Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha
Aviation Meteorology Instructor & Aviation Weather Forecaster E-mail. eshtewib@hotmail.com
METEOROLOGY What exactly is meteorology?
Meteorology is the study of the earth atmosphere and weather phenomena
Atmosphere is the blanket of air around the earth
What is the weather? The weather is just the state of the atmosphere at any given time and place. including things such as temperature .atmospheric pressure ,winds, Precipitation, Cloud and state of the sky..
Weather and Flying closely related linked. The weather is very important part of a pilot life for it determines the conditions in which the pilot will be flying in.
The Atmosphere The atmosphere is a remarkable mixture of life-giving gases surrounding our planet with out the atmosphere there would be no Protection from ultra violet rays and other harmful radiation from the sun. though this protective blanket is essential to life on earth.
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Protection from ultra violet rays support human animal and plant life
Atmosphere Composition the atmosphere is made up of mixture of gases surrounding the earth and the different gases which form this by volume are 78% nitrogen and 21% oxygen. 1% other gases (hydrogen.helium.neon.etc) Water vapor is the most important element in the atmosphere that is responsible for major changes in the weather
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Layers of the Atmosphere Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Layers of The Atmosphere
The atmosphere is divided in to layers based on temperature and are known as
1.troposphere 2.stratosphere 3.mesosphere 4.thermosphere
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.c om
Temperature change with height used to define different layers in the atmosphere
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
The Troposphere layer is closest to the earth and contains the largest percentage of the mass of the total atmosphere (contains most of the earth weather) in this layer the temperature decreases with altitude The height of troposphere layer:
At the equator.from the surface-17km (54.000feet) At the pole. from the surface - 8km (24.000feet)
The average altitude of the troposphere about 36.000feet The boundary between the troposphere
and stratosphere is called tropopause
Tropopause located at the top of the troposphere. The temperature
remains fairly constant here. This layer separates the troposphere from the stratosphere .We find the jet stream here. These are very strong winds that blow eastward.
The tropopause is highest near the equator and lowest at poles
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Atmosphere Layers Troposphere Layer
The stratosphere layer or ozone layer:
Temperature increase with altitude The height of stratosphere layer At the equator 17 – 50km(160.000feet) At the pole 8 - 50km(160.000feet) The boundary between the stratosphere and mesosphere is called stratopause Mesosphere layer .temperature decreases in this layer as altitude increases The height of mesosphere layer 50-85km Thermosphere temperature rises with altitude increases
International Standard Atmosphere (ISA) The international standard atmosphere is based on mean sea level values . At mean sea level the Pressure
1013.25 mb(hpa) =29.92 inch mercury And temperature +15C (59F) Each decreases as height is gained The temperature of the atmosphere falls at rate of 2C per 1000feet (6.5C per 1km) The pressure falls at about 1 mb (hpa)
per 30 feet
For Flight Weather Charts The Following Relationships Are Used. Pressure Level - Flight Level Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
100 mb(hpa) 150 mb(hpa) 200 mb(hpa) 250 mb(hpa) 300 mb (hpa) 400 mb(hpa) 500 mb(hpa) 700 mb(hpa) 850 mb(hpa)
FL530 FL450 FL390 FL340 FL300 FL240 FL180 FL100 FL050
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.c om
The actual atmosphere can differ from the ISA in many way sea level pressure varies from day to day .indeed from hour to hour and the
Temperature also fluctuates
between wide extremes at all levels The variation of pressure throughout the atmosphere both horizontally and vertically – is of a great significant to pilots as it affects the operation of the altimeter
Atmospheric Circulation The movement of air relative to the earth surface is called atmospheric circulation. The atmosphere is fixed to the earth by gravity .and rotates with the earth The dynamic natural of the atmosphere is due in a large part to unequal temperature at the earth s surface.
Heating Effects in The Atmosphere Solar Heating
There is one basic reason we have weather and that is the sun .weather systems start because the sun energy heats up some parts of earth more than others Because of the earth’s curvature The most direct rays of the sun strike the earth in the vicinity of the equator .while the poles receive the least direct light and energy from the sun Concentration of the energy is greats at the equator The Temperature of the air depends on the temperature of the surface directly below
The air surrounding the earth is mainly heated from below by the earth’s surface
The Sun's energy is more concentrated per unit area in A than it is in B A and B are equal and parallel clusters of light rays from the Sun. At A the Sun is overhead and the rays are at right angles to the atmosphere and the surface of the Earth. At B the rays Aviation Meteorology Course Prepared & Designed approach the By.Eng. Eshtewi Benrabha atmosphere Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com from an angle
Temperature
Two system of temperature scales use 1. Celsius system 2. Fahrenheit system To convert from one system to other use this two formula F= 9/5 (C)+32 C=5/9(F-32) Covert 35 C to F F=9/5(35)+32=315/5+32=63+32=95
Covert 95F to C
C=5/9(95-32)=5/9(63)=315/9=35
The Transfer of Heat Energy 1. The transfer of heat by the vertical motion of an air mass is called Convection
2. The transfer of heat by the horizontal motion of an air mass is called Advection 3. The transfer of heat from body to body is called the process of Conduction
4. The transfer of heat as electromagnetic waves is called the process of Radiation
Convection In meteorology. convection refers primarily to atmospheric in the vertical motion’s .so the world of convection is usually reserved for describing transfer by vertical motion The circulation of the air over the earth is largely due to the unequal heating of the earth surface. Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Heat is transported or circulated from one latitude to another .when air is heated its molecules spread apart. As the air expands it become less and lighter than the surrounding air as air cools the molecules become packed more closely together making it denser and heavier than warm air. as a result the cool heavy air tends to sink and replace warmer rising air .this circulation process is known as convection
Three Cell Circulation
A three cell circulation develop in each hemisphere of smooth .homogeneous earth rotating at one revolution per 24 hours .as the earth rotates the single cell Aviation Meteorology Course circulation breaks Prepared & Designed By.Eng. Eshtewi Benrabha up to three cell Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com model distribute heat energy
Hadley cell: Warm air
rises at the equator and flows to word the poles aloft .but that branch of the circulation reaches only 30 latitude where the air sink
Hadley cell: forms between equator and
30 latitude northern and southern hemisphere Ferrel cell: forms between 30 - 60 latitude northern and southern hemisphere Polar cell: Forms between 60 - and the pole north and south hemisphere
Polar cell
Ferrel cell
Hadley cell
Hadley cell
Ferrel cell
Polar cell
Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Atmospheric pressure
The definition of atmospheric pressure as the weight of column of air per unit area directly above the surface Atmospheric pressure is measured by using mercury barometer
Pressure always decreases with altitude
Unequal heating of the surface causes changes in pressure. Meteorologists plot pressure reading on weather maps and connect points of equal pressure with lines called isobar
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aneroid Barometer An aneroid barometer is an alternative to a mercurial barometer; it is easier to read and transport. Mercury Barometer
Isobars :are the line of equal
pressure depicting the horizontal distribution on the earth surface Isobars are useful because they can help to identify pressure systems which are classified as Highs . Lows . Trough . Ridge . and Col area Isobars line can never cross each other
When the isobars are very close together they indicate strong wind Strong pressure gradient is indicated on weather map by closely spaced isobar When the isobars are more widely spaced they indicate light wind A week pressure gradient is indicated on a weather map by spread widely apart
Aviation Meteorology Course
Prepared & Designed
By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Isobars Isobars
Isobars line can never cross each other
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
High (H) is a center
of a high pressure surrounding all sides by lower pressure
Low (L) is a center of a low pressure surrounding all sides by high pressure
Ridge: is an elongates area of high pressure
Trough: is
an elongated area of low pressure
Col area: area between two highs and two lows
Strong pressure gradient is indicated on weather map by closely spaced isobar
A week pressure gradient is indicated on a weather map by spread widely apart
In the northern hemisphere the wind flows clockwise around area of high pressure and counterclockwise around area of low pressure . Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
In the southern hemisphere the wind flows counterclockwise around area of high pressure and clockwise around area of low pressure .
