Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 281702
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1202 PM CDT Wed Jun 28 2017

.DISCUSSION...
For the 28/12Z TAF Issuance.

&&

.AVIATION...
A weakness in the mid levels continues just offshore over the
northern Gulf of Mexico and the result has been widespread showers
and a few thunderstorms in that area. With daytime heating, expect
some convection to develop over land areas and will mention VCTS
at all terminals for the remainder of the afternoon until about
29/02Z with the possibility of MVFR ceilings. The weakness over
the northern Gulf is expect to move onshore on Thursday. Would
expect shower activity to get an early start for the southern most
terminals with VCTS after 29/09Z.

Rua

&&

.PREV DISCUSSION... /issued 934 AM CDT Wed Jun 28 2017/

UPDATE...
Widespread showers and thunderstorms continue over the coastal
waters this morning in association with a low to mid level
weakness extending along the northern gulf coast. Convection
is expected to develop over land by late this morning into the
afternoon in response to daytime heating and the forecast package
already reflects this philosophy. Other forecast parameters are in
good shape and no changes were made this morning.

Jones

PREV DISCUSSION... /issued 609 AM CDT Wed Jun 28 2017/

AVIATION...Rain and thunderstorm will spread inland by mid
morning to the terminals. Periods of lower vis and ceilings can be
expected in storms. Storms will decrease around sunset. Winds will
generally be around 10kts or less and SE.

PREV DISCUSSION... /issued 456 AM CDT Wed Jun 28 2017/

DISCUSSION...
Latest upper air analysis/water vapor satellite imagery depicted
an upper level trof over E TX and into the NW Gulf. SFC to H7
analysis revealed an inverted trof axis stretching from SC LA
across the NW Gulf to near the TX/MX border.

Convection has blossomed over the coastal waters within the past
couple of hours, with some of this activity reaching coastal SE
TX/SRN LA before dissipating as it progresses farther inland.
Upper trof over E TX is forecast to remain quasi-stationary today
while the low to mid level inverted trof axis sharpens a bit and
becomes re-oriented in a more E-W manner over the Gulf waters and
pushes inland tonight. Both the GFS/ECMWF maintain something of an
E-W oriented upper jet (50-60KT) over the central/eastern Gulf
coast states, placing much of coastal TX/LA and the adjacent Gulf
waters in a RRQ. The corresponding increase in low level wind
fields is evident in a 20-30KT LLJ. While neither of these
kinematic features is overly impressive in magnitude, any lift
added to an already moisture laden (PWAT AOA 2") and unstable
airmass will only serve to enhance convective coverage. Thus,
anticipate a generally wet next 48 hrs or so from roughly the I-10
corridor southward, with an attendant risk of locally heavy
rainfall given efficient rain producing convection. Have mentioned
this potential in the grids and will also address in the HWO.

Low/mid level trof axis and its associated MSTR pool will
continue to lift off TWD the NE and begin to pull away from the
area THU night, replaced by a low/mid level ridge and relatively
drier air building into the northern Gulf. Rain chances will
begin to decline then virtually disappear for the weekend and into
early next week.

13

MARINE...
An upper level trof of low pressure over the northwest Gulf coupled
with a surface trough of low pressure along the Texas coast will
result in modest east to southeast winds and numerous showers and
thunderstorms through Thursday. Have headlined exercise caution
today for 15-20KT winds over the Gulf waters, and this may need
extending further in time. Rain chances will decrease as these
features lift to the northeast and away from the region by Friday,
with light to modest south winds prevailing around high pressure
ridging west across the Gulf.

13

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  88  72  85  74 /  30  30  50  20
LCH  85  76  85  79 /  60  70  80  30
LFT  84  73  83  76 /  60  60  80  30
BPT  85  75  85  78 /  60  70  80  30

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Exercise Caution until 7 PM CDT this evening for
     GMZ450-452-455-470-472-475.

&&

$$


AVIATION...07


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