Atmospheric Dynamics @ St Andrews
Simon H. Lee, School of Earth and Environmental Sciences
In global-mean terms, 2026 has been hot, but 2027 will be even hotter. Not just because of the long-term upwards trend in global temperatures, but because a Super El Niño is developing (perhaps becoming stronger than any previously observed; also sometimes bizarrely referred to as a "Godzilla" El Niño). Barring some colossal tropical volcanic eruption, …
Continue reading "Is a globally warm year a locally warm year?"
Fifty years on from the infamous 1976 heatwave, the UK looks set to experience its hottest June day on record – exceeding the maximum of 35.6°C set on 28 June 1976. Extreme summertime heat has quickly become much more common in the UK in recent years. There are myriad ways of demonstrating this, which I …
Meteorologists have a historical penchant for giving names to atmospheric phenomena which, in today's world, sound rather like phrases made up to fit a dramatic headline than real scientific terminology. Bomb cyclone or sting jet are two leading examples. Another term, which has become increasingly used and misused in the wider media in the past …
Twitter was once a great place for science. Specifically, it was a great place for meteorology and climate science, because it enabled real-time discussion of ongoing events which could very quickly reach the public and the media, as well as other scientists. I first became fully aware of the power of the platform in late …
The most commonly-used diagnostic of the strength of the stratospheric polar vortex is the zonal-mean zonal wind at 10 hPa (~30 km) and 60°N (U10-60), which is westerly during winter. It is an easy diagnostic to compute and understand, which probably helped drive its uptake. Reversals of U10-60 to easterlies indicate either a major sudden …
Continue reading "The importance of the polar vortex at 100 hPa"
Only a few years ago, ECMWF's then-twice-weekly 51-member extended-range forecasts were not publicly available -- something that is almost hard to comprehend nowadays, as we have daily, 101-member ensemble forecasts available for free on the ECMWF website. The ensemble size is spectacular, and increases forecast reliability. But I'm more interested in what we gain from …
Continue reading "What’s that coming over the hill, is it a weak vortex?"
Over the last four years (where does the time go?!), I've been working extensively on understanding weather regimes over North America. With our new paper recently published in Journal of Climate, I thought now might be a good time to link together all the publications in one short blog post. Weather regimes represent recurrent, persistent …
Continue reading "North American weather regimes: a summary (so far)"
Currently, the highest officially recorded temperature in the UK is 38.7°C, recorded at Cambridge Botanic Garden on 25 July 2019. Prior to that, the record was 38.5°C (10 August 2003 in Faversham, Kent), which beat the record of 37.1°C set on 3 August 1990 in Cheltenham, Gloucestershire. Before the 1990 heatwave, the record had stood …
I received my PhD from the University of Reading on 29 October 2021, and on 14 November I moved to New York City to start a new job as a Postdoctoral Research Scientist at Columbia University. Somehow, six months have passed since then, and I've been reflecting this week on my time as a postdoc …
Apologies for the long gap between blog updates. But since today's weather in NYC has descended into a snowy, sleety mess, I thought today would be a good day for a blog. Saturday 12 March 2022 Summary: It is increasingly likely that the final stratospheric warming will occur soon, but forecast uncertainty remains large. A …