Good weather is often associated with high pressure (anticyclone)
Bad weather is often associated with low pressure (cyclone)
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Isobars
Anticyclone is an
area of divergence and high pressure
Cyclone is an area
of convergence and low pressure
Aviation Meteorology Course
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High Pressure Low Pressure (Anticyclone) (Cyclone)
Wind Wind can be defined simply as air in motion Wind is caused by horizontal pressure differences. Wind direction always given from where it come from. The term of advection means horizontal movement of air
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
West wind
south wind
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Meteorology relate wind direction to true north .so all winds that appear on meteorological forecasts or observation are in true north. A wind whose direction has changing in a clockwise direction is called veering wind. Example 15025KT to 22030KT this is veered
A wind whose direction has changing in an anticlockwise direction is called a backing wind. Example 10015KT to 03012KT
Buy Ballot's Law states that when you
stand with your back to the wind in the Northern Hemisphere the center of low pressure will be to your left and the high pressure to your right. The opposite is true for the Southern Hemisphere Cyclone – low pressure – anticlockwise in Northern Hemisphere .and clockwise in Southern Hemisphere Anticyclone – high pressure – clock wise in Northern Hemisphere . And anticlockwise in Southern Hemisphere
Flying From High to Low
If an aeroplane in the northern hemisphere is experiencing right drift, the wind is from the left and therefore, according to Buys Ballot's law, the aeroplane is flying towards an area of lower pressure.
Flying From Low to High
If an aeroplane in the northern hemisphere High is experiencing left drift, the wind is from the right and therefore, according to Buys Ballots law the aeroplane is flying towards an area of higher-pressure. High pressure often indicates a more stable atmosphere and generally better weather (although fog Low may occur).
Low
High
Atmospheric Force Our atmosphere is full of forces that becomes balanced and as result we can say something about its motion The forces we talk about is
1. pressure gradient force 2. coriolis force 3. frictional force
Aviation Meteorology Course A pressure gradient creates wind which blows Prepared Designed from high & to low pressure By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Pressure gradient force (PGF) Direction of PGF always from high pressure area to lower pressure area perpendicular to the isobars lines of constant pressure Magnitude of the PGF related to how closely packed the isobars are When the isobars are close together than the pressure gradient is very strong A pressure gradient creates wind which blows from high to low pressure
Although wind blows from areas of high pressure to areas of low pressure .it dos not blow in straight line .why. that because the earth rotating. in the northern hemisphere the spin of the earth causes winds to curve to the right and to lift in the southern hemisphere this is called coriolis force
. That is way in the northern hemisphere winds blow clockwise around an area of high pressure .and counterclockwise around low pressure
Wind can be defined simply as air in motion
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Coriolis Force
The coriolis force is an apparent force that results from the constant rotation of the earth Coriolis force acts to the Right in the northern hemisphere and to the Left in the southern hemisphere The amount of deflection produced by coriolis force also varies with latitude Coriolis force is zero at the equator and increases toward the poles Coriolis force is not that large for slow moving objects or those moving over a short distance. High latitude and high wind speed produces the strongest coriolis force.
Frictional Force
The frictional force always acts in the opposite direction of the wind. it slows the wind speed Frictional force depends on the roughness of the surface Friction is in the direction exactly opposite the direction of the wind
Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Global Wind Pattern
The global wind pattern is also known as general circulation and the surface winds of each hemisphere are divided in to three wind belt tread wind blow from 30 degree latitude to the equator (subtropical high pressure to equatorial low)
westerlies wind blow 30 to 60 latitude (subtropical high pressure to sub polar low pressure)
polar easterlies wind blow from 90 to 60 latitude ( polar high to sub polar low pressure )
Three cell circulation patterns produce: 1. Areas of low pressure over the equator called (equatorial low pressure) and at 60 degree latitude known as (sub polar low pressure)
2. Areas of high pressure near 30 degree latitude and poles Known as
(subtropical high pressure) and (polar high pressure)
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Global Wind Pattern
0 to 30 N Northeast Trades 0 to 30 S Southeast Trades 30 to 60 N,S Westerlies 60 to 90 N,S Polar easterlies Aviation Meteorology Course Prepared & Designed
By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Local Wind Patterns Local wind patterns my be of greater practical importance to the aviation since they usually cause significant changes in the weather of particular area.
Sea breeze During day time land heats up much faster than water a sea breeze blows from the cool water to the warmer land during the day .sea breeze stronger than land breeze
Land breeze
At night a land breeze blows from the cooler land to the warm water. Land breeze usually weaker than sea breeze because of friction Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
The sea breeze blows from the water to the land during the day . and the land breeze blows from the land to the water during night
Valley breeze:
Occurs during the day as the sun warms mountain slopes
Mountain breeze: Occurs at night as the high terrain cools (relative to air over the valley)
Katabatic wind
Any down slope wind can be classified as a katabtic wind The term katabatic is used to refer to downwind flows which are stronger than mountain breeze. Katabatic winds can be either warm or cold depending on its cause.
