Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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FXUS64 KLIX 290842
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
342 AM CDT MON AUG 29 2016

.SYNOPSIS...

TD 9 currently over the Florida Straits northwest of Havana Cuba.
Weak upper low off the Texas coast is producing quite a bit of
convection offshore, mainly over the Lake Charles and Houston
marine areas. A bit of a secondary surge of convection over our
coastal waters west of the mouth of the Mississippi River that
could affect extreme lower portions of our coastal parishes in
that area around sunrise. A good bit of high cloud cover over
about the western 2/3 of our land areas as well. As usual for late
August, temperatures running from the mid 70s to lower 80s at 3
am.

&&

.SHORT TERM...

For the latest information on TD 9, consult products from the
National Hurricane Center. General scenario has not really changed
from the Sunday afternoon forecast package.

The upper low off the Texas coast will continue to allow the
development of convection today, mainly over the coastal waters
and lower portions of the coastal parishes. Precipitable water
values will remain over 2 inches, at least into the afternoon
hours today. Thus, the potential for very heavy rainfall
continues, but primarily over marshes, bayous and other bodies of
water. Will be carrying low precipitation chances, 20-30 percent,
over the northeast half of the area, gradually increasing to
likely POPs to the west of Houma.

Beyond today, precipitable water values drop to the 1.5 to 1.8
range for much of the area through Wednesday. This will mean much
lower rain chances for most of the area Tuesday and Wednesday with
rain chances greater than 30 percent pretty much limited to the
coastal waters.

We should see somewhat warmer temperatures today than Sunday, as
more sunshine will be on tap. Temperatures will gradually creep
into the middle 90s by Wednesday. Heat index values may briefly
get into the 105-108 degree range each day. 35

&&

.LONG TERM...

With TD 9 forecast to start moving from the central Gulf of Mexico
toward the Florida Peninsula, we would expect to see the upper
flow over the area gain much more of a northerly component. This
will bring drier air into the area, and should significantly limit
convective development across the area for at least Thursday
and Friday. Not much more than 20-25 percent POPs for those days,
and that may be too high. This is likely to also mean high
temperatures in the mid 90s for those days. Medium range models
hint at a weak frontal boundary in the area for Saturday into
Labor Day. Will carry slightly higher rain chances and slightly
lower temperatures for those days. 35

&&

.AVIATION...

Some drier air working into the area today should begin to limit the
coverage of convection associated with daytime heating for the more
interior terminals. The TAF sites located closer to the Louisiana
coast will still be under the influence of deeper moisture and will
therefore have a better chance of being impacted by convection
during the day. Otherwise, VFR conditions expected outside
convection. 11

&&

.MARINE...

Persistent moderate easterly flow is expected across the coastal
waters through Wednesday. These winds will be the result of a
tightening pressure gradient between a ridge located to the north of
the area and the lower pressure associated with TD 9 which is later
forecast to become a tropical storm as it moves into the middle Gulf
before then turning to the northeast and moving across the northeast
Gulf and into Florida later in the week. Exercise caution headlines
will be continued in the forecast for the outer waters today and
will likely need to be extended in later forecast packages. This
east wind should also keep tides elevated on east facing shores,
running about 1 to 2 feet above normal. As the tropical system moves
into north Florida later in the week, winds will turn northerly and
northwesterly and diminish to around 10 knots or less. Seas of 3 to
6 feet can be expected through Wednesday before subsiding late in
the week. 11

&&

.DECISION SUPPORT...

DSS code: Blue
Deployed: None.
Activation: None.
Activities: Flood recovery support. Monitoring TD 9.

Decision Support Services (DSS) Code Legend
Green  = No weather impacts that require action.
Blue   = Long-fused watch, warning, or advisory in effect or
         high visibility event.
Yellow = Heightened impacts with short-fused watch, warning
         or advisory issuances; radar support.
Orange = High Impacts; Slight to Moderate risk severe; nearby
         tropical events; HazMat or other large episodes.
Red    = Full engagement for Moderate risk of severe and/or
         direct tropical threats; Events of National Significance.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  92  73  94  72 /  20  10  20  10
BTR  93  72  94  73 /  30  20  20  20
ASD  92  76  93  75 /  30  20  20  20
MSY  91  78  93  79 /  40  20  20  20
GPT  92  77  92  77 /  20  10  20  20
PQL  93  76  93  76 /  20  10  20  20

&&

.LIX Watches/Warnings/Advisories...
LA...None.
GM...None.
MS...None.
GM...None.
&&

$$



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