Marine Weather and Tide Forecast for New Roads, LA

LONG TERM
(Monday through Friday night)
Issued at 219 PM CST Sat Dec 7 2024

Sunday night through Tuesday, a frontal system will be slowly progressing through the area. There has been a few changes in the most recent model trends in terms of the locations and rainfall amounts. Rain chances will increase beginning Sunday afternoon through Sunday evening as light to moderate rain moves through the northwestern portions of our area. The rain totals and overall risk of heavy rainfall looks to have decreased for these northwest areas for Sunday night. And accordingly, we have been downgraded to a Marginal Risk of Heavy Rainfall by WPC.

Looking at the latest trends, there will likely be a bit of a lull in the rainfall amounts during the overnight hours on Sunday night/Monday morning. Light rain will still be expected for the northwestern areas, but instability will be decreasing in these areas. As the front moves eastward, the tail of the system lays up horizontally across our area as it progresses very slowly eastward. Exactly where it sets up is a bit uncertain, since some models set it up over the north/southshores of Lake Pontchartrain, while others have it further east or west. But regardless, as this boundary sets up and pushes through, it will be enhanced by some Gulf moisture, combining to increase rain chances for the area Monday generally from 6a to 6p. This time frame will have the greatest risk of flash flooding, especially the urban areas around the NOLA metro along with the MS Coast.

The environmental conditions look decent with PW values in the 1.8 range, which is well above the 75th percentile for SPC sounding climatology, so the rainfall should be fairly efficient. There is plenty of deep moisture in the atmospheric column, and warm cloud processes will dominate. The biggest limiting factor will be the instability. CAPE has generally been around 500 J/kg, which is marginal/adequate. However, if CAPE continues to increase in subsequent model runs, then this will increase the flash flooding concerns. As it stands now, there is definitely a concern for flash flooding for Monday, especially for the NOLA metro areas (north/southshore) and MS Coastal areas. These areas are particularly vulnerable and flood more easily due to training, given the urban environment as well. A Slight Risk for Heavy Rainfall is in effect for those areas from WPC and a Marginal Risk of Heavy Rainfall is in place for all other areas.

Rain will linger Monday night into Tuesday as well with periods of moderate to heavy rainfall possible. Tuesday looks to be a bit more uncertain in the model consensus regarding rainfall amounts, so we will continue to monitor over the next 1-2 days. But in general, expect rainfall to continue through mid day on Tuesday.
Overall 2-4 inches of rainfall will be possible with locally 3-5 inches possible. Flash flooding will be a concern, especially during the daytime hours on Monday. Given the model shifts today and general uncertainty, this could definitely change as things develop overnight tonight into tomorrow. We will be monitoring closely for changes.

Once this system moves through conditions should be dry with around cool temperatures for the rest of the week. We could see temperatures around freezing for lows for our northernmost areas on Thursday morning after the front moves through. MSW

AVIATION
(00Z TAFS)
Issued at 537 PM CST Sat Dec 7 2024

All terminals are in VFR status still with cigs well abv 3k ft.
Most of the area has a deck around 10-12k. Cigs will slowly lower through the night but likely to remain in VFR status through at least 12z if not slightly longer. Light rain currently out there should begin to dissipate with not much after 6z. Rain may begin to return late morning midday tomorrow but not anticipating rain to be hard enough to drop vsbys much at first but by tomorrow night that should change. /CAB/

MARINE
Issued at 219 PM CST Sat Dec 7 2024

Benign marine conditions prevail tonight through Tuesday evening with moderate winds (10-15kts). The winds will be shifting directions from northerly to southerly as we go through the overnight hours tonight and will remain southerly through Tuesday night. A frontal system will push through the marine waters Wednesday, elevating winds (15-25kts) and seas and shifting the winds to be northerly through Thursday morning. Winds will ease back to moderate (10-15kts) and northerly to northeasterly Thursday through Saturday morning. MSW

PRELIMINARY POINT TEMPS/POPS
MCB 44 67 60 70 / 30 70 90 90 BTR 49 73 65 75 / 30 60 90 90 ASD 46 72 62 73 / 10 30 60 90 MSY 52 73 64 72 / 10 30 50 90 GPT 46 69 61 70 / 10 20 50 80 PQL 43 73 60 75 / 10 10 40 80

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