Winter Weather in New Jersey, December 14, 1999

A slow moving low pressure system moved northeast from southern Texas the morning of the 12th into southern Mississippi the morning of the 13th and into West Virginia the morning of the 14th. A second low pressure system formed near the Delmarva Peninsula during the day on the 14th and moved well offshore that night. At the same time on the 14th, a large high pressure system became stronger as it moved across nearby Canada. The northeast flow around this high brought colder air into Northwest New Jersey. As precipitation moved back into the region during the morning of the 14th, it fell as a mixture of sleet, freezing rain and plain rain over the higher terrain in the county. Most valley areas were warm enough for precipitation to fall as rain. Untreated roads and walkways became very slippery. There was also a slight accretion of ice on trees and power lines. During the evening, enough warm air moved in to raise temperatures above freezing.