We've officially moved into the heart of winter. Average high temperatures hit their lowest and winter storms often ramp up. The start of this year may feature plenty of storms and unsettled weather. Arctic temperatures, on the other hand, may be a bit lacking. Read the details below:
TEMPERATURES
The first week of January has been, and will continue to be, very seasonable. A cold front will be dropping through New England today (January 4), which will bring temperatures down from where they've been, but this drop in temperature will not be enough to bring us below average.
Heading into the second week of the month, a large, persistent trough is expected to stretch over much of the western United States. This would normally favor above average temperatures in the east due to ridging, though there is more uncertainty on temperatures for the east as storm systems look to move through the region. These systems will play a role in how temperatures shake out for New England. Overall, next week is looking to be seasonable to slightly above average.
500mb height anomaly showing an expansive trough over the west next week:
Looking at the big picture, there currently aren't any signs of truly arctic air coming into New England in the extended outlook. Both the 8-14 day outlook and 3-4 week outlooks by the Climate Prediction Center favor above average temperatures for New England. This continues to be indicative of a strong El-Nino winter for New England.
It is worth noting that the more persistent cooler weather across the rest of the northern tier to start the month is not indicative of a strong El-Nino winter. This goes to show that there are many influences of the weather, and one overall large-scale pattern like El-Nino can be overridden by other smaller-scale factors at times. A return to more above average temperatures is expected across the entire northern tier for the second half of the month as El-Nino will continue to dominate long term forecasting.
This doesn't mean there won't be any cold days as we work through January, but rather cold snaps that do come into New England may not be severe or last very long. When it comes to New England in January, there WILL be cold-air intrusions via cold fronts from the polar and arctic air masses to our north.
A strong cold front will be dropping into New England the day this is posted, after all. Also, NAO is turning sharply negative as we head toward the middle of the month. This would support troughing and a path for those cold air intrusions into New England.
Overall, we're predicting a slightly above average month, with some brief cold snaps between more prolonged periods of near to above average temperatures. We're saying slightly above average as the cold snaps will help to balance out the stretches of above average temperatures when looking at the entire month as a whole.
PRECIPITATION
There's above average confidence in increased precipitation this month across New England. This is supported mainly by the factors going into our temperature outlook. The negative 500mb heights and troughing will support a more active pattern. In addition, the sharply negative NAO turn will support more troughing and active weather. The PNA Index is also looking to trend toward negative territory as well.
All of this supports a more active pattern. This can be seen in the coming week with a storm system slated to bring southern New England its first widespread snow of the season this weekend (January 6-7). After a brief break, another, potentially more impactful storm is looking to cross New England in the middle of next week (January 9-11). There are signals for another system the following weekend (January 13-14). Of course, this is getting to the very edge of medium-range forecasting, but the overall setup would support unsettled weather continuing.
Looking toward the second half of the month, there is always a chance for a calmer stretch of weather, but the overall above-average precipitation may generally continue through the month. The million-dollar question becomes how much of this will fall as rain (or a mix) versus snow. With generally above average temperatures, this could lead to more messy mix type storms, but if a storm is timed to a cold snap, such as this weekend, New England will get snow.
LOOKING BACK
December played out just about as expected. We predicted slightly above average temperatures with both cold times and mild times. Boston saw about 17 days above average and about 6 days below average. Other New England cities saw around these same numbers. Boston's daily temperature chart shows both cold and warm times occurred. The warmer times definitely won out, however.
Two large, potent storms brought much above average precipitation. This threw a wrench in our prediction for near-average precipitation. Of course, this isn't completely unexpected as winter is when New England typically will see these large-scale, more powerful storm systems.
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