The image at left is for 15Z (10 AM EST) Wed. March 4, 2008. New England is under the influence of a high pressure system over Virginia and a low pressure system over Northern Labrador. Animation loops at archived sites show that these are stationary systems. Note that the counterclockwise flow around the low pressure system reaches into New England leading to north-northwesterly winds. Animation for earlier in the week (see link) shows that this is the same system that brought the northeast coast over a foot of snow.
A closer look at New England at 21Z confirms a trough (dashed orange line) swinging through from the north. This elongated region of weak low pressure extends southward form the low pressure system over Labrador and explains the decrease in pressure and snow showers onserved over LSC in the afternoon. Temperatures directly to the north of Vermont are not appreciably different, but temepratures further to the northwest are slightly colder (in the mid teens). To the west of Vermont in western New York State and Ontario temperatures are slightly warmer. A slight change in wind direction to the west could lead to warm advection.