You can see, below, warm air moving through New England from late Wednesday through Friday.
A wave of mild air will push across New England Thursday and Friday, raising temperatures 10 to 20 degrees above average.Pivotal Weather
Ever since the second half of November, temperatures across Boston, and really all of New England, have been consistently below the seasonal norm. The jet stream, which acts as an atmospheric fence between cold and warm air, has been consistently diving south of New England, allowing for frigid Canadian air to push into our region more days than not.
This week, a strong high-pressure system building to the south of New England will push the jet stream north into Eastern Canada and allow for warm air to move into the region from the southwest.
The jet stream’s positioning will allow for a brief warmup across New England.Boston Globe
With much of the atmosphere steadfastly cold for such a long stretch (for the past month), it will take a bit of time for us to feel the warmth. Wednesday will likely be what I call an “atmospheric mixing day,” in which this warmer air finally reaches the surface, building to the low and mid-40s across the region.
Highs on Wednesdays will push to the mid-40s across Greater Boston.Boston Globe
Warmth peaks Thursday and Friday
As the warmth peaks Thursday and Friday, strong winds from the southwest will make it feel pretty breezy out there and will amplify the warmth throughout New England.
Boston is set to see a forecast high in the low 50s on Thursday afternoon, with almost the entire region, except for high elevations, reaching the 40s — something we just haven’t seen this month.
Highs on Thursday may crack into the 50s across Greater Boston.Boston Globe
Friday will be the warmest day of all as a surge of moisture in the atmosphere moves in ahead of a potent cold front, keeping the warmth stuck at the surface.
Boston will return to the mid-50s for the high with warmer-than-average temperatures throughout all six states.
Highs on Friday may reach the mid-50s across Greater Boston.Boston Globe
Our heating systems won’t have to work as hard as the second half of the week progresses. Take a look at the overnight lows from Wednesday through early Saturday.
Overnight lows across Boston are expected to rise to the upper 20s and then into the 40s by Saturday morning.Boston Globe
Rainstorm moves in Thursday night
The stronger the temperature difference is between air masses, the higher the chances for a significant storm. A strong cold front will push into New England from the west late Thursday night, bringing widespread rain through the region into at least the first half of Friday. This system will tap into a surge of moisture flowing into New England.
As the front pushes closer, a few bursts of heavy rain may be possible, paired with gusty winds, which could lead to some water pooling on roadways. The combination of rain and excessive runoff from the melting snowpack will pose a low flood threat for portions of Western Massachusetts and Northern New England. With snow on the ground since mid-November, snowpack is dense up north, meaning more runoff is possible from some of the mountainous areas, leading to localized flooding.
Thursday will see a moderate front push rain into the region at night and into Friday.Boston GlobeMoisture will surge into New England as the front passes early Friday.Boston Globe
Most of the region will pick up around a half inch of rain, but there is the chance for nearly an inch across the Berkshires and Northern New England mountains.
Rain totals may reach a half inch or higher overnight Thursday through Friday.Boston Globe
Forecast snowmelt throughout New England
I took a quick look at snowmelt potential in addition to the rain late Thursday and Friday, and most of the region appears to sit below the flooding threshold, with under a half inch of water unlocking from the snowpack, but we’ll continue to monitor.
Snowmelt through Thursday may release a half inch of water across Southern New England. NWS
All warm weather must come to an end sooner or later, which is normal for this time of year, and come Saturday, temperatures will drop back into the 30s.
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Ken Mahan can be reached at ken.mahan@globe.com. Follow him on Instagram @kenmahantheweatherman.