Cold downslope winds
A cold down slope wind can become quite strong as flows downhill from snow covered mountain slopes
Warm downslope wind
A fast moving wind down a mountain slope will warm as it descends sometimes raising the temperature at the base of the mountain
Katabatic wind Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Anabatic Winds
Heating of a mountain slope by day causes the air mass in contact with it to warm, decreasing its density and causing it to flow up the slope. Since its flow up hill is opposed by gravity the daytime anabatic wind is generally a weaker flow than the night-time katabatic wind.
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
The end of section A
Any Question? Good Luck
Prepared & Designed
By Eng. Eshtewi Benrabha
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Atmospheric Stability
Knowledge of air stability is important because it the determine the vertical movement of air The atmosphere resistance vertical motion is called stability The atmosphere is stable with respect to unsaturated air The atmosphere is unstable with respect to
saturated air (moist air) In an unstable atmosphere convection is the rule Air warmer than the surrounding will tend to rise (because of its lower density) Air cooler than the surrounding will tend to sink (because of its greater density) Air at the same temperature as its surrounding will tend be remain at the same height (because there is no density difference)
The stability of an air mass is decreased by warming from below The stability of an air mass is increased by cooling from below
Adiabatic process :
Warm air raises Cold air sinking
rising air cools sinking air warms
When parcel of air Rises pressure decrease and temperature decreases volume increases When parcel of air Sinking pressure increases temperature increases volume decreases
Adiabatic process: change in temperature without heat being added or taken away. but by pressure changes as rises or sinks
Adiabatic cooling mean:
When parcel of air rises – expands and cools
Adiabatic heating mean:
When parcel of air sinking – compresses and warm
Laps rate:
The rate at which temperature decreases with an increase in altitude .and the average rate of temperature change is 2C per 1000 feet
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Adiabatic cooling
Adiabatic heating
ADIBATIC LAPSE RATE
Describes the temperature decreases that occurs when a parcel of air is lifted As air descends it is compressed and warmed adiabatically
DRY ADIBATIC LAPSE RATE (DALR)
Decreases at a rate of 3 degrees Celsius per 1000 feet SATURATED ADIABATIC LAPSE RATE (SALR) Decreases at a rate of 1.5 degrees Celsius per 1000 feet Moist air cools at a slower rate than dry air because heat is released during the condensation process as the air is lifted
Temperature inversions In general pattern of temperature distribution in the atmosphere is that temperature decreases with height .when the temperature increases with altitude temperature inversion exists (Inversion means that the temperature increase as height increases) Temperature inversion occurs in stable air with a little or no wind .below the inversion visibility is often restricted by fog, haze and smoke Visibility is often very poor in a temperature inversion
Moisture If we can think of heat as the energy that drives the weather machine then the moisture in the form of water vapor is the Fuel. Without moisture there would be no cloud or precipitation in other words no weather as know it.
Moisture
Cloud is formed from water vapor that is contained in the atmosphere it is taken up to the atmosphere by evaporation from the oceans and other bodies where water is present. The amount of moisture in the air depends on the air temperature If the air is very moist poor. or sever weather can occur. If the air is very dry the weather usually will be good. Dew point temperature indicates the amount of moisture in the air. High dew point temperature higher moisture
Change of state Water is the only substance that is found naturally in the atmosphere as liquid, solid and gas ( water,ice,water vapor) Change in state occur through the processes of evaporation ,condensation , sublimation ,deposition, melting, and freezing. Adding or subtracting heat make the cycle work
Adding or subtracting heat make the cycle work 1.Evaporation is the change of liquid water to invisible water vapor 2. condensation it occurs when water vapor change to a liquid 3.sublimation is the change of ice to water vapor 4.deposition is the change of water vapor to ice 5.milting is the change of ice to water liquid water 6.freezing is the change of liquid water to ice The process which water vapor is added to the atmosphere by evaporation and sublimation Water in its vapor state is not visible but when the water vapor condense to form water droplets we see it as cloud. fog and mist
Humidity
Humidity simply refers to moisture in the air
Water vapor in the air called humidity Humidity is defined as the amount of water vapor in the air Relative humidity is percent of saturation When the air is saturated relative humidity 100 Relative Humidity and Dew Point are closely related, and are based upon the amount of water vapor in the air and the total amount of water vapor that the air can hold at a given temperature. The warmer the air, the more water vapor it can contain, and the cooler the air, the less vapor it can contain.
Dew Point
Dew point: is the temperature to
which air must be cooled to become saturation Dew point temperature indicating the amount of moisture in the air High dew point temperature equate with moist air Low dewpiont temperature indicted dry air
Clouds often form at the altitude where temperature and dewpoint temperature reach the same value You can calculate the cloud base by using the following formula T. 80 F , Td 62 F
Temperature(F) -Dewpoint(F) /4.5*1000=cloud base AGL
T= 80 F & Td= 62 F 80-62/4.5=18/4.5=4*1000=4000Feet AGL T=26C & Td=16C Air temperature (C) – dewpoint temperature (C) *400= cloud base AGL 26-16=10*400=4000 Feet AGL
Dew and Frost
Dew and frost are most likely to form on clear and cool night Dew forms when moist air contact with a cold surface condenses in to liquid water droplets When the temperature falls below freezing point, the moisture in the air freezes into ice crystals. This is frost. Frost considered hazardous to flight because its spoil the smooth flow of air over the wings
decrease lift and increase drag
Always remove all frost from the air craft surface before flight
Dew
Frost
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Freezing
Aviation Meteorology Course Prepared & Designed
Clouds
By Eng. Eshtewi Benrabha Aviation Meteorology Instructor & Aviation weather forecaster E-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor & Aviation weather forecaster E-mail. eshtewib@hotmail.com
Clouds
When you look in to the sky and see a cloud it’s actually moisture you are seeing. Most of time water vapor in the air can not be seen unless it collects and condenses to form cloud Cloud and fog usually form as soon as the air becomes saturated. Air saturation when the air temperature and dewpoint temperature spread reaches 2C and continues to decreases
clouds, fog and dew always form when water vapor condenses A small and decreasing temperature and dewpoint spread indicates conditions are favorable for formation of fog
Types of clouds
Meteorologists divide cloud in to four basic groups or families depending up on their appearance (form) and the altitudes where they occur. Clouds are classified as: 1. Low clouds 2. Middle clouds 3. High clouds 4. Clouds with vertical development The rain clouds contain the prefix or suffix nimbus which means rain. (The term nimbus describes clouds which produce rain) Nimbostratus & cumulonimbus
Low clouds Low clouds extend from near the surface to about 6.500 feet AGL .when contact with the ground they called fog
1.stratus ( St) 2.stratocumulus (Sc) 3.nimbostratus (Ns)
stratus ( St)
stratocumulus (Sc)
Nimbostratus (Ns)
Fog is low cloud and classified according to way of form:
Radiation Fog:
usually occurs in stable air associated with high pressure forms in moist air over low flat areas on clear calm night little or no wind and small temperature and dewpoint spread
Advection Fog:
When warm and moist air is blown over a cold surface it becomes chilled and my form a blanket of fog called advection fog
Upslope Fog:
forms when moist air forced up sloping land mass Advection fog and up sloping fog depends up on wind in order to exist
Steam Fog :
Which is often called sea smoke Low level turbulence and aircraft icing are associated with steam fog The term of advection means horizontal movement of air
Radiation Fog
Upslope Fog Advection Fog
Steam Fog
Middle Cloud Middle clouds have range from about 6.500 to 20.000feet AGL
1. Altostratus (As) 2. Altocumulus (Ac) Altostratus (As)
Altocumulus(Ac)
High clouds High clouds have bases beginning above 20.000feet AGL.
