Good evening from Southern Connecticut Weather!
After a very active period, we finally have time to produce our latest installment of the two week outlook. It isn’t quite two weeks here, but to maintain consistency, I’ll be covering the last third of the month. If you hated the first half of December, which consisted of multiple winter weather chances and colder than normal temperatures overall, you will like the major changes that are coming.
Grading the last outlook
Not bad. The modeling of the overall pattern was more or less excellent for our part of the world for the first half of December. Temperatures were below normal with multiple arctic shots, and we had a very active period of wintry precipitation. Overall, I give the outlook an A-. No A. I could have been better with the 5 to 7th period and I thought we’d end up colder than we actually were, but that’s not enough to notch down the grade too much. That might have been my best outlook yet!
Week one—Thursday December 1 to Wednesday December 7
Temperatures—below average (moderate confidence) Check
Precipitation—average (moderate confidence) Check
Wintry Precipitation—average (moderate confidence) Meh
Week two—Thursday December 8 to Thursday December 15
Temperatures—below average (high confidence) Check
Precipitation—above average (moderate confidence) Check
Wintry Precipitation—above average (moderate confidence) Check
Two Week Outlook Summary
After a very active period, we finally have time to produce our latest installment of the two week outlook. It isn’t quite two weeks here, but to maintain consistency, I’ll be covering the last third of the month. If you hated the first half of December, which consisted of multiple winter weather chances and colder than normal temperatures overall, you will like the major changes that are coming.
Grading the last outlook
Not bad. The modeling of the overall pattern was more or less excellent for our part of the world for the first half of December. Temperatures were below normal with multiple arctic shots, and we had a very active period of wintry precipitation. Overall, I give the outlook an A-. No A. I could have been better with the 5 to 7th period and I thought we’d end up colder than we actually were, but that’s not enough to notch down the grade too much. That might have been my best outlook yet!
Week one—Thursday December 1 to Wednesday December 7
Temperatures—below average (moderate confidence) Check
Precipitation—average (moderate confidence) Check
Wintry Precipitation—average (moderate confidence) Meh
Week two—Thursday December 8 to Thursday December 15
Temperatures—below average (high confidence) Check
Precipitation—above average (moderate confidence) Check
Wintry Precipitation—above average (moderate confidence) Check
Two Week Outlook Summary
* Note—high confidence (70% or greater belief of event occurring), moderate confidence (36-69%), low confidence (0-35%); nothing significant (less than 1” snowfall and .25” ice)
Week one—Tuesday December 20 to Monday December 26
Temperatures—above average (moderate confidence)
Precipitation—below average (moderate confidence)
Wintry Precipitation—below average (moderate confidence)
The period through Boxing Day looks mostly quiet, with a chance of rain/snow showers on Thursday as a clipper passes to the north and a storm cuts to our west—bringing rain—around Christmas. Temperatures look near normal during the start of the period, but by the end of the week and during the Christmas period we’re looking at temperatures that are above normal.
Week two—Tuesday December 27 to Saturday December 31
Temperatures—above average (low confidence)
Precipitation—average (moderate confidence)
Wintry Precipitation—below average (moderate confidence)
The period after Christmas is a little more uncertain. There are signals that the pattern that’s hostile to wintry precipitation and cold eases a bit by the last few days of December, but I am hesitant to latch onto that solution. I don’t see any strong signals for wintry precipitation, though rain chances may increase a bit.
Technical Discussion
Week one
As good as the first two weeks of December were for winter weather lovers, these next two weeks may be equally bad. There is something to be said about the psychological impact of warmer and snowless conditions around Christmas in New England, and for another year, we look to be staring at a Grinch Christmas in the weather department. The pattern that gave us chances for arctic shots and wintry precipitation was already marginal (as evidenced by cutter after cutter) is retreating, and in its wake we will see warm conditions that limit the possibility of snow. That’s fine for a lot of people!
By Thursday we see what is our only real shot of wintery precipitation as a clipper passes to our north. If there is a trend in our direction, that could keep the possibility to snow showers or light snow open. Right now, I lean towards a northern solution and temperatures warm enough to limit any potential of a winter weather event.
