Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 160853
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
353 AM CDT Sun May 16 2021

.DISCUSSION...
Short Term (Today Through Monday)...
Increasingly dense cloud cover continues to work into the region
this morning in advance of a shortwave wrapping around a west
coast upper low that is presently bisecting Texas meridionally.
Short range guidance has been trending toward more scattered
convection initializing this afternoon across southeast Texas as
the shortwave approaches. PoPs reflect this appropriately. Much
more widespread convection is expected Monday as the trof axis
becomes centered over the region. Forecast max PWAT values are
presently around 1.7 inches. Some nuisance flooding could occur
Monday across areas that see multiple heavy rain producing storms,
but the greater flood risk is expected by mid to late week.

.Long Term (Tuesday through Sunday)...
Still Looking like an active and wet period through Friday, with
some potential for strong convection and heavy rainfall, then rain
chances look to gradually decrease over next weekend.

Surface high pressure will become established over the southeast
CONUS and ridge into the forecast area. This will provide a long
fetch of southerlies in the low levels to bring in abundant Gulf
moisture.

Moisture profiles during the Tuesday through Friday period show
precipitable water values above 1.75 inches, which is above the 90th
percentile of SPC climo for this time of year, to near 2 inches
along the Sabine River Basin. Mean layer relative humidity values
between 1000-500 will also be on the high side and above 70 percent
through that period and above 80 percent at times along the Sabine
River Basin.

In the meantime, an upper level low will be moving slowly east out
of the Rockies to start the period and then will open up and lift
out by Thursday. Disturbances will move out from the low and across
the forecast area with the southwest flow aloft. Each disturbance
will provide the lift for the moist air mass to produce widespread
shower activity.

Moderate instability will be noted, although a lot will depend on
any daytime heating that may occur, so thunderstorm activity is also
expected with the showers. Overall shear values are not too
impressive, which may keep the severe potential down. However, any
strong convection that develops with the instability will allow for
gusty winds, frequent lightning, and torrential rainfall.

A weakness in the sub-tropical ridge will persist through Friday,
keeping rain chances high. Trends in the guidance show an upper level
ridge expanding into the forecast area from the east, and if this
occurs, will help reduce rain chances over the weekend.

Rua

&&

.MARINE...
Small craft should exercise caution today as winds of 15 to 20
knots with higher gusts along with seas of 4 to 6 feet are
expected over the coastal waters. Moderate onshore flow will
persist through the week. A series of upper level disturbances
will cross the region producing daily scattered to widespread
showers and thunderstorms over the coastal waters. Seas are
expected to remain elevated as the pressure gradient will
strengthen.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  83  68  81  69 /  20  40  70  30
LCH  82  70  82  72 /  20  60  70  40
LFT  83  69  82  70 /  10  40  60  40
BPT  81  70  81  72 /  40  70  70  30

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Exercise Caution through Monday evening for GMZ450-
     452-455-470-472-475.

&&

$$


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