@snowcohen.bsky.social
Despite the fact that the ECMWF is now all in predicting the earliest sudden stratospheric warming in the satellite era, the best line from Monday's blog is looking more & more like - "First I don’t rule out the possibility this will all evolve into a stretched #PolarVortex in the end."
November 13, 2025 at 8:37 PM
Despite the fact that the ECMWF is now all in predicting the earliest sudden stratospheric warming in the satellite era, the best line from Monday's blog is looking more & more like - "First I don’t rule out the possibility this will all evolve into a stretched #PolarVortex in the end."
I review in full the October #Siberian #snow cover & what it may portend for the #winter #PolarVortex (PV). O Canada - PV can't seem to quit Canadian Warmings but what does it mean for Greenland blocking & our weather in the upcoming weeks. Blog is now public: published.aer.com/aoblog/aoblo...
November 4, 2025 at 12:13 AM
I review in full the October #Siberian #snow cover & what it may portend for the #winter #PolarVortex (PV). O Canada - PV can't seem to quit Canadian Warmings but what does it mean for Greenland blocking & our weather in the upcoming weeks. Blog is now public: published.aer.com/aoblog/aoblo...
Seems like plenty of hype about the #PolarVortex, is it justified? What does my crystal ball show so far? Lots of winter forecasts coming out-I share my thoughts on the upcoming winter as well but no forecast will be issued before its time. Blog now public published.aer.com/aoblog/aoblo...
October 20, 2025 at 10:34 PM
Seems like plenty of hype about the #PolarVortex, is it justified? What does my crystal ball show so far? Lots of winter forecasts coming out-I share my thoughts on the upcoming winter as well but no forecast will be issued before its time. Blog now public published.aer.com/aoblog/aoblo...
Snow cover is on the move across Siberia, Arctic sea ice is growing and Mother Nature is teasing us with the prospect for Greenland blocking the end of the month. What does this all mean for the #PolarVortex and our weather this upcoming winter? Blog now public: published.aer.com/aoblog/aoblo...
October 6, 2025 at 7:40 PM
Snow cover is on the move across Siberia, Arctic sea ice is growing and Mother Nature is teasing us with the prospect for Greenland blocking the end of the month. What does this all mean for the #PolarVortex and our weather this upcoming winter? Blog now public: published.aer.com/aoblog/aoblo...
"Hello darkness, my old friend, I've come to talk with you again."
It's baaaaack! The #PolarVortex is starting anew over Siberia (where else?) & will strengthen over the North Pole the next two weeks. In today's blog I summarize summer & then quickly pivot to winter published.aer.com/aoblog/aoblo...
It's baaaaack! The #PolarVortex is starting anew over Siberia (where else?) & will strengthen over the North Pole the next two weeks. In today's blog I summarize summer & then quickly pivot to winter published.aer.com/aoblog/aoblo...
September 8, 2025 at 8:41 PM
"Hello darkness, my old friend, I've come to talk with you again."
It's baaaaack! The #PolarVortex is starting anew over Siberia (where else?) & will strengthen over the North Pole the next two weeks. In today's blog I summarize summer & then quickly pivot to winter published.aer.com/aoblog/aoblo...
It's baaaaack! The #PolarVortex is starting anew over Siberia (where else?) & will strengthen over the North Pole the next two weeks. In today's blog I summarize summer & then quickly pivot to winter published.aer.com/aoblog/aoblo...
Our estimate of August & summer temperature anomalies are in. August was remarkably similar to the summer averages. Biggest exception are cool temperatures in Central Canada slide southeastward into the Eastern US. Western Europe, Middle East, Central Asia & Japan continued to sizzle.
September 2, 2025 at 2:27 PM
Our estimate of August & summer temperature anomalies are in. August was remarkably similar to the summer averages. Biggest exception are cool temperatures in Central Canada slide southeastward into the Eastern US. Western Europe, Middle East, Central Asia & Japan continued to sizzle.
Summer is winding down with both Europe & the Eastern US getting fall previews before August is over. Are we done with hot weather for 2025? Also some early hype about a weak #polarvortex for the upcoming winter but what is sea ice telling us? Blog now public: published.aer.com/aoblog/aoblo...
August 18, 2025 at 9:01 PM
Summer is winding down with both Europe & the Eastern US getting fall previews before August is over. Are we done with hot weather for 2025? Also some early hype about a weak #polarvortex for the upcoming winter but what is sea ice telling us? Blog now public: published.aer.com/aoblog/aoblo...
We're in the final stretch of summer, so how are we doing so far? I think the weather this summer has been "well behaved" but what does that mean & will the weather continue to be on its best behavior? Also watching for the Arctic sea ice minimum. Blog now public published.aer.com/aoblog/aoblo...
