923
FXUS64 KLIX 121426
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
926 AM CDT Mon Aug 12 2024

...New UPDATE...

.UPDATE...
Issued at 902 AM CDT Mon Aug 12 2024

Performed a forecast update this morning to bring in latest
short-range guidance following obs/trends. A couple of notable
differences in the 12Z KLIX RAOB this morning compared to 24 hours
ago, namely a noticeable increase in near-surface moisture that
extends aloft to a shallow depth of around 1500ft AGL. Otherwise,
the thermal profile remains similar from yesterday with some
slight uptick in overall tropospheric moisture. Noticing a very
slight lowering in H5 heights representative of a slow trend in
weakness setting in/ridge strength weakening (retrograding west).
Otherwise, likely will see another lake/seabreeze boundary
developing extending from coastal SE LA to around the tidal
lakes/sounds that`ll press inland given differential heating. The
combination of this slight lack of tropospheric subsidence and
increase in surface/near- surface moisture may aid in a few
isolated showers, moreso collocated with the aforementioned
lake/seabreeze boundary nearby maximized lift/support. However,
inadequate tropospheric support will likely prevent sustained
updrafts owing to pulse- type showers/storms with mainly isolated
coverage. Targeted 15 PoP for along the boundary this afternoon
following a ingest in HRRR/NBM blended surface winds to reflect
the northward motion of the lake/seabreeze. Additionally, greater
moisture pooling across the Atchafalaya basin may provide greatest
coverage potential for western areas today - with PoP`s in the
15-30% range this afternoon.

Otherwise, the heat is on again with highs reaching the mid/upper
90`s. Not to get too cute, but did dip highs down ever so slightly
towards the 50th percentile as recent deterministic warmer bias
may be a little too warm. Should this change, will adjust but with
afternoon mixing, dewpoints should refrain from causing
oppressive heat indicies. Probably getting close to/at criteria
for the SW/W areas of the CWA, but coverage and confidence is not
the greatest to introduce hazards at this time. KLG

&&

.SHORT TERM...
(Today through Tuesday)
Issued at 339 AM CDT Mon Aug 12 2024

High pressure moves east to be positioned more directly over the top
of us.  This adds a degree or two to our high temps and, more
significantly, allows some Gulf moisture into the area.  PW end up
around 2.0 today and increase to 2.1ish tomorrow.  Because the high
is directly over us, winds are even lighter than the past couple
days.  Apparent Temperatures push up against the limit for a heat
advisory, but aren`t quite there...yet. The high pressure will
continue to force lower rain chances, but there are enough
temperature differentials to develop some sea/lake breeze boundaries
that may generate enough lift to kick off some convection.  Nothing
severe is expected, but there could be lightning and gusty winds
associated with any pop-up storm that does happen to form.
/Schlotz/

&&

.LONG TERM...
(Tuesday night through Sunday)
Issued at 339 AM CDT Mon Aug 12 2024

Wednesday through the end of the period sees continued high pressure
dominance in our area, but a slight change to the synoptic pattern
sees the possibility of a trough digging in just to our east.  True
impact of this pattern is not high, but is enough to increase rain
chances slightly due to higher moisture availability as well as
increased Apparent Temperature to trigger the need for Heat Advisory
headlines.  Any rain that occurs could be accompanied by lightning
and gusty winds. /Schlotz/

&&

.AVIATION...
(12Z TAFS)
Issued at 614 AM CDT Mon Aug 12 2024

Overall no real issues. All terminals currently in VFR and likely
to remain that way for much if not all of the forecast. The only
slight concern would be a rogue storm or two that develops in the
afternoon along the lake breeze and/or sea breeze. /Schlotz/

&&

.MARINE...
Issued at 339 AM CDT Mon Aug 12 2024

The dominant high pressure remains in place continuing the light
winds and seas. Isolated to scattered showers will be possible
daily primarily in the early morning, which could have lighting
and gusty 30-40mph winds.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  95  73  96  75 /  10  10  20  10
BTR  99  79  99  79 /  20  10  30  10
ASD  98  78  98  77 /  20  10  20  10
MSY  96  80  97  80 /  20  10  30  10
GPT  96  79  96  78 /  10  10  20  10
PQL 100  77 101  77 /  10  10  20  10

&&

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

$$

UPDATE...KLG
SHORT TERM...DS
LONG TERM....DS
AVIATION...DS
MARINE...DS