Folsom, Louisiana Weather Forecast Discussion

079
FXUS64 KLIX 190446
AFDLIX
Area Forecast Discussion
National Weather Service New Orleans LA
1146 PM CDT Thu Sep 18 2025
...New SHORT TERM, LONG TERM, AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1115 PM CDT Thu Sep 18 2025
- Calm/quiet weather expected today thru the upcoming weekend
   with highs in the low to mid 90s. No excessive heat concerns in
   the forecast.
- Can`t rule out an isolated shower or storm for
   northern/northeastern areas this afternoon, but coverage will
   be limited.
- Rain/storm chances have lowered somewhat going into the early
   to middle parts of next week - more routine with scattered
   daily mainly afternoon/evening shower/storm chances.
&&
.SHORT TERM...
(Tonight through Sunday night)
Issued at 1115 PM CDT Thu Sep 18 2025
Quiet and calm early this morning with only some scattered
mid/upper-level clouds around. Main focus for today was on what
was presented by the recent suite of 00Z CAM guidance, attempting
at introducing a few isolated showers or storms mainly for
northern areas, north of I-10/12 and east of I-55. Taking a closer
look a proximity soundings from the HRRR (00Z for KMCB)
illustrates that we will mix out strongly, as we have for weeks
now increasing LCL heights above a dry adiabatic, deep mixed
layer. Subsidence at H6 will keep mid-level temps relatively
"warmer" into the -7 to -8C range, however just enough available
energy between the LCL and inversion base will support scattered
Cu to develop as we warm up. Additionally, the H5 pattern suggests
a generalized weakness aloft where just enough lift and
aforementioned shallow energy could spark a few showers/storms
here and there. Greater confidence will come from any extra boost
likely a northward drifting lake/seabreeze boundary) being an
extra aid/foci in ascent to get a few going. Thus, increased
inherited 01Z NBM PPI01 grids from 0-5% to 15-17% to get a
mention in the forecast. Additionally, as for dewpoints, did lower
guidance utilizing the NBM 25th to 10th percentile this afternoon
to account for the well-mixed PBL we can expect later today.
Observations from yesterday illustrate a few areas hit the upper
50`s, well on the low end of guidance and will keep that lower-end
bias going.
Otherwise, the weekend is looking nice and drier! Highs remain in
the low to mid 90`s. Nothing record-breaking as records are well
into the upper 90`s to near/at 100 for some locations, but is
above average by several degrees. KLG
&&
.LONG TERM...
(Monday through Thursday night)
Issued at 1115 PM CDT Thu Sep 18 2025
Now going into next week, there are a few interesting changes in
trends with long-range guidance. Namely, just by quickly glancing
at deterministic guidance shows the cut-off upper-low over the
mid-west being much less amplified/stronger and overall weaker,
allowing a stronger ridging pattern to build over the southern
US. This upper-low was previously the driving force to send a
weakness/weak trough into the northern Gulf coast states
introducing widespread shower/storm chances. This took some
investigating, and dove deeper into cluster analysis to better
get an idea at what is going on which revealed the northern
US/southern Canadian ridge being stronger, and the cut-off low
originating as a shortwave trough over the PacNW being stuck
under the ridge in a subtle omega pattern. This makes sense, and
loses any momentum during it`s slow eastward drift becoming
weaker/stretching out with time, and in-turn reduces southern US
troughing to allow a 588dm ridge to build in more. Cause/effect
is the NBM lowering PoPs from the 50/60`s Tuesday/Wednesday to
more 20/30`s. Having a very hard time thinking - even with this
trend - that PoPs will get much lower than this, as regardless at
a minimum, we should settle into a more routine summertime
afternoon/evening scattered shower/storm regime, but given this
long-range shift/trend, will advertise showers/storms will be
around and will monitor how this continues to trend over the next
few days. Overall, someone will see rain/storms next week which
with the latest drought monitor illustrating widespread D0 and
pockets of D1, could be seen as useful especially as we close in
on the seasonably driest period of the year according to
climatology. Temperatures remain hot, but not seeing excessive
heat concerns thru the next 5-7 days. KLG
&&
.AVIATION...
(06Z TAFS)
Issued at 1115 PM CDT Thu Sep 18 2025
Expect VFR conditions for all area terminals through the forecast
period. SKC and light/calm winds early this morning, then we`ll
see winds increase to around 6-8kts from 16-18Z thru sunset. Will
see a lake/seabreeze for coastal terminal sites, causing a brief
wind shift but otherwise will some SCT low- level Cu in the
afternoon. Can`t rule out a brief ISO SHRA/TSRA for KMCB to north
of KGPT/KASD this afternoon but impacts will be limited. KLG
&&
.MARINE...
Issued at 1115 PM CDT Thu Sep 18 2025
Quiet/calm conditions for marine waters can be expected thru this
upcoming weekend thanks to a weak ridge of high pressure to our
north, promoting mainly light easterly winds and calm waves/seas.
with light winds and calm waves/seas. Can`t rule out a few isolated
showers each day, but chances go up slightly more as we go into
Monday thru mid-week but will primarily be scattered chances for
now. KLG
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB  66  92  68  92 /   0  20  10   0
BTR  68  93  69  94 /   0  10   0   0
ASD  66  92  68  92 /   0  20  10   0
MSY  73  93  74  94 /   0   0   0   0
GPT  70  91  71  92 /   0  10  10   0
PQL  66  93  68  94 /   0  20  10   0
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
SHORT TERM...KLG
LONG TERM....KLG
AVIATION...KLG
MARINE...KLG

NWS LIX Office Area Forecast Discussion