Lijkt wel Ronald, alsof hij heeft mee gekeken 
Very interesting nuances developing in longer range stuff over the last couple of days. Remember waxing and waning.
We have a developing (anomalous) high pressure cell over Siberia. This is Cohen's first response to anomalous snow cover advance in October. The eastern flank of this has begun to pull the blocking structure over Kamchatka back west.
We also are seeing developing anomalous ridge over wester Russia and eastern Europe in response to lowering heights over Greenland phasing with a longwave trough digging through the North Atlantic. This has important potential ramifications w/r/t stratospheric temperatures in December.
I agree with the sentiments above, the weakness in NWP to place and model troughing in the Atlantic this year. We are likely to see any toughing further south the closer we get, allowing for trough disruption and downstream ridges to get reinforced. We are now effectively early into a winter synoptic, and models are generally pretty weak with the presence of a strong Siberian High pressure cell.
That sets us up with an intriguing prospect. Heights building over the far NE and long term signal to restrogress the ridge towards Greenland (waxing).
Longer term still sees CFS week 4 advertising Greenland High, and NAEFS also leading to this with the rebuilding of a wavelength lead by Kamchatkan ridge. http://forum.netweather.tv/topic/74817-model-output-discussion-2610-2012/page__st__540#entry2397130
& edit onderstaande bijdrage nog erbij
Might be worth keeping on Wave 2 forecasts in about 10 days time.
Longer range modelling is keen to split the developing high pressure cell over Siberia and develop a strong ridge over western Russia and eastern Europe. That's in the 'sweet spot' for wave 2 direction poleward. Current modelling has this development around 11th November. Add 20 days for stratospheric impact, and that gives us a date of around 1st December for earliest sign of vortex split.
http://forum.netweather.tv/topic/74587-stratosphere-temperature-watch-20122013/page__st__440#entry2397122
Deed mij denken aan onderstaande onderzoek:
Many tropospheric Arctic Oscillation (AO) events are preceded by stratospheric AO events and even earlier in time by anomalous upward energy flux associated with Rossby waves in the troposphere. This study identifies lower-tropospheric circulation anomalies that precede largeAOevents in both the troposphere and stratosphere and the anomalous upward energy flux. Compositing analysis of stratospheric warming events identifies regional tropospheric precursors, which precede stratospheric warmings. The tropospheric precursor is found to vary when compositing over polar vortex displacements and splits separately. Prior to vortex displacements the main anomaly sea level pressure center of the tropospheric precursor is located across northwest Eurasia and is associated with the Siberian high. Prior to vortex splits a similar anomaly center is identified in the tropospheric precursor but is weaker and appears to be more strongly related to a shift in the storm tracks. Differences in the sea level pressure anomalies in the North Atlantic and the North Pacific are also observed when comparing the precursors prior to vortex displacements and splits.
Identification of a unique tropospheric precursor to stratospheric warming and subsequent tropospheric AO events can help to improve understanding troposphere–stratosphere coupling. Furthermore, the observational evidence presented here can be compared with model simulations of winter climate variability and lead to potential model improvements. http://web.mit.edu/jlcohen/www/papers/CohenandJones_JC12.pdf
Very interesting nuances developing in longer range stuff over the last couple of days. Remember waxing and waning.
We have a developing (anomalous) high pressure cell over Siberia. This is Cohen's first response to anomalous snow cover advance in October. The eastern flank of this has begun to pull the blocking structure over Kamchatka back west.
We also are seeing developing anomalous ridge over wester Russia and eastern Europe in response to lowering heights over Greenland phasing with a longwave trough digging through the North Atlantic. This has important potential ramifications w/r/t stratospheric temperatures in December.
I agree with the sentiments above, the weakness in NWP to place and model troughing in the Atlantic this year. We are likely to see any toughing further south the closer we get, allowing for trough disruption and downstream ridges to get reinforced. We are now effectively early into a winter synoptic, and models are generally pretty weak with the presence of a strong Siberian High pressure cell.
That sets us up with an intriguing prospect. Heights building over the far NE and long term signal to restrogress the ridge towards Greenland (waxing).
Longer term still sees CFS week 4 advertising Greenland High, and NAEFS also leading to this with the rebuilding of a wavelength lead by Kamchatkan ridge. http://forum.netweather.tv/topic/74817-model-output-discussion-2610-2012/page__st__540#entry2397130
& edit onderstaande bijdrage nog erbij
Might be worth keeping on Wave 2 forecasts in about 10 days time.
Longer range modelling is keen to split the developing high pressure cell over Siberia and develop a strong ridge over western Russia and eastern Europe. That's in the 'sweet spot' for wave 2 direction poleward. Current modelling has this development around 11th November. Add 20 days for stratospheric impact, and that gives us a date of around 1st December for earliest sign of vortex split.
http://forum.netweather.tv/topic/74587-stratosphere-temperature-watch-20122013/page__st__440#entry2397122
Deed mij denken aan onderstaande onderzoek:
Many tropospheric Arctic Oscillation (AO) events are preceded by stratospheric AO events and even earlier in time by anomalous upward energy flux associated with Rossby waves in the troposphere. This study identifies lower-tropospheric circulation anomalies that precede largeAOevents in both the troposphere and stratosphere and the anomalous upward energy flux. Compositing analysis of stratospheric warming events identifies regional tropospheric precursors, which precede stratospheric warmings. The tropospheric precursor is found to vary when compositing over polar vortex displacements and splits separately. Prior to vortex displacements the main anomaly sea level pressure center of the tropospheric precursor is located across northwest Eurasia and is associated with the Siberian high. Prior to vortex splits a similar anomaly center is identified in the tropospheric precursor but is weaker and appears to be more strongly related to a shift in the storm tracks. Differences in the sea level pressure anomalies in the North Atlantic and the North Pacific are also observed when comparing the precursors prior to vortex displacements and splits.
Identification of a unique tropospheric precursor to stratospheric warming and subsequent tropospheric AO events can help to improve understanding troposphere–stratosphere coupling. Furthermore, the observational evidence presented here can be compared with model simulations of winter climate variability and lead to potential model improvements. http://web.mit.edu/jlcohen/www/papers/CohenandJones_JC12.pdf
Bericht laatst bijgewerkt: 04-11-2012 14:32
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