The Impact Of The Harmattan Weather On Aviation Operations In Ghana Opinion/Feature | 8 December 2015 11:02 CET The Impact Of The Harmattan Weather On Aviation Operations In Ghana By Okatakyie Kwasi Adjekum Previous | Next Aviation, probably more than any other mode of transportation, is greatly affected by weather. From thunderstorms to reduced visibility due to hazy conditions, every phase of flight has the potential to be impacted by weather. Commercial aviation in the West Africa, must deal with these adverse types of weather regularly, and the cost is a significant budget item. One of the perennial weather phenomena that have adverse impact on flight is the hazy condition known as Harmattan. The Harmattan is a cold-dry and dusty trade wind, blowing over the West African subcontinent. This northeasterly wind blows from the Sahara Desert into the Gulf of Guinea between the end of November and the middle of March. The Harmattan blows during the dry season, when the subtropical ridge of high pressure stays over the central Sahara Desert and when the low-pressure Intertropical Convergence Zone (ITCZ) stays over the Gulf of Guinea.

The low visibility condition brought about by the Harmattan, poses a significant safety hazard as pilots have to stretch their skills and proficiency to land in such conditions. Ghana has a relatively fledgling domestic aviation market, which is constrained by high tariffs, high fuel cost, relatively low load factor and limited routes. A typical domestic operator’s Direct Operational Cost (DOC) per flight can range between $2500 for a regional jet type aircraft with seating capacity of 50-70 passengers to Kumasi and $3000 for a similar flight to Tamale. Direct costs due to weather on airline operations can be separated into several categories: diversion, cancellation and delay. The direct costs sometimes are eclipsed by the cost of rub-off factors. The costs listed are from a variety of areas, some fixed and then others not: fuel, crew time, aircraft operating costs, lost passenger and cargo revenue, ground-based employee overtime pay. In 2014, there were 4,072 domestic flights to Tamale and 8070 flights to Kumasi. The highest domestic movements were in April (Tamale: 388 and Kumasi: 860).

The lowest movements were in November/December (292 flights to Tamale and 560 flights to Kumasi). Even though there may be other variables, obviously the effect of weather may have a significant impact on these reductions and the economic effects on domestic operators cannot be downplayed (GCAA, 2015). Though the costs associated with delays and cancellations vary, airlines taking such actions risk eroding passenger goodwill and that results in lost future revenue. The impact goes beyond just the lost revenue from ticket sales. The list includes added costs for rescheduling crews, including transportation and hotel costs. Even if the plane doesn't take off, the airline still incurs maintenance cost to get it ready and stock it with food. Ticket agents still show up for work to deal with stranded passengers at the gate. Even though an argument could be made that airlines save on fuel and landing fees from flights that never took off, there are still issues with crew that were on standby, rescheduling of passengers, and repositioning of aircraft. Ground crews still need to shuffle schedules and try to get planes back where they were headed before the cancellation.

Those costs can range from about $2,700 an hour for a carrier operating a regional jet according to masFlight Consultancy and cumulatively lead to loss of millions of dollars in a market where profit margins are rare. The severe Harmattan weather adversely affect operations to Kumasi and Tamale Airports. The irony is that Tamale airport is yet to be upgraded with a precision approach system, such as an Instrument Landing System (ILS) that will provide precision guidance for pilots to land in such low visibility conditions. Recently there were pomp and pageantry during the commissioning of the rehabilitated aeronautical ground lightening system at the Kumasi Airport by the President of Ghana. Strangely, the ILS which was supposed to be functional has not had the requisite procedure for use by pilots officially charted in the Aeronautical Information Publications (AIP) of Ghana by the Ghana Civil Aviation Authority (GCAA). That makes the use of that ILS ‘Illegal’, discretional and a safety hazard due to ambiguity of procedures. The advantages of having navigational aids like an ILS and approach light components at Kumasi and Tamale is that it provides precision vertical and horizontal navigation guidance information during approach and landing.

The attractiveness of ILS lies in the economy of its avionics costs and its wide international acceptance. Technological advances over the years have yielded great improvement in accuracy, dependability, and maintainability. An approach may not normally be continued unless the runway visual range (RVR) is above the specified minimum. When an approach is flown, the pilot follows the ILS guidance until the decision height (DH) is reached. At the DH, the approach may only be continued if the specified visual reference is available; otherwise, a go-around must be flown. Normally the standard for the basic category 1 ILS is a DH of 200 feet above runway threshold elevation (ARTE) and RVR of 550 metres (with touchdown zone and centerline lighting) or 800metres visibility. The installation cost of a typical Category 1 ILS may range between $1. 75 Million –$1.87 Million and an operations/ maintenance tag of about $105,000 adjusted for inflation in 2015-dollar figure (ACI, 2008).

