777
FXUS64 KLIX 281721
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1221 PM CDT Tue May 28 2024

...New UPDATE...

.UPDATE...
Issued at 1131 AM CDT Tue May 28 2024

Forecast update sent to increase PoPs and highs. Yes that is odd
to do both but we are running warmer a little faster than
yesterday and with slightly warmer LL temps. In addition not
expecting a lot of convection till 20z or later so the only real
issue with temps not getting as warm if not warmer than yesterday
will be the cirrus trying to push south. By 1630z it had just
entered southwest MS and should continue to steadily push south
but if it thins out anymore the impact from it will be fairly
minimal. With h925 temps about 1.5 degrees warmer than yesterday
and BTR got to 98 see little reason to think they won`t get at
least 98 again today but it would not be a surprise if BTR peaked
out at 99 and even a very remote shot at 100 (but not willing to
bite on that yet). The one positive thing with respect to temps
is the northern half (almost 2/3rds) of the CWA is mixing in drier
air and dewpoints have fallen into the 60s to lower 70s for those
aforementioned areas. However to the south dewpoints are still in
the mid 70s and even a few lower 80s and those places are already
quite miserable with heat index readings running from 100 to 108.


Now that said it does appear that convection may be a good bit
easy to come by today than yesterday. Much of the same parameters
we saw yesterday are still in place and from a sounding
standpoint we have a very favorable environment for strong to
severe storms. The key is can we get anything to pop and yesterday
that was the problem with no real boundaries moving in/colliding
or any subtle lift transiting the area. Now with a boundary draped
over the area, a LL convergent axis shown at h925 and h85 draped
over the area from the Southshore to Opelousas to the northwest
into west-central LA. This also coincides with an instability
gradient. In addition we could see a seabreeze move north from the
Gulf and collide with a developing lake breeze over the
southshore. This is now providing multiple areas of
convergence/forcing to possibly get a few storms to pop. Once and
if we get some to develop it is likely that storms would then
develop along the line along and just south of I-10 this
afternoon. Last there is a lot of convection upstream crossing
Toledo Bend and this could continue to surge southeast down that
gradient and into the western fringes of the CWA around 19/20z.
There is another even larger area of convection back behind the
previously mentioned one that may catch up to the first. Both of
these have the potential to race down that gradient/convergent
line into the CWA. The most likely timing appears to be from 19z
through 22z with convection possibly spreading out from there to
the ENE right up along the northshore and maybe eventually into
coastal MS. Mid level lapse rates of greater than 8C suggest large
hail is possible and DCAPE values currently around 1350-1550 over
western/southwestern portions of the CWA highlight a rather
impressive damaging wind potential. One other little concern could
be heavy rain. If storms start to pop along the line we have
reference multiple times isolated locations could see multiple
storms before then main threat gets here. That could add quick
bouts of locally heavy rain then add strong/severe storms with
even heavier rain on top and there could be isolated pockets of
flash flooding. One last thing noticed over the past hour is the
southern edge of the first line of convection is starting to hang
up and drift back to the west towards the 2nd line of convection.
If we have that happen as it moves into the region then the risk
for heavy rain will greatly increase.

Keep an eye out for possibility of a Severe Thunderstorm watch and
the potential for localized flash flooding. /CAB/

