Tropical Storm Marie is currently under observation for a potential approach to Southern California during the upcoming Labor Day weekend. The presence of warm waters associated with El Niño is contributing to the formation of multiple tropical systems in the Pacific Ocean, with Marie moving northbound.
While some computer models indicate the storm could move close to the Southern California coast, potentially strengthening into a hurricane, other models show it continuing its path westward into the ocean, away from land. This divergence in projections leads to considerable uncertainty in the storm's forecast track.
If Tropical Storm Marie does reach the region, it could bring heavy rain, gusty winds, and high surf. On Monday, the National Weather Service (NWS) issued a warning for Labor Day beachgoers, noting a high chance of large waves and strong rip currents. The NWS also indicated a moderate chance for impactful coastal flooding along south-facing shores, while assessing a low chance for widespread moderate-to-heavy rain with associated flooding, as well as a low chance of offshore winds.
Forecasters rely on what are known as spaghetti models, which plot various potential paths for tropical systems. The lines on these plots represent billions of computations from powerful computers. When these lines are tightly clustered, they suggest a higher confidence in the forecast. However, the current plots for Marie are notably spread out, signaling the ongoing uncertainty.
Different types of these models exist. Dynamical models use supercomputers to solve physical equations of motion. Statistical models predict based on historical storm behavior and specific details like location and date. Ensemble or consensus models integrate forecasts from multiple other models to provide a combined outlook. All models aim to project a storm's expected track and potential strength.
These models are operated by various governments and private entities globally and are run multiple times daily, meaning forecasts can change rapidly. When interpreting these models, experts typically look for trends and consistency in how the plots shift over time. While no forecast is without its limitations, these models are critical tools for understanding where powerful weather systems may go, aiding in preparedness for residents and local agencies alike.
