The Weather Review

Weather Update

October was mainly unsettled, featuring a high-pressure system mid-month that lead to high energy prices.

The majority of the month has been impacted by tropical maritime air masses that brought storms and rain. This is typical of early winter, as summer and autumn sunlight has heated the Atlantic Ocean, creating low pressure and hot moist air. This and a low jet stream can lead to cyclones and hurricanes. While the UK does not often experience the most violent storms, we have had varied winds and high precipitation, as these systems make landfall and dissipate.

As predicted in last month’s review, mid-month we did see temperatures drop briefly and wind fall away, as a high-pressure system prevented air from rising over the southern UK. During this time, the lack of cheap renewable energy impacted power prices in the short term. Despite this National Grid did not issue warnings as it had in September and was able to use gas for extra power due to the lack of heating demand through the month.

As mentioned, October was warmer than average, with temperatures reaching as high as 15 degrees Celsius (averages for previous years were closer to 10). There are two reasons for this. The first is that weather patterns meant warmer airmasses were drawn from southern Europe. The second is due to warmer waters in the Arctic.

 The amount of Arctic sea ice in September was the 2nd lowest on record. According to climate scientists, sea ice coverage is a major driver of climate and weather patterns that affect the UK and is expected to affect weather this winter. Less sea ice leads to warmer waters in the Arctic, as ice reflects sunlight much better than sea water. There is then a smaller difference in temperature and pressure between the Atlantic Ocean and the Arctic. As the difference reduces, the jet stream can meander and drift lower than usual, bringing strong winds and low pressure close to the UK. This often results in milder, windier weather. The most recent winter outlook anticipates this winter to be milder than average with only a 20% chance of any extreme cold or low wind systems in any given month.

Looking to November, high pressure is expected to be slightly more dominant across the UK. While this may reduce wind level, temperatures are not expected to be extreme in either direction, with the main high pressure just missing us. High pressure may lead to regular mist and fog warnings. Lockdown measures and dry weather in Europe, combined with the lower wind could mean National Grid struggle on some days in terms of power delivery. However, the last week of November is forecast to have major gales as low pressure returns.