Laplace, Louisianna 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

887
FXUS64 KLIX 241727
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1227 PM CDT Sat May 24 2025

...New UPDATE, AVIATION...

.UPDATE...
Issued at 1222 PM CDT Sat May 24 2025

Updated earlier to add PoPs around Lake Pontchartrain and along
the Mississippi coast, as diurnal convection initiated earlier
than anticipated. Didn`t make any changes to high temperatures
with that update.

&&

.SHORT TERM...
(Today through Sunday Night)
Issued at 305 AM CDT Sat May 24 2025

Quite the active day yesterday with convection becoming quite
numerous across the area; definitely felt very much like a more
typical active Summer day with storms initiating around midday and
then being driven by outflow boundaries and sea/lake breeze
interactions. Could that be the case today, that is a good
question and the answer is likely yes however convection may not
be as numerous but a lot will really depend on the MCS starting to
really get going over KS and moving into OK (this was at 7/8z).
Most of the overnight CAMs are not extremely hyped on much
convection today nor the MCS surviving into the CWA. However,
there are a few runs here and there that try to show the MCS just
sneaking in around 23-01z but those are few and far between.
Midday afternoon/convection is rather limited on many of the 00z
CAMs which is leading to low probs shown by the HREF and NBM
through the day but the NBM does have slightly higher PoPs for the
evening, likely due to the remnants of the MCS moving through.

Mid lvl ridge axis is still off to the west and will remain so
through today before finally sliding east overnight tonight and then
being almost completely suppressed into the Gulf Sunday night. Much
like yesterday this still places the area under weak NW flow aloft
and what appears to be rather odd is, though most models CAMs and
global lose convection they all show a noticeable s/w moving through
the CWA late afternoon/early evening. That said they also all show
mdl lvl hghts remaining steady or even inching up 1 dm. PWs are abv
normal and the 00z sndg showed 1.83 here at ASD (which was actually
A LOT higher than what the GFS initialized with) but TPW from GOES19
shows drier air has been filtering in from the WNW and is much
closer to what the GFS is showing between 6-9z (but still slightly
higher). The CAMs (HRRR and RRFS) are even worse with the HRRR
dropping PWs down below 1.2 at 6z when GOES TPW had around 1.5". If
moisture is holding on stronger and the drier air is not quite
filtering in as much then afternoon convection along the sea and/or
lake breeze is probably a good chance with outflow and other
boundary collisions becoming the primary initiator once the 1st few
storms go up. That said with the weak NW flow convection will
probably be mid to late afternoon which could be compounded by cloud
cover. If there is a lot of mid and upper lvl clouds that will hurt
daytime heating some which would hold convection off a little longer
but currently looking at satellite, the high clouds look rather thin
with a number of good breaks.

Current thinking is convection will be a little more limited than
yesterday but feel like we will see more convection than what most
of the mdls are indicating. Likely see some of the first storms go up
around the lake this afternoon and then after that its just where do
boundaries interact. As for the MCS...all CAMs struggle last year
with these southern/central Plains MCS`s working southeast. They all
were to quick to dissipate and underestimated how far southeast and
how fast they moved. As long as the low lvl theta e ridge remains
ahead of the convection and there is some, even weak LL convergence
the MCS should continue. Once it passes the theta e ridge it would
weaken and likely quickly. The other feature is that all of the mdls
show the mid lvl impulse associated with the MCS sliding all the way
through our CWA between 23z today and 3z tonight. If convection is
still healthy and remains attached to that wave I see no reason why
the MCS won`t move into southwest MS and the adjacent FL parishes.

After 2/3z that wave quickly flattens out as the ridge axis begins
to slide ESE quickly. At the same time instability will begin to
wane considerably. With that whatever is left of the MCS if it gets
into the CWA will likely struggle south of I-12 in SELA but should
at least push through coastal MS (if it is there).

