UPDATE
Issued at 1019 PM CDT Sat Sep 7 2024

Drier air slowly creeping into the CWA this evening, although one couldn't tell by looking at our 00z sounding, which still was nearly saturated to 500 mb, with a precipitable water value of 2.15 inches. Lake Charles was somewhat drier at 1.73 inches, and Jackson was at 1.26 inches, so it's not far away. About the northwest 1/3 of the CWA has lost the low and mid clouds, but not sure how much more progress we will see with the clearing overnight. Any remaining light precipitation will be limited to the extreme lower portions of the coastal parishes, and not even sure it will occur there. Had to adjust temperature/dew point trends with slower cooling and drying occurring than what was in grids.

SHORT TERM
(This evening through Sunday night)
Issued at 231 PM CDT Sat Sep 7 2024

Drier air continues to gradually filter into the area from the north with most showers now limited to areas near the immediate coast of SE LA and over the northern Gulf. The drier air will allow temperatures to fall to near or even slightly below normal overnight tonight and Sunday night, with the best chance for lower than normal temperatures along and north of I-10/12.
Forecast calls for a quite pleasant morning across these more northern areas where lows in the morning are forecast to drop into the 60s. South of the interstate corridor, temperatures will generally only drop a few degrees lower than what was seen this morning as the significantly drier air won't work quite that far south.

The influence of drier air and weak upper ridging trying to build into the area will keep convection fairly suppressed on Sunday, though some isolated to widely scattered showers are possible across southern areas due to proximity to the stalled boundary.

LONG TERM
(Monday through Friday night)
Issued at 231 PM CDT Sat Sep 7 2024

The weather during the work week will largely depend on what happens with the disturbance in the southwestern Gulf (Invest 91L). Speaking of invests, just throwing out a quick reminder that an invest designation doesn't mean a whole lot in terms of development itself. It just signifies that NHC wants to continue INVESTigating the disturbed weather
More on 91L later

Going into the work week, Monday will represent a transition period as moisture begins to gradually move back northward across a stalled front near the coast. For the most part, expect showers and embedded storms to remain isolated to scattered in nature Monday, with the best chances across coastal southeast Louisiana.

Expect an upward trend in POPs and associated coverage of showers/storms through midweek as moisture continues to increase across the area. The highest rain chances appear to be during the Wed/Thurs time frame as deeper moisture either directly or indirectly associated with Invest 91L moves through the area.

Ok, let's talk about the elephant... Currently the disturbance known as Invest 91L remains disorganized. While the invest designation allows model guidance to be run specifically for the disturbance, it's important to keep in mind that unless/until the disturbance becomes more organized, model guidance will continue to struggle at times and there could be large differences between the different models and/or model runs. PLEASE DO NOT focus on any individual model runs and instead focus on the official, impact- based messaging from NHC/NWS and other reliable sources.

With that important disclaimer out of the way, what are the current thoughts? It still looks like 91L will slowly become more organized and drift northward through the mid to latter part of the work week. As it does so, a plume of deeper moisture will move northward with it. While there are still uncertainties in exactly where the disturbance will move, the general consensus is that it will remain over the western Gulf until it moves inland somewhere over Texas or southwestern Louisiana. Most available guidance also indicates gradual intensification into a tropical storm.
Regardless of the specific details, though, the local area looks to be on the "wet side" of the system with high rain chances and at least some potential for heavy rain Wed/Thurs.

It does get a little tricky when trying to determine some of the specifics at this lead time since the system's track and intensity (degree of organization) will play a role in determining the local impacts, so I'll briefly mention a couple possibilities. Should the system move farther west and inland over the central Texas coast, local impacts would be more indirect, with less threat of organized banding features in the rain.
However, if it moves a bit farther east and becomes a little more organized, banding features could affect portions of the local area, which would increase the heavy rain threat, and could potentially also result in some coastal flooding impacts. Only time will tell which, of these solutions will verify, or if it will be somewhere in between. Thus it will be important to monitor the forecast for changes over the coming days and be sure that your information is up to date and from a reliable source.

AVIATION
(06Z TAFS)
Issued at 1144 PM CDT Sat Sep 7 2024

VFR conditions across all terminals and expected to remain that way through the forecast period. Most terminals are seeing some ceilings around FL050-FL070 or so, and where those break up, there is a cirrus shield above it. The exceptions are KBTR and KMCB which are mostly clear.

Not particularly confident in how much further south the north edge of the cirrus shield gets before returning northward on Monday. Any significant lowering of the cloud deck or precipitation isn't likely to occur prior to Monday afternoon, and that may be too soon.

Could see northeasterly winds increase to about 15 knots during the day on Sunday as "cold, dry" advection increases. On the Gulf Coast in September, cold is a relative term.

MARINE
Issued at 231 PM CDT Sat Sep 7 2024

Strong winds haven't quite materialized over the coastal waters as forecast yet, but with some stronger winds just west of the local waters, will go ahead and leave the small craft advisory in place for now as these winds could still spread eastward into our western waters. Generally the forecast has not changed with the main impacts to be moderate to occasionally strong winds as a result of deepening low pressure over western Gulf. Rain chances will remain elevated with numerous to widespread showers and some embedded thunderstorms owing to a stalled boundary near the coast and an influx of moisture associated with Invest 91L as it drifts northward through the western Gulf during the work week.

PRELIMINARY POINT TEMPS/POPS
MCB 64 83 62 85 / 10 0 0 20 BTR 69 87 66 88 / 10 10 0 20 ASD 69 87 68 85 / 20 20 20 40 MSY 73 84 73 84 / 20 20 20 50 GPT 69 86 71 84 / 20 30 30 50 PQL 70 89 71 87 / 20 40 30 50

LIX WATCHES/WARNINGS/ADVISORIES
LA...None.
GM...Small Craft Advisory until 7 AM CDT Monday for GMZ550-570.

MS...None.
GM...Small Craft Advisory until 7 AM CDT Monday for GMZ570.