&&

.SHORT TERM...
(Today through Wednesday)
Issued at 323 AM CDT Tue May 28 2024

We will start out with an important feature in the form of a front.
Can`t legitimately call this a cold front since temps are as warm
behind it as ahead of it but by definition it would be because there
is an air mass change across its boundary via dew pts. This front
currently(2am) is located where the storms are ongoing this morning
along the Miss coast. The front is just off the coast south of
Pascagoula coming onshore just east of Gulfport to just north of
Hammond then snakes its way into west central LA and on into TX
south of Dallas. This boundary will help a very large complex of
elevated storms develop later today near the Red River Valley. This
complex should do two things, one is massively cold pool southward
toward the sfc boundary causing all kings of severe wx over central
TX today as it becomes sfc based. Smaller disturbances from this
will be able to use the frontal boundary to ride eastward as well.
This will act as a conduit for our area. The problem is stability
even with this boundary over the area. Numbers show where
stability quickly erodes as one moves west today so the marginal
risk of severe looks well placed as west of I55 is where downburst
numbers and the most severe wx producing numbers are highest
relative to our area. This scenario will play out over the next
few if not several days and it will be important to know where
this or any other boundaries are located on a daily basis.
Instability numbers rise for Wed and again they are indicating
that if something can actually break the cap and produce lightning
it will likely become severe. Again, with upper NW flow regimes,
it is always a daily struggle to find the processes in the
mesoscale environment that will cause trouble. So today is most
visible vs. tomorrow. The current storms moving along the cold
pool boundary to the west from coastal Miss and over the gulf will
eventually modify and stall with the storms gradually weakening.
There is not one CAM that is showing any of this activity, but the
GFS did pick up on this convective burst developing along this
frontal boundary but it did not hang on to it past midnight.
Regardless, this is also the only model that is keeping this
modified cold pool near the western part of the CWA later today.
At least one disturbance should develop near the Toledo Bend area
and move east along the frontal boundary later today as well. It
is this activity that should collide with this modified cold pool
late this afternoon to cause at least some storms over the western
half of the area. The reason we can put a bit more confidence in
this is the existence of the features that will allow it to occur
and provide the travel path. Cloud cover and somewhat slightly
lower dew pts as this front will be near the coast later today
will help keep heat index numbers in check. But it will still be
hot. One can easily tell in this forecast where we and our
neighbors are placing the frontal boundary as the highest precip
numbers will be located along and south of its axis, for us this
mainly be the afternoon/evening hours. Areas to the north of these
higher precip numbers will get somewhat lower heat index values
while cloud cover along and ahead of it will keep others from
those numbers as well.

As a side note, BTR broke the record for the warmest low temp
yesterday(Monday). Also, this record of 82F has not been
reached(with respect to our records) for any day since January 1st
until *JULY 5th*. Yes, July 5th is the first time a low of 82F was
hit for the first time since Jan 1st of any year since records began
in 1892. And the record value of 82F on July 5th was set in 2016.
This record high(low) was not reached for more than another month
away. The odds of this occurring this early is insane.

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 323 AM CDT Tue May 28 2024

If it is difficult to tell what is going to occur tomorrow, it is
almost impossible to give an extended fcast in this kind of
environment. But we can see where the synoptic features should be
located, which gives us a better handle on areas that could be most
vulnerable to these MCS features. Looking at the extended through
the next several days, it looks as if there will be endless MCS
features develop daily and move east along either the sfc boundary
or the 850 boundary which will both be in flux on a daily basis as
these disturbances push and pull it each day. The sfc part of this
boundary fades by late Wed and is somewhat located along the Miss
River Valley by Thu and is out of the picture Fri. The only thing
steering these disturbances later in the week will be ThetaE
gradients or old outflow boundaries.

&&

.AVIATION...
(12Z TAFS)
Issued at 323 AM CDT Tue May 28 2024

VFR will be found at all terminals through this taf period with the
exception of one or two. The most at risk terminal for IFR will be
BTR late today. The next would be HUM. There is a chance to get some
TSRA for these two locations and if this occurs, IFR conditions
could quickly develop for a short time.

&&

.MARINE...
Issued at 323 AM CDT Tue May 28 2024

There is a chance for temporarily getting a northerly brz over
waters to the east of the Miss River. This would be short lived and
would not be an issue as speeds should remain around 5kt. Southerly
winds of 10-15kt will remain over waters to the west of the river
and after today, all areas will be back in return flow at these
levels for the remainder of the week. Any storms that are capable of
developing or moving offshore will be able to produce erratic and
much higher wind speeds.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  92  68  87  66 /  10  10  30  20
BTR  96  73  90  72 /  20  20  30  10
ASD  95  72  91  71 /  10  10  20  10
MSY  94  76  90  76 /  10  10  20  10
GPT  94  73  90  72 /   0  10  10  10
PQL  96  70  92  69 /   0  10  10  10

&&

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

$$

SHORT TERM...TE
LONG TERM....TE
AVIATION...TE
MARINE...TE