It is a tool we use to forecast hurricane tracks. We can take a model, change certain types of weather in the model, and plot out the path a storm might take. It will make a line.
We then change a variable, and run the model again, and we get a different path. We can then plot those paths on top of each other, along with paths from other models.
Sometimes they all follow the same path and we get a good idea where the storm might be headed to. But other times, they are all over the place and look like a giant pile of spaghetti. That's how we get the name.
So lets look at two systems in the Atlantic that are being Googled (that sounds dirty) a bunch today. We begin with Lorenzo.
When we look at the plot, the lines, pretty much, all head in the same direction. Except for one outlier, they all head north into the North Atlantic, and away from us. Woohoo! Now onto Karen...
The models all generally head north for a bit, then they get wonky and start to look like that spaghetti pile I mentioned.
Some take it clear up around Bermuda at the same time others take it to the West toward Florida.
Here's why I'm not worried at the moment: The spaghetti plot is one tool.
You wouldn't build a house with one tool. You would use a hammer, saw, screwdriver, etc. To make a forecast we use lots of tools too. When we look at other tools and models, the high pressure system, that is going to keep us warm and relatively dry all weekend, runs into Karen and blows her apart.
That's why we use lots of tools, instead of just one.
Hopefully this helps and just know, we are using every tool in the toolbox to make sure you and your family stay safe here in North Carolina!