1.cirrus (Ci)
cirrus (Ci)
2.cirrostratus (Cs) 3.cirrocumulus (Cc)
cirrostratus (Cs)
cirrocumulus (Cc)
Cloud With Vertical Development 1. cumulus (CU) Towering cumulus(TCU) 2. cumulonimbus (CB)
Towering cumulus (TCU)
cumulus (CU)
cumulonimbus (CB)
Aviation Meteorology Course Prepared & Designed Cumulus (CU) By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed Towering cumulus (TCU) By.Eng. Eshtewi Benrabha
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Cumulonimbus (CB)
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Precipitation: transfer of water
from the atmosphere back to earth
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Precipitation Precipitation can be defined as any
form of water particles, whether liquid or solid, that fall from the atmosphere and reach the ground. Precipitation contributes to many aviation weather problems, it can reduce visibility, effect engine performance, increase braking distance and cause dramatic shifts in wind direction and velocity.
Precipitation causes:
For precipitation to occur, water or ice particles must grow in size until they can no longer be supported by the atmosphere.
Types of precipitation: Drizzle and Rain
Drizzle (DZ): Very small droplets (less than 0.02inches in diameter) Rain (RA): When it is 0.02 inches in diameter or greater considered to be rain Rain drops that evaporate before reaching the ground are known as virga
Ice Pellets and Hail :( PL. GR.GS)
If the rain falls through a temperature inversion it may freeze the underlying colder air, striking the ground as ice pellets PL. occur with temperature inversion
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PL
Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Hail water droplets that freeze in clouds with strong upward currents my grow in size as they collide with other freezing water droplets eventually the become too large for air currents to support ,and they fall as hail
Ice Pellets. PL Large hail. GR Small hail. GS
Hail GR
Large Hail
GR
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Small Hail
GS
Snow : SN
Snow is precipitation composed of ice crystals Ice crystals that descend from cirrus clouds are called cirrus fallstreaks,or mares tails
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Air Masses
An air mass can be described as the air with similar properties of temperature and moisture which cover a large area.
Source Regions
The area where an air mass acquires the properties of temperature and moisture that determine its stability is called source regions.
Also we can say it is the region over
which an air mass forms and takes on its characteristic temperature and moisture.
Classifications
Air masses are classification according to their source region. The tow source regions are polar (P) and tropical (T) to identify their temperature characteristics and continental or maritime to identify their moisture content. Continental (C) if the source region is over land the air will be relatively dry so the air mass is considered continental. Maritime (M) if the source region is over water the dewpoint will be higher and the air is considered maritime.
There Are Four Basic Air Masses: 1. Continental tropical (cT) Hot and Dry 2. Maritime tropical (mT) Moist and Warm 3. continental polar (cP) Cold and Dry 4. Maritime polar (mP) Moist and Cool
Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Modification
As the air mass moves out of its source region it is modified by the temperature and moisture of the area over which it moves.
The stability of an airmass is decreased by warming from below The stability of an airmass is increased by cooling from below
Fronts
Defined as the boundary between air masses of different temperature and moisture. When two air masses meet the warm air rises above the cooler denser air. the transition region between the two air masses is known as front .the type of front depends on booth the direction in which the air mass is moving and characteristics of the air mass.
One of the most easily recognized discontinuities across a front is a change in temperature
A variation that will Always occur when across A front is a change in the wind
Types of Fronts
There are four types of fronts that will be described below. 1.cold fronts 2.warm fronts 3.occluded fronts 4. stationary front
To locate a front on a surface map, look for the following:
. sharp temperature changes over relatively short distances, . before the passage of cold front the pressure normally DROPS and after the passage of cold front the pressure normally RISES. . changes in the moisture content of the air (dew point), . shifts in wind direction, . low pressure troughs and pressure changes, and Clouds and precipitation patterns.
Cold Front
Cold front: is one where cold air is moving
to displace warmer air. Cold air is heaver or more dense than warm air the cold air is moves under the warm air mass. Cold front moves faster than all other types of front Cold fronts tend to be associated with the most violent weather.
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Cold Front Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Cold Fronts
are indicated on weather maps by using blue line with blue triangles on one side of line.
Cold Front
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Warm Fronts
A Warm front develops when warm air replaces cold air. They usually move at much slower than cold front
If you look up to the sky and see cirrus , cirrostratus cloud followed by altostratus and nimbostratus ,stratus cloud you would be observing the passage of a warm front.
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Warm Front
indicated on weather maps by using red semi-circles on a red line. Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Cold Front and Warm Front
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Stationary Front A front that does not move or barely moves. The weather in a stationary front is usually a mixture of that found in both warm and cold fronts stationary fronts are indicted on weather map as Aviation Meteorology Course
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Occluded Fronts: Because cold fronts move faster than warm fronts, they can catch up to and overtake their related warm front. When they do, an occluded front is formed.
Occluded Fronts are indicted on weather map as Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
There are two types of occluded fronts cold and warm occluded front: 1. Cold front occlusion: occurs when the air mass behind the cold front is colder and more dense than cool air mass in advance of the warm front 2. Warm front occlusion: occurs when the air mass ahead of the warm front is colder and more dense than both the cold air mass behind the cold front and the warm air mass
The end of section B
Any Question?