Other options that are available to operators in Ghana are Performance Based Navigation (PBN) procedures such as the Area Navigation (RNAV), Required Navigational Performance (RNP) based approach, and other Wide Area Augmentation Systems (WAAS) certified terminal procedures.The WAAS will allow Global Navigational Satellite Systems (GNSS) such as the US Global Position System (GPS) and European Union EGNOS to be used as a primary means of navigation from takeoff through Category I precision approach. The advantage of WASS lies within an increased accuracy, availability, and integrity. Other advantages of WAAS are the efficiency of aviation operations due to, new precision approach services, reduced and simplified equipment on board aircraft and significant government cost savings due to the elimination of maintenance costs associated with older, more expensive ground-based navigation aids. However, the operators should have WAAS enabled navigational equipment on board their aircraft, and the crew should be proficient and authorized to use WAAS enabled equipment and approach procedures. There should also be a mechanism to ensure reliability and integrity (Receiver Autonomous Integrity Monitoring). Another viable option will be a Ground-Based Augmentation System (GBAS) system that provides differential corrections and integrity monitoring of Global Navigation Satellite Systems (GNSS).

GBAS provides navigation and precision approach service in the vicinity of the host airport (approximately a 23 nautical mile radius), broadcasting its differential correction message via a very high frequency (VHF) radio data link from a ground-based transmitter. GBAS yields the extremely high accuracy, availability, integrity necessary for Category I ILS. GBAS has several advantages in comparison to traditional ILS. One GBAS station can support multiple runway ends and reduce the total number of systems at an airport. This reduces the Very High Frequency (VHF) requirements and simplifies airport infrastructure. The GBAS approach guidance is steadier than ILS approach guidance. In addition, GBAS requires less frequent flight inspections compared to those required of ILS systems. A recent study by the navigational service provider ASECNA in Dakar (Leopold Senghor International Airport) in 2013, estimated the Net Present Cost (NPC) of a GBAS installation over a 15-year span would be 7.5 million Euros. The initial capital expenditure was estimated at 4.6 million Euros and operational expenditure of 272,000 Euros.

The ILS on the other hand will have a NPC of 6.9 million Euros and capital expenditure of 3.3 million and operational expenditure of 346,000 Euros. Even though the GBAS had a higher capital expenditure, due to the low operational cost, the NPC was similar, with reported economic benefits for GBAS exploitation within 5-6 years. The effectiveness of these navigational infrastructures will be constrained if there is inadequate meteorological support. The era of human estimation of visual range is becoming a past time and we need to equip the Ghana Meteorological Agency with RVR measuring systems. The system measures visibility, background luminance, and runway light intensity to determine the distance a pilot should be able to see down the runway. Each RVR system consists of the following functional elements: Visibility Sensor, Ambient Light Sensor, Runway Light Intensity Monitor, Data Processing Unit and Controller Display(s). Other essential components that will be needed to enhance the capability of aircraft operators to land in low visibility conditions are Approach Light Systems (ALS), which provides the basic means to transition from instrument flight to visual flight for landing. Operational requirements dictate the sophistication and configuration of the approach light system for a particular runway.

For Tamale and Kumasi due to the initial capital expenditure and operational expenditure, at a minimum a MALSR (Medium Intensity Approach Lighting System with Runway Alignment Indicator Lights) is recommended. MALSR is a medium approach intensity lighting system (ALS) installed in airport runway approach zones along the extended centerline of the runway. The MALSR, consisting of a combination of threshold lamps, steady burning light bars and flashers, provides visual information to pilots on runway alignment, height perception, roll guidance, and horizontal references for Category I Precision Approaches. The biggest caveat with all these systems is that their reliability and integrity depends on uninterrupted power supply and the ability to detect internal faults within very short periods. Hopefully the necessary investment will be made to enhance the growth of domestic aviation in Ghana. Okatakyie Kwasi Adjekum @ [email protected] Sources: ASECNA: CNS/SG/5/IP/06 Fifth Meeting of the APIRG Communications, Navigation and Surveillance Sub-group (Nairobi Kenya, 16-19 September2013) Feasibility Studies on Ground Based Augmentation System (GBAS).

