METEOROLOGIST JEFF HABY
Wrap-around snow or wrap-around precipitation is a common term used to describe the precipitation that falls on
the back side (northwest side
and vicinity) of a low pressure system (see image below). Winds will rotate cyclonically around low pressure. Usually, the
moisture flow into a low pressure system will be on the south and east side of the
low pressure. The cyclonic winds rotate this moisture around the low pressure system. Much
of the moisture is lost as the air advects around the low pressure system and rises along
the slope of the warm front. The moisture loss is due to precipitation. As air
rises it cools and can not contain as much
moisture. The precipitation on the back side of a low pressure system is often weaker
in intensity as compared to both the precipitation along the fronts and in the warm sector of the
low pressure. The wrap-around precipitation can be thought of as precipitation from the
left over moisture that has made its way around the low pressure system.
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