The link at the image at left shows a 30 hour loop ending 0Z Thursday 19 Feb, 2008. It shows that the cloud over New England is associated with a low pressure system moving in from Colorado. Systems that follow this track are known as Colorado lows. They usually yield moderate precipitation, although this on seemed a little drier than usually. An occluded front (purple) extends southward from the low centered over Southern Ontario on 0Z Thursday. The warm front appears to further south. A cold front extends until the Texas coast. Ahead of the cold front, thunderstorms break out over the southeastern U.S.

A usual, the flow around the low is counterclockwise and inward. Note that southerly flow east the low pressure system brings moisture and low-level cloud northward. At the same time, the cloud deck appear to move in from the west as the jet stream moves the whole system eastward.