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Winter 2017-18: Discussion
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Kermit.de.frog wrote: »2010 was the only time threads were started beyond 120 hrs as far as I remember.
Maybe, and if so they were probably justified given the synoptics at the time. 120hrs isn't a hard limit to FI when you've got the polar vortex over your head.0 -
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Donegal Storm wrote: »One for syran, just wondering are there any precedents to a strong easterly in late Feb/early March? Obviously we've had plenty of Spring blizzards down the years but they're usually from Atlantic lows undercutting the high, I'm just talking a direct easterly feed.
Just trying to gauge what sort of temperatures & conditions we could expect if the eternal 10 day charts ever come closer. We had -12C 850hPa temps in the second week of March 2013 and I don't think it delivered anything too noteworthy
There's numerous precedents for easterlies in general than specifically strong or weak ones.
One precedent is a strong Siberian High with quite a large snow cover advancement into Europe through the month of October. Why and how is this a precedent? With other factors building up a block to the north like negative AO/NAO or SSW (we haven't had a SSW in November since the 70s and to remind, the November 1962 SSW/CW led to the severest Winter of the 20th century!), the strong Siberian High that builds itself to the east of Europe and over Russia conjoins with this block to form a monster area of high pressure to the north of Europe. This means high pressure over Greenland, high pressure over the Norwegian Sea and Arctic, high pressure over Scandinavia etc. This in turn leads to easterlies because there is no other place the winds can directly blow from - unless the block is too far north obviously. With the snow cover from October, Europe has already been in a bit of a freeze. I'm not the greatest when it comes to this methodology but that's what I know as far as I'm aware. Sometimes like 2013, this fails though because of external factors.
Second precedent is well... I've already said it, SSW lol. Again, this depends on a few factors though such as what type of SSW is it? Is it a displacement of the Polar Vortex? Is it a split of the Polar Vortex? Is it a total obliteration of the Polar Vortex? Examples of each here are:
- Displacement; February 2008. Brought very cold conditions to the east of the US (regardless of the La Nina taking place). Blew up the jet stream for us and we had a very stormy March with a new March low pressure record set for Ireland. However, at times such as mid to late March and early April, we had some significant snowfalls and cold conditions so it wasn't all doom and gloom! These were the most significant March snowfalls since 2006 and most significant April snowfalls since 1999 at the time.
- Split; January 1985. Record breaking cold conditions to the east of the US. Very cold and snowy easterly across Europe including Ireland. Coldest January of the 1980s and the only January to compete it since then is 2010. Of course, February 2018 is a PV split here
- Obliteration; January 2013. Coldest March since 1892 for the CET, coldest on record for the IMT as far as I know - even colder than March 1962. Coldest weather since 2010 generally. Best March blizzards for many many years in the UK and Northern Ireland. Unusually anticyclonic February spell too.
SSW is a high chance for cold or snow to develop for us following it with 2/3 SSW events favouring so. You don't need SSW to get crazy cold as can be seen from Winters like 2009-10 or 2010-11 (though February 2010 had a SSW which led onto the coldest March since 2006 or 2001 and the best March blizzard I have experienced in my life so far). Easterlies are more favoured than northerlies from SSW events.
Warm air advection is another precedent to easterlies. This is when the winds become southerlies with an area of high pressure to the east either over Scandinavia or eastern Europe, sending warm air up into the Arctic and in turn let cold air descend into Siberia which then comes biting in on the easterly. Have a look at previous examples here:
End of January 1991 before February freeze
January 1987 right before the huge but quite brief beasterly
End of December 1984 before the mid-January 1985 cold spell. I included the upper air temperatures in this one because they are a brilliant example to show you the warm air advecting up to the Arctic.
Honestly, there are quite a few precedents you can notice for yourself when it comes to easterlies if you look through the archives and compare each like with the warm air advection.
11 March 2013 delivered snow showers to us - enough to delay flights at Dublin Airport. In the Channel Islands, they had absolute blizzards that were easily better than snow they had in 2010 - the fact that they took place in March is significant enough. This was the scene at Dublin Airport on the 11 March:
courtesy of Finbar Barry
Ireland didn't really get that much from March 2013 especially in comparison to the UK but there was a good few days with falling snow for some. Mind you, parts of Dublin had some significant lying snow on 19/20 and 26/27 March. I remember I could build a snowman on the morning of 27 March. It didn't snow here on the 27th but did on the 26th and it was helped by the severe frost that developed. The thing with March 2013 too that you got to remember was that it wasn't a proper easterly month, it was northeasterly.