Good Luck
Prepared & Designed
By Eng. Eshtewi Benrabha
Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Weather Hazarders Thunderstorms (TS):
Thunderstorms are a great hazard to aviation .
thunderstorm is a storm that contains thunder and lightning.
Usually accompanied by gusty surface wind and icing, hail and heavy rain. All thunderstorms are dangerous. Every thunderstorm produces lightning. Thunderstorm born when warm humid air rises in conditionally unstable atmosphere.
Three conditions must be present for thunderstorm development: 1. unstable condition 2. lifting force 3. high moisture
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Types of thunderstorms There are two basic thunderstorm types described as an air mass thunderstorm and sever thunderstorm.
Air mass thunderstorms: are scattered thunderstorm that occurs in the summer afternoons or in costal areas at night. Sever thunderstorms: characterized by wind gusting of 50 knots or more hail 他 inches in diameter or large and tornadoes
A thunderstorm may exist as single cell, supercell, or if a combined with others in multicell A single cell thunderstorm lasts less than one hour. A supercell sever thunderstorm may last two hours. A multicell storm is a compact cluster of thunderstorm. it is usually composed of air mass thunderstorm in different stages of development ,
in some cases thunderstorm may form in a line, called a squall line it often forms 50 to 300 miles ahead of fast moving cold front. Thunderstorm along squall line may be ordinary multicell,supercell or mixture of storms. the most severe weather conditions such as destructive wind heavy hail and tornadoes are generally associated with squall line
Frontal thunderstorm
is sometimes used to refer to storms which are associated with frontal activity.
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Life Cycle
There are three stages in a thunderstorm life: 1. cumulus stage 2. mature stage 3. dissipating stage
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1.The cumulus stage is the development stage during this stage there is only updraft and no precipitation reaching the ground (Cumulus stage is characterized by continues up drafts)
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
2.The mature stage: during this stage there is both an updraft and downdraft. Thunderstorm reach the greatest intensity during the mature stage which is signaled by the beginning of precipitation. An indication that down drafts have developed and that the thunderstorm cell has entered the mature stage is when precipitation begin to fall from the cloud base.
Aviation Meteorology Course
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3. Dissipating stage in the dissipating stage, the thunderstorm is dominated by the downdraft.
(A dissipating thunderstorm is characterized by downdraft)
Aviation Meteorology Course
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Thunderstorm hazards
The weather hazards associated with thunderstorm are not confined to the cloud itself .for example you can encounter turbulence in clear conditions as far 20 miles from the storm.
Turbulence:
Thunderstorm turbulence develops when air currents change direction or velocity rapidly over a short distance. The magnitude of turbulence depends on the difference between the two air currents. The strongest turbulence occurs in the zone between the updrafts and downdrafts. Sever turbulence often exists in a cumulonimbus cloud ,the most turbulence of all cloud’s.
Lightning is always Aviation Meteorology associated with Course thunderstorm Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Lightning:
Lightning is always associated with thunderstorms. and can occur in several forms Lightning is the visible electric discharge produced by a thunderstorm .and can occurs in several forms, including in cloud, cloud-to cloud cloud to ground.
Hail:
Hail is most likely to be associated with cumulonimbus clouds, any hail can be
dangerous, large with diameters greater than 他 inches can cause significant damage to aircraft.
Hail Aviation Meteorology
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Tornadoes:
Tornadoes is a violently rotating column of air which is found below cumulonimbus clouds. Funnel clouds are violent ,spinning columns of air which descend from the base of a cloud .wind speeds within them may exceed 200 knots If a funnel cloud reaches the earths surface ,it is referred to as a tornado ,if touches down over water it is called a waterspout.
Turbulence
Based on description from pilots. Crew and passengers aviation turbulence is best defined simply as bumpiness in flight. Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation turbulence can be divided in to four categories depending on where the turbulence occurs. 1. low level turbulence (LLT) 2. turbulence in and near thunderstorm (TNT)
3. clear air turbulence (CAT) 4. mountain wave turbulence (MWT)
1. low level turbulence is often defined simply as turbulence below 15.000feet.
Low Level Turbulence includes:
(LLT)
Mechanical Turbulence Convective Turbulence Frontal Turbulence Wake Turbulence
Mechanical Turbulence is often
experienced in the traffic pattern when the wind forms eddies as it blows around hangars, stands of trees, or other obstructions. as the winds grow stronger mechanical turbulence extends to greater heights .for example when surface winds are 50KT or greater, significant turbulence due to surface effects can reach altitude in excess of 3.000feet AGL. Mechanical turbulence is produced down wind of obstruction such as line of trees, building and hills.
Convective Turbulence: which is also referred to as thermal turbulence is typically day time phenomena which occurs over land in fair weather. When sufficient moisture is present .towering cumulus (TCU) clouds indicate the presence of convective turbulence. Frontal Turbulence: occurs in the narrow zone just ahead of a fast moving cold front where updrafts can reach 1000 F.P.M.
Aviation Meteorology Course Mechanical Prepared & Designed
Turbulence
By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Convective Turbulence
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Frontal Turbulence Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Wake Turbulence
Wake turbulence is created by the airplane it self .some times wake turbulence can visible .if you are like enough to fly when the temperature and dewpoint are very close together. The intensity of the turbulence depends on aircraft weight speed, and configuration.
Wake Turbulence
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Clear Air Turbulence (CAT) is that turbulence which occurs in the free atmosphere away from any visible convective activity. Clear air turbulence (CAT) is commonly thought of as a high altitude phenomena it usually is encountered above 15.000feet.it often develops in or near the jet stream .which is narrow band of high altitude winds near the tropopause
Mountain Wave Turbulence
Mountain wave turbulence is possible as a stable air moves across a ridge and the wind is 40 knots or greater. The three types of cloud formation associated with standing mountain waves are:
1. Lenticular cloud 2. Rotor cloud 3. Cap cloud
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So Lenticular,Cap.Rotor clouds signal the presence of mountain wave turbulence.
Mountain Wave Turbulence
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
One of the most dangerous features of mountain wave is the turbulence area in and below rotor clouds.
Lenticular clouds are lens-shaped
clouds which indicate the crests of standing mountain waves they form in the updraft and dissipate in the downdraft. they don’t move as the wind blows through them.lenticular cloud may contain winds of 50kt or more and extremely dangers.
