Area Forecast Discussion
Issued by NWS New Orleans/Baton Rouge, LA

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FXUS64 KLIX 221738
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1238 PM CDT Fri Mar 22 2024

...New AVIATION...

.UPDATE...
Issued at 905 AM CDT Fri Mar 22 2024

An convective band of rain with embedded elevated thunderstorm
activity continues to progress very quickly to the east this
morning. PoP, weather, and QPF forecast has been updated to
account for this faster eastward progression, and now have largly
dry conditions forecast by 18z for most of the forecast area.
There is still the risk of some isolated to widely scattered
showers and storms redeveloping late this afternoon over portions
of the Florida Parishes and Southwest Mississippi during peak
heating hours as the cold core of an upper level low transits
along the I-20 corridor, and PoP of 20 to 30 percent reflects this
in the late afternoon and early evening hours. Water vapor imagery
and the Lake Charles sounding show a very dry mid-level airmass
moving in from the west, and this is allowing for rapid clearing
in the wake of the convective band. Have reduced cloud cover to
mostly sunny conditions through the early afternoon with some
redevelopment of cloud cover later today as the cold core of the
upper level low moves through. Temperatures have not been adjusted
yet, but will monitor for more warming than currently forecast
given the clearer skies expected late this morning into early
this afternoon. Winds have also been tweaked to account for
the brief period of stronger east and northeast winds in the
immedidate wake of the convective band. PG

&&

.SHORT TERM...
(Today through Saturday)
Issued at 330 AM CDT Fri Mar 22 2024

Southern stream shortwave over Oklahoma early this morning, with a
northern stream shortwave over Minnesota. Upper ridge was over the
Intermountain West. At the surface, high pressure was over Lake
Ontario, with weak low pressure near Lake Charles. At 3 AM CDT,
radar indicated a small cluster of thunderstorms near New Iberia,
with a larger line of storms near the Texas-Louisiana border. No
indications of severe weather recently, but certainly we`ll need
to keep an eye on them. Temperatures ranged from the mid 50s to
lower 60s.

The Oklahoma shortwave will continue eastward over the next 36
hours, crossing the local area this afternoon and tonight, and
moving off the South Carolina coast by Saturday evening.
Precipitable water values aren`t particularly remarkable across
the area, about 1.1 inches, but mid level temperatures are
forecast to be fairly cold, around -17C, and mid level lapse rates
are around 7C/km, so there is at least some potential for hail.
Recent gusts have been around 40 mph, and would expect that
potential to continue this morning as storms move eastward across
the area. Most of the strong convection should be east of the
area by mid afternoon, but we probably will hold onto some
isolated showers as late as 8 or 9 pm. Overall, Saturday looks to
be dry, but it may take a pretty good portion of the day to get
rid of the cloud cover with the shortwave in close proximity.

Highs both days in the upper 60s to mid 70s, with overnight lows
tonight generally in the 50s.

&&

.LONG TERM...
(Saturday night through Thursday)
Issued at 330 AM CDT Fri Mar 22 2024

With the shortwave moving off the South Carolina coast Saturday
evening, shortwave ridging will move across the area for the
remainder of the weekend. A large trough moving out of the Rockies
Sunday night into Monday will develop strong low pressure over the
central Plains States. That low will move northeast to Lake
Superior by Tuesday night, then into Ontario. Another line of
showers and thunderstorms will move across the area late Monday
night into Tuesday morning. Forecast wind fields are quite a bit
stronger with this system than what is moving across the area this
morning. We`ll need to keep an eye on the severe potential with
this system, even though it looks like the better threat will be
to the north. Once the frontal boundary gets east of us, the
column dries out some later in the day. However, the upper trough
will be slower to move across the local area, with the axis of the
trough perhaps not getting east of the area until Thursday night.
That may make it a bit more difficult to get entirely rid of the
cloud cover Wednesday and Thursday.

Monday looks to be the warmest day of the batch, with highs mid
70s to around 80, with the remainder of the long term much closer
to, or perhaps a bit below normal. Temperature guidance is
generally pretty similar, so NBM numbers should hold up OK.

&&

.AVIATION...
(18Z TAFS)
Issued at 1233 PM CDT Fri Mar 22 2024

MVFR ceilings will persist at all of the terminals as the cold
core of an upper level low pressure system passes across central
Mississippi. There is a risk of a shower or storm impacting MCB
between 20z and 00z as temperatures warm through the afternoon
hours. If a storm impacts MCB, a brief period of gusty winds,
reduced visibilities, and lightning can be expected. After 00z,
conditions look favorable for low stratus to redevelop and
overspread all of the terminals as a weak elevated temperature
inversion forms. The ceilings will be lowest between 06z and 14z
when a mix of IFR and MVFR conditions can be expected. Ceilings
will vary between 800 and 1500 feet over this period. After 14z,
increased mixing of dry air aloft will allow for the cloud deck to
break up and begin lifting with VFR conditions expected by 18z.
Gusty winds from the north will also impact MSY and NEW tonight
with wind gusts over 30 knots at times. PG

&&

.AVIATION...
(12Z TAFS)
Issued at 651 AM CDT Fri Mar 22 2024

Most terminals were at MVFR at forecast issuance this morning.
Cluster of thunderstorms that had been over western Louisiana
earlier in the night surged eastward a bit quicker than forecast.
Back edge in the process of clearing KBTR at 12z, and at the
current pace, should be east of all terminals prior to 18z.
Earlier, there was concern that there would be redevelopment under
the cold pool, but recent convection allowing models are showing
that this redevelopment may slide just north of even KMCB.

MVFR ceilings are expected to be the prevailing condition for much
of the forecast period, with some potential for IFR ceilings
between 06z-12z Saturday. Additionally, northwesterly winds are
expected to become gusty at the New Orleans terminals beyond 06z
Saturday with gusts to 30 knots or more possible at KNEW into the
daytime hours Saturday.

&&

.MARINE...
Issued at 330 AM CDT Fri Mar 22 2024

Outside of the thunderstorm threat this morning, gradient winds
are expected to briefly relax, and will allow SCA to expire at
12z. Will carry Small Craft Exercise Caution headlines through the
daytime hours into the early evening across the outer open
waters. Will reinstitute Small Craft Advisories starting at mid-
evening for all waters as northerly winds increase behind the
departing trough/frontal boundary. Conditions will slowly relax
Saturday evening, with about a 36 hours period of less hazardous
conditions before the next system affects the area Monday night
into Tuesday.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  52  68  43  70 /  30   0   0   0
BTR  55  74  48  74 /  30   0   0   0
ASD  55  74  47  72 /  20   0   0   0
MSY  57  72  54  72 /  20   0   0   0
GPT  56  72  48  69 /  20   0   0   0
PQL  56  74  45  72 /  20   0   0   0

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...Small Craft Advisory from 10 PM this evening to 5 PM CDT
     Saturday for GMZ530-532-534-536-538-550-552-555-557-570-572-
     575-577.

MS...None.
GM...Small Craft Advisory from 10 PM this evening to 5 PM CDT
     Saturday for GMZ532-534-536-538-550-552-555-557-570-572-575-
     577.

&&

$$

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


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