This week's weather is all about the waves. The snake-like long wave pattern of air circulation well above the earth's surface is going to shift in mid-week. Today and tomorrow the circulation has dipped to our south, allowing all this cold air to be here. By Thursday it looks like we will be warming up under the crest of the wave. Even though today, tomorrow and Wednesday will be a bit warmer than the weekend, we'll still have below normal high temperatures in the mid-40s. Once the circulation shifts the weather will warm up. Thursday, the first full day of spring, and Friday should see highs in the mid-50s to lower-60s. That should get rid of the slush!
In addition to the long wave pattern, we have to deal with a fast moving short wave this afternoon and evening. Short waves are the mysterious "upper level disturbance" that weather people like to talk about on television. The waves are energetic little buggers that move quickly through the long wave circulation, kicking up the air below to produce clouds and precipitation in their wake.
A short wave is zipping toward us, it was in central Canada this morning and will be over Maine tonight. The current radar shows a bit blob of light snow to our west. By the time the precipitation gets here it will likely switch over to rain in the city while remaining snow further north. chance of showers. Once the short wave passes by skies will clear up for a couple of days.
Radar image from Intellicast.com.