Federal Aviation Administration (FAA): , FAA NEXT-GEN Navigation , Ghana Civil Aviation Authority: ICAO ANNEX 6, ICAO ANNEX 10 Vol 1, Chapter 3. Ghana Calendar and Weather - Easy Track Ghana Easy Track Ghana Go back Weather & Calendar The dry season is best for wildlife viewing, but the rain season is best for lakes, rivers and water falls. Holidays like Christmas and Easter are huge events in Ghana, but airfare costs much more during these dates. Plan your trip according to your desired activities. Ghana Calendar See the calendar below for a list of national holidays, noteable events and known festival dates. See our list of Festivals in Ghana for a large, but incomplete, list of festivals, holidays and celebrations held in Ghana during the year. Many of the dates are not set by the chieftancy until very close to the festival date, so it is best to try to confirm the exact date of any festival you are planning to attend. Ghana Climate Ghana experiences a typical tropical climate. It is almost always hot, and the seasons are either wet or dry.

As a rule, temperatures are more mild in the highlands, more humid along the coast and hotter and drier the farther north you go. Driving just 45 minutes north of Accra to Aburi marks a significant change in climate, as Aburi is in the hills which get a cooling mist most mornings and evenings. Ghana is always a very dusty place. Bring zip-lock plastic bags for things you wish to keep dust-free. Pack a camera bag, lens cleaning cloth and a bandanna. Also avoid wearing clothing of solid colors, especially white, as it is impossible to keep clean. Besides the temperature and humidity, the rain and the Harmattan winds are the other two significant weather events in Ghana. Current Weather in Ghana © HotelsCombined.com Rain in Ghana There are two rain seasons in Ghana. The heaviest rain in the south is from April until June, and a lighter rain possible during September and October. In the north, the rain season is continuous, giving rain from April until October. Typically a rain will last for a short time, but on some days during the rain season, the entire day can be raining very hard. Always pack accordingly and be prepared for delays when traveling during the rain season.

Clothing should be fast-drying and your luggage should be able to withstand an unexpected drenching. Harmattan in Ghana The Harmattan is a dry, dusty wind that blows from the Sahara desert in late December and continues sometimes until early February. Most years it is somewhat pleasant because it dims the sun and decreases the humidity. Other years, a bad Harmattan day will look like a thick London or San Francisco fog - except it is dust! The Harmattan is more intense the farther North you travel. This is actually the best time for wildlife viewing because animals congregate at the available water holes during this dry season. You should travel with lip balm, a nasal decongestant and moisturizing lotion during the Harmattan. Shea butter is the best moisturizer for dried skin and lips. Shea butter can be found throughout Ghana, but is most easily and cheaply purchased at in the three northern regions. Ghana Weather Summary Here is a weather summary for the three largest cities: Accra, the capital on the coast, Kumasi in the center of the country, and Tamale in the Northern Region.

Month Ghana Weather, Climate and Geography Ghana Weather, climate and geography Weather & climate Best time to visit : Ghana has a typically tropical climate thanks to its proximity to the equator and low elevations – the entire country lies below 1,000m (3300ft). Daytime temperatures are high throughout the year, approaching or surpassing 30°C (86°F) on most days, and humidity is also very high, especially along the coast. Temperatures tend to drop to around 20°C (68°F) drop at night, more noticeably in the relatively dry north than the humid south. The most temperate part of Ghana is the highlands area flanking the Volta Basin, which is often pleasantly cool after dusk. There are two rainy seasons: from March to July and from September to October Rainfall is highest in the south, with some areas receiving in excess of 2,000mm each year, but the drier north more typically receives about 800mm annually.

The capital Accra, together with the coast running east to Togo and Benin , lies within the Dahomey Gap, a tract of savannah that receives relatively little rain and divides the Upper Guinean forests (running westward from central Ghana) from the Lower Guinean forests (running southward from Nigeria southward to the Congo). A noteworthy climatic phenomenon is the harmattan winds, which blow in from the northeast from December to March, bringing dust from the Sahara and reducing visibility to as little as 1km (0.6 miles). Ghana is fine to visit at all times of year, but if you have the choice, aim for the northern hemisphere winter i.e. October through to April, when humidity is lowest and the weather is typically quite dry. There are also fewer mosquitoes (and a decreased risk of contracting malaria), dirt roads are in better condition, and there is less likelihood of you or your luggage being drenched in an unexpected storm. However, photographers might want to avoid the dull ambient light and grey skies associated with the harmattan in December. Required clothing : Light and loose is the way to go in this humid tropical climate.

