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

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FXUS64 KLIX 192110

Area Forecast Discussion
National Weather Service New Orleans LA
310 PM CST Sun Feb 19 2017

Another spring like day was being observed throughout the region
with warm temperatures and ample sunshine across the forecast area
after some fairly widespread fog and stratus this morning. Fog
development will again be a concern later tonight and early
Monday, although how dense and widespread it will be is somewhat
in question. At this time plan to indicate areas of fog overnight,
but will hold off on a dense fog advisory for now and let the
evening and night shift reassess the situation.

A wet period will be in the offing for the early and mid week
period as a system moving out of the Four Corners region
translates eastward with a closed upper low forming over Texas
and then moving slowly across the northwest Gulf and then
southeast toward Cuba and the Florida Staits. Most of the rain
associated with this system should hold off until Monday night.
However, clouds will be on the increase during the day Monday in
advance of this system and a few showers and thunderstorms will be
possible late in the day toward the Atchafalaya River basin. With
this system passing to our south, the best instability will
reside across the coastal waters. Across inland areas, instability
will generally be lacking and mid level lapse rates are not
impressive. Therefore, showers will dominate with only isolated
thunderstorms expected. This slow moving system and associated
weak surface low and trough will move east across the north Gulf
from late Monday through Tuesday night. POPs will be high during
this period with rainfall amounts of 1 to 3 inches forecast, with
the heaviest rainfall likely to be across coastal areas of
Louisiana. The showers may linger into Wednesday a bit before
clearing out.

Dry weather will return for the Wednesday night through Thursday
night period before a northern stream short wave pushes a cold
front across the Gulf Coast States Friday night. Moisture should
be rather limited with this system, so on a slight chance for
showers is in the forecast for Friday.

Temperatures will remain well above normal through the forecast
period, although there will be a brief cool down on Saturday in
the wake of the cold front. 11


Similar to Saturday, fog and low clouds were slow to clear across
western portions of the area this morning. KHUM still reporting MVFR
ceilings, but satellite trends show that they should improve to VFR
over the next hour or two. Expect one more night of fog and/or low
clouds for all terminals between 06z and 15z Monday, with LIFR
conditions likely. Some indications that terminals along and west of
Interstate 55 such as KHDC...KHUM...KBTR may not improve past MVFR
ceilings during the day tomorrow ahead of next weather system. 35


While areas of fog are anticipated over land tonight, marine fog is
not expected to be a widespread problem. The only exception would be
over the Mississippi River, where water is still at a chilly 50
degrees so fog is expected within the levee systems. For the most
part, that isn`t within a marine zone. While GMZ555 could see some
fog at the mouth of the river, much of that zone probably will not
have fog to deal with.

Tightening pressure gradient between high pressure to the east and
lowering pressure to the west will allow a gradual increase in winds
to near 15 knots western/southern coastal waters tonight. For now
will not raise any headlines.

A cold front associated with an upper level storm system will get a
push from Texas into the northwest Gulf of Mexico Monday night into
Tuesday, however the northern portion of this boundary will not see
much airmass change over areas near the coast and inland. A broad,
slow moving inverted trough, with a possible embedded surface low,
is expected to meander southeast to the central Gulf Tuesday into
Wednesday. A cold front will move through the northern gulf Friday
night. 35


DSS code: Green.
Deployed: None.
Activation: None.
Activities: None.

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.


MCB  55  78  60  71 /   0  10  60  70
BTR  58  78  64  72 /  10  20  70  70
ASD  55  77  61  71 /   0  10  50  70
MSY  59  77  64  72 /   0  10  60  70
GPT  56  73  61  70 /   0   0  30  70
PQL  53  75  59  72 /   0   0  20  60



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