650
FXUS64 KLIX 020458
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1158 PM CDT Wed May 1 2024

...New UPDATE, AVIATION...

.UPDATE...
Issued at 1144 PM CDT Wed May 1 2024

Earlier isolated convection near Baton Rouge has finally
dissipated, so have removed mention from the overnight forecast.
No other changes.

&&

.UPDATE...
Issued at 1004 PM CDT Wed May 1 2024

Convection near Baton Rouge has persisted longer than anticipated
and have gone ahead and updated that area for isolated showers and
storms. A very small area may be seeing heavy rain as cells aren`t
moving much. Anticipating that we should see a diminishing trend
prior to midnight CDT. No other changes made at this time.

&&

.SHORT TERM...
(This evening through Thursday night)
Issued at 211 PM CDT Wed May 1 2024

A fairly strong mid to upper level shortwave ridge axis continues
to dominate the Gulf South today and this will continue into the
overnight hours. Beneath this mid to upper level ridge, southeast
flow off the Gulf of Mexico will continue. This onshore flow
regime will continue to pump Gulf moisture into the low levels,
and dewpoints will remain elevated in the 60s. This will also
limit overnight cooling with lows only falling into the upper 60s
and lower 70s tonight. These values are 5 degrees warmer than
average. Although conditions do not look as favorable for fog
development tonight due to stronger boundary layer winds of around
15 knots and increasing cirrus coverage from storms over Texas,
some patchy fog development could occur right around daybreak over
inland areas.

Tomorrow will see a fast moving shortwave trough axis push in from
Texas. The majority of the forcing with this system will be
shunted to the north of the CWA due to the strength of the ridge
axis aloft, but weakening band of showers and thunderstorms could
push into the northwest third of the CWA tomorrow afternoon. Have
bumped PoP values to 50 to 60 percent for areas to the north and
west of Baton Rouge where the combination of higher upper level
omega and enough cooling aloft to weaken the strong mid-level cap
should be in place to support updraft development. Away from this
region, the influence of the ridge and resultant subsidence will
be strong enough to keep the mid-level cap in place. This is
evident by weak mid-level lapse rates of around 5.5-5.7 C/km
tomorrow afternoon across coastal Louisiana and coastal
Mississippi. Fortunately, for the areas that could see some
convective activity tomorrow afternoon, shear values will remain
weak, and severe storms are not expected. By tomorrow evening, the
convective threat will diminish as the shortwave trough pulls to
the northeast and a brief period of increased ridging and negative
vorticity takes hold of the northwest third of the CWA.
Temperatures will be closer to average tomorrow into tomorrow
night as increased cloud cover reduces overall solar insolation.

&&

.LONG TERM...
(Friday through Tuesday night)
Issued at 211 PM CDT Wed May 1 2024

Another shortwave trough will quickly move through the region on
Friday, and this trough is expected to impact the area more
effectively. This will be due to both the lingering weakness in
the ridge from the previous system on Thursday, but also a more
southern origination over the Texas coast that will push the core
of the shortwave trough the Lower Mississippi Valley. With the
core of the shortwave moving more over the region, the mid-level
cap will break down more easily, and this will allow for greater
MLCAPE of 500-1000 J/KG in the afternoon hours when temperatures
rise into the upper 70s and lower 80s. Have went with fairly high
PoP of 50 to 70 percent for areas along and north of the I-10
corridor in Southeast Louisiana and Southwest Mississippi where
overall forcing and instability will be maximized. A fairly sharp
cut-off in convective activity is expected to the south, and have
only went with a 20 to 30 PoP for areas around New Orleans and the
River Parishes Friday afternoon. PWATS will surge to around 1.75
inches, so some locally heavy downpours will be the primary
concern with the deeper convection that develops. Shear values
will remain limited, so severe storms are not anticipated on
Friday. The trough axis will pull east of the area Friday evening,
and a rapid reduction in convective activity is expected during
the evening hours.

The mid to upper level ridge will intensify over the region on
Saturday and continue to build in strength through early next
week. As this occurs, subsidence and warming aloft will begin to
greatly limit convective potential over the area and also lead to
very warm temperatures for this of year. Saturday will be the last
day with any convective threat as another fast moving shortwave
feature slides through the Mid-Mississippi Valley, but only
isolated storms are expected as mid-level lapse rates start to
weaken with the strengthening cap in place. By Sunday, any rain
chances will be finished with the ridge fully dominating the
region. Temperatures will warm into the mid 80s on Saturday,
and will further warm into the upper 80s and lower 90s by Monday.
With onshore flow and higher dewpoints persisting through the
extended period, lows will only cool into the upper 60s and lower
70s each night. It will be a very Summer-like feel out there early
next week, and extra caution is advised for those working
outdoors due to a lack of acclimation. A few record highs could be
approached or broken.

&&

.AVIATION...
(06Z TAFS)
Issued at 1144 PM CDT Wed May 1 2024

Over the last hour or so, have seen MVFR ceilings...near
FL012...develop at several terminals. Combining that with the NBM
probabilities of visibilities of a mile or less around sunrise coming
in lower than earlier in the evening, it appears this will be more
of a low stratus event. Will be carrying IFR ceilings at most
terminals from 08 or 09z through about 14z, before improvement to
MVFR. Still seeing widely varying solutions regarding convective
expectations on Thursday. That includes the amount of areal
coverage, timing, and how far east storms make it before
dissipating. Primary threat appears to be during the afternoon
hours from about noon to 5 pm, mainly west of Interstate 55 and
north of Interstate 12. With the uncertainty, will carry VCTS at
KMBC/KBTR/KHDC. Beyond 00z Friday, MVFR ceilings likely for much
of the night.

&&

.MARINE...
Issued at 211 PM CDT Wed May 1 2024

A persistent surface ridge centered over the Southeast CONUS will
keep southeast winds of around 10 knots in place through the
weekend and into early next week. Seas will also be fairly
persistent at 1 to 3 feet through the period. Overall, no
significant concerns to maritime operations are anticipated
through early next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  63  84  66  80 /   0  50  40  60
BTR  70  85  70  81 /  10  50  30  50
ASD  67  84  69  83 /   0  30  20  30
MSY  71  84  72  82 /   0  30  20  20
GPT  68  81  71  81 /   0  20  10  20
PQL  65  82  69  82 /   0  10  10  10

&&

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

$$

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