800
FXUS64 KLIX 262118
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
418 PM CDT Wed Jun 26 2024

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

.SHORT TERM...
(This evening through Sunday)
Issued at 415 PM CDT Wed Jun 26 2024

Today has been difficult to say the least with
respect to convection. At one point it looked like we would remain
most rain free until possibly this evening and then around 16//17z
convection begin to fire across a good chunk of the area as we
heated up. But shortly after storm tried to grow they all began to
collapse. The lack of any real mid lvl flow along with very warm mid
lvl temps likely the cause of convection struggling but by mid
afternoon it was becoming apparent that we were getting squeezed as
widespread convection just off to our west and northeast was going
strong. The biggest concern is the convection to our west and
northwest as it could me the main concern for tonight and tomorrow.

As for tonight, looking at current radar trends the line from a
decaying MCS continue to surge south through central LA and into
southwestern and south-central LA. While robust storms are
developing across southwestern LA ahead of the line. These storms
will eventually move east into the area later today/tonight along
with the remnants of the storms in northern MS and northeast LA.
Even if it is just a boundary that drops into the area from the
north that will likely be what helps storms develop quickly tomorrow
morning. So the question is how much convection do we have overnight
and then when and where does convection fire tomorrow and how much.
The hostile environment currently over the area will gradually
improve as mid lvl temps cool with the approach of the disturbance
moving through the Lower MS Valley and mid lvl winds pick up just a
little more. The problem with overnight is we will lose the high
instability we currently have in place. Yes it will still be
unstable but nothing close to what we have in place right now. So do
the improving mid lvls help more than the lowering instability. At
this time given what is on radar it would appear that the improving
mid lvl features combining with multiple colliding boundaries
should keep convection going through the evening till about 5/6z. We
will likely see things die down quickly with isolated to widely
scattered showers through the morning hours and sunrise but after
that once we begin to heat up into the mid to upper 80s storms
should begin to redevelop and could quickly fire up along a
boundary. The biggest concern with convection tomorrow is PoPs may
be too high for southwest MS and adjacent LA parishes. A lot will
depend on the eventual location of the boundary/remnants from the
convection to our north by morning. If this is farther south closer
to I-12 then that northern 3rd could struggle to get much convection
tomorrow. As for temperatures or more so heat, should not be a big
concern tomorrow thanks to convection and cloud cover.

Friday is tricky as we should still have the remnants of the
disturbance dropping into our area tonight. However, at the same
time we will see the ridge to our west start to build to the east
over the region. We may be far enough on the southeastern edge to
allow for one last day of decent rain coverage but on the other hand
the ridge could build in enough to star to shut down convective
potential in the northwest. Given the increase in mid lvl temps
expected and the ridge shown by most models building to the east
quickly and inclined to lower PoPs across the northwest a little.
Temps will already be inching back up but as for the potential for a
heat advisory we should see heat indices remain below 108 for most
of the area.

This weekend looks hot. A few models continue to try and develop
precip across the area but have a very hard time seeing this. The
ridge is expected to be centered over the area or just off to the
northwest while mid lvl temps warm back up and some models are
indicating h5 temps as warm as -2 to -4C. Temps of this magnitude
typically shut down any convection potential yet most models are
still indicating convection. Not confident enough to completely
knock PoPs down but across the northwest both Saturday and Sunday
will begin a trend to drop PoPs into the 20-30% range and see if
models and the NBM swing back that way. As for temperatures ll temps
will be warm and with h85 temps of 20-21C highs in the mid to upper
90s seems likely a highly likely scenario. Combine that with a very
humid airmass and we will see oppressive conditions grip the area
again and it looks like this is only the start as we head into the
new work week. /CAB/

&&

.LONG TERM...
(Monday through Tuesday night)
Issued at 415 PM CDT Wed Jun 26 2024

As northern stream upper level trough moving across the Great Lakes
Sunday evening, it`ll continue eastward into the Atlantic Ocean
Monday. The upper ridge in the wake of this trough will be sliding
east across the entire Mississippi Valley Monday into Tuesday.
Global models are in good agreement that this 596/7dm high pressure
will be centered near the Akrlatex region Monday afternoon.
Excluding rain potential, increasing 500mb heights will bring
already above normal weekend temps up even more. Guidance spread is
fairly minimal and as of 12z runs, Monday has the potential to be
the warmest with highs mid/upper 90s to 100 degrees. Will say though
that GFSbfr 925mb sounding temp is higher Sunday than Monday.
Regardless, convective coverage will probably be the bigger deciding
factor on max temps. A weak residual surface boundary may still be
in place Monday which, combined with forecast temps, would support
scattered to numerous showers and storms. If convective initiation
is early enough, heat indicies will get knocked down quickly.
However, if not too early, widespread upper 70 to 80 degree
dewpoints with hot temps may provoke an Excessive Heat Warning
issuance. Tuesday will virtually mirror with the same
heat/convection timing challenges as the center of the upper ridge
will be progressing eastward fairly slowly. /MEFFER/

&&

.AVIATION...
(18Z TAFS)
Issued at 1134 AM CDT Wed Jun 26 2024

Outside of convection all terminals should be in VFR status with
generally sct cu around 2500 to 4k. Vsbys will remain P6SM as
well. However, convection will bring impacts but confidence is not
great on the amount of convection and exact timing. SHRA and TSRA
are possible through the afternoon with activity waning quickly
during the evening hours until the disturbance to the north drops
towards the region. Moist likely terminals to see impacts from
convection this afternoon will be all but MCB and BTR. These
two have the lowest risk this afternoon but that reverses as both
have the greatest risk this evening and overnight with the
approach of the disturbance. /CAB/

&&

.MARINE...
Issued at 415 PM CDT Wed Jun 26 2024

Weak pressure gradient still in place and likely to remain through
through weak. Light winds will continue with winds slowly shifting
out of the west. Still expect the typical diurnal increase in
winds east of the MS Delta and then winds along the coast and near
shore waters will also be dictated by diurnal fluctuations.
Considering the very moist airmass and light low level winds,
there will be potential for slow moving or nearly stationary
waterspouts at times. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  72  88  72  91 /  60  50  30  50
BTR  77  92  77  95 /  30  70  30  70
ASD  76  89  76  92 /  40  70  50  80
MSY  79  89  80  92 /  20  90  50  80
GPT  76  89  76  91 /  50  90  60  70
PQL  76  92  75  94 /  50  80  60  70

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory until 7 PM CDT this evening for LAZ034>037-039-
     046>048-056>060-064-065-071-076>090.

GM...None.
MS...Heat Advisory until 7 PM CDT this evening for MSZ068>071-077-
     083>088.

GM...None.
&&

$$

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