Cap Cloud
Lenticular
Wind Shear: wind shear is best described
as a change in wind direction and /or speed with very short distance. An important characteristic of wind shear is that it may be associated with a thunderstorm .a low level temperature inversion. A jetstrem .or a front zone
If there is thunderstorm activity in the vicinity of an airport at which you plane to land. You should expect wind shear and turbulence on approach
Microburst is one of the most dangerous sources of wind shear.
Microburst is one of the most Aviation Meteorology dangerous sources of wind Course shear. Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Microburst Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Icing
Condition necessary for icing 1. visible moisture 2. out side air temperature below freezing The accumulation of ice on an aircraft increases drag , weight and decreases lift and thrust . Visible moisture is necessary for structural icing to form .freezing rain usually produces the highest rate or ice accumulation.
There are three general types of ice: 1. Rime ice: this type of ice is encountered in stratus clouds and normally forms in temperature between -15C and -20C. 2. Clear ice: develops in areas of large supercoold water droplets which are in cumulus clouds. Clear ice forms in temperatures between 0C to -10C. 3. Mixed ice: is combination of rime and clear ice and is possible in visible moisture when temperature between -10C and -15C.
Restriction to visibility:
Restriction to visibility can take many forms the most common of which are haze,smoke.smog and dust. HAZE. HZ Haze- fine dry or wet dust particles suspended in the that reduce visibility. SMOKE : FU is the suspension of combustion particles in air the impact of smoke on visibilty is detrmined by the amount of smoke produced,wind velocity,diffustion by turbulence ,and distance from the source.
SMOG: a mixture of smoke and fog .poor visibility over large area. DUST: DU SAND: SA SAND STORM : SS DUST STORM : DS Volcanic ash: VA
The end of section C
Any Question? Good Luck
Prepared & Designed
By Eng. Eshtewi Benrabha Aviation Meteorology Instructor E-mail. eshtewib@hotmail.com
Aviation Meteorology ICAO Aviation Weather ReportsCourse and Forecasts METAR , SPECI / TAF Prepared & Designed By Eng. Eshtewi Benrabha Code Format Aviation Meteorology Instructor Meteorology Warnings & Aviation weather forecaster & Weather Charts E-mail. eshtewib@hotmail.com
Aerodrome Reports and Forecasts
PART A: aviation routine weather report METAR and SPECI PART B: Terminal Aerodrome Forecast TAF
PART A
METAR: is the name of code for aviation routine
weather report (meteorology aeronautical report) also referred as actual weather. METAR: is issued at hourly or half hourly intervals. SPECI: is the name of code for aviation special weather report. SPECI can be issued at any time indicating significant change in one or more elements.
Both METAR and SPECI have the same code format and both may have trend forecast. METAR and SPECI contains the following information: 1 .identification group 2 .surface wind (speed and direction) 3 .prevailing visibility 4 .run way visible range (if available) 5 .present weather 6 .cloud 7 .air and dewpoint temperature 8 .pressure 9 .supplementary information
METAR
Type of Report
Or
SPECI
CCCC station identifier (ICAO four letter aerodrome code) H LLT , DTTA , EGLL , HLLB YYGGggZ (DDhhmmZ ) date and time of report the day of the month and time of observation in hour and minutes followed by letter Z =ZULU (GMT) Modifier: AUTO used when the observation is done by an automatic weather station COR corrected
Wind Group
dddffKT (DDDssKT): the first three digits indicate the wind direction and the two digits indicate wind speed ,When we have gust wind is indicate by G and shows as dddffGfmfmKT (DDDssGssKT): Gust is added if the average wind speed is exceeded by 10KT or more of the mean wind speed. A Variable wind direction will be shown by VRB e.g VRB02KT would indicate that the wind was only 2KT but would not be blowing from fixed direction. (dddVddd)
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Visibility group (VVVVD) (VVVV): Visibility is recorded as four figure group in meters (M).or statute miles (SM ). D: direction variation in visibility when the horizontal visibility is not the same in all direction. D take N- north, E- east , S- south , W-west Example: 2000SW 6000N (2000M the south west and 6km to the north) 9999 indicates that the visibility is 10km or more, CAVOK mean cloud and visibility ok
R36L/1200M means Run way 360 left, visual range is
1200m Run way visual range (RVR) is based on a pilot in moving air craft should see when looking down the run way if included in a meter .RVR will be report following prevailing visibility.
Weather Group :Present weather
Weather obscurations occurring in the vicinity of the airport are shown by (VC)
VC (vicinity) :indicate for the phenomena
observed at about 8km from the air port and not at the air port .
VCTS
means thunderstorm in the vicinity
BR (Mist)
is reported when the visibility is reduced by water droplets or ice crystals to 1000m up to 5000m ( 5/8SM to 3 SM)
FG (Fog)
is reported when the visibility is reduced by water droplets or ice crystals to less than 1000m (less than 5/8 SM)
The intensity indicators for precipitation are:
( - ) Light ( no sign ) moderate ( +) heavy BR Mist FG Fog FU Smoke DU Widespread Dust SA Sand HZ Haze PY Spray SQ Squalls FC Funnel Cloud Tornado Waterspout SS Sandstorm DS Dust storm VA Volcanic Ash
-RA RA +RA
DR Low Drifting BL Blowing SH Shower's TS Thunderstorm FZ Freezing DZ Drizzle RA Rain SN Snow SG Snow Grains IC Ice Crystals PL Ice Pellets GR Hail GS Small Hail
Sky Condition Cloud groups consist of six characters NNNhhh NNN:the first three indicate cloud amount and shown by the following abbreviations. hhh :the last three characters indicate the height of the cloud base in feet above the station level
Abbreviation FEW( few) SCT (scattered) BKN (broken) OVC (overcast)
-
definition
1-2/8 of sky is covered by cloud. 3-4/8 of sky is covered by cloud.
5–7/8 of sky is covered by cloud
8/8 of sky is covered by cloud. NNNhhh / NNNhhh / NNNhhh / NNNhhh FEW020 / SCT030 / BKN050 / OVC030
cumulonimbus indicated by CB
SCT020CB
cumulus of great vertical extent TCU
SCT030TCU
the mountain stations when cloud base is below station level the cloud group should read NNN/// example SCT/// BKN/// when the sky is clear SKC nil significant cloud NSC
C A V O K cloud and visibility ok
Temperature and Dewpoint TT/TdTd
12/08 Temperature below 0c will be preceded by M to indicate (minus) Example -9c is reported as M09
QPPPP
Pressure: QNH
Q. indicator for QNH and PPP pressure value Example : Q1008 , Q 0996 In some countries inches of mercury are used as the unit of QNH in this case the indicator will be A instead of Q Example: A of 30.05 inches is reported as A3005
NOSIG no significant changes in weather
Trend Forecasts
This is only available at selected airfields. It is intended to indicate significant changes of weather in the two hours after the observation is made. If the change is temporary then TEMPO is used followed by the predicted conditions. If the change is permanent them BECMG (Becoming) will be used. Example. TEMPO 3000 SHRA = temporary visibility 3000 meters with rain showers. BECMG 33035KT = becoming 35 kts of wind from 330.
