A wave of thunderstorms hits the southern parts of the Maghreb and the Sahel countries in the last third of August

Arabia Weather - M. Nasser Haddad - Forecasts at the end of the month indicate an increase in the chances of thunderstorms and an increase in their intensity in the southern parts of the Maghreb, including southern Libya, southern Algeria and Mauritania, and later extending towards the highlands of Algeria and the Kingdom of Morocco.

Find out the weather in the last third of August

A wave of thunderstorms, due to the widening of the ITCZ , is heading towards these areas in the last third of the month (20-31 August 2019).

Thunder clouds that intensify in the afternoon and evening hours are formed almost daily, and work to increase the chances of torrential rains and the activity of winds that raise dust.

Humid tropical winds (monsoons) spread towards the highlands of the western Arabian Peninsula in the last third of August, causing an increase in the intensity of thunderstorms in those areas.

What is the reason for the increased rainfall during the period from 20 to 31 August 2019?

The most prominent and direct reason is due to the incursion of monsoons into these areas, as they carry with them very large amounts of relative humidity in the various layers of the atmosphere, especially in the effective layers of the atmosphere, where the density of thunderclouds increases and the rains are abundant.

As the long-range probabilistic weather maps indicate the displacement of the base of the Azorean air high from central Algeria towards the Kingdom of Morocco, which means limiting the rush of cold northern winds, in contrast, the wet monsoon winds from the south find an easy way to spread towards southern Algeria, Libya and Mauritania.

The same thing is expected to happen in the Arabian Peninsula, as it is expected that the tropical elevation will deepen in the north of the Arabian Peninsula, which will prevent the dry northern winds from blowing towards those areas, and the intensity of rain will increase.

How does the ITCZ turn barren lands into green pastures?

Known as the ITCZ line or the line of convergence of the equatorial trade winds or what is also called the tropical separator, it is the imaginary equator geographically and the actual climatically.

The location of the ITCZ line changes according to the seasons, as this line moves north of the equator in the northern hemisphere summer, and back to the south of the equator in the southern hemisphere summer.

With the onset of summer in the northern hemisphere, the trade winds move northwards and take a path in the form of an eastern zigzag, bringing with it large amounts of moisture from the tropical regions north towards areas with average solar radiation of large values, which creates a fertile area for the formation of cumulus clouds that cause thunderstorms. rainy season or what is locally called monsoon rains.

Many regions of the south of the Arab world are affected by the effects of the tropical separator line with a severity that differs from one season to another. In the summer of 2010, the ITCZ line reached the Saudi capital, Riyadh, where the weather of the capital, Riyadh, with a desert climate, turned into a humid and rainy tropical weather for a limited period before the tropical separator retreated to the south, and usually Parts of the southwest of the Arabian Peninsula and Sudan, as well as southern Algeria and Mauritania, are not affected by rainy thunderstorms during the summer, resulting from the movement of the ITCZ to the north, and the transformation of arid lands into green pastures.