Flip In Pressure Pattern Brings Back Atlantic Westerlies

For the past 2 weeks we have enjoyed very settled conditions, if somewhat cool. This has been due high pressure over the North Sea feeding in a cooler but stable easterly flow, which has been slack for the most part. Things are changing, however, and normal business has resumed.

The charts below show the pressure distribution relative to mean values for both the past 10 days and the next 10 days.

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ECMWF surface pressure anomaly forecast for the next 10 days. Image from Vedur.is

Note how pressure has been higher than normal over much of northern Europe, with the normal westerly flow deflected well off to our northwest. This has meant settled conditions with very weak winds, a setup which leads to foggy or very cloudy conditions at this time of year. Rainfall has only been a fraction of the average value for mid October.

Contrast that to the forecast for the next 10 days. The pattern has now shifted, allowing back in those strong westerlies and their feed of low-pressure systems. We got the first of these overnight, with a warm front bringing rain and strong winds, but also a marked rise in temperature. This will ebb and flow as systems come and go, and there is a chance of the first wintry  weather on high ground next week.

October is a month of transition, so these kinds of pattern-flips are common. How things will play out in the coming months is the question on everybody’s lips, but you would do well to take most of the conjecture with a pinch of salt and just buckle up and enjoy whatever the ride will be.

Well ok, if you still want to read a more thought-out forecast then keep an eye on Peter’s winter forecast, the first installment of which can be read here.

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One thought on “Flip In Pressure Pattern Brings Back Atlantic Westerlies

  1. I don’t mind where the winds are from… just as long as the blow the clouds away before sunrise tomorrow… I’d dearly love to get a look at the remnants of the meteor shower! 😉

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