Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 201540
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
940 AM CST Tue Feb 20 2018

.UPDATE...
Tight pressure gradient is noted across the forecast from surface
high ridging in from the western Atlantic and surface low
developing over the Southern Plains. Local vad wind profiles
showing south winds 20 to 30 knots 1k feet off the surface.
Therefore, should be another warm and breezy day across the
forecast area. The upper air sounding from KLCH at 20/12Z was
showing a bit of a cap between 7k and 8k feet. Therefore, some
streamer type showers may develop below the cap with the low level
jet through the day. With daytime heating and approach of an upper
level disturbance, may see more shower activity with a few
thunderstorms over Southeast Texas where pops will be the highest
this afternoon. Satellite pics, web cam views, and surface
observations show the sea fog has pretty much lifted with the
increase in wind speeds, and the marine dense fog advisory was
allowed to expire at 9 am local. Current forecast is on track and
no changes needed at this time.

Rua

&&

.PREV DISCUSSION... /issued 603 AM CST Tue Feb 20 2018/

DISCUSSION...
For 12z TAF issuance.

AVIATION...
Sfc obs show that low clouds have gradually developed over the
forecast area overnight with all terminals now IFR/MVFR...this
trend will continue next few hours before heating commences and
ceilings begin lifting. Main story again today will be the
elevated srly winds with a tight pressure gradient, plus stronger
flow aloft mixing down. A few showers will be possible beginning
this afternoon with good available moisture and attainable
convective temps. Best rain chances come later tonight as better
lift associated with approaching frontal boundary/dynamics aloft
encroaches the region.

25

PREV DISCUSSION... /issued 413 AM CST Tue Feb 20 2018/

DISCUSSION...A deep ridge is centered near the Bahamas this
morning, while a trough covers the wester half to two thirds of
the country. Our region remains between these systems, however the
trough is gradually eroding the western edge of the ridge.

Today the ridge will shift a bit more east while the trough begins
to provide lift. Scattered showers and a few storms will be
possible this afternoon, but mainly across Southeast Texas. At the
surface the region will again experience a fairly tight pressure
gradient, so another breezy day will occur and be on the cusp of
wind adv criteria.

Wednesday a cold front will enter the lakes region and stall,
perhaps just north of the forecast area. High PWATs will stream
along and behind front via the subtropical jet, and with
associated lift, heavy rainfall will be possible near the frontal
boundary.

The boundary will drift back north during Thursday with another
front pushing into the area this weekend. Guidance is a bit split
on if and when the boundary pushes through so confidence in the
weekend forecast is fairly low, especially late.

MARINE...A warm and moist air mass continues to move over colder
shelf waters. This has allowed dense sea fog to redevelop this
morning, however after sunrise mixing will increase and the fog is
expected to thin.

Fog will remain a concern into late week as the area remains in a
south flow, however showers and storms are also expected Wednesday
into the coming weekend as multiple frontal boundaries move into
the area and stall.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  82  67  75  64 /  20  30  90  80
LCH  79  68  77  66 /  20  30  80  60
LFT  83  69  81  67 /  20  20  60  40
BPT  79  68  78  66 /  30  50  80  70

&&

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

&&

$$

PUBLIC...07



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