822
FXUS64 KLIX 261130
AFDLIX

Area Forecast Discussion
National Weather Service New Orleans LA
630 AM CDT Sun May 26 2024

...New AVIATION...

.SHORT TERM...
(Today through Monday)
Issued at 340 AM CDT Sun May 26 2024

Upper ridging from the western Gulf of Mexico into Mississippi
early this morning, with shortwaves over Oklahoma and Colorado. At
the surface, high pressure was centered along the Atlantic Coast.
Southerly winds continued to pump moisture into the area, but it
is only being noticed in surface dew points in the 70s across the
area. Temperatures were mainly in the 70s at 3 AM CDT, but there
were several locations that have struggled to fall below 80
degrees.

The 00z LIX sounding carried a precipitable water value of 1.37
inches, which is actually right at the climatologic median for the
date. Not much in the way of moisture in the sounding beyond the
lowest 4000 feet.

Today is going to look a lot like Saturday across the area, with
only some cumulus clouds during the day, as highs get into the 90
to 95 range across most of the area away from the immediate
coastline. Dew points in the low to mid 70s will generally produce
heat index values in the 100 to 105 range. There will be a bit
more of a breeze this afternoon, which may take the edge off the
heat a bit.

A northern stream shortwave will push a frontal boundary close
enough to the area to give the potential for a few showers or
thunderstorms to southwest Mississippi prior to sunrise Monday.

Monday (Memorial Day) could be a bit interesting, weather-wise. It
currently appears that the main forcing from mid level shortwaves
will be passing east of the area during the morning, with the
frontal boundary near the north edge of the CWA before starting to
become diffuse. For much of the area, precipitable water values
never get much above 1.5 inches during the day Monday. Forecast
soundings across the area generally show convective temperatures
on Monday in the mid 90s or even a little higher. And we could get
pretty close to mid 90s across much of the area. The main
question is whether there is enough forcing to develop convection
by late Monday afternoon. Most of the convection allowing
mesoscale modeling shows no convection developing late Monday
afternoon, but there are a few solutions that do. CAPE values run
3500-4000 J/kg or higher, steep low level lapse rates, DCAPE
values near 1500, Lifted Indices near -10. Bottom line...it`s
entirely possible that most or all of the CWA remains dry
tomorrow, but if convection DOES develop, it will probably become
severe, with damaging winds the main threat.

Prior to storms developing (if they do), it`s going to be hot.
Dew points and temperatures look to run a degree or two warmer
than today, and there will be less wind. The current numbers in
the forecast give heat index values pretty close to our 108F
advisory criteria. Given that this is the first real hot spell of
the season, and there will be a lot of people spending a lot of
time out in that heat with holiday activities, have opted to
issue a Heat Advisory for a large portion of the CWA for Monday
afternoon.

&&

.LONG TERM...
(Monday night through Saturday)
Issued at 340 AM CDT Sun May 26 2024

Northern stream shortwaves will gradually produce troughing over
the Great Lakes and toward the Atlantic Coast during the early
portion of the new week. That troughing will gradually force what
is left of the frontal boundary toward the coast Tuesday and
Wednesday. With the upper flow over the local area becoming more
northwesterly over time, there will be the potential for weak
shortwaves moving toward the mean trough position to develop
convection during the heat of the afternoon each day. The
operational GFS is much more bullish on this occurring than is the
operational ECMWF, which has little or no convection beyond
tomorrow until next weekend. The NBM PoP numbers favor a bit drier
solution than the GFS operational, but not to the extent of the
ECMWF. For now, that appears to be a decent compromise, with
mainly afternoon convection on the isolated to scattered side.

The slow moving boundary also means that the drier air will be a
bit delayed compared to earlier forecasts, with dew points in the
60s probably not arriving until Tuesday night or Wednesday. Areas
south of Interstate 10 may not see dew points fall below 70 all
week. However, if convection does develop, the associated clouds
may aid in holding temperatures below 90 degrees for much of the
area beyond Tuesday. At this time, do not anticipate Heat
Advisories beyond Monday.

&&

.AVIATION...
(12Z TAFS)
Issued at 625 AM CDT Sun May 26 2024

Most terminals VFR this morning, but IFR ceilings currently at
KMCB. KMCB will see conditions improve to VFR by late morning.
There will likely be a brief period of MVFR ceilings as cumulus
field builds during the morning, before bases lift above FL030.
Winds will be a bit stronger today, with 15 knot winds being
rather common during the daylight hours. MVFR ceilings will return
overnight at most or all terminals. There is a low end potential
for TSRA at KMCB toward sunrise Monday, but probabilities too low
to carry that far out in the forecast at this time.

&&

.MARINE...
Issued at 340 AM CDT Sun May 26 2024

May be brief periods this afternoon and overnight where winds
creep up just above 15 knots over the open waters. This may
necessitate Small Craft Exercise Caution headlines, probably
overnight tonight. Beyond tonight, winds over the waters are
likely to remain near or below 15 knots through the rest of the
week.

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  92  72  92  70 /   0  20  20  10
BTR  95  78  96  75 /   0  10  20   0
ASD  93  76  94  74 /   0  10  20  10
MSY  93  78  93  77 /   0  10  20  10
GPT  89  77  91  74 /   0   0  20  10
PQL  91  76  91  73 /   0   0  20  10

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...Heat Advisory from noon to 8 PM CDT Monday for LAZ034>037-039-
     046>048-056>060-064-065-071-076>090.

GM...None.
MS...Heat Advisory from noon to 8 PM CDT Monday for MSZ068-077-083-
     084-086-087.

GM...None.
&&

$$

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