Bring light trousers or skirts made of a natural fabric such as cotton, combined with a stash of cotton T-shirts, and plenty of socks and underwear, also ideally must be made from natural fabrics to prevent fungal infections. Ghanaians are relatively relaxed about dress codes, but women should keep their shoulders covered and wear a skirt below the knees in the predominantly Muslim north. One sweater or sweatshirt should be adequate, since night time temperatures are seldom chilly. As for footwear, a good pair of walking shoes with solid ankle support is a must, but you'll also want sandals or thongs. If you forget anything, don't stress: there is a massive used-clothing industry in Ghana, and having new clothes made from local fabrics is quick and affordable. Geography Ghana is situated in West Africa between latitudes of 4°N and 12°N, and longitudes of 4°W and 2°E. It is a rectangular-shaped country bordered to the north by Burkina Faso , the east by Togo , the south by the Atlantic Ocean and the west by Côte d'Ivoire .

It is bisected by the Prime Meridian (0°longitude), which runs through the port city of Tema, 25km (16 miles) east of the capital Accra, and Cape Three Points, the most southerly peninsula in Ghana, is also the closest land fall to the oceanic intersection of the Prime Meridian and the Equator. Ghana's coastline is dotted with sandy palm-fringed beaches and lagoons. A narrow grassy plain stretches inland from this, widening in the east, while the south and west are covered by dense rainforest. To the north are forested hills, beyond which is dry savannah and open woodland. In the far north is a plateau averaging 500m (1,600ft) in height. In the east, the Akuapim Togo hills run inland from the coast along the Togo border. The country falls almost entirely within the Volta Basin, with the Red, Black and White Volta rivers all flowing into its northern borders from Burkina Faso.

Following the 1960s construction of Akosombo Dam, about 60km (37 miles) inland of the Volta Mouth, much of the river is now submerged by Lake Volta, the world’s most expansive artificial water body. Climate - Nigeria - OnlineNigeria.com Climate - Nigeria Comment Related Content Buhari Killed the Brother of Nollywood (Osuofia) Actor Nkem Owoh Buhari Killed the Brother of Nollywood (Osuofia) Actor Nkem Owoh Buhari Killed the Brother of Nollywood (Osuofia) Actor Nkem Owoh Hausa IDIAGBON: Goodbye to a no-nonsense crusader! What is the matter with General Buhari? Nigerian militarism and the Chilcot Report Why Do Private Universities Charge So Much In Nigeria? Sallah homage and the sinners in President Buhari's cabinet Political or economic malpractice: Which is worse?

We Have No Fraud Information On Buhari's Wife, Says US EFCC Seals First Group Office In Abuja Over Alleged $200 Billion Scam President Buhari Bars Government Officials From Travelling To Rio Olympics Dino Melaye Is A Big Disgrace, Says Bola Tinubu Ihejirika, Minimah, 52 Others Face EFCC Arrest Over Alleged N381b Arms Fraud Fayose Vs Aisha Buhari : Wait Till 2018 To Sue Me For Defamation Tourists describe horrifying scenes as terrorist slaughters 84 in French city of Nice My defence against Reps' charges, by Obasanjo U.S. ruling party honours Nigerian lawyer Onitsha NBA Chairman, Wife Murdered Nigeria Shrugs Off Miss World Boycott Threat Nigerian villagers say oil spill is killing fish and crops Nigeria's president told to resign Nwobodo's son, others shot in Enugu's Assembly violence Oil deal 'off', Nigerian women say I want Babangida Dead Virgin Test For Lagos High School Girls Nigeria wins jailhouse World Cup Climate - Nigeria Nigeria enjoys the humid tropical climate type.

Because of its location just north of the equator, Nigeria enjoys a truly tropical climate characterised by the hot and wet conditions associated with the movement of the Inter-Tropical Convergence Zone (ITCZ) north and south of the equator. The country experiences consistently high temperatures all year round. Since temperature varies only slightly, rainfall distribution, over space and time, becomes the single most important factor in differentiating the seasons and climatic regions. Rainfall occurrence and distribution are however dependent on the two air masses that prevail over the country. Their influences are directly linked to the movement of the ITCZ, north and south of the equator. The two air masses are the Tropical maritime (Tm) and the Tropical continental (Tc). The former is associated with the moisture-laden south-west winds (south westerlies) which blow from the Atlantic Ocean, while the latter is associated with the dry and dusty north-east winds (easterlies) which blow from the Sahara Desert. When the ITCZ, the zone of convergence of the two air masses, is to the south of the equator, the north-east winds prevail over Nigeria, thus producing the dry-season conditions.

