055
FXUS64 KLIX 031008
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
508 AM CDT Wed Jul 3 2024

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

.SHORT TERM...
(Today through Independence Day)
Issued at 456 AM CDT Wed Jul 3 2024

Yes finally there may be some relief but will it be enough to
keep the area from getting these overly oppressive conditions,
that is the biggest question mark and problem in the forecast. The
other feature in the forecast that is causing a lot of undue
anxiety for many is Beryl.

Today should be one last day with the potential of seeing dangerous
heat index values up to 115. This is mainly for the parish along the
MS River from southwest MS to BTR and then the parishes on the north
along the immediate west and north sides of the tidal lakes.
Elsewhere with the exception of the coastal Parishes of SELA likely
only get into advisory criteria and that may actually only be for a
few hours at best as convection does have a much better chance of
developing today. GOES16 TPW shows a deeper surge of moisture slowly
moving into the region from the east-southeast. In addition there
appears to be a weak inverted trough setting up southwest to
northeast from Vermillion Bay to southeast MS. That along with deeper
moisture moving in and daytime heating will likely be more than
enough to get at least scattered convection to develop. Winds also
could be unidirectional and out of the south to south-southwest
across the southeastern half of the cwa and that may allow
convection to develop earlier in the day as well. Looking at current
radar and there is more coverage out there now in the Gulf and
across coastal AL at 8z than we have seen for the past few days and
more than what most of the CAMs were showing at this time as well.
That seems to suggest greater potential for convection and decent
coverage today. That is the main thorn in the temperature and
subsequent heat index forecast today. The northwestern half or more
so third of the CWA may have a much more difficult time of seeing
convection or it will at least be much later in the day. With highs
in the mid to upper 90s expected and just stupid humidity lvls in
the boundary layer it is quite likely that these areas and any area
that stays rain free will have heat index values climb to or abv
113. A heat advisory was already out for most of the northern half
of the CWA but given the concerns about the lack of convection or
delayed timing in the northwest and around the tidal lakes we
decided to upgrade those areas to an Excessive Heat Warning. We also
went with a heat advisory for the New Orleans metro area and a few
parishes just to the west and south of I-10. The biggest concern is
it is already quite oppressive right now with many locations in this
area already seeing heat index values in the mid 90s to lower 100s
at 9z. Unless convection can move inland and/or develop in those
areas before 16/17z it will be nothing for the heat index to climb
to 108 to 110.

As for tomorrow, the 4th of July...heat may be a little more
borderline for many locations but there are a few concerns that make
it a little more likely that we will see solid heat advisory
conditions and impacts would be even greater given that...it is
Independence Day and many people will be outside celebrating.
Convection will likely be a little more difficult tomorrow however,
there will still be scattered to possible  numerous storms out
there. The area with the best chance for rain tomorrow could very
will be the northwest sections which have the lowest chance today.
That said convection would likely hold off till afternoon which
would be more than enough time to warm up enough with heat index
values not having much difficulty getting to 108 to 112. Across the
north and south shores along with coastal MS rain may be a little
more widely scattered and these area will likely warm up enough as
well to allow for the heat index to approach 108-110. As mentioned
earlier given Thursday being a holiday it is probably a good idea to
get a little more awareness out there about the potential for
another oppressive day.

Today and Thursday have been advertised as being the cooler days
after Monday and Tuesday and given what occurred the last few days
this is still expected. But just because it will be less oppressive
doesn`t mean it isn`t oppressive. Morning lows are awful again this
morning and likely to be the case tomorrow morning as well and that
gives everyone a much higher jumping off point making it easier to
get into those dangerous heat index values. That said the biggest
caveat is convection. It will not take much to really keep things in
check and that is likely the biggest fail mode with respect to
actually seeing the very oppressive conditions. /CAB/

&&

.LONG TERM...
(Thursday night through Tuesday)
Issued at 456 AM CDT Wed Jul 3 2024

The extended portion of the forecast really focuses on
temps and rain potential but obviously everyone is paying attention
to the forecast of Beryl and where it may eventually go. We will
discuss Beryl more soon but first the weather conditions expected
Friday and into the weekend. Overall things look to be a touch
cooler relatively and that is more so heat index values and not
necessarily the actual temperatures. Confidence is not that high
given convection is the key determining factor with respect to temps
and the heat but also what influences we possibly see from Beryl
(hint at this time not expecting much outside of possibly
marine/tidal impacts). No deviations made to the forecast from the
latest NBM.

Friday through the weekend, the ridge that has been plaguing the
area and providing the awful heat and lower rain chances will
already be losing some of its influence over the area heading into
Friday but by Friday it should continue to weaken and slide to the
east ever so slowly. By this weekend the western side of the ridge
will weaken if not erode some and this could lead to better rain
chances with less suppressive and lower mid lvl temps. In addition
LL temps will be lower than what we have seen with h925 temps of 27-
30C the last few days to closer to 24-26C over the weekend.

