A tornado watch for 21 New York area counties, including all of Long Island and New York City has expired with no storm conditions in the area.

A strong cold front is expected to move through the region later today, placing New York at "moderate risk" for heavy thunderstorms, the service said. Heavy winds would be the greatest threat in a severe storm, but large hail and tornadoes are also possible, the service said.

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The weather service has also issued a rip tide advisory for Nassau County, southern Suffolk County, Queens and Brooklyn.

The riptide advisory, issued at 5:22 a.m. today, states that "these rip currents will be life threatening to anyone who enters the surf" and swimmers should "please check with lifeguards before entering the water" and "not swim in unsupervised areas."

The rip current is likely because "a strong southerly flow is expected ahead of an approaching low pressure system today," the advisory states.