Conversely, with the movement of the ITCZ into the Northern Hemisphere, the rain-bearing south westerlies prevail as far inland as possible to bring rain fall during the wet season. The implication is that there is a prolonged rainy season in the far south, while the far north undergoes long dry periods annually. Nigeria, therefore, has two major seasons, the dry season and the wet season, the lengths of which vary from north to south. The seasonal pattern of climatic conditions over Nigeria gives rise to four seasons in the south and two in the north. This is the result of annual total rainfall occurrence and distribution, which is more predominant in the south than in the north. The mean annual rainfall along the coast in the south- east is 4000mm while it is only 500mm in the north- east. Southern Nigeria: The four observed seasons are: (i) The Long Rainy Season: This starts in March and lasts to the end of July, with a peak period in June over most parts of southern Nigeria. It is a period of thick clouds and is excessively wet particularly in the Niger Delta and the coastal lowlands.

It is marked by humidity with values hardly below 85 per cent in most parts of the forested south. (ii) The Short Dry Season: This is experi- enced in August for 3-4 weeks. However, the real dry period known as the "August break" is generally observed in the last two weeks of August in most parts of southern " Nigeria". (iii)The Short Rainy Season: This brief wet period follows the "August break" from early September to mid-October, with a peak period at the end of September. The rains are not usually as heavy as those in the long rainy season, although the spatial coverage over southern Nigeria is similar. The two periods of rainfall intensity give the double maxima phenomenon of the rainy season characteristic of southern Nigeria. The short dry season in August between these two rainy periods allows for harvesting and planting of fast-growing varieties of grains, such as maize. (iv) The Long Dry Season: This period starts from late October and lasts to early March with peak dry conditions between early December and late February. The period witnesses the prevailing influences of the dry and dusty north-east winds, as well as the 'harmattan' conditions.

Vegetation growth is generally hampered, grasses dry and leaves fall from deciduous trees due to reduced moisture. Northern Nigeria: The climatic conditions in the northern part of Nigeria exhibit only two different seasons, namely, a short wet season and a prolonged dry season. Temperatures during the day remain constantly high while humidity is relatively low throughout the year, with little or no cloud cover. There are, however, wide diurnal ranges in temperature (between nights and days) particularly in the very hot months. The mean monthly temperatures during the day exceed 36ï¿½C while the mean monthly temperatures at night fall, at most times, to below 22ï¿½C. (i) The Long Dry Season: This period extends from October to mid-May. With the ITCZ in the Southern Hemisphere, the north-east winds and their associated easterlies over the Sahara prevail over the country, bringing dry conditions. The harmattan period during December- January is more intense and longer in the north than in the south. This is the period of little or no cloud cover, resulting in wide diurnal ranges of temperature . (ii) The Wet Season: The wet season covers a relatively short period, from June to September.

Both the number of rain days and total annual rainfall decrease progressively from the south to the north. The rains are generally convectional, heavy and short in duration, often characterised by frequent storms. This results in flash floods, and in some places also in sheet or gully erosion. The few high plateaus of Jos and Biu, and the Adamawa highlands, experience climatic conditions which are markedly different from the generalised dry and wet period in northern Nigeria. Temperatures are 5 - 10ï¿½C lower due to high altitude than in the surrounding areas. Similarly, the annual rainfall figures are higher than in areas around them, particularly on the windward side.

Nigeria can, thus, be broadly divided into the following climatic regions: (a) the humid sub-equatorial, in the southern lowlands (b) the hot tropical continental, in the farnorth (c) the moderated sub-temperate in the high plateaus and mountains (d) the hot, wet tropical, in the hinterland (the middle-belt) ï¿½ Ghana's mid-year cocoa production hit by the Harmattan | Africanews Ghana's mid-year cocoa production hit by the Harmattan 13/06 - 23:59 Ghana Fifty-eight year-old farmer, Mohammed Karim has 10 acres of cocoa trees that he is not sure will yield the kind of harvest he expects at this time of year. The farm, which Karim inherited from his father 18 years ago is located over 150 kilometers southwest of the capital, Accra. Here, as in other cocoa growing regions of Ghana, the Harmattan – cold, dry and dusty winds blowing across West Africa from the Sahara – is sapping soil moisture and spoiling seeds.

In terms of real GDP, for example in 2015 we noticed that because of the harsh weather condition the cocoa sub sector declined by 1.4 percent and that led to a slow down in the growth of the sector. While weather conditions have improved compared with last year, farmers said rains, which started in March and are vital to the development of the light crop, have been insufficient and patchy. “We have been worried by the Harmattan. It could really affect the cocoa farms because there has not been enough rain. We tried to be patient, otherwise we wouldn’t even have bothered and we could have said enough is enough. Now it is raining but it’s not really what we expected. I have also not been receiving farm inputs like fertilizers and all this is a worry for farmers. The government should try and do something for us,” said Karim. Ghana’s 2014/15 output came in at 730,000 tonnes of beans – well below an initial forecast of more than 1 million tonnes – due to poor weather and what farmers said were inadequate supplies of fertilisers and pesticides.

