Severe Weather in Ethiopia

A tornado is formed when a rotating body of air, also known as a vortex tube, forms due to an increased wind speed due to altitude (vertical wind shear). This vortex tube is then lifted off of the ground by the thunderstorm’s updraft. Once the air mass is lifted nearly vertically, it is called a mesocyclone. Finally, the fully developed tornado descends from the lower part of the “wall cloud”.

In the United States, most tornados usually travel southwest to northeast or west to east. Tornados usually travel this path because there is a lot of moisture. These areas tend to be largely agricultural (unfortunately). The dryline also helps initiate tornadoes.

Tornadoes can happen in any country that meets the criteria for tornado formation. This includes having abundant low-level moisture, atmospheric instability, and a trigger i.e. a cold front, etc. that lifts the moist air aloft. That being said, Ethiopia can experience tornados as it is close to the eastern coastal area. However, they probably do not last very long as the terrain can be mountainous, especially the capital city. The average number of tornados observed in the US each year is over 1 thousand (http://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado-climatology). Unfortunately, I couldn’t find a website that provided any information on the average number of tornadoes that occur yearly in Ethiopia.

 

Source:  http://www.windows2universe.org/earth/Atmosphere/tornado/agri_map.html

At first, I didn’t know what to think when I saw that graph as it made sense to me that the number of tornadoes could’ve increased due to global warming, however after reading an article that I found online (http://notalotofpeopleknowthat.wordpress.com/2012/01/05/us-tornado-trendsupdated-to-2011/), it made perfect sense that the “increase” was due to the advancement in technology. Today’s technology makes it easier to monitor and count the number of tornado occurences.

There are three requirements for a hurricane to form. This includes a warm ocean temperature (needed for evaporation), a deep, warm ocean layer, and a coriolis (to initiate spinning). Hurricanes are called hurricanes in the Atlantic and East Pacific regions. It is called a cyclone in the areas of the Indian Ocean near Australia and a typhoon off the coast of China and Indonesia. In the United States, hurricanes travel the warm Gulf Stream and is steered by the west to east flow of the Westerlies and the Jet Stream. This is the dominant direction of hurricane travels because it has the requirements needed to form a hurricane. The Gulf of Mexico has the warm ocean temperature, deep, warm ocean layer, and the coriolis which is the dryline.

Source: http://www.learnnc.org/lp/editions/nchist-recent/6248

According to the hurricane map, hurricanes do not form in Ethiopia, however it is said that hurricane Sandy could have possibly started in the Ethiopian Highlands. In the U.S, there is an average of 5 hurricanes per every 3 years. That comes out to approximately 1.6 hurricanes every year (http://www.ussartf.org/hurricanes.htm). There are no hurricanes that hit Ethiopia (http://www.learnnc.org/lp/editions/nchist-recent/6248).

Global and Local Winds in Ethiopia

The latitude and longitude of Ethiopia is 8.3000°N, 39.1167°E and it is located in the northern hemisphere. Ethiopia is just slightly above the equator and so it belongs to the Hadley cell. Because it is part of the northern Hadley cell, it experiences northeast trade winds, meaning that the wind blows in a northeast to southwest direction.

Ethiopia is located in a Low-pressure belt. It is slightly above the Intertropical Convergence Zone. Ethiopia is located near the Doldrums since it is in the Hadley cell. In this area, the winds are light and the area is general humid, which makes sense since we are talking about the African continent. Ethiopia also experiences a fair amount of winds due to the fact that it is in between high and low pressure areas, coming from areas around South Africa and areas around China, respectively. The winds are moving from the South African area and China with Ethiopia right in between.

Sources: http://www.atmos.umd.edu/

 http://tle.westone.wa.gov.au/

 

 Ethiopia does have mountains; in fact the capital city of Addis Ababa experiences cool weather contrary to the belief that all African countries are humid, due to the fact that it is at a high elevation. Five winds or breezes associated with mountains include eddies, mountain breeze, valley breeze, katabatic winds, and Chinook (Foehn) winds. Eddies occur where wind must pass through an obstacle, in this case mountains. Therefore, Ethiopia experiences eddies. Mountainous areas like Addis Ababa experience mountain and valley breezes just because of the fact that they are mountainous areas. However I do not think that Ethiopia experiences katabatic winds because the wind does not get so cold as to form an ice sheet.

