Op het Britse forum van netweather zijn de discussies over de aanstaande winter in alle hevigheid begonnen.
Aantal punten die opvallen.
1) La Nina is forecast to return by the winter, the latest charts show this (a double dip La Nina is common in -PDO years). With a weak to moderate La Nina with favourable QBO, this is possible good news for Winter prospects
2) The QBO is expected to be the reverse of last year which should aid in high lattitude blocking.
3) The jet stream always wanders about .... don't get any of your arguments here. However, it has this year been again (as for the past few years) in an unusually South position relative to the Norm. Yes, its forecast to move North next week (good news for a possible warm August if it stays that way), but overall the trend has been the same as for the past few years during summer months.
4) Take a look at the Atlantic SST's ...... looking cold.
5) Solar activity is still very very very low ..... it has incrseased against a bckground of next to nothing. Did you not look at the references posted !!
6) The last few years has seen high Northern lattitude volcanic activity ...... the effects of which do not dissapear overnight !.
Reactie hierop
1) La Nina conditions weakened rapidly in spring due to the record breaking final warming which took place during April, the result of this was a an increase in tropical convection which has led to the weakening of La Nina. SOI readings are still barely below 0 and as a result the development of the -QBO during July and August is likely to lead to redevelopment of La Nina although modeling does suggest a weak to moderate outcome is probable.
2) You are correct in point 2 and in regards to September/October i do agree with you however the Azores High has stayed over the Azores because of persistant blocking over the pole during May/June and has been negativly tilted for the most part resulting in what in winter would be described as 'cold' zonality rather than the Bartlett High. The sea surface temperature anomoly pattern in the Atlantic has also played its part.
3) Local SST's make no difference to the larger synoptic pattern. Especially when you consider that we have a huge -2C anomoly west of Ireland and France which we did not have last year. This is also a factor in keeping the Azores High west of the UK.
4) The solar minimum occured in 2008 and yet we have seen three below average winters on the trot. There is evidence to suggest that higher solar activity actually amplifies the effects of a -QBO (statospheric warming) while low solar activity amplifies the effect of +QBO waves. Anologues suggest that solar maximum is 1 to 3 years away.
5) Agreed, while SO2 can have an effect, it is best to ignore the effects in regards to the weather unless we get a Krakatoa.
In summary, i agree with a stormy Autumn (mid August to mid October could be very wet and windy in my opinion) however i disagree with winter. A -QBO coupled with a weak La Nina gives a strong signal for early statospheric warming.
Aantal punten die opvallen.
1) La Nina is forecast to return by the winter, the latest charts show this (a double dip La Nina is common in -PDO years). With a weak to moderate La Nina with favourable QBO, this is possible good news for Winter prospects
2) The QBO is expected to be the reverse of last year which should aid in high lattitude blocking.
3) The jet stream always wanders about .... don't get any of your arguments here. However, it has this year been again (as for the past few years) in an unusually South position relative to the Norm. Yes, its forecast to move North next week (good news for a possible warm August if it stays that way), but overall the trend has been the same as for the past few years during summer months.
4) Take a look at the Atlantic SST's ...... looking cold.
5) Solar activity is still very very very low ..... it has incrseased against a bckground of next to nothing. Did you not look at the references posted !!
6) The last few years has seen high Northern lattitude volcanic activity ...... the effects of which do not dissapear overnight !.
Reactie hierop
1) La Nina conditions weakened rapidly in spring due to the record breaking final warming which took place during April, the result of this was a an increase in tropical convection which has led to the weakening of La Nina. SOI readings are still barely below 0 and as a result the development of the -QBO during July and August is likely to lead to redevelopment of La Nina although modeling does suggest a weak to moderate outcome is probable.
2) You are correct in point 2 and in regards to September/October i do agree with you however the Azores High has stayed over the Azores because of persistant blocking over the pole during May/June and has been negativly tilted for the most part resulting in what in winter would be described as 'cold' zonality rather than the Bartlett High. The sea surface temperature anomoly pattern in the Atlantic has also played its part.
3) Local SST's make no difference to the larger synoptic pattern. Especially when you consider that we have a huge -2C anomoly west of Ireland and France which we did not have last year. This is also a factor in keeping the Azores High west of the UK.
4) The solar minimum occured in 2008 and yet we have seen three below average winters on the trot. There is evidence to suggest that higher solar activity actually amplifies the effects of a -QBO (statospheric warming) while low solar activity amplifies the effect of +QBO waves. Anologues suggest that solar maximum is 1 to 3 years away.
5) Agreed, while SO2 can have an effect, it is best to ignore the effects in regards to the weather unless we get a Krakatoa.
In summary, i agree with a stormy Autumn (mid August to mid October could be very wet and windy in my opinion) however i disagree with winter. A -QBO coupled with a weak La Nina gives a strong signal for early statospheric warming.
„Et nul ne se connait tant qu'il n'a pas souffert, „C'est une dure loi, mais une loi suprème, „Vieille comme le monde et la fatalité, „Qu'l nous faut du malheur regevoir le baptéme, ~Et qu'a ce triste prix tout doit étre acheté. „Les moissons pour murir out besoin de rosée, „Pour vivre et pour sentir l'homme a besoin de pleura, „La joie a pour symbole une plante brisée, „Humide encore de pluie et couverte de fleurs."
?!