Wanstead colder than Aviemore

January 17, 2022 wansteadmeteo Leave a comment

That’s not a statement that applies much, least of all the second week of January. But the current weather pattern has seen this town in the Highlands subject to the warming influence of the Atlantic, to a higher degree than London.

The above 850mb chart, typical of the past week, shows the warmer air aloft and the south of the UK seemingly cut off from outside influence.

Indeed, lack of solar heating at this time of year ensures that any thermal activity is minimal – with very little mixing of the boundary layers by day.

Wanstead Park, being a frost hollow, has seen this phenomena most days during the past week with this part of London markedly colder than elsewhere in the capital.

By the 16th the 7-day running mean at Aviemore was 2.4C higher than Wanstead!

Volcanic eruption

Tonga volcano pressure wave

January 16, 2022 wansteadmeteo Leave a comment

The underwater volcanic eruption near Tonga, along with a tsunami, sent shockwaves around the world.

The eruption at 0410 GMT was felt in Wanstead some 15 hours later. By my calculation the blast some 10,304 miles distant would have travelled around 687 mph, slower than the speed of sound which is 767 mph.

The plot can be seen below.

Mountaineering, Ski touring, UK snowfall, Weather

SMC’s 1978 Scottish Haute Route

January 10, 2022 wansteadmeteo Leave a comment

This mountaineering challenge was first drawn to my attention by Iain Cameron’s Flickr post featuring the Scottish Mountaineering Club’s week long tour from Balmoral to Glen Nevis.

It’s a fascinating feat that was repeated in 2010 by father and son team, Roger and Finlay Wild. Alas, the weather has not allowed the achievement again, at least on skis.

I’d often wondered about what sort of snow you’d need to complete and recently discovered a feature on Ogimet that can scrape old weather data and place it into a table.

Just look at the snow depths below! As the SMC account says the participants would have been better undertaking the tour a week earlier, rather than starting four days into a thaw. The depths in earlier February, however, illustrate just how good the conditions would have been, compared with today!