Industry regulator Cocobod’s 2015/16 production target, set at the start of the season in October, is in line with Ghana’s average annual output of 850,000 tonnes, the bulk of which is harvested during the main crop that runs from October to May. The light crop, also called the mid crop, is expected to open this month, though its start date can vary. Officials from the industry regulator, Cocobod say they are confident Ghana was still on track to hit its target. “We had targeted that we’ll be able to produce 850,000 metric tonnes. We are hoping that the way it performed we would be able to achieve that, but because the rains had just set in we’re yet to see the light crop and how it will also behave and we can then assess the severity or the effect of the long stretch of Harmattan,” said Cocobod spokesman, Noah Amenyah. Cocoa is a backbone of Ghana’s economy along with gold and oil.

Ghana has more than 1 million cocoa farmers who rely on the crop and the lower production this season also hurts government revenue at a time when the country is following an International Monetary Fund loan package aimed at restoring fiscal stability. The country saw growth slow sharply in 2014 due to lower global commodity prices and economic instability including a sharply falling currency, damaging Ghana’s reputation as one of sub-Saharan Africa’s boom markets. “In terms of real GDP, for example in 2015 we noticed that because of the harsh weather condition the cocoa sub sector declined by 1.4 percent and that led to a slow down in the growth of the agricultural sector from 4.6 percent to 2.4 percent. So this is what impact a declining cocoa sector can have on the agricultural sector and the GDP of a country like Ghana,” said Kingsley Martey, an economic analyst in Accra. Local buyers and traders said the overall crop still looked set to end with output below the long-term average. Experts say the Harmattan will also affect mid crop output in neighbouring Ivory Coast, the world’s top cocoa grower.

Reuters weather - Dictionary Definition : Vocabulary.com Random Word weather Weather is the atmospheric conditions, including the temperature, wind, snow, rain, or anything else happening outside. People tend to talk about the weather when they can't think of anything else to talk about. Choose Your Words weather / whether / wether The weather outside is partly cloudy whether you like it that way or not. A wether, on the other hand, is a castrated sheep. You read that right. Continue reading... In some places, people say, "Don't like the weather? Wait an hour and it'll change." Every day, experts try to predict the weather, but they never get it exactly right. You can also use weather to mean "endure something," as in "I weathered the storm at work." That's not a real storm, but a stormy situation. Even though the weather drives us all crazy at times, at least it gives us something to blab about. Weather types Types of Weather Weather type 1 - Clouds There are four basic types of clouds. High clouds, middle clouds, low clouds, and clouds with vertical developement. There are also clouds that don't fall into any of these groups.

Low clouds are from the surface to about 6,500 feet and are usually composed of water droplets unless temperatures are several degrees below freezing. Clouds on the ground are called fog. Middle clouds range from about 6,500 feet to about 20,0000 feet. They are also mostly composted of water droplets unless temperatures are cold. High clouds are above 20,000 feet and are composed of ice crystals. Click the link to get the whole story on clouds . Weather type 2 - Dust Storm Dust storms are created by winds moving across an arid region. Many times a strong dry cold front is the mechanism that creates the dust or sand storm. As strong winds move across an arid landscape, sand or dirt is picked up from the ground. Sometimes the lighter dust particles can be lifted up to 20,000 feet high into the atmosphere. A classic example of this is a sand and dust storm that develops over the Sahara desert. Easterly winds may carry the dust particles across the Atlantic ocean to the Caribbean Islands or Florida. Severe sand and dust storms can obscure visibility to zero and last for days. Picture courtesy of NOAA, George E. Marsh.

Weather type 3 - Fog Fog is a stratus cloud on the ground. There are several types of fog. Advection fog is produced by a hortizontal motion of warm moist air over colder ground. An example of this would be a warm front moving across land with a recent snow or cold weather. Radiation fog is produced as heat from the earth surface is radiated back to space at night. A moist layer and nearly calm winds need to be present. Wind can mix in dryer air aloft, keeping the air below the saturation point. Steam fog forms when cold air moves over relatively warm water. This can be observed as wisps of "steam" rising from lakes, rivers or oceans when a cold air mass moves in. Upslope fog occurs as air is pushed up a mountainside and becomes saturated so that condensation occurs. Fog photographs courtesy of Rich Johnson and NOAA Weather type 4 - Freezing Rain / Ice Freezing rain - known as "ice" occurs when a thin layer of freezing or below freezing air exists near the earth's surface. Typically this occurs when snow falls into warmer air changing the precipitation into rain.

