Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 171743
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1243 PM CDT Sun Mar 17 2024

...New AVIATION...

.UPDATE...
Issued at 1023 AM CDT Sun Mar 17 2024

The wave of showers and thunderstorms is beginning to exit into
southeast Louisiana this morning. Some showers and isolated
thunder remains over the Atchafalaya and lower Acadiana, but
otherwise things are pretty calm. Wrap-around showers and light
rain will linger into the early afternoon, but otherwise the bulk
of severe and flooding threat are done.

Inherited grids were cleaned up a bit to capture the exiting storm
feature: PoPs decreased across western portions of the area, winds
and temps brought into alignment with latest short term consensus
trends.

11/Calhoun

&&

.SHORT TERM...
(Today through Tuesday night)
Issued at 333 AM CDT Sun Mar 17 2024

Convection has begun increasing over the last hour along a
quasistationary frontal boundary approximately twenty miles
offshore as an upper level wave works up the Texas gulf coast.
Expect convection to continue to increase in coverage and
intensity through the morning as the wave transits the region.
Deep moisture through the column will allow for heavy rain
producing storms and much of the region remains highlighted in a
slight risk of excessive rainfall. Despite a bit of a reprieve
yesterday, areas that saw significant rainfall Friday will be
particularly susceptible to street flooding.

A southward diving trof will push a secondary front through the
region by mid afternoon pushing the stalled front and moisture
offshore and bringing precip to an end. Decent cold air advection
will develop behind the front with winds increasing to 15-20 knots
overnight through Monday. High pressure builds across the northern
gulf coast Monday night into Tuesday morning allowing winds to
lessen. Forecast guidance for lows Tuesday morning has been
trending cooler over the last couple of days and a late season
frost appears likely north of I-10. A few spots may even touch
freezing. Precautions should be taken to protect sensitive
vegetation.

The surface high quickly slides east of the area by Tuesday
afternoon with winds turning back out of the south beginning to
push the colder airmass back to the north. Lows Wednesday morning
will be about 10 degrees warmer than Tuesday morning.

Jones

&&

.LONG TERM...
(Wednesday through Sunday)
Issued at 333 AM CDT Sun Mar 17 2024

The long term portion of the forecast period begins Wednesday with
sfc high pressure east of the area, allowing a moistening return
flow to set up off the Gulf. Meanwhile, an initial disturbance
rounding a swrn CONUS shortwave/cutoff low will makes its way from
nrn Mexico towards the forecast area. As lift associated with this
feature begins to encroach the region and work in concert with the
increasing moisture (forecast soundings indicate mean RH values
peaking in excess of 90 percent with PWAT values topping out near
1.5 inches/90th percentile per SPC raob climo), will accordingly see
rain chances beginning over the TX zones Wednesday evening before
spreading west-to-east across the area through the night. POPs then
increase into Thursday as a sfc low sweeps by over the nrn Gulf.
Blended guidance is currently advertising rain chances maxing out in
the good chance/likely categories for Thursday before showers/storms
begin exiting the area with the departing shortwave/weak sfc front
Thursday evening.

The remainder of the forecast period is then expected to be dry as
an initially nwrly flow aloft behind the departing shortwave
gradually turns more zonal while sfc high pressure gradually works
past the region.

Temperature are forecast to gradually warm beginning Thursday, with
warmer than normal temps expected by next weekend.

25

&&

.AVIATION...
(18Z TAFS)
Issued at 1245 PM CDT Sun Mar 17 2024

A large mesoscale convective vortex (MCV) complex has finally
exited the area to the east. In its wake there are still some VCSH
at AEX, LFT and ARA as well as lowered ceilings to IFR levels.
Further to the west at LCH and BPT, some improvement in ceilings
have been noted.

Behind the MCV, winds are variable for now with some random gusts
in the mix. A series of shortwave perturbations moving over
south central Texas are causing another wave of showers and
thunderstorms to develop over Galveston and nearby coastal waters.
These cells are moving east northeast and could impact coastal
terminals in the next few hours so VCSH was left in as mentions at
LCH and BPT.

Expect MVFR ceilings to prevail through the remainder of today
until after 01 to 05Z when dry air begins working into the region.
Ceilings will slowly lift into low VFR by 12Z and will improve
further thereafter.

Variable winds right now should begin to standardize out of the
north-northeast this afternoon. Winds will increase further after
00Z, forcing a cold front down through the region. Expect north-
northeast flow sustained 10 to 17 knots with higher gusts from 00Z
to the end of the TAF period.

11/Calhoun

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  65  46  63  33 / 100  10   0   0
LCH  72  53  66  40 / 100  10   0   0
LFT  72  53  65  39 / 100  20   0   0
BPT  75  54  69  43 /  90  10   0   0

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory from 9 PM this evening to 7 AM CDT Tuesday
     for GMZ430-432-450-452-470-472.

     Small Craft Advisory from 5 AM Monday to 7 AM CDT Tuesday for
     GMZ435-436-455-475.

&&

$$

SHORT TERM...66
LONG TERM....25
AVIATION...11


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