133
FXUS64 KLIX 120448
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
1148 PM CDT Sat May 11 2024

...New AVIATION...

.UPDATE...
Issued at 906 PM CDT Sat May 11 2024

Already have had one storm move into the CWA just west of BTR and
looking back to the west there is a lot of convection developing
over eastern TX. Watching these storms it appears to be associated
with an increase in lift coming across Mexico and TX along with
the surge of moisture. This activity should start to spread
across the northern half of the CWA from west to east around and
after midnight. Looking at GOES16 WV there is quite a bit of lift
and given the unstable conditions and increasing moisture there
will be thunder and if this continues to trend up even more then
the PoPs will need to be increase again in the next few hours.
/CAB/

&&

.SHORT TERM...
(This evening through Sunday night)
Issued at 209 PM CDT Sat May 11 2024

Tonight through Sunday evening, zonal flow will dominate the upper
level pattern. Surface winds will shift from northerly to
southerly overnight tonight, which will help to reintroduce
moisture into the area. This will also help increase instability
somewhat. Conditions, looking at the models, will be fairly dry
tonight through tomorrow night, but an isolated shower or two is
possible for our northern areas tomorrow morning.

A weak upper level impulse will influence the area Sunday night
through Monday morning (beginning of the long term forecast).
Southerly surface winds will continue to advect humid and moist
air into the area, increasing instability. Scattered showers and
storms are possible Sunday night into Monday morning. These look
mostly fairly weak overall and stratiform, but there are a lot of
uncertainties in the models regarding timing of the impulse and
beginning of the rain. Some localized flash flooding concerns will
be possible early Monday, but not as likely as later in the
daytime on Monday (which is covered in the long term forecast). MSW

&&

.LONG TERM...
(Monday through Friday night)
Issued at 209 PM CDT Sat May 11 2024

By Monday morning, upper ridging will move to the eastern Gulf near
Florida. The surface and mid level cyclone will be over Kansas with
moderate southerly flow across the local area. While there will be a
break between warm advection precipitation Sunday night into Monday,
the airmass is expected to destabilize again with precipitable water
values returning to around 2 inches overnight. Instability and shear
would be sufficient for a severe weather threat, with details
depending on the evolution of events Sunday night into Monday. Heavy
rain will also be a significant threat with current forecasts of 2-3
inches across a large portion of the CWA from late Monday afternoon
through Tuesday morning.

Once the upper system and surface front progress to the east of the
area during the first half of Tuesday, there will be probably a 36
to 48 hour period of quiet weather until the next trough approaches
from the west. Precipitable water values will remain below an inch
for much of the period from midday Tuesday to midday Thursday.
Precipitable water values then increase to near 2 inches again
with plenty of instability available for thunderstorms. The
current global model solutions hold most of the heavy rainfall to
the north of our CWA, but considering this is 6 days out, don`t
feel comfortable lowering any messaging regarding a wet pattern at
this time. Interaction, or lack of, between northern and southern
stream shortwaves could produce significantly different results
as there are large differences even between the 50th and 90th NBM
percentile QPF values, as much as 2-3 inches for Thursday into
Friday. Beyond Friday, global solutions fall out of any
significant agreement, as the GFS drags a southern stream
shortwave across the area next weekend, while the ECMWF solution
is dry.

With some uncertainty in timing of systems during the extended
period, will stick to the NBM deterministic numbers for
temperatures. RW

&&

.AVIATION...
(06Z TAFS)
Issued at 1143 PM CDT Sat May 11 2024

All terminals remain in VFR status but impacts will begin shortly
as rain and thunderstorms moves into the area. This may not lead
to lowered vsbys or lowered cigs into MVFR status but it will
impact most terminals none the less. Rain will likelyt taper off
some if not completely around or shortly after 14/15z but this
will be short lived as we expect convection to begin to move back
into the area during the evening and overnight hours. During the
overnight hours there will be a much greater chance of seeing
lowered cigs and reduced vsbys. /CAB/

&&

.AVIATION...
(18Z TAFS)
Issued at 1205 PM CDT Sat May 11 2024

VFR conditions prevail at all area airports and will persist
through the forecast period. Wind shifts greater than 30 degrees
will be expected at all area airports throughout the forecast
period. MSW

&&

.MARINE...
Issued at 209 PM CDT Sat May 11 2024

Marine conditions will remain calm/benign through tomorrow
afternoon. A system will be moving through the area Sunday night
through Tuesday morning, which will cause strong (15-25kts) southerly
winds and higher seas through Wednesday morning. Winds will ease
shift northerly Wednesday into early Thursday behind the system.
Another system will likely move through the area Thursday through
Saturday morning, which will strengthen the southerly winds
(15-25kts) and bring higher seas. MSW

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  61  78  64  83 /  50  40  70  90
BTR  67  85  72  88 /  40  40  60  70
ASD  66  85  70  86 /  30  20  60  80
MSY  71  85  74  86 /  10  20  60  70
GPT  67  83  71  84 /  30  10  60  90
PQL  63  85  69  85 /  30  10  50  90

&&

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

$$

SHORT TERM...MSW
LONG TERM....RW
AVIATION...CAB
MARINE...MSW