Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 210558
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1158 PM CST Tue Feb 20 2018

.DISCUSSION...
21/06Z TAF Issuance.

&&

.AVIATION...
Southerly winds ~8-12 KT will persist overnight. Expect IFR cigs
to prevail tonight into Wednesday morning before lifting back to
MVFR. Current radar mosaic shows a band of TSRA acrs south TX and
recent HRRR guidance indicates this band will continue to lift
northeast overnight into Wed morning, potentially reaching the
BPT terminal by 14-15Z. Convection is expected to progress
eastward, affecting the LCH/AEX terminals by midday with activity
becoming more sctd toward ARA/LFT. The frontal boundary
associated with the convection will remain west of the area, so
southerly winds should prevail through the period. Winds will
strengthen during the day, with gusts 20-25 KT possible.

24

&&

.PREV DISCUSSION... /issued 759 PM CST Tue Feb 20 2018/

UPDATE...
Winds have settled this evening and the Wind Advisory has been
allowed to expire. A few showers linger to the northwest this
evening... this activity is lifting to the northeast. Winds to
remain up overnight as a frontal boundary approaches from the
northwest.

19

PREV DISCUSSION... /issued 604 PM CST Tue Feb 20 2018/

DISCUSSION...
21/00Z TAF Issuance.

AVIATION...
Gusty southerly winds will diminish some over the next couple of
hours, but are expected to remain sustained around 10 KT
overnight. Low clouds will increase resulting in the development
of low MVFR cigs by 02-03Z, then LIFR by 06-08Z. Isltd -SHRA will
stream northward over the area tonight, with shower chcs
increasing from west to east during the day Wednesday as a cold
front moves into the area. Cigs are expected to lift back to MVFR
during the morning, as southerly winds strengthen to 13-18 KT with
gusts 20-25 KT during the day.

24

PREV DISCUSSION... /issued 352 PM CST Tue Feb 20 2018/

SYNOPSIS...
A surface high ridging in from the western Atlantic and a surface
low over the Southern Plains are keeping breezy and gusty south
winds across the forecast area. Sustained wind speeds have been
between 20 and 25 mph with gusts to 35 mph. Therefore, a wind
advisory is in effect for the remainder of the afternoon. The
increase in the low level jet and daytime heating has allowed some
scattered showers to develop, mainly across northern portions of
the forecast area.

Rua

DISCUSSION...
In the near term, winds are expected to decrease by sunset, and
therefore, the wind advisory will probably be allowed to expire at
6 pm. Also, scattered showers will decrease with the loss of
daytime heating.

Over the next few days, a broad upper level trough over the
western US will eject energy eastward and help push a cold front
to the fringe of the northwestern portion of the forecast area on
Wednesday. As this feature meets up with a strong upper level sub-
tropical ridge, it will loose its push and stall late Wednesday
and hang around into early Thursday.

Much above seasonal anomaly and high moisture content air will be
transported into the forecast area. Lift from the approaching
trough will bring about the development of showers and a few
thunderstorms, with the biggest focus right along and behind the
frontal boundary. Therefore, through Thursday there will likely be
a big QPF and POP gradient across the forecast area, with of
course the highest of these near the frontal boundary, tapering
off further to the southeast.

Widespread rainfall amounts northwest of a Marksville to Beaumont
line will average between 1 and 2 inches through early Thursday,
with locally higher amounts. The locally higher amounts could near
flash flood guidance, and therefore, a marginal to slight risk of
excessive rainfall has been outlined in that area by the WPC.
Southeast of that line, rainfall amounts will average from one
quarter to three quarters of an inch, again with some isolated
higher amounts.

The cold front will move back north late Thursday into Friday,
keep the forecast area in a very unseasonably warm and humid air
mass.

Still some uncertainty over the weekend as to the next cold front.
Operational guidance is still optimistic with bring the cold front
through the forecast area late Saturday night before stalling
offshore on Sunday, which would allow for a decent Sunday if this
happens. However, ensemble means still show front could hang up
over the forecast area. Therefore, will keep forecast close to
Superblend.

Rua

MARINE...
A cold front will stall north of the coastal waters on Wednesday.
This will keep southerly flow across the coastal waters through
the end of the week. A tight gradient will keep elevated wind
speeds and seas over the outer waters, and Small Craft Exercise
Caution will be headlined for that area through tonight and likely
into Wednesday. The southerly flow will also bring a warm moist
air mass over cooler Gulf shelf waters. Therefore, sea fog for the
near shore waters will be possible beginning this evening as the
winds relax just enough. This fog will likely become dense and a
marine dense sea fog advisory will be in effect for the near shore
waters west of Marsh Island through the night.

Rua

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  68  75  65  77 /  40  80  70  60
LCH  69  77  67  78 /  30  70  50  50
LFT  70  79  69  80 /  20  50  30  30
BPT  68  76  67  77 /  30  80  50  50

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Exercise Caution until 6 AM CST Wednesday for GMZ470-
     472-475.

     Dense Fog Advisory until 9 AM CST Wednesday for GMZ450-452.

&&

$$


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