834
FXUS64 KLIX 282106
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
406 PM CDT Tue May 28 2024

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

.SHORT TERM...
(This evening through Wednesday night)
Issued at 400 PM CDT Tue May 28 2024

Convection is firing as expected across the area just a tad farther
to the southwest than initially expected but there is still quite
a bit of convection off to the west trying to slide towards our
area. Thee is still a convergent line in the LL just south of the
Southshore (NO metro) and runs WNW to LFT. This has nudged south
from where it was a few hours earlier and it will likely keep the
strongest convection contained to area along and south of I-10
with little if anything around I-12 and especially north of that
for the remainder of the afternoon and through the evening. Storms
that have fired off to our west have had a history of producing
severe hail and severe winds with hail up to 1.25" so far but
multiple reports of winds 50 to 60 and a peak wind speed near
Beaumont of 73 mph! The closest report to our CWA so far has been
New Iberia (ARA) with a measurement of 58 mph at the ASOS.

After we start to lose the daytime heating these storms will begin
to wane and could dissipate quickly as there is no real disturbance
associated with this activity as they have been almost been
exclusively driven by mesoscale features such as boundary collision
(sea, lake, outflow, differential heating, etc). The atmosphere is
just juicy enough that storms just needed to get going and then the
storms could basically provide the rest until we lose the
instability.

Tomorrow and Thursday we will continue to see the possibility of
convection and just like today and yesterday it will primarily be
driven by what develops overnight upstream across TX, Red River
Valley, and Arkansas. The digging L/W trough over the eastern CONUS
will try to place the area under weak northwest flow and this
usually leads to convection being later, sometimes much later in the
day. But the ridging over the western Gulf may nudge north into the
area and this could suppress convection but the key will be if
convection to our northwest dives southeast eroding the s/w ridging
or if the ridging is too strong and forces most of the convection
more south just off to our west. Thursday seems to be fairly similar
but possibly a touch better for rain potential as we should at least
see the Gulf ridge retro grade with much more energy working to the
Plains and southern Plains Wednesday night through Thursday. Again
the thing to watch will be convection upstream as that will dictate
what happens here. As for the potential for strong to severe this
risk should not be as impressive as today with not as favorable mid
lvl lapse rates, slightly cooler temps leading to less instability
over the area as well. Only thing to keep an eye on is the
possibility of the seabreeze activating. With the sfc high becoming
established across the CONUS between the MS Valley and the
Appalachians we will see onshore flow return with mostly southerly
winds from the sfc to h85 and this could help provide enough LL
convergence and forcing to get a few storms to pop but with that and
the possibility of weak northwest flow, wouldn`t anticipate much
convection until at least the afternoon if not mid afternoon. /CAB/

&&

.LONG TERM...
(Thursday through Monday night)
Issued at 400 PM CDT Tue May 28 2024

Forecast is not getting any easier in the extended portion of the
forecast. Some of the medium range models have trended in the
opposite direction from where they were the past 48 hours with the
ECMWF trending wetter for Friday and the GFS now slightly drier
(not dry just not quite as bullish as yesterday). That said there
is more confidence now that ridge building west of the current
eastern CONUS L/W trough will not be quite as stout and the base
will be north of the region. This provide weak northwest to
possibly mostly zonal flow and thus any disturbances that dig into
the southern Plains and central/east TX should be able to
undercut the ridge enough to push into our area. Again looking at
the NBM and it has increased the PoPs for almost each through
Sunday. With the increase in confidence in the pattern this is a
good trend and will stick with the 40 to even 60% PoPs it is
advertising at times. The biggest question is the afternoon highs.
These will absolutely be dictated by timing over convection and
cloud cover and with no confidence at all in the overall timing
best option is to stick with what the NBM has however if we have a
great deal of cloud cover and rain most of these daily highs in
the forecast will likely be too warm. On the other side with the
LL temps being advertised if we find ourselves in a break at the
wrong time (basically mid morning through the afternoon) the
current forecast is a few degrees too cool.

Friday may be the one day with the least amount of convection. The
L/W trough will dig across the eastern seaboard and the ridge will
amplify in response but as long as it is connected with the broad
riding to the SSW over the Gulf and across Mexico we should still be
able to get some afternoon convection. LL temps of 22-24 would
suggest highs in the upper 80s to maybe mid 90s but with the
expectation of clouds and storms providing cooling rain mid 80 to
near 90 is probably the right call.

This weekend looks to provide one possibly two good shots of rain
across the area. The trough currently coming onshore out of the
Pacific will work across the CONUS over the next few days and there
may actually be multiple impulses associated with it as it tries to
merge with some energy coming out of the Pacific over Mexico and
southern TX. Multiple things being to take place late Friday and
into the weekend. First our L/W trough over the east coast slides
east into the Atlantic with the ridge continuing to work east as
well. This will lead to less of an impact from the ridge. In
addition the ridge over Mexico builds but is centered along the
western Mexican coast with the ridge axis building into the 4
corners late Saturday. This will help to place the CWA in northwest
flow but there will be a few disturbances that work through the
Lower MS Valley. Timing these right now is futile but when these
occur we can expect to see scattered to numerous storms across the
region. Good thing is as of right now it doesn`t look like there is
that much of a threat of strong to severe storms. Biggest impact
could be in the form of heavy rain. /CAB/

&&

.AVIATION...
(18Z TAFS)
Issued at 1247 PM CDT Tue May 28 2024

At this time all terminals are in VFR status and this will remain
the case until convection moves in and impacts the area. Locations
like MCB and GPT have the least chance of seeing any impacts from
convection while ASD and HDC are on the fringe. BTR and then
south and southeast towards HUM, MSY and NEW, fully expect these
locations to deal with impacts from approaching and developing
convection. There is a threat of some of these storms being
strong to severe with large hail and damaging straightline winds
the main concern. These could lead to downbursts very close to a
few terminals later this afternoon and evening these storms
should should be monitored closely. Best likely chance of seeing
severe winds and/or large hail is BTR and HUM. BTR should be
between 19Z and 22Z while HUM could be similar and may last a
little longer. /CAB/

&&

.MARINE...
Issued at 400 PM CDT Tue May 28 2024

No major concerns over the coastal waters outside of convection.
The one thing to keep a close eye on is the possibility of a wake
low tonight if current convection over south-central and southeast
LA starts to surge to the southeast again. The is a rather
impressive meso high behind the convection and if this continues
we could see a wake low develop providing a 2-3 hours window of
strong winds over the coastal waters west of the mouth of the MS
this evening. High pressure will be come re-established well off
to our north and northeast and onshore flow will redevelop and
become moderate at times through the rest of the week and into the
weekend. /CAB/

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  67  89  66  87 /  10  30  20  50
BTR  72  93  73  89 /  10  30  20  60
ASD  72  93  71  90 /  10  20  10  30
MSY  75  92  76  91 /  20  20  10  40
GPT  73  90  73  88 /  10  10  10  20
PQL  70  93  69  91 /   0  10  10  20

&&

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

$$

SHORT TERM...CAB
LONG TERM....CAB
AVIATION...CAB
MARINE...CAB