SPC currently has our area in general thunder and overall the severe
risk is not the greatest we can never truly rule out one or two
strong to severe storms in late Spring and through the Summer. There
will be sufficient instability and with DCAPE fcst to be around 1200-
1300 j/kg again wet microburst are possible. In addition if that MCS
makes it into the northwest we could see a slight enhancement in the
wind risk from that as well.

Sunday and Sunday night really not much to say but possibly a
slightly lower chance of the same weather today. Biggest negative
for Sunday is the ridge will be over the area and that should really
hinder daytime convection. Some of the mdls once again develop an
MCS over the southern Plains overnight but that wouldn`t become a
concern until Monday if it makes it down our way. /CAB/

&&

.LONG TERM...
(Memorial Day through Friday)
Issued at 305 AM CDT Sat May 24 2025

Mdls all in agreement that things become far more active next
week with multiple days with a rather high chance of rain.
Actually quite impressively the GFS and ECMWF are in very good
agreement overall through much of next week and only by Friday do
they begin to have timing issues that said they both show a rather
strong trough axis pushing through the CWA by the end of the week
or during next weekend. That would be welcome as it should
provide much more pleasant weather especially for late May and
early June.

For Memorial Day the ridge axis will continue to slide east and we
quickly transition from weak zonal flow to weak WSW flow. We will
be warm and humid and convection will be possible as we heat up but
it will again be dictated by daytime heating and sea/lake breezes
initially. Also a slower moving ridge axis could keep convection in
check. If you are going to any Memorial Day services just keep an
eye on the radar to see if convection is developing but also make
sure you have plenty of water to drink. Winds will likely be on the
lighter side most of the day and with the heat index in the upper
90s to lower 100s you don`t want to succumb to the heat.

The pattern of a flat ridge stretching across central Mexico
and through the Gulf and into the Bahamas and a very positive
tilted L/W trough from the Great Lakes to west of the Baja will
remain in place from late Monday through Thursday. It is not a clean
looking L/W trough as there will be many closed low embedded in it
but that is what will make it somewhat slower to move out. This set
up will send multiple impulses across the TX and the Southern Plains
which will move through the Lower MS Valley likely bringing
scattered to numerous showers and thunderstorms, possibly each day,
beginning Tuesday and through Thursday. The end of the week or into
the weekend we will likely see one last good round of storms
associated with a cold front as the L/W trough finally begin to kick
out and pushes across the central and into the eastern CONUS. /CAB/

&&

.AVIATION...
(18Z TAFS)
Issued at 1222 PM CDT Sat May 24 2025

Generally VFR conditions at forecast issuance time. Isolated TSRA
were in the vicinity of KMSY/KNEW/KASD/KGPT. Potential for direct
impacts, which would be MVFR ceilings, IFR or lower visibilities
and potential for rather gusty winds. Most TSRA should dissipate
around 00z. Could see some flight restrictions around sunrise
Sunday, but don`t expect them to be widespread. Brief MVFR
ceilings Sunday morning as cumulus field develops, but most
convection should hold off until beyond 18z Sunday.

&&

.MARINE...
Issued at 305 AM CDT Sat May 24 2025

Light gradient winds will generally rule most of the forecast
period the main concern during the forecast period will be
thunderstorm development, producing localized higher winds and
seas. Threats will be greater over the protected waters (lakes and
sounds), especially from Monday onward. Do not expect any
prolonged periods of winds above 15 knots. The only other thing of
mention is that we are beginning to get more and more into the
Summer setup so we will see that nocturnal jet begin to set up
most nights east of the MS delta. The biggest issue is that small
area around Breton and Chandeluer Sounds and south of MS Sound
will likely see a bump in winds of 3-5 kts compared to much of the
coastal waters. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  90  70  92  72 /  40  30  40  10
BTR  93  73  93  75 /  30  10  40  10
ASD  90  72  90  73 /  30  30  20  10
MSY  91  76  91  77 /  30  10  20   0
GPT  88  75  88  75 /  30  20  20  10
PQL  89  72  89  72 /  30  20  20  10

&&

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

$$

SHORT TERM...CAB
LONG TERM....CAB
AVIATION/UPDATE...RW
MARINE...CAB