Metro Boston, North Shore and Metro West: We officially welcome Spring on Thursday with changeable skies, early showers and mild temperatures. The low pressure system that was responsible for last nights precipitation and the showers early this morning will lift into Canada during today. That will bring an end to the showers in the morning as skies turn partly cloudy this afternoon. Breezy south to southwest winds will become more westerly later in the day. A disturbance in the upper levels will maintain mostly cloudy skies at night. There really is no big push of cold air behind the departing low so we can expect temperatures to hang around near seasonable levels tonight, Friday and into the weekend.
High pressure expands across the South, Midwest and then into the mid-Atlantic Thursday and Friday, moving offshore by Friday night. Meanwhile, a vigorous low pressure system will move out of the upper Plains Friday and across the Great Lakes during the day. By Saturday morning the low is expected to be centered in western New York State, tracking across central and northern New England during the day. It will drag a cold front through here later Saturday or Saturday night as the low moves rapidly into eastern Canada.
Late Friday night and Saturday morning we may deal with periods of showers as the low tracks to our north. We remain on the milder side of the system and therefore most of the precipitation should be in liquid form Saturday. But, it could be just cool enough for snow showers later on Friday night before milder air arrives during the day on Saturday.
Originating in western Canada a strong high pressure system will build in behind the departing cold front, expanding across the Plains, Great Lakes and then to be centered over New England by Tuesday. This high will be accompanied by chilly arctic air and therefore we do cool back down to below normal readings by Sunday night and especially on Monday and Tuesday. Temperatures may run some 10 to 15 degrees below normal early next week. So, although the calendar may say its Spring a Winter chill returns for a few days.
Sunday will be cooler and brisk with a risk of a passing flurry or snow shower.
Three Day Outlook:
Thursday: Morning showers will give way to partial clearing. Becoming milder in the afternoon as temperatures climb into the 50s. Breezy south to southwest winds becoming westerly later in the day.
Thursday night: Mostly cloudy and cool. Slight chance of a snow flurry. Lows in the upper 20s to low 30s. Gusty west winds 20 to 25 mph.
Friday: Sunny early followed by partly cloudy skies. Not as mild. Highs in the low to mid 40s. Gusty west winds.
Friday night: Turning mostly cloudy. Slight chance of a late night snow flurry or snow shower. Lows in the upper 20s to low 30s.
Saturday and Saturday night: Chance of early snow showers inland changing to rain showers with generally rain showers across the coastal plain. Periods of sunshine developing in the afternoon. Milder as morning temperatures in the 30s top out near 50 degrees in the afternoon. Becoming partly cloudy overnight with lows in the upper 20s to low 30s.