We warm gradually as the week continues, and by the holiday weekend we may not be torching like last year, but there isn’t a big winter chill in the air. Around the Christmas period, there is a signal for a storm to cut to our west, potentially bringing warm air and rain. It’s still a bit early to hone in on those details, so stay tuned to our daily discussions for talk about that. I think traveling before and after the holiday look fine at this point.
Week one—Tuesday December 20 to Monday December 26
Temperatures—above average (moderate confidence)
Precipitation—below average (moderate confidence)
Wintry Precipitation—below average (moderate confidence)
The period through Boxing Day looks mostly quiet, with a chance of rain/snow showers on Thursday as a clipper passes to the north and a storm cuts to our west—bringing rain—around Christmas. Temperatures look near normal during the start of the period, but by the end of the week and during the Christmas period we’re looking at temperatures that are above normal.
Week two—Tuesday December 27 to Saturday December 31
Temperatures—above average (low confidence)
Precipitation—average (moderate confidence)
Wintry Precipitation—below average (moderate confidence)
The period after Christmas is a little more uncertain. There are signals that the pattern that’s hostile to wintry precipitation and cold eases a bit by the last few days of December, but I am hesitant to latch onto that solution. I don’t see any strong signals for wintry precipitation, though rain chances may increase a bit.
Technical Discussion
Week one
As good as the first two weeks of December were for winter weather lovers, these next two weeks may be equally bad. There is something to be said about the psychological impact of warmer and snowless conditions around Christmas in New England, and for another year, we look to be staring at a Grinch Christmas in the weather department. The pattern that gave us chances for arctic shots and wintry precipitation was already marginal (as evidenced by cutter after cutter) is retreating, and in its wake we will see warm conditions that limit the possibility of snow. That’s fine for a lot of people!
By Thursday we see what is our only real shot of wintery precipitation as a clipper passes to our north. If there is a trend in our direction, that could keep the possibility to snow showers or light snow open. Right now, I lean towards a northern solution and temperatures warm enough to limit any potential of a winter weather event.
We warm gradually as the week continues, and by the holiday weekend we may not be torching like last year, but there isn’t a big winter chill in the air. Around the Christmas period, there is a signal for a storm to cut to our west, potentially bringing warm air and rain. It’s still a bit early to hone in on those details, so stay tuned to our daily discussions for talk about that. I think traveling before and after the holiday look fine at this point.
Above is the GEFS 7 day precipitation anomaly plot. Most of the week is quiet, which results with a below normal depiction which I agree with.
All one needs to do is look at the 500mb height map to see why the signal for warmer conditions is clear. Below, everything is lined up for warmer than normal conditions. There is no Atlantic blocking in the NAO/AO region and the west looks hostile. Any storm that does develop is likely to cut in this regime.
All one needs to do is look at the 500mb height map to see why the signal for warmer conditions is clear. Below, everything is lined up for warmer than normal conditions. There is no Atlantic blocking in the NAO/AO region and the west looks hostile. Any storm that does develop is likely to cut in this regime.
Week two
The second week becomes a bit more convoluted. Right now, I think that any modeled pattern change is more likely than not to be pushed to January, but as you can see above, there is a hint that we are cooling down temporarily by the end of December. Maybe we get a bit more active, but with no real blocking in place, I expect cutters to be the rule rather than the exception if this is a stormy period.
The second week becomes a bit more convoluted. Right now, I think that any modeled pattern change is more likely than not to be pushed to January, but as you can see above, there is a hint that we are cooling down temporarily by the end of December. Maybe we get a bit more active, but with no real blocking in place, I expect cutters to be the rule rather than the exception if this is a stormy period.
If you look at this EPS plot though, although it doesn’t go further out, you can see the danger of the end of December. This is a close the shades pattern if you like winter. Not much else to say with a big ridge in the east and trough in the west.
Overall, it looks like winter is taking a backseat, at least for a while. Warmer than normal temperatures should dominate, and with it, the odds of significant winter weather events are diminished significantly.
As always, don’t forget to like us on Facebook and share our discussions, and follow us on Twitter @southernctwx and retweet our posts!
Thanks for reading SCW.
-DB
Overall, it looks like winter is taking a backseat, at least for a while. Warmer than normal temperatures should dominate, and with it, the odds of significant winter weather events are diminished significantly.
As always, don’t forget to like us on Facebook and share our discussions, and follow us on Twitter @southernctwx and retweet our posts!
Thanks for reading SCW.
-DB
