal parishes. A few of these showers
and storms could produce wind gusts of 30 to 40 mph and brief
heavy rain. early morning temperatures ranged from the mid 70s
over southwest Mississippi to the mid 80s near Lake Pontchartrain.

Main forecast issue for this package will be the areal coverage
and timing of showers/thunderstorms, both today and Friday.
Mesoscale modeling hasn`t been particularly helpful over the last
couple of days, but does seem to be in somewhat better agreement
this morning. The ongoing convection is being depicted, albeit a
bit slow. Most solutions eventually build this convection offshore
later this morning and then eventually redevelop storms around
the Interstate 10/12 corridor by mid to late afternoon, where
differential heating, as well as lake/sea/outflow boundary
interaction, will help to produce lift. Current indications are
that these storms should dissipate by mid to late evening.

The troughing that is moving into the area this morning is
expected to become strung out near or just off the coast over the
next 36 hours. This is likely to provide a focus for convective
development again tomorrow, although there is some question as to
how far northward convection can develop, considering the very
warm mid level temperatures (500 mb of -2C to -4C).

The additional cloud cover and precipitation potential should
prevent high temperatures from getting much hotter than 90 to 95
today and Friday. This should alleviate the need for Heat
Advisories, but we`ll continue to monitor each day.

&&

.LONG TERM...
(Friday night through Wednesday)
Issued at 325 AM CDT Thu Jun 27 2024

The troughiness along the coast in the short term will eventually
wash out as the upper ridge takes up residence between Interstate
20 and Interstate 40 to our north through at least the middle of
next week. Forecast soundings show that there won`t be a lot of
day to day change in moisture levels with precipitable water
values generally remaining between 2 and 2.3 inches, which is near
or above the 90th percentile for late June. No real indications of
any capping mechanism, so we will likely see at least isolated to
scattered thunderstorm development each day once the convective
temperature is reached. Considering the high precipitable water
values, any cell could produce locally very heavy rain if it lasts
long enough.

Daily highs are going to be driven by convective development.
Areas that see development will have trouble getting much higher
than the 90 to 95 range, but if an area remains dry, they could
reach upper 90s. We`ll have to go day by day, but Heat Advisories
may be necessary if convection fails to develop, or if the upper
ridge axis moves closer to the coast than currently expected.

&&

.AVIATION...
(12Z TAFS)
Issued at 636 AM CDT Thu Jun 27 2024

At forecast issuance time, all terminals were VFR with the
exception of KMCB, where IFR ceilings were occurring. Those
ceilings at KMCB should improve to MVFR in the next hour or two,
then to VFR by midday. Scattered TSRA were generally south of
Interstate 10 at 11z, but it appears that in the short term, the
only forecast terminal(s) that would be impacted would be KHUM,
and possibly KMSY. Direct impacts would be IFR or lower
visibilities, MVFR ceilings, and wind gusts to perhaps 35-40
knots. The current round of convection is likely to move offshore
or dissipate prior to 17z. A second round of TSRA will be possible
for most terminals by late afternoon as the airmass will have had
time to destabilize with surface heating. The exceptions would be
KMCB/KBTR/KHDC, where subsidence behind the shortwave may limit
development. That round should dissipate by mid-evening, roughly
03z Friday.

&&

.MARINE...
Issued at 325 AM CDT Thu Jun 27 2024

Will carry Small Craft Exercise Caution headlines through mid
morning for the tidal sounds and open waters, as winds have fairly
consistently remained in the 15-18 knot range for the last couple
hours away from thunderstorms. Those winds will likely settle down
late this morning, but can`t rule out the need for additional
headlines the next several evenings. Otherwise, the main issue
will be thunderstorms for the next several days/nights.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  90  72  91  74 /  50  20  50   0
BTR  94  77  94  79 /  50  20  70   0
ASD  92  76  92  78 /  60  40  70  10
MSY  92  78  92  81 /  70  40  80  10
GPT  92  76  91  78 /  70  60  70  30
PQL  93  76  93  78 /  80  60  70  40

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

$$

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