Glacier Point said:Where do you see the GWO going in the next few days Mark ? If it's back to phase 1-2, some support for Icelandic block, phases 3-4 and more of the Atlantic influence perhaps ?
Ok I will start a new thread for dicussions along this line and perhaps I will draw on some ideas expressed in the stratospheric thread and artic sea ice thread. I guess you would be the best person to explain all this GP but for those who don't know this thread is about global angular momentum and how it oscialltes up and down (Global Wind Oscillation) along the lines discussed by Ed Berry.
Angular momentum is of course a measure of the turning force in the winds, so could perhaps be considered a measure of the strength of low pressure systems, but also relates to how much the jetstream undulates and how much blocking we have.
The budget of angular momentum goes up and down as energy is lost as weather systems crash into mountains and increases as cold air meets warm. Each phase of increasing and decreasing momentum suggests different types of weather for the UK. Looking at the current GWO plot we see a liklihood of going into phases 3 and 4 based on how it usually cycles round.
This implies increasing angular momentum as the various torques including mountain torque diminish (i.e those things which take energy out are not active).
This is certainly true of mountain torque.
For frictional torque and gravity wave torque then the jury is out.
Overall it looks like global angular momentum is on the increase.
The tendecy during december has been upwards.
Short term I think we are looking at phases 3-4 and more of an Atlantic influence. What I am guessing at though is that low pressure systems crossing the US will increase mountain torque, equally the jet stream across india is not a weak flabby one which might increase asian mountain torque. The strong jet in the western pacific along with OLR charts suggest strong trade winds with a stationary high to the north east of Australia and convectional activity to the north west of Australia. So back to phase 1-2 fairly quickly I think afterwards.
All maps are available in the link below.
I am sure GP will tell us what he expects from the MJO and convectional activity in the pacific and how and if he expects rossby wave development as a result. It is those Rossby waves which in part will affect the stratospheric vortex and the low angular momentum could be linked to a more blocked pattern and sea ice build up to our north which I talked about in associated threads.
What we should always remember though that this a complex interaction of parts of which the stratosphere plays a large part during the winter.
Please note that this post and subsequent comments have been copied from the forum, so the dates/times of the comments are not correct.
Edited by Paul