049
FXUS64 KLCH 181803
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
103 PM CDT Tue Jun 18 2024

...New AVIATION...

.UPDATE...
Issued at 1136 AM CDT Tue Jun 18 2024

PTC 1 consists of a very broad area of rotation in the southwest
Gulf of Mexico. A should of light rain is beginning to move into
the area from this disturbance. A few isolated thunderstorms may
develop within the mix but ultimately there is a low risk of
severe weather. However an isolated gust or brief, weak tornado
could be possible.

11/Calhoun

&&

.SYNOPSIS...
Issued at 454 AM CDT Tue Jun 18 2024

Latest IR and WV imagery shows Potential Tropical Cyclone 1
situated over the Bay of Campeche, with a broad plume of tropical
moisture streaming north across the Gulf of Mexico into LA early
this morning. This was producing a swath of light to moderate rain
over eastern portions of the CWA and the adjacent coastal waters,
with an occasional lightning strike in a few embedded stronger
cells over the waters per KLCH radar. Radar estimated rainfall
amounts over the past couple of days shows an area of 2-4 inches
across portions of southern LA along with some isolated amounts to
around 5 inches, while most areas have had less than an inch
elsewhere.

The latest guidance from NHC keeps the system in the southwestern
Gulf of Mexico the next few days, eventually moving west northwest
to west toward the northeast coast of Mexico by late Wednesday
into early Thursday. While the system will remain well south of
our area, impacts will still be felt primarily over our coastal
waters with strong and gusty easterly winds, large and very rough
wave and flooding in coastal areas of SE TX and SW LA. Abnormally
high moisture content in the atmosphere (with PWATs exceeding
2.2 inches) will also contribute to the potential for very heavy
rainfall in some of the showers or storms, mainly across our
lower SE TX and SW LA zones.

Conditions will remain unsettled at least through Wednesday, but
should begin to improve some by Thursday. However, coastal
flooding may persist into the latter part of the week as water
levels will be slow to recover as easterly winds gradually
diminish.

24

&&

.SHORT TERM...
(Today through Thursday night)
Issued at 454 AM CDT Tue Jun 18 2024

Deep southeasterly flow between an elongated midlevel trough over
the western Gulf associated with PTC 1 and ridging over the mid-
Atlantic coast will continue to tap deep tropical moisture from
the southern Gulf and western Caribbean. The latest LAPS
Precipitable Water analysis shows PWATs near 2.1 inches, and these
values are expected to surge to between 2.2 and 2.5 inches across
our SW zones later today into tonight. Broad ascent within the
very moist and uncapped atmosphere will facilitate development of
widespread showers across the region again today, Given the
unusually high moisture content, precipitation efficiency will be
maximized resulting in the potential for torrential downpours with
rainfall rates of up to 3 inches an hour. Needless to say, this
would be problematic in any urban areas, and a Flood Watch remains
in effect for portions of lower SE TX. The good news is that
guidance continues to show most of the heavier rainfall
consolidating further to the southwest, and this is reflected in
the latest ERO for today with the Moderate Risk (level 3 out of 4)
now confined mainly to Jefferson County, with the Slight Risk
(level 2 out of 4) from Hardin County southeast toward Vermilion
Parish. The northern sections (roughly north of Highway 190) are
no longer outlined in any excessive rainfall risk.

The risk for coastal flooding has remained consistent over the
past couple of days. P-ETSS guidance continues to indicate tide
levels between 2 and 3 FT MHHW at Texas Point and between 1.5 and
2.5 FT MHHW at Calcasieu Pass at times of high tide between
late tonight into Wednesday morning. Guidance spread has narrowed
some, with the boundary of the 10th and 90th percentiles within
flood warning criteria. The Coastal Flood Warning for Jefferson
County and Cameron Parish remains in effect, and has been extended
through 12Z Thursday as another high tide could reach 2.0 FT MHHW
again. A Coastal Flood Advisory remains in effect for southern Calcasieu
Parish and southern Orange County around Sabine and Calcasieu
Lakes, as well as further east across lower Vermilion, Iberia,
and St. Mary Parishes.

