A Pembrokeshire Dangler

I checked the weather app on my phone last night and noticed the unmistakable cloud formation over the Irish Sea known as a Pembrokshire Dangler:

The Dangler is the strip of rain  over the Irish Sea extending North from the Pembrokeshire coast in Wales. I knew I had mentioned this phenomenon before on this blog and when I check it turns out to have been almost exactly four years ago. That’s not very surprising as winter is definitely the season for dangling. There has been a northerly airflow over Ireland for a few days now, which is why it has been so cold here, though in relatively sheltered Maynooth we have been spared the worst of the effects of Storm Arwen.

The situation required for the formation of a Pembrokeshire Dangler (which quite often involves snow rather than rain) is a cold northerly airflow down into the Irish Sea from the Arctic. This combines with slightly warmer air in the form of land breezes from the Irish coast to the North West and the Scottish coast to the North East, funneling the airflow into a narrow channel over the Irish Sea in which convection cells form, leading to precipitation. The configuration is quite stable as long as the dominant northerly airflow continues so although the strip of cloud tends to persist for some time once it has formed.

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