Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 201204
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
704 AM CDT Thu Jul 20 2017

.AVIATION...
Light and variable winds expected today with VFR conditions
prevailing. Added VCTS for this afternoon all areas as moisture
and daytime heating could kick off a few storms across the area
offset by drier air working southward into the area this
afternoon. Convection should dissipate by sunset. Overall,
expect VFR conditions and light winds to prevail through the
period.

&&

.PREV DISCUSSION... /issued 349 AM CDT Thu Jul 20 2017/

SYNOPSIS...
Weak sfc high pres extends over the southeastern US, with winds nearly
calm acrs the area. Conditions are warm and muggy, typical for
summertime along the Gulf Coast. Nocturnal convection so far has
been isolated, but recent trends per KLCH radar shows activity
beginning to increase some over the northwest Gulf.

Aloft, an expansive ridge of high pres remains centered acrs the
southern plains toward the lower MS valley, while an upper trough
was located over the eastern seaboard. WV imagery shows a wedge of
drier air working southwest acrs MS/LA, with deeper moisture
along the coast and over the Gulf. KLCH 20/00Z sounding did show
precip water slightly lower than it did 24 hours ago, just below
1.9 inches, with drier values noted north and northeast of the
area.

24

DISCUSSION...
While the main ridge axis is expected to remain north of the area,
its influence is expected to build southward some today and Friday.
This will bring some slightly drier air further southwest over
the area, and also provide a little more subsidence which will
keep daytime convection more isolated each day, with chcs
slightly better acrs Acadiana where interactions with sea/bay
breezes will provide a focus. On the flip side, the decrease in
convection will result in daytime temperatures climbing a little
higher, especially acrs inland areas. Aftn highs today and Friday
are expected to reach the lower to middle 90s outside of any
locations that see showers. The combination of heat and humidity
will result in heat index values between 102-107 degrees, which is
just below advisory criteria.

Shower and tstm chcs will again increase over the weekend as a
portion of the trough over the east coast begins to translate
around the southeastern and southern periphery of the upper ridge.
The trough will migrate west over the northern Gulf of Mexico,
with precip water values climbing back to around 2 inches by
Saturday. Increased instability/lift associated with the
disturbance will produce more numerous showers and tstms Saturday
and Sunday. With the increase in showers and clouds, daytime
temperatures will trend slightly below normal, with highs in the
upper 80s/around 90.

Rain chcs will begin to decrease on Monday as the upper trough
moves further west. A return to warmer daytime temperatures and
lower POPs can be expected after Monday as mid-level ridging
begins to build back over the region.

24

MARINE...
Light winds and low seas will prevail through the first half of
the weekend as high pres remains over the Gulf of Mexico. A modest
increase in winds and seas can be expected Sunday into Monday as
the pres gradient strengthens slightly. Widely sctd to sctd
showers and tstms can be expected through Friday, mainly during
the early morning hours, with shower and tstm chcs increasing
over the weekend as low pres aloft moves west over the Gulf of
Mexico.

24

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  95  75  95  75 /  20  10  20  10
LCH  93  77  93  77 /  20  10  20  20
LFT  94  77  93  77 /  30  10  30  20
BPT  92  76  92  77 /  20  10  20  20

&&

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

$$


AVIATION...06


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