588
FXUS64 KLCH 281632
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1132 AM CDT Sun Apr 28 2024

...New UPDATE, AVIATION, MARINE...

.UPDATE...

Wx map shows surface high pressure off the East Coast and a low
pressure trough across the Central Plains southward to Central
Texas. Over our region, a tight pressure gradient remains, keeping
moderate southeast winds over the region, although not as strong
as Saturday. Winds around 20 mph with gusts to 30 mph occurring
now along and south of the I-10 corridor. Further north, sustained
winds of 15 mph with gusts to 25 mph occurring, and these values
expected to continue this afternoon. Wind Advisory remains for
the I-10 corridor south to the coast through 9 PM.

Minor coastal flooding still likely, although current observations
between 1.5 to 1.8 feet Mean Higher High Water (MHHW) have peaked
the last couple of hours and beginning to fall. Latest P-ETSS
guidance still a little high compared to current trends, but have
come down some as well. Further up the Sabine and Calcasieu
basins, high tide has yet to come, and these tides are continuing
to rise and likely to peak during the afternoon hours. Also
considering the duration of these southeast winds keeping tides
1-2 feet above astronomical tide over two days now, sufficient
infiltration into the marshes and low lying coastal areas have
likely occurred. Thus, will keep the ongoing Coastal Flood Warning
for Southern Jefferson & Orange Counties and Cameron & Southern
Calcasieu Parishes. Further east across coastal Vermilion, Iberia,
and St. Mary Parishes, tides reached 1.5 feet Mean Higher High
Water (MHHW) during the times of high tide. Thus, kept the ongoing
Coastal Flood Advisory. With southeast winds expected to diminish
before next high tide cycle, do not anticipate extending any
coastal flood warning or advisories for Monday.

The other story will be the approaching longwave mid to upper
level trough over Central Plains expected to move slowly as the
shortwave within the base of the trough ejects northeastward
through Monday. This will place our region in the diffluent flow
aloft later tonight into most of the day Monday. Thus, chances of
showers and thunderstorms will increase later this evening, along
with expected rainfall amounts. Fine tuning of the rainfall
amounts, along with the severe and flooding risk, expected with
the full afternoon package generation cycle.

08/DML

&&

.SHORT TERM...
(Today through Tuesday night)
Issued at 425 AM CDT Sun Apr 28 2024

Well, get ready because this forecast package includes a lot of
updates with quite a big upgrade in wording and expectation for
the next 24 to 36 hours.

To start with hazards... The Wind Advisory was cut back down to
the HWY 190 corridor for much of today. High pressure has moved
further east allowing for the pressure gradient to relax in
comparison to yesterday. Strong south-southeast winds with gusts
up to 40 MPH along the coastline are still likely, but further
inland, expect breezy conditions below Advisory criteria
(sustained 20 to 34 MPH).
Due to the continuation of long fetch over the Gulf, waters will
continue piling up along the coastline. As we move towards high
tide, expect water levels 2 or so feet above tide predictions
which would result in coastal flooding. Areas most concerning are
Jefferson and south Orange counties, and Cameron and south
Calcasieu parishes which are under a Coastal Flood Warning. All
other coastal zones are in a Coastal Flood Advisory for waters
1.5 to 2.0 feet above tide predictions.

The mention of an upgrade in wording for this forecast package
comes due to a sudden upgrade to Slight Risk for severe weather
for all Texas counties and Louisiana parishes west of I-49;
Marginal Risk of severe weather east of I-49. A series of low
pressure areas are moving across the central US underneath mid
level shortwave trof. This trof axis swings towards east Texas
late today before another shortwave pulse develops and moves
overtop Louisiana on Monday. There is already a long area of
thunderstorms which developed from the main shortwave that now
stretches from the Upper Midwest southwestward into southwest
Texas. The expectation is for storms to repeatedly die off and
redevelop along this line as it moves east underneath the
primary shortwave trof today. At this time, we are now expecting
a line of strong to severe thunderstorms to arrive into southeast
Texas sometime late this evening into early Monday morning. Short
term guidance is struggling to sort out exactly what time this
feature will move through our region with earliest arrival being
about 10 PM tonight and latest arrival a few hours after midnight.

