-- Discussion containing changed information from previous version are highlighted. --
076
FXUS64 KLIX 251617
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1117 AM CDT Tue Jun 25 2024

...New UPDATE...

.UPDATE...
-- Changed Discussion --
Issued at 1116 AM CDT Tue Jun 25 2024

Quick update to the forecast to adjust hourly temps, dewpoints,
and PoPs. Overall forecast still on track for another hot day with
oppressive conditions and then possibly some quick relief from
storms. As previous forecaster mentioned storms will be dictated
by boundaries and boundary interactions. We are already seeing a
few popcorn showers mainly along the river parishes where an old
outflow boundary is likely starting to interact with the lake
breeze coming southwest off of the lake and the sea breeze coming
out of the Gulf and Vermillion Bay region. Outside of the rain
look for temps to top out in the mid to possibly upper 90s with a
heat index likely ranging from 105 to 112. If rain is late this
afternoon around 21-23z that should help cool things finally but
it will still be oppressive as these areas would have warmed up
already. If storms occur around midday and early afternoon it
could be worse as temps would likely be able to warm back up
quickly and then combine that with the extra boundary layer
moisture from rain could lead to the higher heat index values
mentioned earlier (110-112 can`t rule out slightly higher in
isolated locations). Grids and zones have already been sent. /CAB/
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&&

.SHORT TERM...
(Today through Wednesday)
Issued at 325 AM CDT Tue Jun 25 2024

Upper ridging extended from southern California to western
Louisiana early this morning with troughing just off the Atlantic
Coast to the northeastern Gulf of Mexico. There was a shortwave
moving through the western Great Lakes and another over Nebraska
and Kansas.

Temperatures at 3 AM CDT were in the 70s across most of the area.
There were a few showers over the Gulf of Mexico to the south of
the Mississippi coast, which isn`t all that unusual for this time
of year.

The primary concerns over the next 36 hours will be the heat, and
the potential for thunderstorms. While the shortwave that
triggered yesterday`s thunderstorms has moved away from the area,
there will still be remnant outflow boundaries around. As
temperatures heat up into the middle 90s in most areas by midday,
we should see at least isolated to scattered development of
storms. Low level wind fields are pretty weak, so any storms that
develop today won`t be moving much, just propagating along
outflows. Most storms should die out by sunset. Before the
thunderstorms develop, conditions are likely to be pretty
oppressive with heat index values approaching, if not exceeding
110F in many areas. Will keep the Heat Advisory in place for
today.

The one change on Wednesday as compared to today is that a
shortwave moving out of the Plains states will move into the area
around midday, which is expected to enhance areal coverage of
showers and storms during the afternoon into the early evening
hours. Depending on the timing of convective development, it could
keep our heat index values just below advisory criteria tomorrow.
We won`t extend the advisory beyond this afternoon for now, but
there`s certainly potential that we will need one, especially west
of Interstate 55.

As there isn`t much spread in the guidance, will not make
significant departures from the NBM deterministic for now.

&&

.LONG TERM...
(Wednesday night through Monday)
Issued at 325 AM CDT Tue Jun 25 2024

We may still have shortwave energy impacting the area on Thursday
with ridging well to the west of the area. That would lead to
fairly good areal coverage of storms across the area, and
potentially be the least uncomfortable day of the extended. Beyond
Thursday, both the GFS and ECMWF operational runs build the ridge
back toward the area. At this point, the main question is whether
the ridge builds over the local area or just to the north of the
area. If it builds over the area, it would limit any significant
development of thunderstorms, and allow for hotter daytime
temperatures. If it becomes centered to the north of the area, it
may allow for at least some afternoon convection, especially near
the coast. At this point, the more favored solution would allow at
least some thunderstorm development during the afternoon hours and
hold high temperatures in the middle 90s.

&&

.AVIATION...
-- Changed Discussion --
(18Z TAFS) Issued at 1116 AM CDT Tue Jun 25 2024

All terminals are currently in VFR status as any MVFR cigs earlier
has finally scattered out. Through the rest of the day VFR
conditions will continue unless convection impacts the terminal
which is highly possible at most terminals. MCB may have the best
chance of not seeing much in the way of impacts but elsewhere it
is very uncertain. Convection will be dictated by sea/lake breeze
and outflow boundary interactions.

Will continue to carry VCTS for most terminals, but confidence in
a particular terminal is not high. Obviously if convection
directly impacts any terminal it would most likely be IFR
visibilities and wind gusts around 30 knots. Any convection that
does develop should wind down near or shortly after 00z. Still
holding off on any vsby restrictions of lower cigs during the
early morning hours as this will be highly determined by if and
where any heavy rain falls today. /CAB/
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&&

.MARINE...
Issued at 325 AM CDT Tue Jun 25 2024

No large scale pressure systems are expected to impact the coastal
waters over the next several days. So, outside of the usual
diurnal increase in wind speeds during the evening hours, the only
real concern will be the development of thunderstorms. Generally,
that would impact the tidal lakes and sounds during primarily the
afternoon and evening hours and the open waters during the late
night and early morning hours.

&&

.PRELIMINARY POINT TEMPS/POPS...
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MCB  94  74  92  74 /  20  20  60  40
BTR  97  78  96  78 /  30  30  60  30
ASD  96  77  94  77 /  20  10  60  30
MSY  94  79  93  79 /  30  10  70  30
GPT  95  78  94  77 /  20  10  60  40
PQL  98  77  96  77 /  10  10  50  40
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&&

.LIX WATCHES/WARNINGS/ADVISORIES...
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LA...Heat Advisory until 7 PM CDT this evening for LAZ034>037-039-
     046>048-056>060-064-065-071-076>090.

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

GM...None.
-- End Changed Discussion --
&&

$$

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