Mandeville, Louisianna 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

545
FXUS64 KLIX 310134
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
834 PM CDT Sun Mar 30 2025

...New UPDATE...

.UPDATE...
Issued at 807 PM CDT Sun Mar 30 2025

Will be pushing an update in the next 30-45 minutes to indicate
an earlier arrival for line of potentially severe thunderstorms.

In the very near term, earlier convection is east of all land
areas but still some showers over the far eastern coastal waters.

The 00z LIX sounding is rather concerning, with CAPE values near
4000 J/kg, Lifted index of -10, Wet Bulb Zero of 9500 feet, lapse
rate between about 690 mb and 500 mb of 8.3C/km with very little
in the way of mid-level inhibition.

Thunderstorms have already developed over Arkansas and east Texas,
where Severe Thunderstorm Watches are in effect. Recent model
solutions are signaling that the arrival time of the thunderstorm
line could be 1-2 hours sooner than earlier anticipated for the
major metro areas. This could bring storms into the Baton Rouge
Metro area by 5 AM CDT, New Orleans, Houma and Slidell by 8 or 9
AM, and the Gulfport/Biloxi/Pascagoula areas prior to 10 AM...and
those arrival times may not be fast enough.

With the potential for an earlier arrival time, and how the LIX
sounding looks, the Storm Prediction Center has brought the
Enhanced Risk area overnight further southward, nearing Interstate
12, and the Slight Risk to Interstate 10. Will be bumping up PoPs
for the late night hours as well to fit above timing.

&&

.SHORT TERM...
(This evening through Monday night)
Issued at 350 PM CDT Sun Mar 30 2025

Multiple impulses moving eastward along the northern Gulf Coast
are producing scattered convection this afternoon with most of the
activity in our area occurring along the Mississippi coast and
over our eastern coastal waters. The airmass is very moist and
unstable with temperatures in the lower and middle 80s outside of
where storms are occurring, while dew points are generally in the
lower 70s. With precipitable water values near 1.7 inches (at the
upper end climatologically for late March), storms have been very
efficient precipitation producers with a few locations already
seeing 1.5 to 2.5 inches of rain along the Mississippi coast.

Once the storms along the Mississippi coast move out in the next
few hours, our attention will turn to the west. A shortwave will
move out of the Rockies across the southern Plains States late
tonight and Monday morning. A line of thunderstorms is expected to
develop just in advance of the associated cold front. These storms
could potentially reach our southwest Mississippi counties and
southeast Louisiana parishes northwest of Baton Rouge just before
sunrise. Storms will move eastward, and should be out of most of
the area by early afternoon, although some of the convection
allowing modeling indicates potential to linger along the
Louisiana far lower coastal parishes. Moisture, instability and
shear will all be more than sufficient for severe storms to
develop, with all modes of severe weather possible. Most of the
CWA will be in a Slight Risk of severe weather on Monday, with an
Enhanced Risk over portions of Jackson County Mississippi, where
surface heating during the morning may help enhance instability.

The frontal boundary should slide offshore Monday night, allowing
slightly drier air to move into the area.

&&

.LONG TERM...
(Tuesday through Saturday night)
Issued at 350 PM CDT Sun Mar 30 2025

A large scale trough will move through the Plains States Tuesday
night and Wednesday, but at this time, it appears that any impacts
will be to the north of our area. With upper and surface ridging
over the Bahamas, upper flow will become southwesterly at midweek,
with multiple shortwaves moving from west Texas toward the Great
Lakes through the end of the work week. A frontal boundary will
eventually sag into the area next weekend, with the ECMWF
operational run being a little quicker to do it than the GFS
operational. Can`t rule out a few stray showers by Wednesday or
Thursday, but any significant areas of precipitation should remain
out of the area until at least Friday, and more likely over the
weekend. At those time scales, will just run with the NBM PoPs
for now.

One thing for sure, it`s going to be very warm. Some guidance is
indicating potential for 90 degree highs at several locations
Wednesday through Friday, which is roughly 2 weeks ahead of when
most record high temperatures hit 90 degrees. Normal highs are mid
70s this week.

&&

.AVIATION...
(00Z TAFS)
Issued at 625 PM CDT Sun Mar 30 2025

Earlier convection has just about died out, although a SHRA had
just re-developed just west of KGPT. Borderline IFR ceilings at
KHUM and KPQL at issuance, with MVFR at KGPT. Will carry VCSH
at KGPT at issuance. Expect quiet conditions for the next few
hours, before MVFR to IFR ceilings set in at all terminals after
06z. Main concern will be a line of TSRA that is expected to move
across all terminals tomorrow morning. These may reach KMCB and
KBTR as early as 12z, and are expected to be east of all forecast
terminals around 17-18z. Will carry a 2 hour TEMPO with best
estimate of timing at each terminal. Direct impacts will produce
IFR or lower ceilings and visibilities, and potential for 45 to 50
knot (or higher) wind gusts. Expect improving conditions during
the afternoon hours with the passage of the cold front. MVFR
ceilings during the early afternoon, and VFR near or prior to
sunset Monday.

&&

.MARINE...
Issued at 350 PM CDT Sun Mar 30 2025

Main concern over the next 24 hours will be convection related,
with winds generally remaining below 15 knots outside of storms.
On the larger scale, winds and seas are likely to move into
hazardous ranges as early as Tuesday night, with advisories
probably necessary from that point into at least Thursday.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  67  83  60  83 /  60  90  10  20
BTR  69  85  64  85 /  60  80  10  10
ASD  68  84  64  84 /  20  80  10  10
MSY  70  84  67  83 /  20  80   0  10
GPT  66  80  63  78 /  10  80  10  10
PQL  66  80  61  82 /  10  80  10  10

&&

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

$$

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