510 dam line instances

[damianslaw]

Something I always look for during the winter months, and Spring.. is the 510 dam line, normally it sits well to the north of the UK, but on occasion usually with a long fetch northerly / north easterly flow and easterly it can approach the UK and on odd occasion move into parts of the UK - namely Scotland, but on rare instances well into England and Wales.

I think the last time the 510 dam line encroached into England at least was late Feb 2018, other than that I don't recall many instances in the last 20-30 years.. Dec 2010 did the trick and unusual to happen so early in the season...

Anyone with charts, stats, info please share knowledge when 510 dam line last encroached England, mention of Scotland is fine as well.

 

[MP-R]

Early Feb 1991 and early-mid Jan 1987 definitely did. Add to that January 1979.

  

[damianslaw]

32 minutes ago, MP-R said:

Early Feb 1991 and early-mid Jan 1987 definitely did. Add to that January 1979.

  

Ooh thanks for these, all within sub -12 uppers. 1987 was epic for extensiveness and depth of cold. Do you have the charts for 28 Feb 2018, 16-20 Dec 2010?

[MP-R]

2 hours ago, damianslaw said:

Ooh thanks for these, all within sub -12 uppers. 1987 was epic for extensiveness and depth of cold. Do you have the charts for 28 Feb 2018, 16-20 Dec 2010?

2010 never actually had the 510 dam line over the UK... it came very close at times but never overhead.#

2018 on the other hand:

Two other good examples going further back:

 

I'm sure there are others before but dam data doesn't seem to feature pre 1950. Other than 1st March 2018, I couldn't find another March example of 510 dam over the UK so if we achieve that this year, it would be truly exceptional.

[damianslaw]

18 hours ago, MP-R said:

2010 never actually had the 510 dam line over the UK... it came very close at times but never overhead.#

2018 on the other hand:

Two other good examples going further back:

 

I'm sure there are others before but dam data doesn't seem to feature pre 1950. Other than 1st March 2018, I couldn't find another March example of 510 dam over the UK so if we achieve that this year, it would be truly exceptional.

Thanks again for these, surprised 2010 didn't quite do it, possibly a little early in the season and it was also a northerly flow, assuming it was the second cold spell that nearly delivered rather than the late Nov- early Dec cold spell. Seems that it is easterlies rather than northerlies deliver the goods, I guess its easier for cold pools to make it into the UK from the east rather than the long fetch sea track from the north.

Any examples from the north of 510 dam line encroaching Scotland would be good to see.

In all cases it seems sub 510 dam air comes with uppers lower than -12 degrees. -10 degrees are quite common from the north but not the -12 degrees.

[cheeky_monkey]

upper air temps here currently are below -28 degrees don't know what that would translate to?