Marine Weather and Tide Forecast for Laplace, LA

LONG TERM
(Thursday through Monday night)
Issued at 245 PM CST Tue Jan 14 2025

Split flow regime continues into the early part of the weekend. A southern stream shortwave will approach the area ahead of a northern stream shortwave on Friday. Precipitable water values increase rapidly on Friday from around 0.25 inch in the morning, to about 1.5 inches in the evening. There will be some limited instability Friday night, so thunderstorms can't be entirely ruled out, but this system is more likely to just be a rain maker Friday night and Saturday morning.

A northern stream shortwave rapidly on the heels of the southern stream shortwave will introduce a surge of much colder air to the area on Sunday, which will carry into most or all of next week.
Once we fall below 50 degrees Saturday night, it may be a week before northern portions of the area rise above 50 again.

Beyond that point, we'll need to address the elephant in the room. By Monday morning, sub-freezing temperatures are likely across most of the CWA with the possible exception of immediately south of Lake Pontchartrain (New Orleans) and lower Plaquemines Parish. How deeply into the area this cold air penetrates will determine the weather into the middle of next week. This will set up potential for non-liquid precipitation at some point early to mid week next week. Medium range models aren't quite in agreement on timing of precipitation, nor on which type of precipitation would be the preferred solution for Monday night and beyond next week. Also in question would be the amount of precipitation that occurs, with some possibility that the heaviest precipitation stays offshore. MEX high temperatures for Monday and Tuesday look significantly too warm.

High confidence that the temperatures will be much below normal Sunday through the end of the forecast period. Low confidence in specifics on timing and precipitation type Monday night and beyond. Stay tuned as we are able to refine the potential threats over the next several days.

AVIATION
(00Z TAFS)
Issued at 526 PM CST Tue Jan 14 2025

VFR conditions are forecast for the whole forecast period. Clouds will gradually build in some more but should not have an impact at terminals. At the very end of the forecast period there is a low chance of rain but confidence is low currently so left out the mention for now.
-BL

MARINE
Issued at 245 PM CST Tue Jan 14 2025

Will hold onto Small Craft Exercise Caution headlines for all open waters and Breton/Chandeleur Sounds overnight, with the expectation those headlines need extended into Wednesday for portions of the waters by later shifts. Likely to reach Small Craft Advisory criteria (20 knots) Friday night, then again Sunday into early next week. If there is going to be a window of quieter conditions over the open waters during this forecast period, it would be late Thursday into the first part of Friday, and that's not a sure bet.

PRELIMINARY POINT TEMPS/POPS
MCB 37 56 34 59 / 0 0 10 0 BTR 42 59 39 63 / 0 10 20 10 ASD 40 58 40 62 / 0 10 20 10 MSY 45 57 46 60 / 10 10 30 10 GPT 40 57 42 60 / 10 0 20 10 PQL 39 60 40 64 / 10 10 10 10

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