NOSIG = no significant changes in weather
To help remember the sequence, think of 3 Word's at the beginning-
Where, When, and Wind This works for METAR as well as TAF!
OK, that's the details so lets take a look at some examples. First we look again at the METAR I copied from Amsterdam METAR EHAM 121050Z 24015KT 8000 RA SCT025 BKN040 10/09 Q1010 NOSIG This is a typical METAR and is quite easy to decode. The report was measured 12 at 1050 UTC and it shows that Amsterdam was reporting a wind of 240 at 15 kts, the visibility was 8km (8000m), it was raining, cloud was scattered at 2500 ft and broken at 4000 ft. Temperature was 10C and dew point 9C, the sea level pressure (QNH) was 1010 mb and there was no significant change expected in the next two hours.
A METAR can be quite brief sometimes:
METAR EGLL 110920Z 27005KT CAVOK 15/10 Q1013 NOSIG This shows that Heathrow at 0920 UTC was giving a slight 5kt westerly wind with no cloud or visibility problems, Temperature was 15C and dew point 10C , pressure 1013 mb and there was no significant change expected in the next two hours. SPECI EGLL 110930Z 29020G35KT 5000 SHRA BKN015 OVC020 10/10 Q 1012 NOSIG
On the other hand, in bad weather a METAR can look much different.... Have a look at this one at EGBB is Birmingham, UK. in poor visibility:
METAR EGBB 141550Z 26005KT 0550 R23L/0450 FZFG OVC002 M02/M02 Q0994 NOSIG which shows a met visibility of 550 meters and a RVR reading on 23L of 450 meters in freezing fog with a 200 ft cloud base. Temp and Dew Point are down at -2C and there was no significant change expected in the next two hours.
METAR HLLT 211130Z 33012KT 280V010 9999 SCT030 18/07 Q1015 NOSIG METAR HLLB 212345Z 17015KT CAVOK 12/06 Q 1016
HLLS 211050Z 22O15KT CAVOK 26/O3 Q1O15 METAR LMML 211115Z 29027G38KT 250V320 9999 SCT040 12/01 Q1010 NOSIG METAR DTTA 211130Z 30021G31KT 270V330 9999 SCT026 SCT093 12/00 Q1016 NOSIG
PART B
Terminal Aerodrome Forecast (TAF) Aerodrome forecast TAF is complete
description of the meteorological elements expected at and over the aerodrome throughout the whole of the forecast period including any changes considered to be significant to aircraft operation. Usually for a 9 , 24 and 30 hours period. The standard 9 hour TAFs is updated and reissued every three hours. 24 and 30 hours TAF is updated and reissued every 6 hours
TAF : prepared by professional staff who
using the latest available regulations TAF: describe the forecast prevailing conditions
at an aerodrome and cover a period of nine hour (9), (24) and (30) hours The 9 hour TAFs issued every three hours and called short TAF The 24 and 30 hour TAFs issued very 6 hours and called long TAF TAFs valid for 9 hours update every 3 hour intervals. TAFs valid 24 hours and 30 hours update every 6 hour intervals. Both short and long TAFs will be issued between 60 and 35 minutes in advance of start of the TAF
Example 9 hour TAF Aviation Course Issue Meteorology time valid time
DD2300Z DD00/dd09 Prepared & Designed DD0200Z DD03/dd12 By Eng. EshtewiDD06/dd15 Benrabha DD0500Z DD0800Z DD09/dd18 Aviation Meteorology Instructor DD1100Z DD12/dd21 DD1400Z DD15/dd24 DD1700Z DD18/dd03 DD2000Z DD21/dd06 Where DD refers to day of month at issue and start of TAF and dd refers
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to day of month at end of TAF
Example 24 hour TAF Issue time valid time DD2300Z DD0500Z DD1100Z DD1700Z
DD00/dd24 DD06/dd06 DD12/dd12 DD18/dd18
Where DD refers to day of month at issue and start of TAF and dd refers to day of month at end of TAF
Example 30 hour TAF Issue time valid time DD2300Z DD0500Z DD1100Z DD1700Z
DD00/dd06 DD06/dd12 DD12/dd18 DD18/dd24
Where DD refers to day of month at issue and start of TAF and dd refers to day of month at end of TAF
TAF (Terminal Aerodrome Forecast)
TAF HLLT 201100Z 2012/2112 06012KT 9999 SCT026 BECMG2021/2023 VRB02KT 7000 PROB 40 TEMPO 2102/2106 4000 BR FM210700 36014KT 8000 SCT025 BKN090 TEMPO 2107/2112 6000 SHRA OVC020
type of report (TAF) or TAF AMD amendment Location identifier. ICAO four letter identifier issuance date and time DDHHmmZ valid period DDFm/DDTL .DD day of the month . beginning (Fm) and ending time (TL) in hours (Z)
Forecast elements
1. Forecast wind 2. Forecast visibility 3. Weather 4. Forecast sky condition .significant changes expected during the forecast period. TEMPO temporary condition Forecast change group FM (from) BECMG (becoming) PROB% probability 30 or 40 percent issued if higher probability is expected TEMPO is used (PROB 40 TEMPO 2102/2106 4000 BR) means 40% probability temporary change between 0200Z and 1600Z.
