National Weather Service United States Department of Commerce

Gusty Winds in the Mid-Atlantic and Northeast; Atmospheric River to Impact the Northwest

Gusty winds are expected from portions of the Mid-Atlantic into the Northeast through the night following the system that brought rain to the area. An atmospheric river will move into the Northwest late today into Saturday bringing moderate to heavy rainfall, mountain snow, windy conditions, and high surf to the area over the weekend. Read More >

Surface to 1km Lapse Rate

A lapse rate is the rate of temperature change with height. The faster the temperature decreases with height, the "steeper" the lapse rate and the more unstable the atmosphere becomes. Values less than 5.5-6.0 degrees C/km represent stable conditions, while values near 9.5 degrees C/km are considered unstable. Between these values, lapse rates are considered conditionally unstable, meaning that it may become unstable if enough moisture is present. For more information on lapse rates, please click here.