Here's why Hurricane Henri shifted east, became a tropical storm

Long Islanders bracing for the first hurricane to land here since 1985 woke up Sunday to what officials cautiously called "good news" for the region — it was now a tropical storm and heading east of Montauk.

Here’s why that happened.

Through part of Friday and most of Saturday, forecasters predicted Hurricane Henri would strike Long Island directly. The Category 1 hurricane would have been the first such storm to make landfall on Long Island since Hurricane Gloria arrived Sept. 27, 1985.

Newsday meteorologist Bill Korbel said a low-pressure system over the Appalachians was expected to pull Henri to the west, toward Long Island.

"That obviously did not happen," he said Sunday.

"The luck was great, because it missed us. It didn’t happen. So, Henri broke away from that flow, and moved straight north, passing between Montauk and just about right over Block Island."

Plus, the storm weakened a little once it got closer, Korbel said. "It fell apart over the cool water," he said.

In addition, he said, "The left side of a northward moving storm is the weaker side," and that’s where Long Island sat.

The storm’s track shifted multiple times in the days leading up to Sunday. Just a few days ago it had been expected to hit western parts of Cape Cod. Then it moved closer to central Suffolk County before heading back east.

"A difference of 30 miles when compared to the Earth’s diameter of 7,900 miles may not seem like much, but it can be when you’re dealing with a hurricane," Korbel said. "These forecasts are never going to be perfect. We try to do the best we can and it’s always better to be overprepared than underprepared."

By Scott Eidler

scott.eidler@newsday.com@ScottEidler

Scott Eidler is a deputy editor for the towns department at Newsday. Scott has worked at Newsday since 2012 and previously covered municipal government and education.