By Wednesday, the bulk of the moisture and energy associated with
the system will shift westward into TX, with slightly drier air
beginning to filter into the region as the ridge over the east
coast builds west. The weather pattern will begin transitioning on
Wednesday and Thursday toward a more seasonal one with mainly
scattered daytime convection forming along the seabreeze and other
mesoscale boundaries.

Daytime temperatures will be cooler than normal thanks to
widespread clouds and showers today, and highs could struggle to
reach the middle 80s. As rain chances begin to diminish over the
next few days, highs will warm back to around 90 or into the lower
90s each afternoon.

24

&&

.LONG TERM...
(Friday through Tuesday)
Issued at 454 AM CDT Tue Jun 18 2024

Large mid to upper level ridge of high pressure over the Gulf and
Southeastern U.S. states expected to be the dominate weather feature
Friday through Sunday. Lingering moisture across the Gulf expected
to keep chances of showers and thunderstorms across the coastal
waters, diminishing chances further inland as the ridge provides
additional subsidence. Afternoon temperatures in the lower 90s
expected Friday. With the ridge of high pressure nearly overhead
Saturday and Sunday, afternoon temperatures expected to increase in
the mid to upper 90s north of I-10, lower to mid 90s further south.
Lows in the lower to mid 70s. Heat index values expected to rise as
well, likely in the 102-107 range, possibly approaching Heat
Advisory criteria (heat index of 108-112 for our region).

Monday and Tuesday, the mid to upper level ridge weakens as a broad
mid to upper level trough prevails over the Central U.S. The trough
should allow moisture from another tropical disturbance across the
Southwest Gulf of Mexico to advanced further northward, increasing
chances for showers and thunderstorms further inland. Blended
guidance shows 40-60% for Monday and Tuesday, mainly during the
afternoons. Highs in the lower to mid 90s north of I-10, and upper
80s to lower 90s closer to the coast.

08/DML

&&

.AVIATION...
(18Z TAFS)
Issued at 1238 PM CDT Tue Jun 18 2024

Tropical airmass and rainshield is moving over the area with most
terminals seeing MVFR ceilings and light rain showers. Expect the
trend of light to moderate showers, low ceilings, gusty east winds
and vicinity thunder to continue for coastal terminals into the
late overnight hours.

The only exception being Alexandria where primarily diurnal showers
and VCTS last through this afternoon.

Potential Tropical Cyclone 1 will continue moving into east Mexico
/southeast Texas through tonight which will pull convection to the
south tomorrow. Vicinity showers should remain offshore through
18Z with a northward progression after 18Z. Breezy easterly winds
will prevail.

11/Calhoun

&&

.MARINE...
Issued at 454 AM CDT Tue Jun 18 2024

Potential Tropical Cyclone 1 will gradually move west northwest across
the southwestern Gulf of Mexico toward the northeast coast of
Mexico by Wednesday night. A rather large wind field associated
with the system, along with a tight gradient across the northwest
Gulf of Mexico, will provide moderate to strong and gusty east to
southeast winds in the 20 to 30 knot sustained range with
occasional gusts up to 40 knots. This will also allow for wave
heights to increase in the 7 to 14 foot range. A Small Craft
Advisory will be in effect through mid week.

As long as the system stays weak, deep moisture will be out from
the north side of the system, keeping widespread showers and
storms through mid week.

24/Rua

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  85  72  89  72 /  40  40  30   0
LCH  84  75  89  76 /  70  70  70  30
LFT  84  76  91  77 /  70  50  60  10
BPT  86  75  88  77 /  70  70  80  40

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...Coastal Flood Warning until 7 AM CDT Thursday for LAZ073-074.

     Coastal Flood Advisory until 7 AM CDT Thursday for LAZ241-
     252>254.

TX...Coastal Flood Warning until 7 AM CDT Thursday for TXZ615.

     Coastal Flood Advisory until 7 AM CDT Thursday for TXZ616.

     Flood Watch through Wednesday evening for TXZ201-515-516-615-616.

GM...Small Craft Advisory until 7 AM CDT Thursday for GMZ450-452-455-
     470-472-475.

&&

$$

SHORT TERM...24
LONG TERM....08
AVIATION...11