Area Forecast Discussion
Issued by NWS Lake Charles, LA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KLCH 041727
AFDLCH

Area Forecast Discussion
National Weather Service Lake Charles LA
1127 AM CST Sun Dec 4 2016

.AVIATION...Deep moisture continues to hold over the region as
low pressure over old Mexico edges east. IFR ceilings will prevail
through the forecast with rains continuing.

&&

.PREV DISCUSSION... /issued 1017 AM CST Sun Dec 4 2016/

UPDATE...
Another wet day across the forecast area. Coastal trough/frontal
boundary looks like it has slipped a little further offshore
during the overnight and early morning. This will likely allow for
less low level convergence and forcing today, and therefore
intensity of convection and rainfall rates are also expected to be
less. Will still see a mainly steady light rain...with pockets of
moderate rain through out the day, as upper level low remains over
northwest Mexico and moist active southwest flow ahead of it will
continue to stream across the region and over-ride the frontal
boundary. Flash Flood Watch will remain in effect for a majority
of the forecast area through Monday afternoon. This is mainly due
to the now wet ground conditions...low flash flood guidance...and
the next round of heavy rainfall expected later tonight into
Monday. Only slight changes to the grids at this time, and
basically to adjust temperatures and qpf values based on latest
observations and guidance trends.

Rua

PREV DISCUSSION... /issued 605 AM CST Sun Dec 4 2016/

DISCUSSION...
For 12z TAF issuance.

AVIATION...
Expecting widespread showers/associated poor (mainly LIFR) flying
conditions to persist through the period as copious Gulf moisture
lifts nwd over a persistent coastal trof over the region. A brief
period of better conditions in the coming hour or so looks
possible over the lower Acadiana sites as srly flow ahead of an
advancing sfc low brings a little relief...but nrly flow and very
reduced ceilings are expected to return by mid-morning as the low
scoots off to the ene.

25

PREV DISCUSSION... /issued 419 AM CST Sun Dec 4 2016/

DISCUSSION...A surface trough remains along the Louisiana coast
this morning, however the trough is a bit farther east than it was
24hrs ago. Aloft an upper low is still slowly southeast over
Northwest Mexico.

Today, overrunning rain is expected to continue, however the
heavier axis is expected to mainly over Acadiana. Accumulations
are expected to be lighter than over the past 24hrs, however 1 to
3 inches may still occur on areas that have already received 2 to
8. With the 2 to 4 over Lafayette and southward and the potential
for another few inches the flash flood watch was expanded east.
Northern Hardin, Tyler, and Northern Jasper missed most of the
rain over the past day with totals under 3 inches. The heaviest
rain is also expected to generally miss these zones over the next
couple of days, but it is still not totally out of the question
some locations here may pick up a few more inches, so kept the
watch going.

Tonight and into Monday, the upper low will gradually turn east
then speed up while moving northeast. Another surface low will
develop along the South Texas Coast and move northeast. This low
is expected to move onshore in Jefferson County or Cameron Parish
then keep on northeast. To the right of the low warm and moist air
will spill in from the gulf. To the left cool over running rain
will continue. Areas across Acadiana and to the east may be
unstable enough to have a few isolated strong to severe storms.

Behind the low during Monday afternoon or night a drier air mass
will move in ending the rain into Wednesday.

By mid week an arctic air mass will spill out of the plains into
the gulf coast. Scattered showers will be possible along and ahead
of the front, but the main story will be the cold temps behind the
boundary. The end of the week temperatures will run much below
normal with a couple of nights of freezing temperatures expected.
Most of the area will fall below freezing by Friday Morning,
possibly even at the coast. Wind chills may be in the upper teens
to mid 20s. High temperatures will be around 20 degrees below
normal Friday with another freeze possible Saturday morning.

MARINE...As low pressure develops along the South Texas coast
later today the pressure gradient will gradually tighten. East
winds will increase into Monday Morning as the low approaches.
West winds will remain above 20kts in the gulf waters through
early Tuesday.

A very strong cold front will move across the region Thursday.
Strong offshore winds will occur late in the week with gale force
gusts possible.

&&

.PRELIMINARY POINT TEMPS/POPS...
AEX  53  49  57  48 /  90  80 100  40
LCH  57  53  62  51 / 100 100  90  20
LFT  61  56  70  53 /  90  80  90  30
BPT  57  53  62  50 / 100 100  90  10

&&

.LCH WATCHES/WARNINGS/ADVISORIES...
LA...Flash Flood Watch through Monday afternoon for LAZ027>033-
     041>045-052-053-073-074.

TX...Flash Flood Watch through Monday afternoon for TXZ180-201-215-
     216-259>262.

GM...SMALL CRAFT EXERCISE CAUTION through late tonight for GMZ450-452-
     455-475.

     Small Craft Advisory from 9 PM this evening to 6 AM CST Monday
     for GMZ470-472.

     SMALL CRAFT EXERCISE CAUTION until 9 PM CST this evening for
     GMZ470-472.

&&

$$


AVIATION...23



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.