Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 280358
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1058 PM CDT Thu Apr 27 2017

.DISCUSSION...
Main updates were for issuing marine hazards, see discussion
below. For the inland locations, rather tranquil this evening. Wx
map shows SE winds increasing offshore with retreating warm front
near the coast this evening. Increasing MVFR low clouds invading
northward near the front, and will cover the entire area by
daybreak. Thus, previous forecast on track.

DML

&&

.MARINE...
Southerly winds will continue increasing overnight and Friday,
becoming quite strong and gusty Friday Night and Saturday as a
cold front approaches the area. Gusts in excess of Gale Force are
possible Saturday and Saturday Night. For this, have upgraded to
Small Craft Advisory for the 20-60nm zones overnight, expanding to
all marine zones by Friday night through early Sunday morning.
Gusts over Gale force is likely, and a Gale warning may have to be
considered for Saturday and Saturday night. This strong southerly
flow will also result in above normal tide readings the next few
high tide cycles, especially Saturday and Sunday mornings. Winds
will subside and become northwesterly from west to east on Sunday
as the cold front pushes through the area.

DML

&&

.PREV DISCUSSION... /issued 602 PM CDT Thu Apr 27 2017/

AVIATION...VFR conditions are expected through much of this
evening, however as midnight approaches MVFR ceilings will begin
to develop. Ceilings may lower to around 1kft by sunrise, but
then lift somewhat through mid morning. Winds will continue to
veer SE and then become gusty tomorrow.

PREV DISCUSSION... /issued 451 PM CDT Thu Apr 27 2017/

DISCUSSION...
Generally pleasant conditions across the area this afternoon with
plenty of sun and temperatures in the upper 70s/mid 80s. What
remains of the front that pushed through the area yesterday is
already beginning to show signs of retreating northward through
the NW Gulf.

Southerly flow is progged to return to the area tonight, which
will begin the process of ushering Gulf moisture back into the
region. This process will accelerate late tonight into early
Friday as the aforementioned warm front lifts north through the
area, and a deeper/stronger southerly fetch becomes establishes
courtesy of an initial lee cyclone over the Central/Southern
Plains. Some light shower activity is possible early tomorrow in
association with the retreating warm front, with a thunderstorm
or two over East Central LA by afternoon. Guidance otherwise
indicates an unstable but capped atmosphere with little in the way
of any forcing mechanisms. South winds over the coastal counties
and parishes will near Wind Advisory criteria, but look to
generally remain just below. Thus, a cloudy, somewhat breezy, and
warm day is on tap.

The initial lee cyclone is forecast to weaken and lift out to the
NE on FRI, only to be quickly replaced by another over the TX
panhandle FRI night, further strengthening low level winds fields.
Winds on SAT will almost certainly exceed Wind Advisory criteria,
with frequent gusts to 35 mph expected along and south of the I-10
corridor. Global models diverge a bit on convective prospects SAT,
with the ECMWF and CMC generating activity during the afternoon,
as an apparent subtle shortwave ejects out ahead of the main upper
trof still progged to be just east of the Four Corners. Less
convective inhibition and greater shear are progged, so any deep
convection that can get going will have some severe potential
during the afternoon/evening hours.

By the overnight period, as the upper trof and associated SFC low
begin to lift out TWD the E/NE, the trailing CDFNT will push into
E TX accompanied by widespread showers and thunderstorms, and
continue east through LA during the day on Sunday. There remains
some spread in model guidance regarding the speed/timing of the
frontal passage, but they area in generally good agreement that
most of the rain should be east of the area by SUN evening.

While moisture content will be impressive (PWATs in excess of 2")
the relative speed of the system will help mitigate widespread
flooding concerns, though locally heavy rain is certainly
possible, and has been added to the gridded forecast. Deep
convection in particular will be capable of very high rainfall
rates. There will also be an accompanying severe weather risk
given forecast parameters, with all modes seemingly in play.

Dry and mild weather expected in the wake of the front Sunday
night into Tuesday, with good rain chances returning mid to late
week as another upper trof takes aim at the region.

13

MARINE...
East winds will gradually become more southerly and increase
tonight as surface high pressure moves off toward the northeast
and pressures fall over the Central and Southern Plains. Modest
onshore flow will continue tomorrow, and become QUITE STRONG AND
GUSTY Friday night and Saturday AS A COLD FRONT APPROACHES THE
AREA. Gusts in excess of Gale force are possible Saturday and
Saturday night. This strong southerly flow will also result in
above normal tide readings the next few high tide cycles,
especially Saturday and Sunday mornings. Winds will subside and
become northwesterly from west to east on Sunday as the cold front
pushes through the area. Widespread showers and thunderstorms are
expected ahead of and along the front.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  65  87  75  85 /  20  20  20  40
LCH  69  85  76  82 /  20  10  20  50
LFT  72  87  77  86 /  20  10  10  40
BPT  70  86  77  84 /  20  10  20  50

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory from 4 AM Friday to 7 AM CDT Sunday for
     GMZ472-475.

     Small Craft Exercise Caution until 4 AM CDT Friday for GMZ472-
     475.

     Small Craft Advisory from 7 PM Friday to 7 AM CDT Sunday for
     GMZ450-452-455-470.

     Small Craft Exercise Caution through Friday evening for GMZ450-
     452-455-470.

     Small Craft Advisory from 1 AM Saturday to 7 AM CDT Sunday for
     GMZ430-432-435.

     Small Craft Exercise Caution from 4 AM CDT Friday through late
     Friday night for GMZ430-432-435.

&&

$$

PUBLIC...08



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