This means that even with the presence of factors potentially juxtaposed towards a neutral or negative NAO, there will likely be a background climate change modulation of these factors towards a milder outcome.
The best of the drier intervals are expected in southern and central regions. This may suggest the presence of a -NAO “background signal” within the atmosphere at this stage.
email. Through the Autumn of 2010, significant surface decay of the warm sea surface temperatures occurred over the central tripole belt.
The following chart, with depth placed on the left axis nicely shows this re-emergence into the winter of 2010. Causes for this can’t be absolutely narrowed down, however at a surface-level this is likely related to inflation of the Azores high and resultant more northerly track of the jet stream. These cold surface temperatures can become “masked” over the summer only to re-emerge during December. So, confidence that the SSTs will redevelop into a tripole-“esque” pattern for Winter 2020 is low. Because the harsh winters of 2009 and 2010 occurred right around (2009) and just after (2010) solar cycle 23-24 minimum, I would like to explore the link between solar minimum and solar maximum using more recent data.
Causes for this can’t be absolutely narrowed down, however at a surface-level this is likely related to inflation of the Azores high and resultant more northerly track of the jet stream. Nontheless, this winter certainly makes a bold statement via it’s La Nina + solar minimum combination and thus likely stands in the highest 30% class if ranking winters based on their factor juxtaposition towards a negative NAO. Forecast Issued 31/08/2020. All of this and more in our first winter forecast 2020 – 2021. Northern regions have wet and windy periods and during the middle part of the week rain is likely to affect southern counties too. 1.6k shares 16hr ago ALL. The C.E.T average for winters with moderate or high solar activity is 5.2C. Solar activity has a significant influence on jet stream behavior, via a process known as down-welling which is the pressure-induced warming of lower layers of the atmosphere following a SSW. We now know what La Nina is, and how it impacts the jet stream.
send. The theme is expected to be an unsettled one with wet and windy conditions prevailing. A reasonable start to the month is likely in the southern half of the UK with above average temperatures and quite a lot of dry weather. Powder Alert: 1-2 FEET of Snow For Many Ski Resorts Across The West 15k shares 21hr ago ALL.
In the north more changeable conditions are forecast and gradually they spread southeastwards with an increasing chance of wet and windy spells.
Slightly above the 30 year average taken over the three month period as a whole. Furthermore, for solar minimum winters characterized by a La Nina the winter C.E.T average was 3.5C which is significantly below the average, compared to solar minimum + El Nino which yields 4.3C. Colder snaps in northern regions bring the possibility of sleet or snow, especially over higher ground. The best of the drier spells are likely to be in southern and central regions. Theory: solar minimum and just after solar minimum. Taken as a whole a milder and wetter than average autumn is favoured. This is for information purposes only and likely any other probabilistic forecast, it is not definite and occurrence of any of the 3 classes outlined is possible. Spring - March 1st, Summer - June 1st, Autumn - September 1st, Winter - December 1st. Interestingly, the temperature increased greatly towards strong La Nina events which have an average C.E.T of 5.2C. 2) Other sea surface temperature anomalies. This can be seen nicely on NOAA Sea Surface temperature anomaly maps from May (left), August (centre) and December (right) on the image below.
pin.
We decided to focus on the 3 main (or most used) seasonal models.
At other times the south should be mostly dry. Due to the earlier weak signals, may be that some tripole signal does exist, however it somewhat fragmented. However, due to uncertainties in the method and due to climate change a reduction of 10% seems apparent. Temperatures are forecast to be slightly above average over the period as a whole. Using links between “factors” and likely NAO outcomes, it can still be suggested when occurrence of this 15% probabilistic risk is more or less likely. It has been discussed by some that the strange QBO behavior is in association with expansion of the Azores high (mild signal), however I will leave this for later discussion. The average winter C.E.T for winters which have ENSO values between 0.6 and 1.2C below normal is 3.8C, which is slightly below average. I have used solar cycles 21 to 24 for this.