Good evening from Southern Connecticut Weather!
The first half of December has been frigid, but as expected, a move toward milder weather is afoot. The supply of deep could from our source region in southeast Canada is being reduced as a massive ridge develops over the central U.S. in the coming week.
Before we likely warm up however, we will be on the razor's edge of the boundary between warmth and cold. In a continued fast flow regime with several weak systems rocketing through, it looks like we have one candidate for a weak winter storm right before the Christmas holiday, and perhaps another right after Christmas. The signal for the earlier event is far stronger, but let's take a quick look at both.
The first half of December has been frigid, but as expected, a move toward milder weather is afoot. The supply of deep could from our source region in southeast Canada is being reduced as a massive ridge develops over the central U.S. in the coming week.
Before we likely warm up however, we will be on the razor's edge of the boundary between warmth and cold. In a continued fast flow regime with several weak systems rocketing through, it looks like we have one candidate for a weak winter storm right before the Christmas holiday, and perhaps another right after Christmas. The signal for the earlier event is far stronger, but let's take a quick look at both.
Above: the 18z GFS model depiction of the Tuesday system, which even has an inverted trough bringing snow on Christmas Eve verbatim.
Tuesday's Potential
This is our shot at a white Christmas, if you're into that kind of thing.
If you like winter, be glad you're not living in Missouri this coming week. For most of the month, we've had a favorable WPO for cold air intrusions overwhelming other more muted teleconnections. This has allowed repeated legitimate Arctic blasts, as the coldest temperatures in the hemisphere have been pushed over North America.
As the WPO's power wanes, a massive ridge will develop over the central U.S. and absolutely torch much of the continental U.S., perhaps through the rest of the month. Note on the EPS below how the colder blasts over our region get cut off as the ridge over the central U.S. develops and flexes. Note also how the biggest anomalies are to our west. That puts us in the battle zone between cold and warmth.
Tuesday's Potential
This is our shot at a white Christmas, if you're into that kind of thing.
If you like winter, be glad you're not living in Missouri this coming week. For most of the month, we've had a favorable WPO for cold air intrusions overwhelming other more muted teleconnections. This has allowed repeated legitimate Arctic blasts, as the coldest temperatures in the hemisphere have been pushed over North America.
As the WPO's power wanes, a massive ridge will develop over the central U.S. and absolutely torch much of the continental U.S., perhaps through the rest of the month. Note on the EPS below how the colder blasts over our region get cut off as the ridge over the central U.S. develops and flexes. Note also how the biggest anomalies are to our west. That puts us in the battle zone between cold and warmth.
Overall, for Tuesday we are mostly on the colder side of the boundary. Another cold front will pass through the region tomorrow, bringing in a fresh cold air mass for Monday and Tuesday.
As this happens, a weak ripple in the flow will try to amplify as it dives down from Canada. This depiction, also from the 18z Euro, shows how it tries to amplify at 500mb...
And the result at the surface:
Now if you're comparing and contrasting between the GFS and Euro runs I posted, there's a split in the overall evolution. Yes, it looks like there will be enough cold for a period of snow on Tuesday, but there are still significant questions on track and amplitude.
First, on one hand, a system diving down from Canada (basically a clipper) can be good for ensuring a colder flow--depending on the track. A further north track would keep a surface front to our north, likely causing a change from snow to rain, especially at the coast. A further south track keeps the column colder for longer.
Second, how strong will this get? There are some models that try to turn this into a redeveloping coastal storm, which introduces a different type of evolution and heightened potential for eastern CT depending on the speed of development and the storm itself. For now, that's discounted but something to watch.
Third, is there really inverted trough potential? Now, longtime readers know that inverted troughs are always highly suspect and are very difficult to predict. If there is some sort of inverted trough feature as some of the guidance tries to develop, that could lead to higher accumulation potential.
The bottom line is that although this looks like a weak event, there's a lot to be sorted out. Stay tuned.
December 26 Potential
This won't get much discussion yet, but in the wake of our Tuesday event we get a reinforcing shot of cold for Wednesday (Christmas Eve). That will be short lived, as it looks like we will warm up some on Christmas Day. This doesn't look like a torch though, like much of the rest of the country.
First, on one hand, a system diving down from Canada (basically a clipper) can be good for ensuring a colder flow--depending on the track. A further north track would keep a surface front to our north, likely causing a change from snow to rain, especially at the coast. A further south track keeps the column colder for longer.
Second, how strong will this get? There are some models that try to turn this into a redeveloping coastal storm, which introduces a different type of evolution and heightened potential for eastern CT depending on the speed of development and the storm itself. For now, that's discounted but something to watch.
Third, is there really inverted trough potential? Now, longtime readers know that inverted troughs are always highly suspect and are very difficult to predict. If there is some sort of inverted trough feature as some of the guidance tries to develop, that could lead to higher accumulation potential.
The bottom line is that although this looks like a weak event, there's a lot to be sorted out. Stay tuned.
December 26 Potential
This won't get much discussion yet, but in the wake of our Tuesday event we get a reinforcing shot of cold for Wednesday (Christmas Eve). That will be short lived, as it looks like we will warm up some on Christmas Day. This doesn't look like a torch though, like much of the rest of the country.
Above: An 18z Euro surface temperature anomaly depiction. It's warm just about everywhere, but it's relative. While it's a blowtorch in the Midwest, here are our Christmas afternoon temperatures--mid to upper 30s for most.
Above: 18z Euro temperatures Christmas afternoon. Image courtesy of Weathermodels.com.
The temperature profile in the wake of the Tuesday event is extremely important for the post-Christmas period, as models are signaling a potentially stronger system moving though the region the day after Christmas.
There may be enough cold in place at the surface for a mixed bag event, or a rain event. While the GFS keeps us on the warm side of the boundary here to bring a rain event.
The temperature profile in the wake of the Tuesday event is extremely important for the post-Christmas period, as models are signaling a potentially stronger system moving though the region the day after Christmas.
There may be enough cold in place at the surface for a mixed bag event, or a rain event. While the GFS keeps us on the warm side of the boundary here to bring a rain event.
The Euro has a colder temperature profile that could bring an impactful winter weather event on December 26.
That above image might not look like much, but that's trouble for travel if we trend colder.
Stay tuned.
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Stay tuned.
As always, please like, share, and interact with us on our social media--on Facebook to share our discussions, and follow us on Twitter @southernctwx to retweet our posts. Hit the buttons below to join.
Thank you for reading and trusting SCW.
