http://www.metoffice.gov.uk/media/pdf/k/s/A3-plots-temp-SON.pdf
http://www.metoffice.gov.uk/media/pdf/i/e/A3-plots-precip-SON.pdf
The Met Office contingency planners forecast now covers the period of September to November
Temperature Summary
The balance of probabilities suggests that September will be slightly warmer than average whilst for the period September-October-November UK-averaged temperatures will be near the 1981-2010 climate mean.
The probability that UK-mean temperature for the September-October-November period will fall into the coldest of our five categories is around 20% whilst the probability that it will fall into the warmest of our five categories is around 15% (the 1981-2010 probability for each of these categories is 20%).
Detailed outlook
Development of weak to moderate El Niño conditions is currently underway in the equatorial Pacific, although the atmospheric conditions do not yet display the typical characteristics of such an event. Therefore no clear influence on the likely weather pattern over Europe can be anticipated at this stage. It is noteworthy that Arctic sea ice coverage has now reached exceptionally low values and is already approaching the record low amount observed in 2007.
Research is currently in progress to ascertain how this might influence the weather patterns around the UK. Computer models show reasonable consistency in the overall dominance of higher-than-normal pressure across the UK (and northern Europe) in September; this usually favors above normal temperatures. Although the skill of long-range forecasting models for this time of year is relatively limited, the current sea surface temperature pattern in the eastern Atlantic would normally favor a bias towards such a blocked pattern. For September-October-November as a whole, the models tend towards slightly higher than average pressure over northern Europe, with the seasonal-mean temperature likely to be near average.
Autumn is a transitional time of year in which a given circulation pattern can result in very different temperature outcomes between the beginning and end of the season. For example, a settled
weather pattern in September usually results in above normal temperatures whilst a similar pattern in November would usually yield colder-than average conditions. Therefore, although near-average temperatures are favored over the season as a whole, this does not exclude spells of unusually warm or cold weather. Shorter-period forecasts should therefore be monitored on a regular basis for additional details.
Rainfall Summary
For UK averaged rainfall the predicted probabilities weakly favor below normal values during September. For the period September - October - November as a whole the forecast favors a slightly higher than usual risk of above average rainfall, whilst the risk of dry conditions remains around climatological levels. The probability that UK rainfall for September - October - November will fall into the driest of our five categories is around 20% whilst the probability that it will fall into the wettest of our five categories in around 25% (the 19812010 probability for each of these categories is 20%).
Detailed Outlook
Computer models show reasonable consistency in the overall dominance of higher than normal pressure across the UK in September, which normally favors drier than average conditions. However, in the forecast there is a large range of possible outcomes (pink points on the left hand panel of figure P2). Following a predominantly unsettled end to August, there are already significant uncertainties in the rainfall pattern going into September. Although the September - October - November mean pressure patterns slightly favor higher than normal pressure over northern Europe, the forecast suggests some periods of
unsettled weather. If these occur in October they can produce heavy rain because the surrounding ocean is still warm, potentially off setting a drier than average September. On balance there is a slightly enhanced risk of wetter than average conditions for the whole 3month period the probability of a drier than average season for the UK as a whole is at climatological levels. Regional variations in forecast rainfall relative to long term averages cannot be specified. Therefore, shorter period forecasts should be monitored on a regular basis for additional
http://www.metoffice.gov.uk/media/pdf/i/e/A3-plots-precip-SON.pdf
The Met Office contingency planners forecast now covers the period of September to November
Temperature Summary
The balance of probabilities suggests that September will be slightly warmer than average whilst for the period September-October-November UK-averaged temperatures will be near the 1981-2010 climate mean.
The probability that UK-mean temperature for the September-October-November period will fall into the coldest of our five categories is around 20% whilst the probability that it will fall into the warmest of our five categories is around 15% (the 1981-2010 probability for each of these categories is 20%).
Detailed outlook
Development of weak to moderate El Niño conditions is currently underway in the equatorial Pacific, although the atmospheric conditions do not yet display the typical characteristics of such an event. Therefore no clear influence on the likely weather pattern over Europe can be anticipated at this stage. It is noteworthy that Arctic sea ice coverage has now reached exceptionally low values and is already approaching the record low amount observed in 2007.
Research is currently in progress to ascertain how this might influence the weather patterns around the UK. Computer models show reasonable consistency in the overall dominance of higher-than-normal pressure across the UK (and northern Europe) in September; this usually favors above normal temperatures. Although the skill of long-range forecasting models for this time of year is relatively limited, the current sea surface temperature pattern in the eastern Atlantic would normally favor a bias towards such a blocked pattern. For September-October-November as a whole, the models tend towards slightly higher than average pressure over northern Europe, with the seasonal-mean temperature likely to be near average.
Autumn is a transitional time of year in which a given circulation pattern can result in very different temperature outcomes between the beginning and end of the season. For example, a settled
weather pattern in September usually results in above normal temperatures whilst a similar pattern in November would usually yield colder-than average conditions. Therefore, although near-average temperatures are favored over the season as a whole, this does not exclude spells of unusually warm or cold weather. Shorter-period forecasts should therefore be monitored on a regular basis for additional details.
Rainfall Summary
For UK averaged rainfall the predicted probabilities weakly favor below normal values during September. For the period September - October - November as a whole the forecast favors a slightly higher than usual risk of above average rainfall, whilst the risk of dry conditions remains around climatological levels. The probability that UK rainfall for September - October - November will fall into the driest of our five categories is around 20% whilst the probability that it will fall into the wettest of our five categories in around 25% (the 19812010 probability for each of these categories is 20%).
Detailed Outlook
Computer models show reasonable consistency in the overall dominance of higher than normal pressure across the UK in September, which normally favors drier than average conditions. However, in the forecast there is a large range of possible outcomes (pink points on the left hand panel of figure P2). Following a predominantly unsettled end to August, there are already significant uncertainties in the rainfall pattern going into September. Although the September - October - November mean pressure patterns slightly favor higher than normal pressure over northern Europe, the forecast suggests some periods of
unsettled weather. If these occur in October they can produce heavy rain because the surrounding ocean is still warm, potentially off setting a drier than average September. On balance there is a slightly enhanced risk of wetter than average conditions for the whole 3month period the probability of a drier than average season for the UK as a whole is at climatological levels. Regional variations in forecast rainfall relative to long term averages cannot be specified. Therefore, shorter period forecasts should be monitored on a regular basis for additional
„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."
