As we approach the end of the calendar year, meteorologists, once again, encounter a significant weather phenomena that can sometimes be a challenge to forecast: The Harmattan Winds.
Harmattan winds are derived from a dry and dusty, northeasterly trade wind that originates in the Sahara. As the monsoon trough shifts south during the boreal winter, the trade winds will travel further south reaching the West Coast of Africa. This type of wind is strengthened by low pressure over the north coast of Guinea and high pressure over Northwest Africa. The Harmattans can carry desert dust into the Atlantic and the Gulf of Guinea leading to hazardous operations on and offshore. Another element to the strength of the Harmattan is eastward movement of a low pressure system over Europe and its subsequent surface cold front that will move over the Mediterranean into North Africa. While the cold air will mix and warm over Africa, the wind will continue to surge south carrying with it the blinding dust covering everything in its path. Crop soil from the Sahel, the region between the Sahara desert and humid savannas, can also be mixed up in the winds further dropping visibility.
The influence of the Harmattan wind can be paralyzing for those areas affected as visibilities drop to zero halting flights, increasing risk of flu and asthma and also, at times, delaying the rainy season. The delay is significant as timing of the rainy season guides the farmers of when to plant crops across this otherwise fertile middle belt.
These Harmattans usually last 2-3 days. The lack of observation stations offshore West Africa can bring a forecasting challenge amongst meteorologists worldwide. Therefore, a skilled forecaster is crucial to accurately predict the potential of a debilitating Harmattan wind.