As for Beryl, lets begin with this, take a deep breath and continue
to follow the latest forecast. NHC`s latest forecast still has Beryl
tracking to the WNW across the Yucatan Friday, into the Bay of
Campeche and then approaching the north Mexican coast late Sunday.
Beryl is continuing to work under the influence of a large ridge
which continues to stretch from north of the Greater Antilles west
all the way across the TX and Mexico border. This is what will
continue to drive Beryl to the west and west-northwest through at
least early Saturday. Many of you have obviously seen at times
different solutions or even ensemble forecast that show Beryl
beginning to turn and even a hard turn to the northwest and even
north-northwest Saturday and Sunday. Some even show Beryl getting
into the far northwestern Gulf and this is a highly unlikely
solution. Not impossible but very unlikely.

Why the turn, this is due to the west side of the ridge beginning to
erode (as we mentioned in the previous paragraph). A disturbance
currently coming onshore over the PAC northwest will drop southeast
across the northern Plains and into the Upper and Mid MS Valley
Friday. As that happens the western side of the ridge erodes and
could allow Beryl to slow down and turn to the NW but a lot will
depend on how far north Beryl can get over the next 48 hours and
what the structure is after it exits the Yucatan and emerges into
the Gulf. Even if Beryl is a little farther north than the current
forecast, it will likely not start to make any noticeable turn till
late Saturday and by then Beryl will probably be halfway across the
Bay of Campeche by then. How much of the ridge erodes will also be a
major factor. Looking at some of the global models the jet core
associated with the s/w will be downstream of the s/w axis by late
Friday and that should keep it from digging much more and then how
much of the ridge really erodes. Even if the ridge erodes as
anticipated or even slightly more Beryl will very likely be too far
west to have any direct impacts for our area. The most likely
scenario for SELA and coastal MS is indirect impacts as there could
be an increase in onshore flow and possibly a swell emanating out of
the southeast. This could bring some tidal concerns to the area this
weekend and into early next week. /CAB/

&&

.AVIATION...
(12Z TAFS)
Issued at 456 AM CDT Wed Jul 3 2024

Mostly VFR conditions currently however a few bounces into MVFR
due to low clouds leading to cigs around 2100-2500 ft has been
occurring early this morning. These low clouds likely won`t cause
too many problems with most terminals remaining in VFR status.
That is the main impact outside of convection which could begin
much earlier today especially along the coast around GPT and HUM.
Terminals at ASD/MSY/NEW could also see convection impact them
later this morning possibly as early as 16z but more likely around
17/18z. HDC/BTR/MCB likely start to see impacts from convection
during the afternoon hours. /CAB/

&&


.MARINE...
Issued at 456 AM CDT Wed Jul 3 2024

At this time benign marine conditions expected in the next 7
days. Generally, moderate (10-15kts) and southerly winds expected.
Convection is already impacting the coastal waters this morning
and should continue to do so through the morning before mostly
moving inland around midday and through the afternoon. Very high
moisture content in the low levels along with unstable conditions
and a weak inverted trough across the coast could lead to a better
chance of waterspouts this morning.

We did say "At this time" in the first sentence as there is a very
small chance that some indirect impacts could occur from Beryl
this weekend and possibly into Monday. A lot will depend on how
strong Beryl is and how far north it is when it departs the
Yucatan Friday night/Saturday. This could provide a swell out of
the southeast and maybe lead to slightly strong southeast/east-
southeast winds late this weekend. It along with the area
approaching spring tide could also lead to some very minor coastal
flooding concerns. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  94  75  92  74 /  60  30  70  10
BTR  96  80  95  78 /  60  20  80   0
ASD  92  78  94  78 /  80  30  80  10
MSY  92  80  92  80 /  80  30  80  10
GPT  90  79  91  78 /  70  30  70  10
PQL  93  78  94  77 /  70  30  60  10

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Excessive Heat Warning from 9 AM this morning to 9 PM CDT this
     evening for LAZ034-035-046>048-080-082>086.

     Heat Advisory from 10 AM to 7 PM CDT Thursday for LAZ034>037-039-
     046>048-056>060-064-065-071-076>090.

     Heat Advisory from 9 AM this morning to 9 PM CDT this evening
     for LAZ036-037-039-056>058-060-064-071-076>079-081-087-089.

GM...None.
MS...Excessive Heat Warning from 9 AM this morning to 9 PM CDT this
     evening for MSZ068.

     Heat Advisory from 10 AM to 7 PM CDT Thursday for MSZ068>071-077-
     083>088.

     Heat Advisory from 9 AM this morning to 9 PM CDT this evening
     for MSZ069>071-077-083>088.

GM...None.
&&

$$

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