You’ve heard the early forecasts. Most of them say things like “the snowstorms are coming back” or “we’re definitely getting more snow than last year”, reasoning based mainly on the post El Nino and currently emerging weak La Nina pattern. While those statements have a decent chance of being at least somewhat correct, they are rather bold, as many other factors will determine the final outcome.
Leading to this winter, our main concern has been the ongoing drought. Some of it got chipped away at by better rainfall in October, though November to-date has gone back to the drier side. With rainfall deficits still above 6 inches for the year in many locations, and significantly greater than that over the span of the last 3 years, we are looking at the need for several months of above normal precipitation to seriously reduce and eventually end the drought. So even a wetter winter than last would not end the drought, but would just take steps in the right direction. Will we have a wetter winter than last winter? For many areas, probably, as the pattern is likely to feature a fairly active Pacific jet stream. What will likely be fairly absent will be a subtropical jet stream and Gulf of Mexico moisture, as much of the southern US may be on the dry side. At least the early part of winter should feature a weakening polar vortex. This will often send cold air further south. During the mid to late autumn, we’ve seen fairly persistent cold over a good portion of Europe and Asia with above to much above normal snowfall there, while the snow was off to a slower start in a milder North American pattern. I’ve struggled with trying to figure out the temperature pattern for the winter. The recent pattern has been up and down in New England but with generally brief cold shots followed by mild air. As the Pacific jet gets a little more active as we head through the last week of November into early December, this may be the pattern that we see at least for a good part of the first half of winter. This would allow for some more pronounced cold shots, provided we drawn some of the Siberian cold across the pole and into Canada. There are signs of this taking place in the next few weeks. Then you have the Pacific jet pattern which tends to produce milder weather. So the bottom line is, battles and air mass changes. We’ll have to see how much moisture carries from the Pacific all the way across the Rockies, Plains, Midwest, Great Lakes and into New England. Sometimes these storms can spend much of their moisture before arriving, and in order to produce meaningful rain or snow in this area, they need to draw from the Atlantic, as Gulf of Mexico moisture will likely be limited. We’ll also have to monitor as we go other indices that can alter the pattern somewhat. What I’m getting at is that we’re probably in for a winter where the only consistent aspect is that we’ll see frequent changes and temperature and frequent minor to moderate storm systems, with a risk of larger storms coming mainly when the system intensifies just offshore. It’s not known how often this may happen. Putting it all together, it looks like this winter will favor temperatures near normal but arriving there by way of frequent changes. Precipitation may be closer to normal. Snowfall is going to likely be dependent on location, with the greatest risk of a little less than normal over southeastern areas, and near to above normal further north and west. A brief month by month breakdown follows…
Breakdown: Weak La Nina pattern, and some blocking expected. This pattern would produce Pacific low pressure systems coming across the country, the track determining precipitation type. Behind these systems would come some pretty good shots of cold air, but low pressure systems that track far enough north would allow milder air to enter the region.
Temperature: Near normal northern areas, near to above normal southern areas.
Precipitation: Near to above normal northern areas, near to below normal southern areas.
Snow: Near to above normal northern areas, below normal southern areas.
Breakdown: Same general pattern as December, but transitional blocking allowing more cold in Canada should help snowcover build up there and intensify the cold shots behind departing low pressure areas.
Temperature: Near to below normal northern areas, near to above normal southern areas.
Precipitation: Near to above normal northwestern areas, near to below normal southeastern areas.
Snow: Near to above normal northwestern areas, below normal southeastern areas.
Breakdown: Weak La Nina should persist and allow a ridge to be more dominant in the Southeast as the dry winter there allows some early warm-up as the sun angle increases. This may tend to push Pacific systems a bit further north as they exit the Midwest.
Temperature: Near to above normal.
Precipitation: Below normal.
Snow: Near normal northwest, below normal southeast.
Breakdown: The trend of the Southeast ridge should continue, making the month somewhat similar to February.
Temperature: Near to abpve normal.
Precipitation: Below normal.
Snow: Below normal.
WINTER SEASON OVERALL
Temperature: Near to above normal, with the milder departures favoring areas to the east and south.
Precipitation: Near normal northwestern areas, below normal southeastern areas.
Snow: Near normal northwestern areas, below normal southeastern areas.
-Boston 30-40 inches
-Worcester 50-60 inches
-Providence 20-30 inches
-Hartford 35-45 inches