For the next week or so, New England will be firmly embedded under a rather strong and expansive area of high pressure. This will bring about a stretch of mainly sunny, quiet and mild days across the entire region. This high pressure, in all likelihood, will give portions of New England it’s last string of 70° temperatures. For interior southern New England and the valleys of northern New England, widespread highs in the upper 60s to mid 70s will be likely from Saturday through the middle of next week.
A mild air mass aloft combined with surface high pressure to New England’s southwest (along with sunny skies) makes for a favorable setup for temperatures to shoot up once the sun rises. This high pressure system over New England will be on the stronger side, around 1,035 millibars. For comparison, neutral pressure (neither high nor low) is around 1,013 millibars.
Below: Pressure Saturday morning:
Conditions will also remain favorable for chilly mornings. For temperatures to bottom out overnight, there needs to be a lack of humidity, calm winds and clear skies. With a strong area of high pressure overhead, all three of these conditions will be present. Widespread morning lows in the 30s to low 40s will continue through Sunday morning. That means it will take time to reach the upper 60s and 70s in the afternoon, but it should get there under favorable conditions.