If a very thin layer of freezing air is present near the ground the rain will freeze on objects such as power lines, trees, and cars. Ice accumulations begin to cause serious problems when the ice is 1/2" or greater on objects. Freezing rain pictures courtesy of Nick Stefano. Weather type 5 - Hail The exact processes that creates hail are still being studied. Traditionally, textbooks showed hailstones being formed as a water droplet was carried aloft with an updaft into subfreezing air and freezing. As the ice moved into a downdraft, more water coated the hailstone. The cycle continued with the hailstone continuing to grow with each ride up and down the updraft and downdraft. More recent studies suggest that super cooled water droplets are carried aloft by strong updrafts in thunderstorms. A small ice particle forms and grows as "waves" of supercooled water droplets continue to bump into the ice particle. A new coat of ice grows with each cycle. The hailstone is kept aloft by the strong updraft. The stronger the updraft the greater the force to keep the heavier hailstones aloft.

The hailstone eventually falls to the grown when the the weight is too great for it to remain aloft or when it gets pushed out of the updraft. Sometimes hailstones bump into each other while being bombarded with supercooler water droplets and stick together giving the hailstone a spiked appearance. The largest known hailstone fell on Vivian, South Dakota on July 23, 2010. The hail stone weighed 1.9 pounds and was eight inches in diameter. The previous record was from a storm on June 23, 2003 in Aurora, Nebraska and had a diameter of seven inches and weighed almost one pound. Another heavy hailstone fell in Coffeeville, Kansas on September 3, 1970. It weighed 1.7 pounds. Hail is considered severe when the diameter reaches one inch or quarter size. Hail photographs courtesy of NOAA and Jim Reed - jimreedphoto.com Weather type 6 - Hurricane Check out our complete library on hurricanes on our hurricane school page. We also have hurricane tracking charts so that you can follow the path of hurricanes. Check out just about anything you want to know about hurricanes on the hurricane library tab at the top menu.

Hurricane pictures courtesy of NOAA. Weather type 7 - Lightning Lightning is simply a discharge of electricity in the atmosphere. For a complete look at this interesting phenomenon, check the facts about lightning page. Lightning photographs courtesy of Jim Reed - jimreedphoto.com Weather type 8 - Rain Rain is precipitation in liquid form. Liquid precipitation can occur as mist, drizzle, or rain. Droplet size differentiates the type that it is classified. Mist is generally 50-500 microns in size. Drizzle is .5 to 2 millimeters in size and rain is 2 millimeters to 1 centimenter in size. Rain is formed when condensation of water vapor occurs condenses into water droplets. Precipitation in the form of rain can be created in a number of different ways. First, two types of processes cause minute droplets to form rain drops. Collision coalescence is a process where tiny droplets gradually grow in size by bumping into each other and growing. This is mostly a warm cloud process where temperatures are above freezing. The second process is a cold cloud process where super cooled water droplets freeze on ice nuclei. These ice nuclei grow into ice crystals.

The snowflakes fall and turn into rain drops as the temperatures rise above freezing closer to the ground. This is the primary process that produces rainfall. Lifting to produce rainfall occurs in a number of differnt ways. 1. A low pressure system and associated fronts 2. Mountains or higher terrain 3. Atmospheric convection Weather type 9 - Sleet Sleet is transparent frozen raindrops. Sleet or ice pellets are created when snow falls into air above freezing and melts into rain drops. If another below freezing layer below the warm air is of sufficient depth, the rain drops freeze into balls of ice or ice pellets. Any significant amount of sleet is farily rare. This is due to the fact that there needs to be just the right conditons to get a perfect layer of warm air in between the layers of cold air. There have been cases of storms producing several inches of sleet. A mix of snow and sleet and sleet and rain is more common. Sleet pictures courtesy of NOAA. Weather type 10 - Snow Snow is the accumulation of crystal snowflakes. Snowflakes are made as water ice crystalizes.

The crystals may form in many different shapes dictated by the water content and temperature in the cloud as the snowflakes are forming. Snowflakes can take the shape of columns, dendrites, plates, needles and other six sided shapes. It is possible for it to snow several degrees above freezing if the air aloft is very cold and the above freezing layer is shallow near the ground. The greatest 24 hour snowfall in North America was 76" Silver Lake, Colo. April 14–15, 1921. The greatest amount of snow for one storm in North America was 189" at Mt. Shasta Ski Bowl, California, Feb. 13–19, 1959. The one season snowfall record for North America was 1,140" at Mount Baker, Wash. 1998–1999. Snow pictures courtesy of winter weather expert Paul Kocin. Weather type 11 - Sun Sunny weather or clear skies is defined as less than 1/8 sky cloud cover. Mostly sunny skies is characterized by 1/8 - 2/8 sky cloud cover.

