021
FXUS64 KLIX 132250
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
550 PM CDT Tue Aug 13 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 546 PM CDT Tue Aug 13 2024

Afternoon convection dissipating rapidly, and likely to be little
or no precipitation beyond about 7 PM CDT. There will be at least
one update this evening to remove headlines regarding today`s heat
advisory.

&&

.SHORT TERM...
(This evening through Wednesday night)
Issued at 330 PM CDT Tue Aug 13 2024

Upper ridging centered near the Texas-Oklahoma border, extending
northward through the Plains States, with troughing over the
Pacific Northwest and Appalachians. That is producing a bit of
northerly flow over the Mississippi coastal counties that is
allowing convection in that area to move southward, whereas, over
most of the area, convection is nearly stationary. Areal coverage
remains on the isolated side, providing only very limited relief
from the heat. In most areas, heat index values are reaching
advisory criteria, at least briefly. Temperatures at 3 PM were
mostly in the mid and upper 90s with dew points in the 70s.

While precipitable water values were generally near 2 inches this
morning, the center of the ridging is expected to shift a bit
eastward to near Shreveport tomorrow. That is expected to drop
precipitable water values to around 1.7 inches. That would lead
one to believe that areal coverage of storms should be less than
today, with only isolated storms expected. That should also lead
to high temperatures creeping up a bit from today. That should
solidly place much of the area in the upper 90s. The main question
will be dew points, which may be a bit too high in current
guidance. For now, will carry a Heat Advisory for tomorrow, but
it`s not out of the question that an Excessive Heat Warning may
be necessary for a portion of the area. If that happens, it would
probably be for portions of the area surrounding Lake
Pontchartrain, the Atchafalaya Basin and perhaps the Mississippi
coastal counties.

&&

.LONG TERM...
(Thursday through Monday night)
Issued at 330 PM CDT Tue Aug 13 2024

Moisture levels rebound on Thursday, with convective coverage
rebounding accordingly, although it may take a good bit of the
afternoon to develop. Heat index values will continue to support
heat related products on Thursday and probably Friday.

As axis of ridging retreats to the Rockies for Friday into the
weekend, a weak frontal boundary may approach the area. Keeping in
mind it is mid-August, an actual frontal passage would qualify as
a low probability event. No indications of any lowered dew points
in the GFS guidance to provide any sustained relief from the heat,
but the ECMWF deterministic solution would argue for drier
conditions for Monday and Tuesday. Didn`t depart from the NBM
solutions for now.

&&

.AVIATION...
(00Z TAFS)
Issued at 546 PM CDT Tue Aug 13 2024

Convection is dissipating rapidly, and no plans to carry a mention
of TSRA this evening. VFR conditions are anticipated across all
terminals during the overnight hours. The only mention of VCTS
during the daytime hours tomorrow will be at KGPT, where moisture
levels may be high enough to justify thunderstorm development once
the convective temperature is reached around midday.

&&

.MARINE...
Issued at 330 PM CDT Tue Aug 13 2024

No surprises in the marine forecast with the potential for
thunderstorms during the late night and morning hours for the most
part. Outside of thunderstorms expect winds to generally remain 10
knots or less with 1-2 foot seas.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  75  97  75  97 /  10  20  10  40
BTR  79  99  80  99 /  10  20  10  30
ASD  77  98  78  98 /  10  20  10  40
MSY  79  97  80  97 /  10  20  10  40
GPT  78  97  79  97 /  10  20  10  40
PQL  77 101  77 100 /  10  20  10  40

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory until 7 PM CDT this evening for LAZ034>037-039-
     046>048-056>060-064>071-076>090.

     Heat Advisory from 10 AM to 7 PM CDT Wednesday for LAZ034>037-
     039-046>048-056>060-064>071-076>090.

GM...None.
MS...Heat Advisory until 7 PM CDT this evening for MSZ068>071-077-
     083>088.

     Heat Advisory from 10 AM to 7 PM CDT Wednesday for MSZ068>071-
     077-083>088.

GM...None.
&&

$$

SHORT TERM...RW
LONG TERM....RW
AVIATION...RW
MARINE...RW