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

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000
FXUS64 KLIX 220950
AFDLIX

AREA FORECAST DISCUSSION
National Weather Service New Orleans LA
350 AM CST Sun Jan 22 2017

.SHORT TERM...
Water vapor imagery shows an upper level low currently wrapping up
around the northern Texas/southern Oklahoma border. Surface analysis
shows a cold front associated with the low moving eastward across
western Louisiana. The cold front extends northwest into Oklahoma,
where the boundary has occluded into the center of a surface low.
Both the upper and surface lows will deepen while they track east-
southeast across northern Louisiana this morning. Showers and
possibly a few thunderstorms will pass across the forecast area this
morning ahead of the cold front. The 06Z local sounding from last
night showed the atmosphere still has very steep lapse rates in the
mid levels with an inversion at the surface. There will initially be
a short window of opportunity for a few cells to become severe with
elevated cores. The HRRR is aggressive with convection on the
southern half of the CWA. It seems to have been a little too
aggressive there for the last couple days. Thus thinking along and
north of the I-12 corridor is the most likely place to see any hail.
That`s if anyone does at all and not all that confident that any
will develop.

Strong westerly winds will develop over the forecast area right
behind the cold front as it progresses through mid morning. Model
soundings show boundary layer winds to be around 40 knots. This
layer will begin to mix out during the day which will allow for
stronger winds to approach the surface. This will put winds around
25 knots with frequent higher gusts across many portions of the
forecast area. This will especially be the case from New Orleans to
the Gulf Coast. Strong cold air advection will limit decoupling of
the boundary layer for at least the first part of the night.
Therefore, will be issuing a CWA-wide wind advisory for late morning
through this evening.

.LONG TERM...
The first part of this week will be a dry period as post-frontal
high pressure moves in. Temperatures will fall quite a bit, to near
normal on Monday. This will be short lived as upper ridge quickly
builds in over the area from the west on Tuesday. Temperatures will
moderate back up into the lower 70s.

The next chance of rainfall comes on Wednesday as an upper level low
moves eastward across the central plains and sends a weak cold front
into the region. Lack of instability will keep precip limited to
just showers as the boundary moves through. Continential high
pressure will continue to build in from the north thorugh the rest
of the week and into the weekend as a broad longwave trough engulfs
much of the country. Below normal temperatures are expected through
that period.

MEFFER
&&

.AVIATION...
Ceilings will be a little more stable today with OVC020 for the most
part. This morning will see a few lower ceilings transiting the area
at BKN006. Some SHRA during the morning but this will quickly
transit the area bringing SCT040 by afternoon. Another deck may move
through around dark at about OVC050 but this should also be short
lived.

&&

.MARINE...

The big story today will be the strong gales over most of the
coastal waters starting this morning. Westerly gales will also cause
water to pile a bit on the west side of Plaquemines Parish initially
but should stay around 1 foot above normal levels. Otherwise, the
other big issue will be the extreme low tide levels at all other
locations. Tides will run around 1/2 to 2 feet below normal which
can be just as dangerous for the marine industry moving through
protected water systems such as bayous, canals, lakes, and rivers.
This is a more unusual case than most as westerly winds will be more
effective in moving water out of these systems. Normally, we observe
strong northerly winds which just transport the bulk of water to
south shore locations, but the water remains in the system for the
most part.

These conditions should continue into Monday before easing somewhat.
Lake Pontchartrain, Lake Borgne, and Mississippi Sound areas will
not be included in a gale warning at this time, but winds will be
sustained around 25-30kt with gusts over gale force at times in
these areas. Conditions rapidly improve into Tuesday as winds abate.

&&

.DECISION SUPPORT...
DSS code: YELLOW
Deployed: None.
Activation: High Impact Desk
Activities: Gale Warning. Wind Advisory

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  64  47  62  42 /  60  20   0   0
BTR  66  47  64  45 /  50  10   0   0
ASD  69  51  65  45 /  50  10   0   0
MSY  72  51  63  48 /  40  10   0   0
GPT  72  51  63  43 /  60  10   0   0
PQL  72  51  63  42 /  60  10   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Wind Advisory from 9 AM this morning to midnight CST tonight for
     LAZ034>037-039-040-046>050-056>072.

GM...Small Craft Advisory until 6 AM CST early this morning for
     GMZ536-538-550-552-555-557-570-572-575-577.

     Gale Warning until 6 AM CST Monday for GMZ536-538-550-552-555-
     557-570-572-575-577.

     Low Water Advisory from 9 AM this morning to noon CST Monday for
     GMZ530-532-534-536-538.

     Small Craft Advisory until 6 AM CST Monday for GMZ530-532-534.

MS...Wind Advisory from 9 AM this morning to midnight CST tonight for
     MSZ068>071-077-080>082.

GM...Small Craft Advisory until 6 AM CST early this morning for
     GMZ538-550-552-555-557-570-572-575-577.

     Gale Warning until 6 AM CST Monday for GMZ538-550-552-555-557-
     570-572-575-577.

     Low Water Advisory from 9 AM this morning to noon CST Monday for
     GMZ532-534-536-538.

     Small Craft Advisory until 6 AM CST Monday for GMZ532-534.

&&

$$


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