Area Forecast Discussion
Issued by NWS Lake Charles, LA

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FXUS64 KLCH 021608

Area Forecast Discussion
National Weather Service Lake Charles LA
1008 AM CST Fri Dec 2 2016

Current forecast looks to be on track at this time and no changes
coming for the morning update. Mosaic radar and water vapor
imagery shows first blob of rain has developed off the lower Texas
coast moving to the northeast and should be near the forecast area
this evening.



.PREV DISCUSSION... /issued 552 AM CST Fri Dec 2 2016/

AVIATION...VFR conditions are expected through mid day, however
light rain will gradually spread across the region from southwest
to northeast this afternoon and tonight. While the majority of the
rain is expected to be fairly light during this period, mvfr vis
and ceilings will be possible tonight. Winds will be northeast to
east through the period and become gusty tonight.

PREV DISCUSSION... /issued 545 AM CST Fri Dec 2 2016/

Apologies for the delayed discussion. Lots to digest this morning
in what will be an active weather period over the next few days.
Latest WV satellite imagery/upper air analysis showed an upper
trof digging into the Desert SW, with the downstream flow aloft
over the NW Gulf Coast Region taking on a more SW direction and
beginning to usher in a fetch of Pacific moisture. Mid/High level
clouds already overtaking the area as the atmosphere continues to
steadily moisten. This process is expected to accelerate this
afternoon into this evening amid intensifying low level southerly
flow, with precipitable water expected to climb above 1.5 inches
over the southern half or so of the forecast area. Isentropic
lift coupled with impulses ejecting through the SW flow aloft
ahead of the digging upper trof/low is expected to yield
widespread rain with embedded convective cells/thunderstorms.

Heaviest rainfall should be initially near the coast tonight,
then lift nwd in tandem with and be focused along the sharpening
H85 trof axis which is progged to extend roughly SW to NE across
interior SE TX into NW LA. It is forecast to remain in this
general vicinity thru SAT night, weakening on SUN as a northern
stream trof crosses the Plains into the Upper Midwest. Isentropic
lift will remain, however, as the upper low crawls slowly eastward
across Northern MX and enters W TX SUN Night.

The upper low is forecast to open up and eject NE twd the ARKLATEX
on MON, inducing a weak SFC low to form along the SFC trof and
subsequently lift NE through the region, initially pulling a
WMFNT northward out of the GULF and then subsequently dragging a
cold front through from the west. This time period represents the
best potential for SFC based and possibly severe convection, with
SPC painting low end probabilities over parts of SC LA.

Dry weather expected in the wake of this system TUE, with low/mid
range chance PoPs returning WED with the approach and passage of a
strong cold front. Still some timing difference to work out with
this one, but aside from that the global models agree that this
will a very cold airmass, with widespread freezing or sub-
freezing nighttime temperatures leading into the weekend.


East winds will steadily strengthen today as high pressure at
this surface lifts to the north and a coastal trough of low
pressure begins to form off the Texas coast in response to an
approaching upper low. Wind gusts to near gale force are possible
over the Gulf waters by tonight. This persistent and
strengthening east flow is expected to produce a minor tidal pile
up along the Southeast Texas and Southwest Louisiana coastlines
tonight, with tide levels averaging around 3.5 feet mean lower low
water late this evening and during the overnight hours.

Widespread showers and some thunderstorms are expected to begin
affecting the coastal waters later today and persist through the
weekend as this upper low only slowly moves east across northern
Mexico. An area of low pressure is forecast to develop along the
southern end of the surface through Sunday night and subsequently
lift to the northeast in tandem with the ejecting upper low on
Monday. West winds and drier weather will prevail in the wake of
this system for mid week.



AEX  64  47  52  50 /  10  80  90  70
LCH  67  54  63  59 /  10  90  80  60
LFT  66  53  63  61 /  10  70  70  60
BPT  67  57  64  60 /  20  90  90  80


LA...Coastal Flood Advisory from 6 PM this evening to 6 AM CST
     Saturday for LAZ073-074.

TX...Coastal Flood Advisory from 6 PM this evening to 6 AM CST
     Saturday for TXZ215.

GM...Small Craft Advisory until 6 AM CST Saturday for GMZ450-452-455-

     SMALL CRAFT EXERCISE CAUTION from 6 PM CST this evening through
     late tonight for GMZ430-432-435.



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