Northern Hemisphere’s ‘Shortest’ Day of The Year

Winter Solstice is upon us…

The winter solstice is a single moment in time when the Sun is exactly over the Tropic of Capricorn in the Southern Hemisphere. This year that moment occurs on December 21st at 1044UTC or 4:44AM CDT.

A common misunderstanding with the winter/summer solstice regards the Sun’s distance from Earth. Distance does not create the seasons, the tilt of the Earth does. Earth’s 23.5° tilt is the reason each hemisphere receives various amounts of sunlight from season to season. The winter solstice marks the day the North Pole is tilted furthest away from the Sun.Read More »

Harmattan Dust in West Africa

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 African Journal of Environmental Science and Technology Harmattan DustAfrica. 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.  

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A quick mid-year review of the 2016 Atlantic hurricane season

To this date, the 2016 Atlantic hurricane season has recorded twelve named storms and one tropical depression, including Hurricane Alex from January. By the end of September we will likely see the next storm develop as signs of strengthening continue with an active tropical wave (97L). Currently, 97L is located roughly 470 miles east-southeast of Barbados tracking to the west about 15-20 knots. The tropical wave will either intensify into Tropical Depression Fourteen or Tropical Storm Matthew. The 30-year average (1981-2010) for the Atlantic basin consists of twelve named storms. With two months left in the 2016 Atlantic hurricane season, one can conclude that an above average recording of named storms will likely occur.

midyear-review-graphic

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