CEILING: The height of the lowest layer of clouds, when the sky is broken or overcast
TAF HLLB 021700Z 0218/0318 06015KT 8000 SCT025 BKN080 PROB 40 TEMPO 0300/0308 6000 -RA BKN020 FM030800 02008KT 9999 FEW030 BECMG 0314/0316 8000 SCT026 BKN100
TAF LMML 052300Z 0600/0609 28013KT 9999 FEW011 PROB30 TEMPO 0600/0606 8000 BKN007 TAF HLLM 081100Z 0812/0821 06012KT CAVOK TAF EGBB 021700Z 0218/0318 24006KT 9999 SCT040 PROB30 TEMPO 0303/0307 24015G25KT 6000 SHRA BECMG 0307/0310 31011KT
TAF DTTA 021700Z 0206/0306 34010KT 9999 SCT026 BECMG 0212/0214 30010KT TEMPO 0314/0318 7000 SCT016 BECMG 0301/0304 VRB02KT 6000 TAF EGLL 021100Z 0212/0312 26007KT 9999 SCT045 PROB30 0303/0309 7000 RA BKN014 OVC045 TAF DTTJ 021700Z 0218/0318 08012KT 8000 SCT020 BKN100 PROB40 TEMPO 0218/0305 VRB25KT 5000 -TSRA SCT030CB BECMG 0306/0308 03016KT BECMG 0314/0316 VRB03KT 9999 FEW016
TAF DTTJ 061700Z 0618/0724 12008KT 6000 FEW020 SCT026 PROB30 TEMPO 0618/0622 26019G31KT 3000 SA -TSRA FEW033CB BECMG 0622/0624 36019G31KT BECMG 0701/0703 03012G23KT SCT016 BECMG 0708/0710 9999 SCT023 BECMG 0716/0718 04017G29KT BECMG 0721/0723 04014KT 8000
TAF EHAM 061100Z 0612/0718 06012KT 9999 SCT035 BKN100 BECMG 0617/0620 04007KT BECMG 0706/0709 09006KT SCT020 BKN040 BECMG 0712/0715 VRB03KT 7000 -RA SCT012 BKN025 PROB30 TEMPO 0715/0718 4000 TSRA SCT008 SCT018CB BKN020
Pilot Weather Report Pilot Weather Report (PIREPs) include information such as the height of bases and tops of cloud layers in-flight visibility ,icing conditions ,wind shear and turbulence
Area Forecasts (FA)
FA is used to determine enroute weather including conditions at air port that do not have terminal forecasts. Area forecast are normally issued three times daily and are valid for 18 hours .an FA has four sections 1. A header: describes the source of the FA the date and time of issue. the valid times and areas the FA cover. 2. Precautionary statements: describe IFR and mountain obscuration .thunderstorm hazards and states that all heights are MSL unless other wise noted. 3. synopsis: is brief summary identifying the location and movement of pressure systems ,fronts, and circulation patterns the 18 hours forecast . 4. VFR cloud and weather: section lists expected sky conditions visibility and weather for the next 12 hours and an outlook for the following 6 hours. The four section of area forecasts are: 1. header 2. precautionary statements 3. synopsis 4. VFR cloud and weather
AIRMET
AIRMET is a acronym for airman’s meteorology information . AIRMETs are issued every 6 hours with amendments issued, as necessary. AIRMET warn of weather conditions which are particularly hazardous to small, single engine aircraft. AIRMETs are issued for moderate icing ,moderate
turbulence, wind of 30knots or more at the surface, ceilings less than 1000feet and /or visibility less than 3 miles affecting over 50 percent of an area at one time and extensive mountain obscuration,
AIRMETmessage shall be prepared in abbreviated plain language. using approved ICAO abbreviation and numerical values.
International AIRMET Message
YUCC AIRMET 2 VALID 221215/221800 YUDOYUCC AMSWELL FIR MOD MTW OBS AT 1205Z AND FCST N48 E10 FL080 STNR NC Meaning: The second AIRMET message issued for the AMSWELL flight information region (identified by YUCC amswell area control center by the donlon /international meteorological watch office (YUDO) since 0001 UTC;the message is valid from 1215 UTC to 1800 UTC on the 22nd of the mounth;moderate mountain wave was observed at 1205 UTC at 48 degrees north and 10 degrees east at flight level 080;the mountain wave is expected to remain stationary and not to undergo any changes in intensity
SIGMET
(Significant Meteorological Information) A SIGMET identifies weather condition that are hazardous to all types of all aircraft.
CONVECTIVE SIGMET
Convective SIGMET warning of weather hazards including tornadoes, embedded thunderstorms, and hail 3/4inch or greater in diameter. SIGMET information shall be cancelled when the phenomena are no longer occurring or are no longer expected to occur in the area.
International SIGMETs are issued worldwide by ICAO meteorological watch offices International SIGMET for turbulence:
YUCC SIGMET 2 VALID 221215/221600 YUDO YUCC AMSWELL FIR SEV TURB OBS AT 1210Z YUSB FL250 MOVE E WKN
Meaning: The second sigmet message issued for the amswell flight information region (identified by YUCC amswell area control center) by the donlon international * meteorology watch office (YUDO) since 0001 UTC; the massage is valid from 1215 UTC to 1600 UTC on the 22nd of month ;sever turbulence was observed at 1210 UTC over siby/bistck (YUSB) AT FLIGHT LEVEL 250; the turbulence is expected to move eastward and weaken in intensity.
AERODROME WARNINGS
aerodrome warnings shall give concise information in plain language of meteorological conditions which could adversely affect aircraft on the ground including parked aircraft, and the aerodrome facilities and service. the warnings shall be issued in accordance with local arrangements to operators, aerodrome service and others concerned, by the meteorological office designated to provide service for that aerodrome
Aerodrome warning should relate to the occurrence or expected occurrence of one or more of the following phenomena: Sand storm , dust storm , rising sand or dust , strong surface wind and gusts , squall , frost , thunderstorm , tropical cyclone , hail , snow , fog , mist
upper air & Significant Weather Charts
For Flight Weather Charts The Following Relationships Are Used.
Pressure Level
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
100 150 200 250 300 400 500 700 850
mb(hpa) mb(hpa) mb(hpa) mb(hpa) mb (hpa) mb(hpa) mb(hpa) mb(hpa) mb(hpa)
- Flight Level FL530 FL450 FL390 FL340 FL300 FL240 FL180 FL100 FL050
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.c om
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Prepared & Designed Aviation Meteorology Instructor
By.Eng. Eshtewi Benrabha
e-mail. eshtewib@hotmail.com
Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Prepared & Designed Aviation Meteorology Instructor
By.Eng. Eshtewi Benrabha
e-mail. eshtewib@hotmail.com
Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By.Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
Aviation Meteorology Course Prepared & Designed By Eng. Eshtewi Benrabha Aviation Meteorology Instructor e-mail. eshtewib@hotmail.com
The End
Please direct any questions or comments to:
Eng. Eshtewi Benrabha Aviation Meteorology Instructor
& Aviation weather forecaster
E-mail. eshtewib@hotmail.com
Thank You
And good luck for all