080
FXUS64 KLIX 022047
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
347 PM CDT Sun Jun 2 2024

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.SHORT TERM...
(This evening through Monday night)
Issued at 254 PM CDT Sun Jun 2 2024

No significant change in the overall synoptic level pattern is
expected through tomorrow night. The region will remain embedded
within a zonal flow regime, and a series of weak shortwave troughs
will slide through the Lower Mississippi Valley. The first of
these troughs is currently pushing through the region, and this
has provided enough forcing to support convective development
along pre-existing mesoscale boundaries throughout the day. This
convection is largely driven by increased instability associated
with daytime heating, and is expected to dissipate through the mid
to late evening hours as temperatures cool back into the 70s.
Another shortwave trough axis will slide through the area
tomorrow, and this will once again provide the needed forcing to
support scattered convective development as temperatures warm back
into the mid 80s during the afternoon hours. PWATS will remain
high at between 1.75 and 2 inches, so locally heavy rainfall will
continue to be a concern. Overall, have went PoP values in the 40
to 60 percent chance range for tomorrow afternoon.

&&

.LONG TERM...
(Tuesday through Saturday night)
Issued at 254 PM CDT Sun Jun 2 2024

Tuesday will be a very typical early June day across the forecast
area. Zonal flow will remain in place aloft and widely scattered
convection will develop along weak mesoscale boundaries like the
seabreeze and outflow boundaries from previous convection as
temperatures warm into the upper 80s and lower 90s. Thunderstorm
activity will peak in the mid to late afternoon hours when SBCAPE
values are highest at around 2500 to 3000 J/KG. These storms will
be short-lived as updrafts become cold pool dominated and collapse
in generally an hour or less, and there will be a risk of brief
heavy downpours producing an inch or two rain with these
thunderstorms. The strongest updrafts could reach into a drier
airmass aloft, and this dry air entrainment could lead to a few
storms producing locally higher wind gusts. Overall, have went
with PoP that is right in line with climatology at around 30
percent for Tuesday afternoon.

A pattern change is then expected to take shape on Wednesday as a
very strong northern stream trough deepens in the Great Lakes
states. In advance of this trough, a shortwave ridge over Texas
and western Gulf will extend more toward the forecast area, and
this will help to cap off most convective potential on Wednesday.
This will be due to the stronger subsidence aloft not only drying
but also warming the mid-levels enough to produce a strong mid-
level temperature inversion. Any updrafts will struggle to break
through this layer of warmer air, and this will limit rain chances
to a few showers during the afternoon hours over more inland areas
where afternoon heating is greatest. Speaking of heating,
temperatures will be much warmer in the lower 90s over inland
areas and the upper 80s along the coast.

By Thursday, the northern stream trough will have deepened enough
to drive a frontal boundary through the forecast area. This front
will tap into a moderately unstable airmass as noted by SBCAPE
values of 1500 to 2000 J/KG to produce a convective line along the
front. There could be some stronger wind gusts with the line as it
moves through. This is supported by high DCAPE values of 1000 to
1200 J/KG and steep low level lapse rates. Temperatures will also
be quite warm with highs climbing into the lower to even middle
90s in advance of the cold front. The front will clear the
offshore waters Thursday night, and the convective threat should
diminish.

The area should then find itself embedded with deep layer
northerly flow on both Friday and Saturday as a strong upper level
ridge dominates the Plains and the deep trough dominates the
eastern seaboard. This northerly flow pattern can be tricky during
the Summer months, as temperatures quickly climb into the low to
mid 90s each afternoon and a collision between the seabreeze and
this northerly flow ensues. This collision, depending on moisture
and instability in the low to mid-levels could support isolated
strong to occasionally severe thunderstorms. A review of model
sounding data indicates that Friday is the more likely of the two
days for this to occur, and have included a low PoP of 20 percent
in the forecast to reflect this convective risk. If storms do
form, and the updrafts become sufficiently deep, the risk of
damaging winds and heavy rainfall will increase substantially.
Away from the isolated convection, hot, sunny, and humid weather
can be expected both Friday and Saturday.

&&

.AVIATION...
(18Z TAFS)
Issued at 254 PM CDT Sun Jun 2 2024

A thunderstorm is currently in the vicinity of NEW and may impact
the terminal over the next hour. Given this threat, have included
a TEMPO group from 18z to 19z that includes a mention of gusty
winds, thunderstorms, and MVFR ceilings and visibilities. A
similar threat exists at all of the other terminals through around
00z as the atmosphere remain moist and unstable, but thunderstorm
probabilities are too low to include as a prevailing or TEMPO
group. Instead, have included periods generally ranging from 2 to
4 hours of prevailing rain shower activity with vicinity
thunderstorms between 19z and 00z at all of the terminals.
Ceilings will range from 2000 to 3000 feet over this period. If a
thunderstorm is expected to directly impact a terminal, an
amendment with TEMPO group will be added. After 00z, the
thunderstorm activity will wane with the loss of daytime heating.
Prevailing MVFR and VFR conditions are expected from 00z through
18z tomorrow at nearly all of the terminals. Only MCB could see a
brief period of IFR ceilings and MVFR visibilities develop
beneath a weak low level inversion between 10z and 13z tomorrow
morning.

&&

.MARINE...
Issued at 254 PM CDT Sun Jun 2 2024

No significant weather concerns are anticipated in the coastal
waters through the end of the week. Winds will initially remain
out of the south and southeast at around 10 knots through
Wednesday and seas will remain in the 1 to 2 feet range. On
Thursday, a weak front will slip through the waters, and winds
will briefly turn northerly at 10 to 15 knots on Friday.
Otherwise, the only concern through the week will be the risk of
locally higher winds and waves near any thunderstorms that form
this week. It is safe to say that we are moving toward a very
typical Summer pattern this week.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  68  87  71  89 /  20  50  50  30
BTR  71  88  73  90 /  40  40  30  20
ASD  71  88  74  89 /  30  20  20  30
MSY  74  87  76  88 /  40  30  20  30
GPT  74  86  76  86 /  20  20  20  30
PQL  72  86  74  86 /  20  20  20  30

&&

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

$$

SHORT TERM...PG
LONG TERM....PG
AVIATION...PG
MARINE...PG