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

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FXUS64 KLIX 181805
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
105 PM CDT Wed Jul 18 2018

.AVIATION...

Generally VFR conditions across the terminals at present. Threat
for scattered TSRA will continue through the afternoon hours into
the early evening. If convection is expected to directly impact a
terminal, it will likely cause IFR or lower visibilities and MVFR
to IFR ceilings, as well as wind gusts around 30 knots. Will amend
as necessary. Most convection will dissipate by 03z with VFR
conditions overnight, but terminals near the coast could again
see convection as early as 10z or so. One more day with a
significant convective threat on Thursday, with terminals possibly
impacted as early as 14-15z. 35

&&

.PREV DISCUSSION... /issued 350 AM CDT Wed Jul 18 2018/

SHORT TERM...
The constant sh/ts coverage will begin to decline over the next
few days. But that only means more sun, heat and humidity. The
stacked ridge out west will begin to nudge back east causing a
stronger inversion to cap the area by Friday with all but a
dotting of sh/ts across the area. Thursday looks to be a
transition day as temps will climb into the lower 90s and into the
mid 90s by Friday and remain into early next week. A few locations
may approach the upper 90s as well by the weekend. The moisture
will remain locked in the boundary layer as well which when
combined with the hot temps will make for some oppressive
conditions Friday through Monday and possibly Tuesday.

LONG TERM...
By Tuesday, the upper trough along the east coast begins to get
another shot of energy on its west side which will try to develop
a broad baroclinic sfc low near the Fla panhandle. This could
start to develop as early as Friday. It does not look to be close
enough to keep our area in some form of cloud cover at the moment.
But that would be the only break from the heat. The sfc trough/low
will quickly kick off to the northeast over the weekend.

The upper trough maintains a sfc trough axis in the area Monday
and Tuesday but the dry air that has moved into the area by that
time may preclude most sh/ts development. Now for the best part
of the fcast. This is within the Wed or later time period. Global
suites would like to dump a large amount of dry air that is cool
at first but gets modified quite a bit as it moves south. But the
dry air stay in tact, at least from a model stand point. This new
reinforcing front would bring dew pt temps in the low to mid 60s
by mid to late next week. This may not sound like a big deal, but
this is the end of July and we are deep into summer by this time
which makes this fairly rare. Before buying off on this, we would
like to see this become a trend with each run cycle.

AVIATION...
Some light patchy fog has developed at a few terminals this morning.
The fog is not very dense but it is reducing vsbys at these
terminals. Fog should mix out quickly after sunrise. Expect VFR
conditions to prevail throughout the forecast outside of convection
that is expected to develop once again this afternoon into the
evening. Expect roughly the same coverage today as there was
yesterday. Expect heavy downpours, gusty winds, and reduced vsbys
with thunderstorms this afternoon. 13/MH

MARINE...
High pressure will continue to prevail over the Gulf with light
westerly winds for the remainder of the week. The exception is some
periodic 15 knot wind speeds over Chandeleur Sound and some mainly
eastern coastal waters at times during late afternoon and nighttime
hours. A decaying front will tighten the pressure gradient enough to
produce more widespread 10 to 15 knot wind speeds in the overnight
hours of Tonight and Wednesday. Seas will be mostly 1 to 3 feet.
There will be an increase in thunderstorms this week and this will
cause periodic higher winds and seas during late night into morning
hours through Friday.

DECISION SUPPORT...
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; Marginal risk severe or excessive rain.
Yellow = Heightened impacts with short-fused watch, warning or
         advisory issuances; radar support for slight risk severe or
         excessive rain.
Orange = High Impacts; Enhanced risk severe; nearby tropical events;
         HazMat or other large episodes.
Red    = Full engagement for Moderate to high risk of severe and/or
         excessive rainfall, or direct tropical threats; Events of
         National Significance.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  91  73  94  73 /  50  50  40  10
BTR  92  76  93  76 /  50  30  40  10
ASD  92  76  92  77 /  60  40  50  20
MSY  91  77  92  78 /  60  40  50  20
GPT  91  76  92  77 /  60  40  50  30
PQL  93  75  93  75 /  50  40  50  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&

$$


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