Evening -
Well just a minor update -
After a bit of a rollercoaster for the models last week the prospects of more 'unseasonal' blocking continues to tease us like one of the old 1p ' look what the butler saw reels' - lets hope our money doesnt run out when we get to December !!!
We have seen a very sedated vortex early doors this year & as highlighted before October is knocking on the door of a 66 year record - IE the -AO. Whilst perhaps its not a significant record for the UK - in the bigger picture, especially Up past 60N - This is a significant record. It shows a very disjointed & fragmented Vortex.
The record for the month is -1.5 & he were are at the 22nd -
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml I would say -2 by the 25th is a realistic figure & with a significant trend across today from the 00z ( used for the AO ) to the 12z has been all 1 way..- building a bigger block.
So based on this I think the landing zone will be around -2.25. A record breaker & the only October in history sub -2.
As said - 1 swallow doesnt make a Summer, however today we have seen that potentially for the opener to November the AO/NAO is ramped !
The models are reacting to the overall ensemble mean around that all important 60N zonal wind - This is basically the end result of all the feedbacks fed upwards & downwards into the atmosphere.
I need to go a check what constitutes what speed represents a negative zonal wind however we may be close after todays modelling -
http://www.atmos.albany.edu/student/hattard/realtime/u_65N_10hpa.png This is significant dropping below 1 standard deviation from Climotology - & with a double dip - the possibility of dropping past 2.
The strat is also reflecting a split now at day 7 - which is very very different to the October mean
http://www.atmos.albany.edu/student/hattard/realtime/nh_strat/nh_stanom.php Anyway, more strat features come online for November - from the Berlin site. Which will give us a clearer picture-
So - in a nutshell we are in the best possible place we could ever be on the entry to November.
Also PS - as regards svalbard snowcover,I agree with a post above- the recent october Blocking tendancies have put Svalbard in almost exactly the wrong position for October snow with all the cold going to the East & south of that locale ... for them the Oct snow has almost been wiped off the map in a matter if years !
Cheers