What are spaghetti models?

ALLISTER AALDERS weather@saltwire.com @allistercanada Allister Aalders is the weather specialist for the SaltWire Network, providing forecasts and analysis for Atlantic Canada. #AskAllister



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There are many terms you hear used when it comes to weather forecasting — ridges, troughs and spaghetti. No, I'm not forecasting a delicious-sounding supper. A spaghetti model is a frequent term you hear during hurricane season. Spaghetti models, also known as spaghetti plots, are lines resembling strands of spaghetti often used to represent the potential tracks of where the centre of a tropical cyclone may go. When the lines are closer together, it represents greater certainty. A larger spread between the models indicates uncertainty, often found beyond day three. Spaghetti models feature numerous models — some tailored specifically to hurricanes. Others, like the GFS, Canadian and European models used in day-to-day forecasting, are also included. Some spaghetti models display only one model but with several tracks, known as ensembles. Supercomputers used in weather forecasting run equations based on current atmospheric conditions to produce a forecast. However, in ensemble forecasting, slight changes are made to initial starting conditions, producing a group of individual ensemble members. Ensembles can be very useful for short to long-range forecasting of tropical storms and hurricanes if you compare them with other ensembles. As always, it is important to remember a few things about spaghetti models. The first is understanding what the spaghetti models are showing and making sure you refer to official tracks and forecasts for the most accurate information. Spaghetti models do not represent the potential impacts associated with a storm, and can fluctuate, especially in the early stages of development. Still, though, spaghetti models are a delicious-sounding way to keep tabs on the tropics.