After an unseasonably warm week, Israel was preparing Wednesday for a sharp drop in temperatures and heavy rains, with a chance of snow in Jerusalem and the north of the country.

A heavy winter storm is expected to hit Thursday and to last throughout the weekend, bringing rain, high winds and snow in high altitudes. Emergency services across the country were put on alert ahead of the storm’s arrival.

Wednesday started clear or partly cloudy, but high winds and rain were set to spread across the country in the evening, accompanied by plummeting temperatures, the Israel Meteorological Service said.

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As weather conditions began to change, a tornado-like formation was spotted off the coast of the southern city of Ashdod. Experts say the twister was not in fact a tornado but a waterspout, a less rare local weather phenomenon caused by weak rotating columns of air over water.

The spectacle was caught on camera and broadcast by Channel 2 news.

Snow is expected to fall on the Golan Heights as early as Thursday morning, making its way south to the Upper Galilee region by the evening. Snowfall in those areas will continue Friday and is likely to spread to central high-altitude locations, including Jerusalem, but forecasters do not predict a build-up on the ground in the capital.

Ahead of the storm, police and fire crews raised their alert level and beefed up deployment, while the Israel Electric Corporation called on the public to report any fallen electrical wires and readied crews in case of electricity outages.

Authorities have also warned of possible flooding in towns in central Israel as well as flash floods in rivers and streams in the Judean Desert and Jordan Valley, and sandstorms in the south.

Tel Aviv and other cities prepared their drainage systems and readied for high coastal winds.

In October, one person was killed and dozens more were injured as high winds and heavy rain buffeted the country, knocking down trees and a crane in central Israel, and flooding roads in the south. Hundreds of thousands of Israelis were left without power for days, sparking a torrent of criticism from politicians and others, who accused the Israel Electric Corporation’s union of instructing workers to drag their feet, and the company of failing to have proper infrastructure in place.