Winter Storm and Winter Weather in Maryland, January 2 to 3, 1999

An area of low pressure moved from the Ohio Valley to the Eastern Great Lakes on the 2nd, spreading precipitation across the Mid-Atlantic region from midday on the 2nd to early morning on the 3rd. High pressure centered over New England brought a shallow layer of sub-freezing air to locations east of the Appalachian Mountains. Across Western Maryland this layer of cold air was deep enough to allow up to 5 inches of snow to fall. East of Hagerstown in Washington County, this layer of cold air was shallower, forcing much of the precipitation to fall in the form of sleet and freezing rain. Shortly after midnight on the 3rd, a warm front from the Atlantic Ocean moved into Central and Northern Maryland. This front rapidly turned all freezing precipitation into rain east of Washington County for the remainder of the morning. Snowfall amounts included 4 to 5 inches in Allegany County, 2 to 4 inches in Washington County, and 1 to 2 inches in Frederick and Carroll County. A trace of snow and sleet fell in Northern Baltimore, Howard, and Montgomery County, in addition to an ice accumulation up to 1/4 inch. The aftermath of this storm included icy roads and dense fog.