Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 180913
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
413 AM CDT Mon Jun 18 2018

.DISCUSSION...
Satellite imagery this morning continues to show an area of
disturbed weather associated with mid/upper-level low pressure
over the wrn Gulf...while sfc analysis notes associated inverted
trof near the coast from Deep South TX up through swrn LA. Combo
of these features, along with copious Gulf moisture to the tune of
sfc-h5 mean RH values near 80 percent and PWAT values 2.0-2.2
inches per area 00z soundings, is producing another round of late
night convection covering much of the adjacent coastal waters.
Some of this activity has been making its way onshore, most
notably from Marsh Island wwd.

Not many changes to previous forecast thinking this morning as
tropical wave continues its slow wwd migration across the Gulf.
Ridiculous moisture streaming nwd on back side of this feature
will continue to produce widespread showers/some thunder through
the day, with highest POPs again expected over coastal sern TX/wrn
Cameron. Latest WPC guidance indicates mean areal QPFs around 2
inches for today over the area of max POPs...latest flash flood
guidance for these areas generally show 4 to 5 inches in a 6-hour
period needed for flash flooding to start. Given the high moisture
content over the area at this time, localized higher amounts are
certainly possible, and WPC has put the extreme swrn portions of
the forecast area in a slight risk for flash flooding through
tonight...however given the disparity with FFG values for now,
have elected to refrain from issuing any flood watches at this
time. A repeat pattern is expected into Tuesday as the whole
system continues pushing slowly wwd into the TX coast.

We can also expect a pair of additional byproducts of the
disturbance pushing past the area the next day or so. First, we
will see a continued elevated srly flow today with speeds
approaching 20 knots near the coast...with 10-15 knot winds
expected as far inland as past I-10. For today and tomorrow, the
additional rainfall and cloud cover will lead to much cooler than
normal conditions primarily across the wrn 1/2 of the forecast
area with max temps expected to run only in the lower/mid 80s.

Elevated rain chances linger through mid-week, mainly across the
wrn and nrn zones as the disturbance leaves behind a weak
trof/shear axis. Forecast soundings indicate a continuation of
copious Gulf moisture persisting across the region, thus good rain
chances are being carried across the wrn areas Tuesday/nrn areas
Wednesday.

Rain chances begin to gradually return to more seasonal values
Friday and on into the weekend as weak ridging aloft over the
sern CONUS begins building back into the region. We should also
see a return of more summerlike temperatures with maxes forecast
in the lower 90s for all but the coastline each afternoon.

&&

.MARINE...
Extended the SCA for the coastal waters through the evening hours
tonight, while also adding SCEC headlines for Calcasieu Lake and
Vermilion Bay through today.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  88  70  86  70 /  50  20  40  20
LCH  83  74  85  75 /  80  50  60  30
LFT  86  75  89  75 /  70  30  40  20
BPT  81  75  83  76 /  80  70  80  40

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...None.
TX...None.
GM...Small Craft Advisory until midnight CDT tonight for GMZ450-452-
     455-470-472-475.

     Small Craft Exercise Caution through this afternoon for GMZ432-
     435.

&&

$$

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