August 4, 2025 at 2:20 PM
We're in the final stretch of summer, so how are we doing so far? I think the weather this summer has been "well behaved" but what does that mean & will the weather continue to be on its best behavior? Also watching for the Arctic sea ice minimum. Blog now public published.aer.com/aoblog/aoblo...
We're in peak summer and it's looking like this summer is following the recent decadal trend, who will be hot & who not so hot? And can you believe we're only a little more than a month from the return of the #PolarVortex, who's excited? Blog is now public: published.aer.com/aoblog/aoblo...
July 16, 2025 at 7:34 PM
We're in peak summer and it's looking like this summer is following the recent decadal trend, who will be hot & who not so hot? And can you believe we're only a little more than a month from the return of the #PolarVortex, who's excited? Blog is now public: published.aer.com/aoblog/aoblo...
Sick & tired of the heat & humidity & you need a cool, refreshing break? How about a free article on the polar vortex & how it's fickle nature is bringing surprising winter temperature trends to the US, including warming to some parts & cooling to others: www.science.org/doi/10.1126/...
Cold-air outbreaks in the continental US: Connections with stratospheric variations
Extreme US cold linked to two variations of a stretched stratospheric polar vortex can explain a Northwest US cooling trend.
www.science.org
July 13, 2025 at 7:56 PM
Sick & tired of the heat & humidity & you need a cool, refreshing break? How about a free article on the polar vortex & how it's fickle nature is bringing surprising winter temperature trends to the US, including warming to some parts & cooling to others: www.science.org/doi/10.1126/...
It's my favorite term these days to describe the summer pattern - "ring of fire" as heat domes slosh around the continental mid to high latitudes. But where will the heat domes call home for most of the summer bring the warmest weather? Blog is now public: published.aer.com/aoblog/aoblo...
June 23, 2025 at 6:21 PM
It's my favorite term these days to describe the summer pattern - "ring of fire" as heat domes slosh around the continental mid to high latitudes. But where will the heat domes call home for most of the summer bring the warmest weather? Blog is now public: published.aer.com/aoblog/aoblo...
The tropospheric circulation is beginning to form the "ring of fire" pattern that I often use to describe the summer features favoring widespread warmth across the continents. Also included is the AER summer forecast. Do you think any resemblance? Blog is now public published.aer.com/aoblog/aoblo...
June 9, 2025 at 6:55 PM
The tropospheric circulation is beginning to form the "ring of fire" pattern that I often use to describe the summer features favoring widespread warmth across the continents. Also included is the AER summer forecast. Do you think any resemblance? Blog is now public published.aer.com/aoblog/aoblo...
They say timing is everything. Well the #PolarVortex disruption of March with its impacts reaching a crescendo in late May is timed to equally frustrate winter lovers and those eager for an early start to summer, bringing March weather in May. Blog is now public: published.aer.com/aoblog/aoblo...
May 19, 2025 at 9:24 PM
They say timing is everything. Well the #PolarVortex disruption of March with its impacts reaching a crescendo in late May is timed to equally frustrate winter lovers and those eager for an early start to summer, bringing March weather in May. Blog is now public: published.aer.com/aoblog/aoblo...
The #PolarVortex (PV) might be gone but not forgotten. The PV left a party favor some will view as a treat & others a trick. Memorial Day is the unofficial start of the summer but promises to be chilly for the beach or pool in the Eastern US & Europe thanks to the arrival of high-latitude blocking.
May 15, 2025 at 6:31 PM
The #PolarVortex (PV) might be gone but not forgotten. The PV left a party favor some will view as a treat & others a trick. Memorial Day is the unofficial start of the summer but promises to be chilly for the beach or pool in the Eastern US & Europe thanks to the arrival of high-latitude blocking.
The large #PolarVortex disruption from the 2nd week of March is coming to its climatic end the 4th week of May with the largest polar cap heights finally making its way to the mid-troposphere, Greenland blocking & relatively cool temperatures in Europe, the eastern US & East Asia. Who isn't excited?
May 9, 2025 at 3:55 PM
The large #PolarVortex disruption from the 2nd week of March is coming to its climatic end the 4th week of May with the largest polar cap heights finally making its way to the mid-troposphere, Greenland blocking & relatively cool temperatures in Europe, the eastern US & East Asia. Who isn't excited?
Excited about our new review paper (Ye et al., 2025) on the relationship between snow/ice variability & weather extremes. I will highlight our analysis that shows a strong relationship between fall Siberian #snow cover & cold extremes in eastern North America:
www.nature.com/articles/s41...
www.nature.com/articles/s41...
May 6, 2025 at 3:55 PM
Excited about our new review paper (Ye et al., 2025) on the relationship between snow/ice variability & weather extremes. I will highlight our analysis that shows a strong relationship between fall Siberian #snow cover & cold extremes in eastern North America:
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Well it is called the #PolarVortex (PV) blog so I am hanging in there until the PV takes it last breadth, which is imminent. But I do discuss the PV's parting shot on our weather (Greenland blocking anyone?) as it heads for the exit until the fall. Blog isnow public published.aer.com/aoblog/aoblo...
