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Zero999:
It's been disproven a long time ago that the Gulf Stream is the main driver for mild European winters. The west of England is milder and wetter, than the east, because the west is closer to the Atlantic and the east is nearer to the continent. A similar pattern repeats over North America, from west to east.

Yes, it's the jet stream which governs our weather. It's true it's affected by sea surface temperatures, but the correlation isn't direct. A warm North Atlantic doesn't necessarily mean milder winters for Europe. The temperature of the North Pacific, has a greater impact.

Links to sea surfaces temperature anomalies, at the end of Novembers 2010 and 2015, which preceded the coldest and mildest Decembers ever recorded in the UK. The Atlantic was much warmer at the end of 2010, than 2015. The difference was the Pacific was much colder in 2010, especially the north.
https://www.ospo.noaa.gov/data/sst/anomaly/2010/anomnight.11.29.2010.gif
https://www.ospo.noaa.gov/data/sst/anomaly/2015/anomnight.11.30.2015.gif

Of course there are many other factors. The weather has changed from cold in the first half of February, to near record breaking warm this week, because the jet stream has moved northwards, due to the North Atlantic oscillation flipping to the positive phase and now the wind is now coming from the Azores, rather than Svalbard. The sea surface temperatures haven't changed much and Gulf Stream didn't go way when it was cold and return now it's milder.

bsfeechannel:

--- Quote from: james_s on February 24, 2021, 05:16:47 pm ---I'd much rather deal with -15C temperatures than 40C temperatures. It's a lot easier to warm up than it is to cool down.

--- End quote ---

Can't agree more.

JohnnyMalaria:

--- Quote from: Zero999 on February 24, 2021, 10:47:59 pm ---It's been disproven a long time ago that the Gulf Stream is the main driver for mild European winters. The west of England is milder and wetter, than the east, because the west is closer to the Atlantic and the east is nearer to the continent. A similar pattern repeats over North America, from west to east.

Yes, it's the jet stream which governs our weather. It's true it's affected by sea surface temperatures, but the correlation isn't direct. A warm North Atlantic doesn't necessarily mean milder winters for Europe. The temperature of the North Pacific, has a greater impact.

Links to sea surfaces temperature anomalies, at the end of Novembers 2010 and 2015, which preceded the coldest and mildest Decembers ever recorded in the UK. The Atlantic was much warmer at the end of 2010, than 2015. The difference was the Pacific was much colder in 2010, especially the north.
https://www.ospo.noaa.gov/data/sst/anomaly/2010/anomnight.11.29.2010.gif
https://www.ospo.noaa.gov/data/sst/anomaly/2015/anomnight.11.30.2015.gif

Of course there are many other factors. The weather has changed from cold in the first half of February, to near record breaking warm this week, because the jet stream has moved northwards, due to the North Atlantic oscillation flipping to the positive phase and now the wind is now coming from the Azores, rather than Svalbard. The sea surface temperatures haven't changed much and Gulf Stream didn't go way when it was cold and return now it's milder.

--- End quote ---

NOAA seems quite convinced of the importance of the Gulf Stream: https://scijinks.gov/gulf-stream/

And you can't really decouple the two: http://www.actforlibraries.org/jet-stream-gulf-stream-polar-shifts-and-climate-changes/

boffin:

--- Quote from: dolbeau on February 24, 2021, 06:08:09 pm ---
--- Quote from: drussell on February 24, 2021, 05:48:59 pm ---Actually, Nova Scotia is one of the more prolific wine producing regions in Canada...

--- End quote ---

Well, you learn something new every day. Wine and Frenchmen... we think we know everything and unsurprisingly it turns out we don't :-)

And looking at the Wines of Nova Scotia website (could have checked *that* before posting...), they're trying for Pinot Noir as well. Kinda intrigued I must say. Not that any shops here will carry any of it for me to try (if you want to meet an angry french shopkeeper, ask for some New World wines in a french wine shop...).

--- End quote ---

Wine regions can be somewhat unexpected.  The hottest temperatures in Canada, and the only largish region growing Bordeaux or GSM wines is the very southern end of the Okanagan Valley the towns of Penticton/Oliver/Osoyoos, temps reach 40C in the summer, and only get 15-30cm rain/year.  Even getting 50km from the US border, the weather changes enough that from Penticton north, it's more Pinot Noir and white varietals.

Someone else mentioned Salem Oregon, and from a wine point of view, many French producers purchased land in the area, feeling it was the only appropriate terroir for Burgundy, outside of Burgundy itself and the produce some very good Pinots along with quite excellent sparkling wine.

Nominal Animal:

--- Quote from: Zero999 on February 24, 2021, 10:47:59 pm ---The west of England is milder and wetter, than the east, because the west is closer to the Atlantic and the east is nearer to the continent. A similar pattern repeats over North America, from west to east.
--- End quote ---
Not very similar, though:


I do not know what is the main driver, but I definitely would not claim the Gulf Stream is irrelevant.  (Note, neither did Zero999; they just said it is not the main driver.)  The average winter temperature difference between Nunavut, Canada; Southern Greenland; and Iceland, breaks the "east-west part of continent dictates it" assertion, as they are all surrounded by ocean.

The main reason I am wary of any simple explanations, is that Medieval Warm Period occurred, between c. 950 and 1100 Common Era.  During this time, Vikings in (the southernmost tip of) Greenland had cattle, sheep, and goats, and only a quarter of their diet was seafood.  By 1300, three quarters of their diet came from seal hunting, as livestock just couldn't handle the harsh winters.  We do not know why it occurred: all we know is correlation, and can only guess (and try to simulate to ascertain) the causation.

I grew up in Finland, north of the arctic circle (so about 6° further north), and for example potatoes, carrots, rutabaga, and onions grow just fine even at 330m above sea level there. (At the bottom of a couple of fell lakes, well above the treeline, there are still rather large tree trunks from the Medieval Warm Period, too.)  So, it is not a small difference in winter temperatures; it is a clear difference that affects the entire biome.

The exact circulation patterns in the North Atlantic are rather interesting,


Finally, comparing to the 10°C July mean isotherm (red line),

we can see that the summer mean temperature differs quite a bit from the winter mean temperatures in eastern Siberia and Alaska.  This supports the reasoning for continental effect on the climate (continental winters being colder, summers hotter).  However, the way Bering Sea summers are much colder than say Iceland clearly undermines that reasoning.  In other words, simple theories based only on the polar jet stream, or only on the Gulf Stream, are doomed to fail even a cursory examination.

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