New portal improves forecasts of devastating storms in West Africa
Online tool will enable forecasters to provide communities with more
reliable warnings

Date:
May 3, 2022
Source:
UK Centre for Ecology & Hydrology
Summary:
Storms in the Sahel region, which can reach over 100km in size,
have become more extreme since the 1980s due to global warming, with
more intense rainfall. An online portal will enable forecasters in
West Africa to provide communities with earlier and more reliable
warnings about large storms.



FULL STORY ==========================================================================
An online portal developed by the UK Centre for Ecology & Hydrology
(UKCEH) will enable forecasters in West Africa to provide communities
with earlier and more reliable warnings about large storms.


========================================================================== Storms in the Sahel region, which can reach over 100km in size, have
become more extreme since the 1980s due to global warming, with more
intense rainfall.* Severe flooding during the monsoon from June to
September causes human and livestock deaths, plus damages property and infrastructure, leaving thousands of people without homes and livelihoods.

State-of-the-art weather forecast models struggle to predict where new
storms will hit and how strong they will be, which makes it difficult to provide warnings to people in affected areas so they can protect their
property and livestock or get out of harm's way.

National forecasting agencies in Africa can already make predictions of
how storms will behave in the next couple of hours by observing current atmospheric conditions, and analysing hundreds of historical storms.

Now, thanks to a recent breakthrough by UKCEH scientists, they can make
these short-term forecasts, known as 'nowcasts', for six hours ahead
and with a higher degree of accuracy. The new research found drier
soils can increase the intensity of storms when they are on the move,
affecting where they travel and the amount of rainfall they produce.

These novel nowcasting predictions and related satellite observations
for West Africa are available via UKCEH's new free portal, which has
been funded by the Natural Environment Research Council (NERC).



========================================================================== National forecasters can interpret the data and make localised forecasts, sending out warnings to people in areas that are expected to be hit by
a storm.

Last year, as part of a trial of the nowcasting tool, forecasters in
Senegal used it to issue a severe weather warning to the public via
text message.

Dr Steven Cole of UKCEH says: "The portal is a great example of how new scientific understanding can be translated into useable real-time tools
by working with forecasters. Importantly, this will support communities in
West Africa to better manage flood risk from intense rainfall." A recent
study found that using data about land surface temperatures improves predictions about the path and strength of an approaching mesoscale
convective system (MCS) up to 12 hours ahead. These 'megastorms' can be
bigger than the size of England and unleash over 100mm of rainfall in
just an hour.

"We found a surprising level of predictability of storms from land
surface temperatures when testing our methodology on historical data,
and West African forecasters are finding our approach very useful for
their work," says Professor Chris Taylor of UKCEH.

"We would expect mesoscale convective systems elsewhere in the world
to also be influenced by drier soils. Therefore, our methodology could potentially be used to improve storm and flood warning systems in
tropical regions such as South Asia and Australia, as well as parts of
USA and South America." The new nowcasting portal allows forecasters
to observe storm clouds in near real-time via satellite and compare
them with historical storm behaviour, plus view data on current land
surface conditions. The online tool then uses these data, updated every
15 minutes, to calculate the probability of a mesoscale convective system reaching different areas of the Sahel between the current time and six
hours ahead.

UKCEH scientists are continuing to work with forecasting services in
West Africa to increase the advance warning time and its reliability by combining more factors influencing storm behaviour within their nowcast modelling, in addition to land surface temperature. These include soil moisture, atmospheric humidity, wind conditions and the amount of rainfall there has been in preceding days.

As part of a collaboration with ANACIM, the national meteorological
service in Senegal, UKCEH has also developed short-term forecasts of
potential flood impacts and risk in Dakar which are available on the
portal. It also hopes to work with other forecasting services to provide
this service for other areas.


========================================================================== Story Source: Materials provided by
UK_Centre_for_Ecology_&_Hydrology. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Christopher M Taylor, Cornelia Klein, Cheikh Dione, Douglas
J Parker,
John Marsham, Cheikh Abdoulahat Diop, Jennifer Fletcher, Abdoul Aziz
Saidou Chaibou, Dignon Bertin Nafissa, Valiyaveetil Shamsudheen
Semeena, Steven J Cole, Seonaid R Anderson. Nowcasting tracks of
severe convective storms in West Africa from observations of land
surface state.

Environmental Research Letters, 2022; 17 (3): 034016 DOI:
10.1088/1748- 9326/ac536d ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/05/220503190227.htm

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