On Tuesday, September 22, 2015 at 7:46:09 PM UTC+1, wrote:
On Tuesday, September 22, 2015 at 9:31:15 AM UTC+1, wrote:
b No that is too close to sea level down here. More like 250 metres. Last
winter was classed as mild but even so there were many days on Dartmoor with
snow lying above 500 metres. A colder flow will bring that snowline down,
perhaps closer to sea level up north.


Might be interesting up here in such a scenario. Lying snow in a straight westerly showery airstream (as opposed to a NW)isn't all that common here but it does happen, especially in late winter when the sea is obviously colder.

We will see if this pattern of a colder Atlantic persists, it's been around for a while now I think, late spring/early summer?

Col

It's been around most of the year, but changed gradually, especially over the last 4 months. It is now considerably further south. Back in June it was around 10 degrees further north, rather more intense, but didn't extend anywhere near as far eastward. In fact at the end of June SSTs were above normal in the eastern Atlantic everywhere from Ireland to northern Spain. It extended eastward in August.

From a purely observational point of view, based on past events, I expect it to drift further south & become less of a feature. The forecast change in pressure patterns is lightly to aid this (or is it vica versa - these chickens & eggs are real problems).

The chance of me being wrong is quite significant!

Graham
Penzance

SNIP
We will see if this pattern of a colder Atlantic persists, it's been around for a while now I think, late spring/early summer?

Col

It's been around most of the year, but changed gradually, especially over the last 4 months. It is now considerably further south. Back in June it was around 10 degrees further north, rather more intense, but didn't extend anywhere near as far eastward. In fact at the end of June SSTs were above normal in the eastern Atlantic everywhere from Ireland to northern Spain. It extended eastward in August.

From a purely observational point of view, based on past events, I expect it to drift further south & become less of a feature.

Graham
Penzance

Thought I'd return to this as it's starting to look like the cool anomaly is indeed drifting south and becoming less significant http://www1.ncdc.noaa..gov/pub/data/...vy-anom-bb.gif

The trouble with anomaly maps is they give an impression of a pool of cool water, when in fact the just normally indicate a variance from the normal temperature gradient. Obvious I know, but it is important to look at actual SSTs at the same time, http://www.wetterzentrale.de/pics/Reursst.gif

Graham
Penzance 'andsome yesterday my lovelies http://www.easterling.freeserve.co.uk/hm.html

On Sunday, September 27, 2015 at 8:00:20 AM UTC-4, Graham Easterling wrote:
SNIP
We will see if this pattern of a colder Atlantic persists, it's been around for a while now I think, late spring/early summer?

Col

It's been around most of the year, but changed gradually, especially over the last 4 months. It is now considerably further south. Back in June it was around 10 degrees further north, rather more intense, but didn't extend anywhere near as far eastward. In fact at the end of June SSTs were above normal in the eastern Atlantic everywhere from Ireland to northern Spain. It extended eastward in August.

From a purely observational point of view, based on past events, I expect it to drift further south & become less of a feature.

Graham
Penzance

Thought I'd return to this as it's starting to look like the cool anomaly is indeed drifting south and becoming less significant http://www1.ncdc.noaa.gov/pub/data/o...vy-anom-bb.gif

The trouble with anomaly maps is they give an impression of a pool of cool water, when in fact the just normally indicate a variance from the normal temperature gradient. Obvious I know, but it is important to look at actual SSTs at the same time, http://www.wetterzentrale.de/pics/Reursst.gif

Graham
Penzance 'andsome yesterday my lovelies http://www.easterling.freeserve.co.uk/hm.html

===========

Well, an area around 55 deg N did have record low SSTs for the period Jan-Aug 2015 but I agree with you about the analysis of anomalies.

The idea that Greenland ice melt is going to help to slow the AMOC is going to gain momentum, and it's worth considering. But talking with a colleague offered a simpler explanation - persistent anomalous westerlies across the North Atlantic since the latter part of last year have been forcing surface waters southwards via Ekman transportation.

Stephen.

On Sunday, 27 September 2015 16:38:14 UTC+1, Stephen Davenport wrote:

The idea that Greenland ice melt is going to help to slow the AMOC is going to gain momentum, and it's worth considering.

If the AMOC slows, then the warm water from the Gulf Stream will collect in the North Atlantic. I can't see that causing a cooling :-)

Cheers, Alastair.