686
FXUS64 KLIX 190435
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1135 PM CDT Mon Aug 18 2025

...New SHORT TERM, LONG TERM, AVIATION, MARINE...

.SHORT TERM...
(Today through Thursday night)
Issued at 1101 PM CDT Mon Aug 18 2025

Today and tomorrow will continue to see slightly drier air aloft
associated with a broad upper level high that will help to keep
PWATS near or slightly lower than average. This drier air aloft
will do things, slightly suppress convective development and also
allow for warmer than average daytime highs. In terms of
convective activity, the convection will tend to start later in
the day with the most convection occurring in the late afternoon
and evening hours. Given the drier air aloft, some gusty winds
will be a concern with the strongest storms, but the severe wind
gust threat will remain extremely limited. With convection
suppressed until later in the day, temperatures will quickly warm
into the mid to upper 90s by the early afternoon hours. Although
some dry air will eventually mix down into the boundary layer,
there will be a period of time in the late morning and early
afternoon where heat index values could climb to between 108 and
112 degrees tomorrow. Given this, a heat advisory remains in place
for much of the forecast area. Only the immediate coast will see
heat index values remain below 108 as temperatures are moderated
by the seabreeze. Today will be the warmest day of the week, but a
heat advisory will likely be needed for Wednesday as heat index
values are expected to climb back to around 110 degrees in a few
locations.

Conditions will finally begin to shift to a cooler and wetter
pattern as we move into Thursday and Thursday night. The broad
ridge over the area will weaken and shift to the west. As this
occurs, a weak trough will begin to deepen over the eastern CONUS.
Hurricane Erin will be moving off the eastern seaboard and will
assist in driving this trough and associated cold front closer to
the region. The wind field will also start to turn more southerly
in advance of the approaching trough and this will allow for
deeper tropical moisture to feed back into the area. PWATS will
quickly respond by climbing to around 2 inches on Thursday. The
combination of increasing moisture, ample instability as
temperatures warm back into the mid 90s, and increased forcing
from the positive vorticity moving into the region will support
more numerous shower and thunderstorms from the late morning into
the afternoon hours. Heat index values will still be warm at
around 105 degrees, but a heat advisory is not anticipated for
Thursday.

&&

.LONG TERM...
(Friday through Monday night)
Issued at 1101 PM CDT Mon Aug 18 2025

The trough and associated front will become stalled over the
region on Friday as Hurricane Erin quickly lifts away from the
eastern seaboard. Over the weekend, the trough and front will then
gradually dissipate along the Gulf Coast. Ample moisture will be
in place with PWATS in the 90th percentile each day, so fairly
numerous showers and storms will fire up over land by late
morning. The storms will persist into early evening before
dissipating. These higher rain chances are reflected by PoP
forecast in the 60 to 70 percent range each day. The increased
moisture and cloud cover from the convective activity will also
help to limit daytime heating with highs generally staying closer
to average in the lower 90s from Friday through Sunday. Although
dewpoints will be in the upper 70s, heat index values will only
climb into the lower 100s each afternoon due to the lower air
temperatures. These conditions are fairly close to average for
mid to late August.

Monday is an interesting day as there is a signal that another
northern stream trough will sweep through the Great Lakes and into
the Mid-Atlantic states. As this trough axis sweeps by to the
north, there may be just enough of a push to pull the dying front
over the region offshore into the northern Gulf. Both the GFS and
the ECMWF indicate this occurring, and confidence is a bit higher
than average, for a day seven forecast, of this pattern
occurring. Given this, have opted to lower dewpoints substantially
into the upper 60s and lower 70s on Monday and also reduce PoP
values to 20 to 30 percent as PWATS plunge to between the 25th and
50th percentiles for this time of year. Of course, cold air does
not really accompany these Summer fronts, so temperatures will
correspondingly warm into the mid 90s. Fortunately, the dry air in
place will keep heat index values in the upper 90s and lower 100s
or slightly lower than normal. The lower dewpoints may even allow
lows to dip into the upper 60s over more inland parts of the
forecast area Monday night.

&&

.AVIATION...
(06Z TAFS)
Issued at 1101 PM CDT Mon Aug 18 2025

Another round of scattered storms will fire back up as temperatures
warm above the convective temperature by 18z. PROB30 wording is
back in place again for several of the terminals as these
scattered pop up afternoon storms continue into the evening hours.
Outside of the convective threat, some light patchy fog
development is included in the forecast at MCB between 11z and
13z with 5 miles visibilities due to rainfall earlier this evening
saturating the soils just before sunset. Otherwise, VFR
conditions will be the rule at at the terminals when convection is
not occurring.

&&

.MARINE...
Issued at 1101 PM CDT Mon Aug 18 2025

There has been no change in thinking from the previous forecast
concerning the winds and seas in the coastal waters. Conditions
will remain benign as winds stay below 10 knots and seas remain at
2 feet or less through the end of the week. The only concern will
be locally higher winds and waves along with a few waterspouts
forming with any thunderstorm activity the fires up across the
waters. Thunderstorms will be most common in the early to mid
morning hours over the offshore waters and will be more common in
the afternoon hours in the tidal lakes due to the normal
seabreeze/landbreeze cycle each day.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  73  95  73  95 /  30  20  20  40
BTR  75  95  75  95 /  40  30  20  40
ASD  74  95  74  95 /  30  20  20  30
MSY  79  93  79  94 /  20  20  20  30
GPT  76  92  77  92 /  20  20  20  30
PQL  75  93  76  93 /  10  20  20  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from 10 AM to 7 PM CDT Tuesday for LAZ034>037-039-
     046>048-056>060-064-065-070-071-076>090.

GM...None.
MS...Heat Advisory from 10 AM to 7 PM CDT Tuesday for MSZ068>071-077-
     083-086.

GM...None.
&&

$$

SHORT TERM...PG
LONG TERM....PG
AVIATION...PG
MARINE...PG