The United States' deep and widespread Arctic Blast is now beginning to gradually retreat. While no major warm-up is on the docket, seasonable temperatures more typical of a standard New England winter will be re-entering the picture. A generally zonal flow over the region will lead to benign weather with minimal chances for precipitation over the next several days, though it won't be completely quiet.
As for the Arctic Blast from this week, the core of the air mass is now sliding away from North America. This will promote a gradual return to more seasonable weather. This is evidenced by this morning's low temperatures. They're a good 15-25° warmer than yesterday morning, though this only translates to low temperatures this morning of 0-15° as opposed to yesterday's -10 to -25°. High temperatures today will moderate back to the 20s north to 30s south. A slight warm-up will continue into early next week with the key word being 'slight'. Overnight lows will likely remain on the cold side.
Zonal flow (which is when the jet stream has a stronger west to east motion and lays flatter across the United States, as seen above) tends to promote near average temperatures as deep troughing or ridging is absent, though weaker troughing will hang over New England. This will keep highs over the several days hanging around the 30s for most in New England. Another dip in temperatures may come around or after the middle of next week.
Aside from temperatures, zonal flow also promotes unimpactful weather as storm systems don't have the setup to organize and become stronger. Overall, this will be a repetitive pattern for New England over the next week or so as several northern stream disturbances cross the region. These disturbances will be weak and extremely moisture-starved.
This begins today as a northern stream system fails to phase with a weak, offshore storm system. The coastal system will try to spread some snow showers across Cape Cod and Downeast Maine today. Accumulations will be none to very light in these areas with an inch to maybe an inch and a half across coastal Downeast. The separate northern stream system may be able to spread some snow showers into northernmost New England as well, amounting to nothing. Elsewhere will just see some clouds.
Below: NAM showing potential weather early this afternoon:
The parade of northern stream clipper systems will continue from now through the middle of next week. These weak systems aren't looking to produce much by way of precipitation for New England. It's best to say that it will be mainly dry and calm during this time with periods of scattered snow showers popping up, mainly across the north. The periods where snow shower activity could become the most widespread will likely be in the Sunday and Tuesday time frames.
Below: Daily Weather Prediction Center maps from Friday through Wednesday, showing multiple northern stream systems moving through the region with little precipitation:
The strongest system of this bunch will likely come in the Monday to Tuesday time frame. This clipper appears to have more instability and lift with it, bringing the potential for a quick hit of some snow for the northern tier of New England. The system will drag a cold front across the region, which could provide a focus for a line of snow showers or squalls across New England. This will be the main feature to watch over the coming days.
Below: Euro showing potential weather Tuesday afternoon:
This cold front associated with the system will likely usher in another bout of colder air. It doesn't look quite as cold as the air currently exiting New England, but it will likely bring another notable cool down from the average temperatures that will be building to that point. This surge of colder air will likely be focused over New England late next week, though the exact timing on potential snow showers and the cold air intrusion remains a bit uncertain this far out.
The lack of more powerful and organized storm systems for the region can be attributed to the zonal flow keeping southern stream systems to the south of New England. These southern systems are the moisture-rich ones thanks to the Gulf of Mexico. Northern stream systems, which will be moving through New England during this time, are typically more moisture-starved and, without the interaction with the southern stream systems, can struggle to produce much precipitation.
Zonal flow supports the main moisture source for New England to be from the Pacific rather than the Gulf. So by the time it reaches New England, there is little left to work with by the time it makes it across the country. A trough over the southwest United States this weekend into early next week may set up a split-flow regime, helping to keep the northern and southern streams separate. Without interaction with these streams, organized storm systems have trouble forming.
Below: Jet stream map early next week, showing the split-flow. This supports coastal storm systems remaining south of New England:
With all of that said, little by way of precipitation is expected for New England over the coming days, especially southern New England. The current seven day precipitation forecast shows a mere 0.01-0.25 inches of total QPF with southern New England currently seeing a shutout in QPF.
Below: Current seven day precipitation forecast:
This upcoming dry spell of storms will allow the drought that developed last fall to continue to hang around. While drought conditions have improved markedly so far this winter, a moderate drought continues for much of New England with a severe drought across central Massachusetts. This January has been generally below average in terms of precipitation.
Below: US drought monitor update this morning:
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