530
FXUS64 KLIX 070453
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1153 PM CDT Sat Jul 6 2024

...New AVIATION...

.UPDATE...
Issued at 936 PM CDT Sat Jul 6 2024

Most evening convection has died out, but there is one weak storm
at the south end of the Lake Pontchartrain Causeway. Would expect
that storm to eventually rain itself out as well. Most of the
night should be rain free over land, until the usual late night
marine convection gets going. Still a fairly wet sounding with a
precipitable water value of 2.2 inches on the 00z LIX sounding,
although that`s not as wet as most over the last few days. Still
looking like most precipitation on Sunday should remain west of
Interstate 55.

Will send a ZFP update along with the usual evening CWF update to
limit precipitation wording overnight.

&&

.SHORT TERM...
(This evening through Sunday night)
Issued at 318 PM CDT Sat Jul 6 2024

A broad upper level trough is centered along the midsection of the
country and encompasses all but the western/eastern fringes of the
country. A frontal boundary associated with this feature moved in
yesterday and basically is no longer discernible. The lift from this
boundary was part of such high coverage yesterday and less forced
lift has certainly limited convection so far today. Subsidence from
high pressure around Beryl is possibly stunting convection as well.
Do think the bigger player is less moisture, both at the surface and
mid levels. While it`s not a huge difference, when combined with the
other factors above definitely has delayed appreciable initiation.
Just starting to see a few showers develop along/north of I-12 in LA
and SW MS. SPC meso analysis shows moisture convergence to be
greatest in this portion of the CWA. This lines up with surface obs
showing persistent southerly winds from the coast to here and clouds
on VIS are growing vertically the most along there. CAM solutions
over the next 3-6 hours generally agree fairly decently but
intensity and overall coverage confidence is relatively low. Any
storms that develop could produce sub-severe gusty winds and brief
heavy rainfall. Once we lose daytime heating, convection will
dissipate with time.

Sunday will be fairly similar but with possibly even less coverage.
The CWA is on the outer periphery of Beryl and thinking that
subsidence from it across the local area will play an even bigger
part to limiting convection. The CAMs appear to do a great job
recognizing this, while the NBM doesn`t. The GFS model forecast of
the precipitable water spatially does show a swath of dry air on the
eastern side of Beryl surging northward into the CWA. The gradient
of this dry air and tropical airmass is right on the western edge of
the CWA. Therefore, have modified POPs tomorrow to account for
higher and lower rain chances with higher to the west and lower
coverage to the east. Then, when it comes to heat, still held off on
borderline heat advisory. Cloud cover potential along with slightly
lower temps/dewpoints compared to previous days makes the go/no go
decision a bit tough. So will pass it on the later shifts.

&&

.LONG TERM...
(Monday through Friday night)
Issued at 318 PM CDT Sat Jul 6 2024

The biggest thing to watch after this weekend will be isolate areas
of heavy rainfall. As the remnants of Beryl are being absorbed by
the upper trough to the north and track east across the lower
Mississippi Valley. As seen in previous decaying tropical systems
tracking northward, models show the trough dragging a tail of
rainfall along the eastern side of the remnants extending from the
base of the trough/remnant Beryl to well south into the Gulf of
Mexico Tuesday through Wednesday. Forecast PW`s in the 2.4-2.6"
aren`t surprising and quite concerning, especially when combined
with ample instability in place. No  way to know where one of these
tropical rain bands lines up but with very efficient precip
processes expected, certainly could see some surprisingly high
streaks of very heavy rainfall.

&&

.AVIATION...
(06Z TAFS)
Issued at 1148 PM CDT Sat Jul 6 2024

Earlier convection has dissipated for the most part, and any
additional convective development overnight should mainly be over
the coastal waters. While most terminals were VFR at 05z, low
ceilings and/or visibilities will be possible, if not likely, at
several terminals between 10z-13z. This will especially be the
case at KMCB, where they have already had a few periods of
ceilings below FL010. Likely to see MVFR ceilings at mid morning
at most terminals as cumulus field builds. At this time, it
appears that any significant convective development on Sunday is
likely to be limited to the western terminals, mainly KMCB, KHUM
and KBTR.

&&

.MARINE...
Issued at 318 PM CDT Sat Jul 6 2024

A broad upper level trough is centered along the midsection of the
country and encompasses all but the western/eastern fringes of the
country. A frontal boundary associated with this feature has stalled
along the northern Gulf Coast and broken down the surface pressure
gradient. This lack of a driving pressure field is why the wind
field is so light across the local marine areas. That`ll change for
open Gulf waters west of the MS River Sunday into Tuesday as Beryl
tracks through the western Gulf of Mexico into Texas. The overall
size and wind field is quite a bit smaller in size compared to
Alberto from June. So while Small Craft Advisory wind speeds are
possible, more likely looking at 48hr-ish period of Exercise caution
conditions in those non-tidal lake zones. Then, once the remnants of
Beryl eject northward, benign conditions return to the coastal
waters.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  73  93  74  93 /  40  20  10  50
BTR  78  96  78  96 /  40  30  10  60
ASD  77  95  77  93 /  30  20  10  60
MSY  80  94  80  93 /  40  20  10  70
GPT  78  93  79  92 /  30  20  10  50
PQL  77  95  77  95 /  30  20  10  50

&&

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

$$

SHORT TERM...ME
LONG TERM....ME
AVIATION...RW
MARINE...ME