Sunny skies many times are observed when a high pressure area is dominating the weather pattern. High pressure signifies a region of sinking air which tends to dry out the atmosphere resulting in less mositure to form clouds. Deserts are locations with sunny or mostly sunny skies due to high pressure systems influencing the weather pattern much of the year. Weather type 12 - Thunderstorm Thunderstorms are cumulonimbus clouds that produce thunder and lightning. Discover more about thunderstorms here. Thunderstorm photographs courtesy of NOAA / NSSL and Rich Johnson. Weather type 13 - Tornado A tornado is a violently rotating column of air usually produced by severe thunderstorms. For much more about tornadoes, check out our tornadoes page. Tornado photographs courtesy of Jim Reed. jimreedphoto.com Weather type 14 - Wind Wind is air in motion in the atmosphere. Windy weather is caused by an imbalance of heating in the atmosphere. It can be caused from an imbalance from solar heating or a difference over a boundary such as a front. The uneven heating generates an unbalanced pressure field. Air from a high pressure area flows toward a region of low pressure to balance the pressure field.

A wind vane points to the direction from where the wind is blowing from and an anemometer measures how fast the wind is blowing. The strongest surface wind gust was 253 mph on Australia's Barrow Island during Cyclone Olivia in 1996. The previous wind record was 231 mph set on top of Mount Washington, New Hampshire on April 12, 1934. Photographs courtesy of Rich Johnson and the Sydney Morning Herald. Talk about weather on the weather message boards . Ghana: Geography, Location, weather etc Today's Weather The climate of Ghana is tropical, but temperatures vary with season and elevation. Except in the north two rainy seasons occur, from April to July and from September to November. In the north the rainy season begins in April and lasts until September. Annual rainfall ranges from about 1,100 mm (about 43 in) in the north to about 2,100 mm (about 83 in) in the southeast. The harmattan, a dry desert wind, blows from the northeast from December to March, lowering the humidity and creating hot days and cool nights in the north.

In the south the effects of the harmattan are felt in January. In most areas the highest temperatures occur in March, the lowest in August. The average annual temperature is about 26oC (about 79oF). Annual Rainfall: 736.6mm / 29" Temp January: 27 Sunny skys Feb 28 ---" - March 28 ---" --- April 28 light rains May 27 heavy rains June 26 " July 25 light rains August 24 Scattered showers September 25 " October 26 Sunny skies November 27 ---"--- December 28 Sunny skies (dry) Sierra Leone Weather, Climate and Geography Sierra Leone Weather, climate and geography Weather & climate Best time to visit : The climate is tropical and humid all year. Between November and April, it is very hot and dry, although the coastal areas are cooled by sea breezes. In December and January, the dry, dusty Harmattan wind blows from the Sahara. Rainfall can be torrential during the rainy season between May and November.

In March there are sporadic rains, accompanied by strong winds, in the provinces when the heat of the dry season reaches its peak. If you decide to travel to the provinces during the month of March it is advisable to bring waterproof clothing to avoid getting drenched when you least expect it. In August, during the rainy season there is a period called the ‘seven day rainfall’ when the rain keeps falling for seven days straight without interruption. This time of the year is best avoided if you are looking for a sun soaked holiday on Sierra Leone’s beautiful beaches, but it is also the time when wildlife activity is at its peak and therefore a period of the year that attracts a lot of nature lovers. Required clothing : There are no restrictions on clothing for men or women, with casual attire such as sleeveless shirts, flip flops and sandals the norm. Lightweight and light-coloured, cotton clothing is recommended due to the hot and humid climate. During the rainy season it is advisable to wear wet-weather clothing, while a light jersey or jacket may be needed in the months when the Harmattan winds blow. Geography Sierra Leone is bordered to the northwest, north and northeast by Guinea Republic, and to the southeast by Liberia .

To the south and southwest lies the Atlantic Ocean. A flat plain up to 110km (70 miles) wide stretches the length of the coast except for the Freetown peninsula, where the Sierra Lyoa Mountains rise to 1,000m (3,280ft). In some coastal areas, sand bars have formed that stretch out as far as 112km (70 miles). Behind the coastal plain is the central forested area, drained by eight principal rivers, which has been cleared for agriculture. The land rises in altitude eastwards to the Guinea Highlands, a high plateau with peaks rising to over 1,830m (6,000ft) in the Loma Mountains and Tingi Hills area. The Mende tribe is prominent in the southeast and the Temne in the western and northern areas.

Question: What type of weather condition is a harmattan?
Answer: Wind