March 2013 is my personal least favourite month because of personal experience and how dull it was. Ugh, disgusting month.Photography site - https://www.sryanbruenphoto.com/
Weather photo portfolio - https://sryanbruen.myportfolio.com/weather-1
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sryanbruen wrote: »There's numerous precedents for easterlies in general than specifically strong or weak ones.
One precedent is a strong Siberian High with quite a large snow cover advancement into Europe through the month of October. Why and how is this a precedent? With other factors building up a block to the north like negative AO/NAO or SSW (we haven't had a SSW in November since the 70s and to remind, the November 1962 SSW/CW led to the severest Winter of the 20th century!), the strong Siberian High that builds itself to the east of Europe and over Russia conjoins with this block to form a monster area of high pressure to the north of Europe. This means high pressure over Greenland, high pressure over the Norwegian Sea and Arctic, high pressure over Scandinavia etc. This in turn leads to easterlies because there is no other place the winds can directly blow from - unless the block is too far north obviously. With the snow cover from October, Europe has already been in a bit of a freeze. I'm not the greatest when it comes to this methodology but that's what I know as far as I'm aware. Sometimes like 2013, this fails though because of external factors.
Second precedent is well... I've already said it, SSW lol. Again, this depends on a few factors though such as what type of SSW is it? Is it a displacement of the Polar Vortex? Is it a split of the Polar Vortex? Is it a total obliteration of the Polar Vortex? Examples of each here are:
- Displacement; February 2008. Brought very cold conditions to the east of the US (regardless of the La Nina taking place). Blew up the jet stream for us and we had a very stormy March with a new March low pressure record set for Ireland. However, at times such as mid to late March and early April, we had some significant snowfalls and cold conditions so it wasn't all doom and gloom! These were the most significant March snowfalls since 2006 and most significant April snowfalls since 1999 at the time.
- Split; January 1985. Record breaking cold conditions to the east of the US. Very cold and snowy easterly across Europe including Ireland. Coldest January of the 1980s and the only January to compete it since then is 2010. Of course, February 2018 is a PV split here
- Obliteration; January 2013. Coldest March since 1892 for the CET, coldest on record for the IMT as far as I know - even colder than March 1962. Coldest weather since 2010 generally. Best March blizzards for many many years in the UK and Northern Ireland. Unusually anticyclonic February spell too.
SSW is a high chance for cold or snow to develop for us following it with 2/3 SSW events favouring so. You don't need SSW to get crazy cold as can be seen from Winters like 2009-10 or 2010-11 (though February 2010 had a SSW which led onto the coldest March since 2006 or 2001 and the best March blizzard I have experienced in my life so far). Easterlies are more favoured than northerlies from SSW events.
Warm air advection is another precedent to easterlies. This is when the winds become southerlies with an area of high pressure to the east either over Scandinavia or eastern Europe, sending warm air up into the Arctic and in turn let cold air descend into Siberia which then comes biting in on the easterly. Have a look at previous examples here:
End of January 1991 before February freeze
January 1987 right before the huge but quite brief beasterly
End of December 1984 before the mid-January 1985 cold spell. I included the upper air temperatures in this one because they are a brilliant example to show you the warm air advecting up to the Arctic.
Honestly, there are quite a few precedents you can notice for yourself when it comes to easterlies if you look through the archives and compare each like with the warm air advection.
11 March 2013 delivered snow showers to us - enough to delay flights at Dublin Airport. In the Channel Islands, they had absolute blizzards that were easily better than snow they had in 2010 - the fact that they took place in March is significant enough. This was the scene at Dublin Airport on the 11 March:
courtesy of Finbar Barry
Ireland didn't really get that much from March 2013 especially in comparison to the UK but there was a good few days with falling snow for some. Mind you, parts of Dublin had some significant lying snow on 19/20 and 26/27 March. I remember I could build a snowman on the morning of 27 March. It didn't snow here on the 27th but did on the 26th and it was helped by the severe frost that developed. The thing with March 2013 too that you got to remember was that it wasn't a proper easterly month, it was northeasterly.
March 2013 is my personal least favourite month because of personal experience and how dull it was. Ugh, disgusting month.
Brilliant post!0 -
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sryanbruen wrote: »I have to disagree with the boring comments, this has been one of the most interesting Winters I have experienced with so much bizarre things taking place. 2016-17, now that was boring.... mild and dry in Winter? Ew.
Have to disagree there. There is not a thing wrong with Mild and Dry in Winter if theres no hope of cold and snow!
:D:D 0
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