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000
FXUS64 KLCH 251735
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1235 PM CDT Sun Jun 25 2017

.DISCUSSION...
18Z TAFS

&&

.AVIATION...
Scattered convection has gradually increased across southeast
Texas through the morning, the effects of which are presently
being felt at BPT. Expect convection to gradually spread east into
Louisiana along and south of the I-10 corridor as the afternoon
progresses. Further north, a weak frontal system is pulling in
drier dewpoints across AEX this afternoon and current thinking is
that this should limit convection across central Louisiana. This
front is progged to slowly move south through the afternoon which
could serve to simultaneously enhance convection along it while
suppressing convection in its wake. All convection is expected to
dissipate around sunset this evening. With drier dewpoints
anticipated across the region this evening, fog does not appear to
be as likely as it has been the previous two nights.

Jones

&&

.PREV DISCUSSION... /issued 1053 AM CDT Sun Jun 25 2017/

DISCUSSION...
Weather map show frontal boundary to the coast with northeasterly
winds behind it. Slightly drier air with dewpts in the upper 60s
across Central Louisiana, but further south dewpts still in the
mid/upper 70s. Radar shows lingering showers with isolated
thunderstorms over Southeast Texas, with scattered showers and
thunderstorms over the western coastal waters.

Minor updates to shower and thunderstorm chances this morning.
Little changes to the afternoon and evening. Still thinking
showers and thunderstorms will develop behind the surface boundary
along the I-10 corridor this afternoon and slowly push southward
into the coastal parishes/counties and coastal waters this
evening. No other changes made to forecast.

DML

PREV DISCUSSION... /issued 644 AM CDT Sun Jun 25 2017/

DISCUSSION...
25/12Z TAF Issuance.

AVIATION...
Winds at the southern terminals have shifted to the northeast
overnight, with the weak sfc frontal boundary sitting over the
region. Recent KLCH radar imagery shows a few sctd SHRA/TSRA just
off the coast early this morning, with little, if any, convection
inland. Ample moisture remains over the area with IFR cigs and
patchy fog at all southern sites while fog/low cigs at AEX have
lifted. Conditions should improve to VFR acrs the area through
15Z, with sctd convection developing by late morning, with the
best coverage expected near the southern terminals. Showers and
storms will diminish around sunset with VFR to prevail overnight.

24

PREV DISCUSSION... /issued 354 AM CDT Sun Jun 25 2017/

SYNOPSIS...
Surface frontal boundary working its way to the south across the
forecast area this early morning. As of 25/07Z boundary is located
roughly between the Highway 190 and I-10 corridors. Frontal
boundary looks to be shallow when looking at area vad wind
profiles with shower activity still lingering behind the frontal
boundary across interior Southeast Texas and west central
Louisiana...and typical summertime nocturnal shower activity has
also developed over the Gulf. Moisture profiles still on the high
side with LAPS and GPS-MET data as of 25/08Z indicating
precipitable water values between 1.9 and 2.1 inches across the
forecast area.

Rua

DISCUSSION...
Surface frontal boundary will slowly move down to the coast before
stalling later today. Still plenty of rich Gulf moisture to work
with as PWAT values to remain around 2 inches and Mean RH over 70
percent. Aloft, upper level weakness and shear axis will remain
over the region. Therefore, combination of these features will
allow for elevated rain chances today. Best chance for pops during
the morning hours look to be northern zones along and just behind
the frontal boundary, then in the afternoon further south as
decent lift should set up along the convergence region between the
surface front and the sea breeze.

With high moisture content and weak steering currents, could be
some isolated heavy rainfall, especially where focus occurs along
colliding boundaries, as rainfall rates will likely be around 2
inches with the stronger convection. Thus, a marginal risk for
excessive rainfall has been outlined for the forecast area by the
Weather Prediction Center, mainly if these high rainfall rates
occur over poor drainage urban areas. Also, conditions will be
favorable for the formation of tropical funnel clouds, especially
in the development stage of convection near colliding boundaries.

Frontal boundary will stall along the coast and hang out over the
next couple of days, with drier air pivoting northeast to
southwest into the region as high pressure tries to build in
behind the front. Therefore, best chance for shower activity for
Monday and Tuesday will be confined to coastal regions. The mixing
in of some continental air will lower PWAT values and also
reduce the risk for heavy rainfall.

By mid week, high pressure will set up off the Mid-Atlantic coast
and ridge westward. This will allow for a deep southeasterly flow
to again bringing in rich Gulf moisture and an increase in rain
chances, especially on Thursday, as a bit of a disturbance rotates
around the ridge and across the forecast area.

By the end of the week into next weekend, typical summertime
weather pattern sets up with the sub-tropical ridge off the
Southeast coast building into the forecast area. Hot and humid
conditions with a small chance of a daily afternoon showers and
storms will be the result.

Rua

MARINE...
Weak pressure pattern across the coastal waters will be noted for
the remainder of the weekend into early next week as a weak
frontal boundary meanders near the coast. This will allow for a
light east to east-northeast wind flow and rather low seas.
However, high moisture values will interact with the front for
elevated chances of showers and thunderstorms into Monday. Winds
and seas will be locally higher near the storms.

By mid week, high pressure off the southeast coast will ridge
across the northern Gulf with a more predominate moderate
southeast flow developing and building seas for Wednesday and
Thursday.

Rua

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  67  88  68  88 /  20  20  10  20
LCH  73  87  73  88 /  50  40  20  30
LFT  71  87  70  87 /  50  30  10  30
BPT  72  87  73  88 /  50  40  20  30

&&

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

$$


AVIATION...66