Ethiopia is a landlocked country so it does not have a coastline, however, is it a good distance from the Red and Arabian Seas, only being blocked by Djibouti, Eritrea, and Somalia. The land and sea breezes are associated with coastlines. Ethiopia experiences land and sea breezes, however not evenly because it is a landlocked country. However, it is within a reasonable distance from large bodies of water to experience these winds at certain parts of the country.

Typical Weather and Tourism in Ethiopia

The winter solstice is on December 21^st. The average max temperature is about 73° Fahrenheit. The average minimum temperature is about 41° Fahrenheit. During the winter, morning frost is most likely to occur, especially during the month of January. It is also a season for occasional rain.

The summer solstice occurs on June 21^st. The average maximum temperature during this month is about 75°F. The average minimum temperature during this month is about 51°F.  Heavy rain is common during the summer months of June to August. The capital city of Addis Ababa experiences hail and more cloud cover so this plays a role in the cooler temperatures.

The spring equinox occurs on March 20. The average maximum temperature is about 77°F. The average minimum temperature is about 49°F. There is not much precipitation during this season. It is known in Ethiopia as the harvest season. This season is probably the best time to go if you want to visit Ethiopia.

The autumnal equinox occurs on September 23. The average maximum temperature is about 70°F. The average minimum temperature is about 51°F. This season experiences occasional showers, but nothing too heavy. May is known for being the hottest month in Ethiopia.

If you are interested in visiting the city of Addis Ababa, the spring season (September to November) would be the best time to go. This is in comparison to the other seasons. June through August, in the city, is known for experiencing heavy rain.  December through February, the winter season, is dry with morning frosts. Lastly, the autumn season (March through April) has occasional showers, but May is known for being the hottest month in Ethiopia.

Ethiopia has a number of beautiful scenic places that are ideal to see during the spring. One of these is the Blue Nile Falls, which is located in Bahir Dar, north of Addis Ababa. This waterfall is located on the shores of Lake Tana, which is the biggest lake in Ethiopia. Another sight to see is the Semien Mountains, which is farther north of Lake Tana. The Semien Mountains are a UNESCO world heritage sight and is a plateau separated by valleys and rising to pinnacles. The tallest peak, Ras Dashen, is 4,500 meters high.

            There are no potential weather hazards in the spring season. I recommend those interested in travelling to Ethiopia to go during the spring because the temperature is very comfortable. An average maximum temperature of 77°F is definitely not too hot or too cold. Also, there is not much precipitation during the spring months, so it is an ideal time to go especially if you’re a nature lover and want to see some of Ethiopia’s scenic places.

Semien Mountains and Blue Nile Falls, respectively. Picture sources: wikipedia.org, artmundus.wordpress.com

Ethiopia: See nature’s old gifts and live life untamed!



Sources:
http://www.weather-and-climate.com/average-monthly-min-max-Temperature-fahrenheit,Addis-Abbeba,Ethiopia
http://www.ethiopiantreasures.co.uk/pages/climate.htm

Temperature Controls in the city of Addis Ababa in Ethiopia

In this post, I will briefly explain the climate Addis Ababa, the capital city of Ethiopia (9.0300° N, 38.7400°E). My expectation when I was researching what the temperature was like in this city was that it was going to be extremely hot. However, I was shocked to find out that it was not that hot at all, by Hawai’i standards. According to http://www.weather-and-climate.com, the warmest month in Addis Ababa, which is May, is 77°F while the coolest month, July, is 68°F. Based on that information, the annual range of temperature for Addis Ababa is 9°F.

            This surprisingly cool temperature is due to a few factors, but for now I’ll focus on elevation. Addis Ababa has an elevation of 2,536m or 7,730ft. That is very high in comparison to Mt. Ka’ala (highest point on O’ahu) which is 1,227m or 4,025ft. The effect that elevation has on air temperature is due to less atmospheric pressure and density as altitude increases . As this pressure decreases, the air molecules have more room expand and thus the cooler air temperature. One temperature control that does not affect the city is its geographic location away from the open ocean. Because the city is pretty far from the Red Sea, Gulf of Aden, and the Arabian Sea, differential heating has no large affect on it. Differential heating is when land heats faster than water or vice versa. The warmer air pulls the cooler air in.

            Because of the high elevation and position near the equator, Addis Ababa has a moderate year round temperature. It is not affected by ocean currents too much, and should sea levels rise, its high elevation would not harm the city negatively. Since Addis Ababa has a subtropical highland climate, drought would not be a problem as well. It seems that it is a safe place to be with regards to future climate change, as it is in an ideal geographical position.


Source: http://www.weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine-fahrenheit,Addis-Abbeba,Ethiopia