Why is it so cold? Well, first of all, we're into the end of January. That's the coldest month of the year in the northeast. Arctic air has had lots of time to chill in the permanent arctic nights of December and January. The map at left shows a mass of very cold arctic air over Hudson's Bay (below -30 at its core). New England is on the leading edge of that air. Notice that Southern New England (high 20's) is not as cold as Northern New England (below 10). In January, ice cold and not-so-cold air is usually close by, so a high or low pressure system can change things quickly.

The image at left gives a hint of why it will get colder earlier in the week. Note a family of four low pressure systems around the east coast of the U.S. They are combining to give us some scattered light snow. Systems like these have been crossing the northeast all week and continue to do so this week. They travel northeastward towards Newfoundland (see HPC archive page for loops) . Here you will find more intense low pressure systems (note the bunched together isobars). Winds blow counterclockwise around these lows, and they combine to produce northwesterly winds behind them that carry air from the cold pool over Hudson's Bay directly to New England. Brrrrrr.

Finally, here is a model forecast for Monday Morning at 12UTC (7 AM EST). The blue contours marked -30 indicate the cold core closer to Vermont over central Quebec. The low pressure systems have intensified off the coast. Northerly winds behind them blow that cold air towards us. Another low pressure system just west of the Great Lakes promises to do the same thing to us on Wednesday. Will it ever end???