Damaging Wind in Louisiana, August 13, 2025

Area Forecast Discussion
National Weather Service New Orleans LA
326 PM CDT Wed Aug 13 2025

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(This evening through Thursday night)
Issued at 325 PM CDT Wed Aug 13 2025
Through the remainder of the afternoon seeing convection
continuing to bubble up across the region. Latest mesoanalysis
suggest the best LL convergence is mainly north of the I-10/12
corridor taking on a slight WNW to ESE orientation. That said
locally enhanced convergence along the seabreeze over coastal
SELA is leading to storms over that area as well. Obviously being
it is the Summer deep layer shear is practically nonexistent but
there is slightly better upper lvl divergence across the northwest
and this is where some of the strongest convection has been noted
luckily it has just remained outside of the CWA. That said as we
continue to heat up additional storms are likely to develop
especially where any boundaries collide. We are rather unstable
and given the high DCAPE values draped across much of SELA it is
not out of the question to get a few wet microburst.

Heading into tonight convection should taper off by mid/late evening
with a rather warm and humid night in store. As high pressure begins
to build in from the east there isn't much relief in sight with
respect to drier air and that is going to lead to some warm nights.

The next 2 days becomes a question of how much convection we will
see and how that impacts temps. High pressure will begin to build in
from the east tonight through the remainder of the week and into the
weekend. This will begin to increase the suppression aloft over the
region but as mentioned before given the origination of this ridge
being off to our east it isn't that western CONUS death ridge that
brings in much hotter temps and completely suppresses convection.
This is more of a dirty ridge which will inhibit convection some but
given the amount of moisture available and synoptically weak sfc winds
we will see diurnal fluctuations in the boundary layer winds
allowing the sea/lake breezes to develop daily becoming land breezes
overnight. These areas of convergence especially over SELA where
they can intersect will help develop convection tomorrow.
Northwestern portions of the CWA is a little more difficult to say.
It will see the impacts of the ridge building in later than the rest
of the area. The biggest question in the northwest is convection
that fires just off to our northwest. There will still be some
troughiness laid up southwest to northeast across the Lower MS
Valley between the ridge building in across the Gulf from the east
and the ridge over the 4 corners that will begin to slide WNW. That
weakness/trough will allow convection to fire northwest of the area
with additional storms firing off of any outflow boundaries to
emanate from it. Those could move into our northwest zones but
trying to bank on that happening and is a little difficult at this
time and because of that we did back down PoPs that the NBM was
showing 60 to near 70% across southwest MS down to 50%. Coastal MS
and the northshore should have the lowest risk of seeing storms
tomorrow as the ridge noses in more across this area and the only
real forcing mechanism would be the sea/lake breeze sliding north.

This now brings up the potential for Heat hazards. We are likely to
remain quite warm tonight with the Southshore seeing lows in the
upper 70s to near 80 and much of the rest of the area struggling to
get below 75 tonight. This provides a rather favorable jumping off
point to heat up quickly. Convection likely holds off a little
longer tomorrow, likely midday early afternoon. Combine that with
afternoon highs a touch warmer, if all else is equal see no reason
the area doesn't at the very least get to where we got this
afternoon and likely a touch higher on the heat index side.
Confidence is not the highest but given all of that we decided to
issue a heat advisory for the areas mainly along and between the
10/12 corridor. This area is going to hold onto the higher boundary
layer moisture given much of that area is marsh and surrounding the
very warm tidal lakes. This may need to be expanded to cover more
areas but will allow the evening shift to revisit and make that
decision.

Friday will be another warm day and likely could be a carbon copy of
Thursday so a persistence style fcst may be the best fcst. The ridge
will continue to build in from the east helping to suppress
convection a tad more but the one caveat is the weakness between the
2 ridges will get squeezed as the western ridge continues to build
to the northeast (centered over MO Friday afternoon). That weakness
will be even closer to northwestern/northern section of the CWA and
this may allow for afternoon convection to fire. Even with the
building ridge there will still likely be scattered convection
associated with the sea/lake breeze but overall the PoPs will
continue to be around 30-50%. Additional heat products are likely
Friday. /CAB/

&&

.LONG TERM...
(Friday through Tuesday night)
Issued at 325 PM CDT Wed Aug 13 2025

The extended forecast has changed much. It is Summer it
looks warm with daily thunderstorms. That said what looked like a
warmer and drier weekend may be shifting more to still warm but
scattered to numerous storms each day. That said the way the pattern
may be setting up there may be slightly better chance of seeing
strong to isolated severe storms. The ridge that built in over MO
will be the main ridge with a weakness over the area Saturday as the
ridge that moved across the Gulf slides west and more so merges with
that ridge. This then places the area under northerly flow which
leads to convection developing late but could be quite potent. This
also will allow the region to warm up considerably and we could see
a few upper 90s this weekend. The only thing that will hold that off
would be convection. Heading into next week models are hinting at
the base of that trough/weakness that we have mentioned earlier,
breaking up a slowly working west across the northern Gulf. That
would increase the rain chances again and bring down the higher
temps we will see this weekend. /CAB/

&&

.AVIATION...
(18Z TAFS)
Issued at 137 PM CDT Wed Aug 13 2025

Currently all terminals are in VFR and will likely remain that way
unless impacted by convection. Scattered TSRA will be possible
through the afternoon and early evening hours. obviously any
terminal that see convection will also have impacts to both vsby
and cigs but another issue could be gusty winds. TEMPO's have been
included in most terminals through the remainder of the
afternoon. Convective coverage should be a little lower Thursday
as high pressure builds in. /CAB/

&&

.MARINE...
Issued at 137 PM CDT Wed Aug 13 2025

Convection will continue to impact the coastal waters especially
overnight and early in the morning tonight and tomorrow before
slowly decreasing in coverage heading into the weekend. High
pressure centered to the east will slowly work west over the
central and north-central Gulf leading to generally light winds
Friday and through the weekend. Otherwise the main impacts is
really just showers and thunderstorms. With any thunderstorm
locally higher winds and seas are expected and waterspout will be
possible. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  74  94  73  93 /  30  50  20  50
BTR  77  95  76  95 /  30  50  10  50
ASD  75  93  75  93 /  20  40  10  40
MSY  79  94  79  94 /  20  50  10  50
GPT  76  93  76  92 /  20  30  10  40
PQL  75  92  75  93 /  30  30  10  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from 10 AM to 6 PM CDT Thursday for LAZ048-057-058-
     060-064-076>089.

GM...None.
MS...Heat Advisory from 10 AM to 6 PM CDT Thursday for MSZ086.

GM...None.
&&

SHORT TERM...CAB
LONG TERM....CAB
AVIATION...CAB
MARINE...CAB