[Latest satellite image of the powerhouse Pacific Ocean storm; courtesy NASA]
Overview The ingredients are coming together for another significant winter storm in the DC metro region that will likely include both an ice buildup and accumulating snow in the period from late Sunday night into Monday night. The first player in this upcoming event is a powerhouse storm system that will slam into California later today with substantial rainfall, thunderstorms, and strong wind gusts. This system will then cross the country over the weekend and its significant supply of moisture will arrive in the Mid-Atlantic region by Sunday night. A second crucial ingredient to the upcoming snowstorm is an extensive area of Arctic high pressure that will set up across the southern tier of Canada by the end of the weekend. One humongous high pressure system will be anchored over south-central Canada by Monday and there will be an extension of this into the southeastern part of Canada.
Preliminary storm details Light rain is likely to break out later on Sunday in the DC metro region and with temperatures up in the 40’s, there will be no problems on the roadways. Arctic cold air – anchored by strong Canadian high pressure – will slowly filter into the Mid-Atlantic region late Sunday night and early Monday and, as the colder air oozes in from the north, the rain will change to a wintry mix for awhile causing an icy build-up in the region. As the increasingly colder air continues to advance to the south and east, a changeover from a wintry mix to all snow will take place and accumulations of 3-7 inches are possible by the time the storm winds down later Monday evening with the higher amounts in the N and W suburbs of the District and the lower amounts on the southeast side. Temperatures will drop through the 20’s on Monday afternoon and will bottom out at very cold levels by early Tuesday morning – perhaps even down into the single digits in some spots. Bitter cold conditions will stick around for the rest of the day on Tuesday as clean-up efforts continue.
Updates will be posted this weekend at “thesiweather.com”.