May 5, 2025 at 7:23 PM
Well it is called the #PolarVortex (PV) blog so I am hanging in there until the PV takes it last breadth, which is imminent. But I do discuss the PV's parting shot on our weather (Greenland blocking anyone?) as it heads for the exit until the fall. Blog isnow public published.aer.com/aoblog/aoblo...
Most have probably moved on from the #polarvortex (PV), thinking of beach days & summer vacations but not me. The PV is still lurking out there & it looks to make another pass at the Northeastern US in early May, what weather could it bring? Blog is now public: published.aer.com/aoblog/aoblo...
April 21, 2025 at 10:54 PM
Most have probably moved on from the #polarvortex (PV), thinking of beach days & summer vacations but not me. The PV is still lurking out there & it looks to make another pass at the Northeastern US in early May, what weather could it bring? Blog is now public: published.aer.com/aoblog/aoblo...
The large #PolarVortex disruption now a month in duration is still influencing our weather with tentacles descending from the stratosphere & touching our weather. Latest tentacle bringing winter in spring but when is the next and/or last one. Blog is now public: published.aer.com/aoblog/aoblo...
April 7, 2025 at 10:55 PM
The large #PolarVortex disruption now a month in duration is still influencing our weather with tentacles descending from the stratosphere & touching our weather. Latest tentacle bringing winter in spring but when is the next and/or last one. Blog is now public: published.aer.com/aoblog/aoblo...
No blog today but weather still happens. Drip, drip, drip, next tentacle from large early March #PolarVortex disruption reaches surface accompanied by Greenland blocking (as seen in polar cap geopotential heights limited to North Atlantic region) and cooler temperatures in Europe.
March 31, 2025 at 2:01 PM
No blog today but weather still happens. Drip, drip, drip, next tentacle from large early March #PolarVortex disruption reaches surface accompanied by Greenland blocking (as seen in polar cap geopotential heights limited to North Atlantic region) and cooler temperatures in Europe.
As uneventful the #PolarVortex (PV) split has been so far, it is rare (or even unprecedented) to be able to say one daughter PV center is over merry ol' England and the other daughter PV center is over New England!
March 28, 2025 at 8:56 PM
As uneventful the #PolarVortex (PV) split has been so far, it is rare (or even unprecedented) to be able to say one daughter PV center is over merry ol' England and the other daughter PV center is over New England!
I haven't shared our estimate of the Northern Hemisphere snowfall anomalies all winter but here it is for winter 2024/25. Big winners - Japan, coastal Alaska, Great Lakes, Eastern Canada and in general higher latitudes and altitudes. Notable mention, parts of the Southeastern US.
March 25, 2025 at 5:46 PM
I haven't shared our estimate of the Northern Hemisphere snowfall anomalies all winter but here it is for winter 2024/25. Big winners - Japan, coastal Alaska, Great Lakes, Eastern Canada and in general higher latitudes and altitudes. Notable mention, parts of the Southeastern US.
The very large #PolarVortex disruption continues unabated with multiple PV centers circumnavigating the globe in record time. I discuss why with such an impressive PV disruption the weather impact is underwhelming & could that change? Blog is now public: published.aer.com/aoblog/aoblo...
March 24, 2025 at 10:35 PM
The very large #PolarVortex disruption continues unabated with multiple PV centers circumnavigating the globe in record time. I discuss why with such an impressive PV disruption the weather impact is underwhelming & could that change? Blog is now public: published.aer.com/aoblog/aoblo...
Large #PolarVortex (PV) is entertaining with multiple passes from different PV centers over the Northeastern US maybe unprecedented? But what will be the weather impacts? I also present verification of the AER #winter temperature forecast. Blog is now public:
published.aer.com/aoblog/aoblo...
published.aer.com/aoblog/aoblo...
March 17, 2025 at 11:05 PM
Large #PolarVortex (PV) is entertaining with multiple passes from different PV centers over the Northeastern US maybe unprecedented? But what will be the weather impacts? I also present verification of the AER #winter temperature forecast. Blog is now public:
published.aer.com/aoblog/aoblo...
published.aer.com/aoblog/aoblo...
After a #winter at a frenetic pace of changes, the #PolarVortex is settling into a large & long duration disruption. There will be a smaller, immediate impact but what & when could be the greater & longer lasting impact to our weather. Blog is now public: published.aer.com/aoblog/aoblo...
March 10, 2025 at 9:03 PM
After a #winter at a frenetic pace of changes, the #PolarVortex is settling into a large & long duration disruption. There will be a smaller, immediate impact but what & when could be the greater & longer lasting impact to our weather. Blog is now public: published.aer.com/aoblog/aoblo...