coastal GFS model shows storm well out into the Atlantic off the coast of New England Monday (

On Tuesday, I wrote some computer models were simulating a possible coastal storm for the Mid-Atlantic.  They have since moved away from the scenario.

I also said yesterday there was a 40 percent chance the storm would impact the East Coast. I’d revise that downward to just 30 percent chance now. And if there’s any impact, it would most likely be in eastern New England with some gusty winds, high seas and rain.

We’ll continue to keep an eye on this possible storm, as there is still time for shifts in its track.

Evolution of the ensemble runs of the GFS model for the Atlantic storm (Graphic by Steve Tracton, NOAA data)

And now, a cautionary note about blog posts pertaining to distant storms…

Just because we’re writing about model simulations of storms several days into the future, doesn’t mean we think they’re going to happen.  Pay close attention to the probabilities we assign and our levels of confidence.  Models are generally less than reliable the farther into the future you go, but some storms are more predictable than others.

European model brushes eastern New England with some rain, onshore winds in this simulation ( European model brushes eastern New England with some rain, onshore winds in this simulation (

There is a school of thought that even writing about or mentioning a storm four or more days into future or more can be misleading, because some people will simply see “possible storm” and assume it’s going to happen.  And that’s how rumors and false information can spread.  This is especially true with snowstorms.

I suppose we could only write about more immediate storm scenarios for which there is greater confidence, but there are a lot of people who are interested in longer range forecasts and trickier  scenarios.

So, I’m reluctant to stop coverage just because there is uncertainty and some people may misinterpret or misunderstand our posts.  Not only does knowing about longer range possibilities help many people plan, it’s also very interesting/entertaining to track how different threats and non-threats evolve.