Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 152326
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
526 PM CST Fri Dec 15 2017

.AVIATION...A few breaks in the clouds are expected through the
evening, however clouds will thicken and gradually lower during
Saturday morning. Ceilings will remain around 5 KFT or above
through the period keeping conditions VFR. Winds will become light
and VRB this evening and then east at 5 to 10 kts during mid
morning.

&&

.PREV DISCUSSION... /issued 401 PM CST Fri Dec 15 2017/

DISCUSSION...
Partial clearing this afternoon has allowed temperatures to warm
into the lower/mid 50s over most of the area, though upper 40s are
holding firm amid clouds and light rain over South Central LA.
Guidance is in good agreement that these areas of rain inland and
over the Gulf waters will come to an end over the next few hours,
yielding a dry evening/overnight period. Chilly night is on tap as
cold SFC high pressure continues settling into the area, with the
calm winds and enough breaks in the cloud cover over northern
areas permitting temperatures to fall close to SFC dewpoints,
yielding a light freeze for parts of Central LA.

The SFC high will shift off to the east on SAT, with ridging
aloft downstream of an upper low lifting NE from the Baja. This
feature is forecast to open up as it ejects TWD the TX/OK
panhandles by SAT evening. A weak SFC low is progged to develop
over the western Gulf, then subsequently track NE along the TX
coast and into the Sabine River Valley SAT night. Strengthening
east and then southerly flow will transport increasing moisture
northward into the region, which combined with strong lift, will
yield widespread areas of rain with embedded showers and isolated
thunderstorms overspreading the area. The marginal risk of severe
mentioned yesterday appears even more marginal today, with SFC
based convection likely remaining offshore until the daytime hours
Sunday over South Central LA and points east. Lift is progged to
decrease sharply by afternoon as the upper trof and associated SFC
low lift quickly off to the NE, but a lingering SFC boundary and
MSTR pool will still result in a chance of scattered convection
SUN afternoon and evening.

By the overnight period and into MON, yet another upper trof will
begin to approach the region, with the lingering SW to NE SFC
boundary likely serving as a focal point for additional
convection. Global models continue to diverge with the eventual
evolution of this trof as it translates eastward, with the ECMWF
considerably slower than the GFS/CMC. Leaned heavily on a
consensus approach for the TUE-FRI period.

13

MARINE...
Areas of rain will continue across the coastal waters this
afternoon, diminishing this evening. Gusty north winds will
continue before decreasing this evening as high pressure settles
into the area. An upper trough will approach the area late
Saturday into Sunday resulting in widespread showers and
thunderstorms. East and then southeast winds are forecast to
increase as an associated weak area of low pressure develops and
tracks northeast along the Texas coast into the Sabine River
Valley. A short duration small craft advisory will likely be
needed late Saturday afternoon and night. Winds will subside on
Sunday. The south winds will aid in transporting very moist air
northward atop relatively cool nearshore shelf waters, so there is
some potential for marine fog starting late Saturday night and
possibly persisting for a few days. A second upper trough follows
Monday keeping rain chances elevated for the early part of next
week.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  31  58  48  70 /   0  10 100  60
LCH  39  59  55  71 /   0  10 100  60
LFT  39  59  55  72 /   0  10  70 100
BPT  41  60  53  70 /   0  10 100  40

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory until 6 PM CST this evening for GMZ470-472-
     475.

&&

$$


AVIATION...05



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