778
FXUS64 KLCH 311759
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1259 PM CDT Fri May 31 2024

...New AVIATION...

.UPDATE...
Issued at 955 AM CDT Fri May 31 2024

A slowly weakening and less organized MCS continues to work
through Southeast Texas and into Southwest Louisiana at this hour.
While storms have remained sub severe, they are likely producing
some brief gusty winds along their leading edges. CAMS guidance
continues to perform very poorly with this event, as they have for
the last several events. Initializations look poorly rendered
giving little confidence to their solutions. That said, the latest
iterations depict less development with the previously depicted
second MCS that was expected later this evening in the wake of the
ongoing event. While this makes some meteorological sense as the
atmosphere is likely to be fairly worked over, confidence is very
low owing to the poor model guidance.

Increased PoPs this morning along and ahead of the advancing MCS,
but didn`t make any changes to PoPs through the afternoon or
tonight. Also added small craft exercise caution wording to the
coastal waters to account for moderate gradient winds expected to
develop behind the MCS.

Jones

&&

.SHORT TERM...
(Today through Sunday night)
Issued at 400 AM CDT Fri May 31 2024

A very active and unstable weather pattern will continue into
Saturday before thunderstorm chances decrease slightly on Sunday.

Once again for today, a very moist and unstable air mass will be
in place. PWAT values are expected in the 1.8 to 2.1 inch range
which is over the 90th percentile of SPC daily climo. Meanwhile,
CAPE values are expected to recover during the morning hours back
above 2500 j/kg with 0-3km shear over 30 knots. Timing for the
convection is tricky as short term guidance has not been handling
the evolution of upper level energy and associated meso storm
complexes.

For today, looking at a MCS coming out of central Texas that will
enter the forecast area by mid-morning. This activity should re-
intensify as it moves across through the afternoon hours.
Parameters are in place that damaging straight line winds will be
possible with the thunderstorms as bow segment features are
expected. There is also a low end probability of some quick spin
up tornadoes embedded with this features as 0-1 helicity values
will get over 150 m2s2. SPC has outlined the southeast Texas, and
central and southwest Louisiana portions of the forecast area in
Slight Risk (level 2 out of 5) and a Marginal Risk (level 1 out of
5) for the remainder of the forecast area.

With the high moisture and PWAT values, high rainfall rates are
likely with the storms with 1 to 3 inch per hour probable.
Therefore, the forecast area has a Slight Risk (level 2 out of 4)
for excessive rainfall that may lead to flooding.

A second MCS is expected to enter and move across during the late
afternoon into early evening hours. However, there is less
confidence in this feature, as well as just how strong it will be
if it does develop as the air mass may be still worked over from
the first.

On Saturday, still plenty of moisture around to go along with
expected moderate to high instability, and a general weakness
aloft. Therefore, scattered to numerous showers and thunderstorms
are expected to develop with daytime heating. Any storm that
develops with have a chance to produce downburst wind gusts and
heavy rainfall. A Marginal Risk for both severe storms and
excessive rainfall will be outlined for the forecast area.

On Sunday, upper level ridge will try to build into the forecast
area with lower PWAT air and no strong upper level energy noted.
Therefore, more seasonal diurnal shower and thunderstorm activity
is expected.

Rua

&&

.LONG TERM...
(Monday through Friday)
Issued at 400 AM CDT Fri May 31 2024

Monday continues into an unsettle rainfall pattern with a fairly
active subtropical jet upstream along Baja while localized pattern
consists of mainly zonal flow with some subsidence ridging in the
lower troposphere. Do note, while the movement is rather zonal,
there are perturbations of pressure which remain consistent of
setting the stage for isolated activity to organize into more
scattered / widespread storm clusters. Timing and location are
aspects that will remain uncertain until this period comes closer
into the range of the CAM guidance. Thus, POPs do not completely
diaspora through mos of the long range, but remain lowered to
reflect the confidence in timing given this nature of the unsettled
wet pattern.

While daytime highs climb to the upper 80`s and 90`s with periodic
clearing of skies, forecast dewpoints will remain primarily in the
mid 70`s which will elevate risk of heat related illnesses for more
sensitive populations during prolong periods of physical activity
without proper hydration. Meanwhile, as the week progresses, an
upstream shortwave stalls along NW Mexico which enhances upper level
flow across S`rn Tx and Gulf of Mexico trending through Wednesday
morning with another wave developing downstream, closer to home,
over the E`rn GOM. As it stand presently, this upper level feature
appears to produce much of the precipitable rain east of the the
Mississippi, across the SECONUS while shifting over the Florida
Peninsula Thursday. Models show the potential in a drying trend late
week with departures of temperature and dewpoint growing stronger as
a broad upper level ridge develops over the Midwest. Again, should
be noted this long range outlook remains unsettled with more
variable solution s as the northern jet and the subtropical jet
begin to interact over the Midwest late in the upcoming work week.
Therefore, while there are some signals, particularly in the
national blend of models for some drying trend, consistency has not
been demonstrated.

 Kowalski/30

&&

.AVIATION...
(18Z TAFS)
Issued at 1251 PM CDT Fri May 31 2024

A broken MCS continues to progress across the region this
afternoon. Precipitation has already come to an end at BPT and
will do so at LCH shortly. AEX, LFT and ARA will continue to see
visibility reducing heavy rainfall, and gusty winds through 21Z.
Guidance has backed off additional development this evening. Areas
of fog will be possible overnight where heavy rainfall was
observed but confidence in this is too low to explicitly mention
at this time. Another round of scattered to widespread showers and
storms will develop Saturday morning and continue through the
afternoon. Confidence on the timing of the initialization of
Saturday`s storms is very low and could occur prior to sunrise.

Jones

&&

.MARINE...
Issued at 400 AM CDT Fri May 31 2024

Surface high pressure will ridge westward across the northern Gulf
of Mexico into the coastal waters. This will provide a light to
occasionally modest onshore wind flow with mainly light seas
through the weekend into early next week.

There will be a chance for complexes of thunderstorms to move
across the coastal waters this morning into the afternoon, then
again this evening. Strong wind gusts and frequent lightning can
be expected with these storms.

Scattered showers and thunderstorms can be expected on Saturday,
before rain chances begin to decrease on Sunday into early next
week as an upper level ridge builds in.

Rua

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  69  85  70  87 /  50  80  30  50
LCH  75  86  75  87 /  40  70  20  50
LFT  75  88  75  89 /  40  70  20  50
BPT  75  88  76  89 /  40  60  10  30

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...None.
&&

$$

SHORT TERM...66
LONG TERM....30
AVIATION...66