New research could make it easier to predict path of devastating megastorms

New research will make it easier to predict the path of some of the world’s most powerful storms, helping communities protect themselves from flooding, the UK Centre for Ecology & Hydrology (UKCEH) said Monday.

It had been believed the path of such potentially catastrophic events – known scientifically as mesoscale convective systems (MCS) – was largely unpredictable, but the study shows land surface “frequently affect[s] the direction and intensity of these ‘megastorms’”.

UKCEH’s Dr Cornelia Klein, lead author of the new study, explained that once storms were moving it was thought they were not affected by the state of the ground: “However, we found that drier soils increased the intensity of an MCS mid-storm, affecting the amount of rainfall they release and also where they travel.

“Conversely, we found storms were often weakened over moister soils [and] for the first time, we can predict, from satellite-observed surface conditions, how these extremely large West African storms may behave when, for example, they approach a city.

“A more effective alert-system will enable local people to take action to protect themselves as well as their homes, livestock and possessions, and plan emergency responses.”

‘We found a surprising level of predictability’

UKCEH said that in Sahelian Africa, these extreme storms have tripled in frequency since the 1980s due to global warming, referring to an earlier study in 2017 which described them as “some of the most explosive storms in the world”.

The UKCEH researchers say their new finding could assist short-term forecasts of storm behaviour several hours ahead in the Sahel, and even potentially worldwide.

Another of the study’s authors, Professor Chris Taylor, added: “We found a surprising level of predictability. Very dry soils influenced around half of storms in late afternoon or early evening, when they are at their peak.

“Further research and advances in satellite technology will increase our certainties about their movement.”

‘Nowcasts’

UKCEH is also working with the meteorological service of Senegal to see how useful very short-term forecasts called nowcasts are for emergency response, and this collaboration has recently generated a nowcasting tool that forecasters are trialling which will incorporate these new findings next year.

“Together with our partners at l’Agence Nationale de l’Aviation Civile et de la Météorologie, we have developed new short-term forecasts of convective activity and also potential flood impacts and risk in Dakar,” said the collaboration’s UKCEH lead, Dr Steven Cole, the centre’s Group Leader, Hydrological Forecasting.

“This is a great example of how new scientific understanding can be translated into real-time tools for African stakeholders to better manage the flood risk from intense MCS rainfall.”

UKCEH’s MCS study was supported by the Department for International Development and the Natural Environment Research Council as part of UK Aid’s Future Climate for Africa research, and the nowcasting work by the same bodies’ Science for Humanitarian Emergencies and Resilience programme; both include Climate Centre researchers.

A dust storm bears down on the village of Hombori in Mali. (Library photo: Françoise Guichard-Laurent Kergoat/CNRS)