Op basis van de stratosfeer is het niet erg waarschijnlijk dat het nog tot noordelijke blokkades komt, maar dat de blokkades van 'boven' 'afgeroomd' worden door depressies. Heel normaal in positieve QBO winter.
Temperatures in the stratosphere
One of the key elements of last winter’s cold weather was above average temperatures in the upper atmosphere high over the Arctic which promoted ‘blocking’ highs displacing polar air into Europe.
This year we expect the combination of low solar activity and a westerly wind over the Tropics to be less conducive to blocking highs with colder than normal atmosphere over the Arctic driving polar westerlies which tend to favour blocking highs further south around the UK.
Seasonal Model Guidance (Climate Forecast System)
Model guidance is for high pressure close to or north and west of the UK for the majority of the winter with a slight tendency to shift further away to the west during February.
Model sees average or slightly colder than average temperatures for the UK, coldest in the south-east and mildest in the north with central Europe slightly below average.
Model sees rainfall below average.
Good consistency between model updates and output appears to be consistent with historical analogue guidance adding confidence to forecast.
Winter Forecast details
December
High pressure likely to be centred to the north-west of the UK with winds from the north-west with northerly interludes.
Temperatures likely to be below average, the largest departure of the three months compared to long term averages with the coldest temperatures in the south-east. Rainfall likely to be much below average.
January
Large area of high pressure in the central Atlantic gradually edging towards the UK although an unsettled phase likely with potential for snow, particularly in western areas. Likely to be cold to start with fog and frost persistent. Rainfall below average.
February
High pressure centred over the UK with a lot of settled weather. Temperatures likely to be slightly above average although surface temperatures may be depressed by fog and cloud.
http://www.netweather.tv/index.cgi?action=other;type=winter-forecast;sess=
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