After Ireland had such a dry and fairly warm Summer overall the pattern of weather that Autumn has greeted us with has come as a bit of a shock to the system. There has been rain on most days and no sign at all of any dry weather.
But what is causing all this? Let's go through some of the causes step by step.
1. The sea temperatures.
Over the Summer the sea temperatures had been very warm. However as High Pressure was over or near Ireland at this time the moisture being built up over the warm Oceans was kept well off our shores. When eventually the next Low was to come it would bring quite large rainfall amounts. So if all this rainfall then has fallen why are we still getting more.
2. The pressure
Unfortunately the High that was over us in the Summer has simply migrated slightly East to Europe meaning that Ireland is stuck with a conveyor belt of low pressure systems driving rain to our shores. But how come there's so many lows? I thought there was only one or two low pressure systems at a time.
3. The Dumbbell Effect
What the hell is the dumbell effect I hear you cry. Well it's the name given as the same low pressure system keeps reinvigorating itself as it has nowhere to go due to the high pressure to the East of the UK (where they are also seeing endless rain). So why is the rain so heavy and thundery? Doesn't this just happen in High Summer?
4. "High" temperatures
The High Pressure that lies over Europe is drawing up very warm air as we have seen over parts of Europe in the past week with temperatures of 30.3c in San Sebastian and 35c in Seville and 32c in France. To the West of the High the Low Pressure systems are pushing cooler air but as it meets the drier warmer air convection is occurring causing sparks and very heavy rain. So is there any reason why suddenly from being so quiet that the weather has taken such a nasty turn?
5. The Jet Stream
We often hear Met Eireann and the UK Met Office talk about how the jetstream affects our weather. Well here at weathergossip just think of it this way. If the jet is weak or to our North we tend to get benign weather but an active jet like we have now causes very unsettled weather when it is near or over Ireland. Think Summers 2007 to 2012. Yes yuk. OK so are we stuck with this unsettled weather?
6. Nothing lasts forever...even cold November rain
Well that's what Guns and Roses told us and maybe they had a point. Despite the fact that it seems like the weather is going to be endlessly unsettled due to these "dumbbell lows" it more than likely won't be. So what is going to end this period of unsettled wet weather? Read on
7. How this unsettled weather will likely end
The weather came from the South during most of October Repeated rainfall from the South can last weeks on end pressed up against such a strong high. But there has been a bit of a pattern shift. We have seen a more Southwesterly pattern emerge and this could mean things beginning to settle down around mid November especially in the South and East. There is still likely to be light rain or drizzle in the West and North but with lighter winds later in November temperatures should improve into the mid teens. So get over the next 10 days and things should begin to dry out then.
