Will Henri impact the Hudson Valley?

Update #460a

Tropical Storm Henri is fuzzball of cloud between the Bahamas and Bermuda this Friday morning, with sustained winds of 60-65 mph near its center.

It’s currently what we call a “fish storm” (out over the open ocean), but this won’t be the case for much longer — it will begin to move northward with some speed today.

By Saturday morning, Henri will be strengthening well offshore of North Carolina, likely reaching hurricane strength at some point during the day.

As the storm continues to churn north on Saturday night, it will likely reach its peak intensity — a category 1 hurricane. Wind gusts are predicted to exceed 100 mph near the storm’s center.

The official track from the National Hurricane Center (NHC) calls for a landfalling hurricane somewhere east of New York City but west of Cape Cod early Sunday afternoon.

A hurricane is an area, not a point, so impacts are often spread far away from the storm’s center.

Here are the key messages from the NHC:

So is the Hudson Valley out of the woods?

As of Friday morning, a direct impact from Henri in the Hudson Valley is not looking likely.

Moisture streaking out ahead of the storm will cause scattered showers and thunderstorms during the afternoon today and Saturday.

Depending on how far west the storm tracks on Sunday, the region could get in on Henri’s rain bands, some of which could be heavy. The timing would be later Sunday into early Monday.

If some the heavier rain bands did reach the Hudson Valley, flooding would be a possibility.

How likely is a more westerly track?

Around a 20-30% chance.

One way to assess forecast uncertainty is to use an ensemble — a collection of model “members” whose initial conditions are tweaked very slightly to give a range of possible forecast outcomes.

The more the model members agree, the higher forecast confidence usually is.

In the plot below, there are 50 possible tracks for Henri, color-coded by storm strength. The black line represents the average of the 50 possible tracks and is usually considered the most likely track.

Colloquially, this is known as a spaghetti plot because of its resemblance 🍝

Notice how there are a handful of tracks that do bend west near the Hudson Valley. So while the most likely track is to our east, we can’t 100% rule out a hard left turn.

That means I’ll have another update tomorrow!

In the meantime, you can follow me and my hurricane tracking bot on Twitter and Facebook.