Severe concerns with this line are for some tornadoes and strong
to severe thunderstorms; some hail up to 1 inch. Other concern
is for very efficient rainfall associated with the line that may
result in areas of flash flooding. It is hard to say where the
line of greatest rainfall will set up, but with the rain we`ve had
recently, it`s not going to take much to cause flooding in urban
centers nor for creeks to come out of their beds. QPF forecasts
and rainfall total probabilities have only increased and now
place 3 to 5 inches with some higher amounts across much of
southeast Texas and central/southwest Louisiana from late Sunday
into Tuesday morning. The bulk of rainfall is expected from after
midnight tonight through Monday evening.

As of now, we urge folks to prepare for severe weather and flash
flooding as we start this next work week.

The secondary trof moves overhead Monday afternoon which should
assist with moving the bulk of showers and thunderstorms out of
the area by evening. However, the boundary these storms are tied
to won`t clear down into the GoM under weakening flow aloft.
Expect the boundary to move back onshore on Tuesday with another
round of showers and storms (lighter rain and lower severe risk)
Tuesday afternoon.

11/Calhoun

&&

.LONG TERM...
(Wednesday through Sunday)
Issued at 425 AM CDT Sun Apr 28 2024

Weak SFC and mid level ridging exists to the east giving way to more
of a trof across the region by mid week. Meanwhile the southern
stream jet, while not strong, remains across the Gulf Coast through
this period. Guidance continues to show multiple disturbances
traversing the flow from mid to late week, with an eventual cold
front approaching by late week into the weekend. It appears this
frontal bndry will become stationary meandering through the weekend.

Given the ample moisture and instability, daily showers and
thunderstorms look like an increasing likelihood. Severe weather is
not out of the question given the presence of the disturbances and
jet support, but confidence is on the low side. An active and
unsettled period of weather with increased chances for above average
rainfall has much higher confidence.

Daytime highs remain a nearly copy and paste forecast through the
entire extended. Highs each afternoon will be in the middle to
upper 80s, warmest into the weekend ahead of the frontal bndry.

78

&&

.AVIATION...
(18Z TAFS)

MVFR ceilings expected to prevail through the afternoon and
evening. Southeast winds ~ 20 kts with gusts near 30 kts expected
to continue for southern terminals this afternoon and evening,
slightly less for AEX. The expected increased lift likely to
generate an MCS later today/evening and move across the region
overnight into Monday. Looks to be a prolonged event, so outlooked
the remainder of the terminal forecast with prevailing TSRA
towards daybreak into the morning hours. Timing highly dependent
on place and eventual evolution/movement.

&&

.MARINE...
A tight pressure gradient between high pressure off the East Coast
and low pressure across the Central Plains will keep moderate
southeast winds through Monday morning. Winds and seas expected
to gradually diminish as a surface trough from the west approaches
the region and relaxes the pressure gradient on Monday. Chances
of showers and thunderstorms will increase tonight through Tuesday
morning as the surface trough and deep layer upper level trough
approaches the area.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  87  65  78  64 /  20  60 100  20
LCH  85  69  80  70 /  20  60  90  20
LFT  88  72  81  70 /  10  30  90  40
BPT  82  71  82  71 /  30  70  80  20

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...Wind Advisory until 9 PM CDT this evening for LAZ027>033-044-045-
     055-073-074-141>143-152>154-241>243-252>254.

     Flood Watch from 7 PM CDT this evening through Monday evening
     for LAZ027-028-030>032-141.

     Coastal Flood Warning until 5 PM CDT this afternoon for LAZ073-
     074-241.

     Coastal Flood Advisory until 5 PM CDT this afternoon for
     LAZ252>254.

TX...Wind Advisory until 9 PM CDT this evening for TXZ180-201-259>262-
     515-516-615-616.

     Flood Watch from 7 PM CDT this evening through Monday evening
     for TXZ180-201-259>262-516.

     Coastal Flood Warning until 5 PM CDT this afternoon for TXZ615-
     616.

GM...Small Craft Advisory until 1 AM CDT Monday for GMZ430-432-435-
     436.

     Small Craft Advisory until 1 PM CDT Monday for GMZ450-452-455-
     470-472-475.

&&

$$

SHORT TERM...08
LONG TERM....05
AVIATION...08