With the use of a diagram show the symbols for Fronts.
Explain the term Cold Front.
Cold front: The leading edge of a relatively colder air mass which separates two air masses in which the gradients of temperature and moisture are maximized. In the northern hemisphere winds ahead of the front will be southwest and shift into the northwest with frontal passage. In the southern hemisphere winds ahead of the front will be northwest and shift into the northeast with frontal passage.
Explain the term Frontogenesis.
Frontogenesis : The formation of a front occurs when two adjacent air masses with different densities and temperatures meet and strengthen the discontinuity between the air masses. It occurs most frequently over continental land areas such as over the Eastern US when the air mass moves out over the ocean. It is the opposite of frontolysis.
Explain the term Frontolysis.
Frontolysis: The weakening or dissipation of a front occurs when two adjacent air masses lose contrasting properties such as the density and temperature. It is the opposite of frontogenesis.
Explain the term Occluded Front.
Occluded front: The union of two fronts, formed as a cold front overtakes a warm front or quasi-stationary front refers to a cold front occlusion. When a warm front overtakes a cold front or quasi-stationary front the process is termed a warm front occlusion. These processes lead to the dissipation of the front in which there is no gradient in temperature and moisture.
Explain the term Ridge
Ridge: An elongated area of relatively high pressure that is typically associated with a anticyclonic wind shift.
Explain the term Stationary Front.
Stationary front: A front that has not moved appreciably from its previous analyzed position.
Explain the term Trough
Trough: [Trof] An elongated area of relatively low pressure that is typically associated with a cyclonic wind shift.
Explain the term Warm Front.
Warm front: The leading edge of a relatively warmer surface air mass which separates two distinctly different air masses. The gradients of temperature and moisture are maximized in the frontal zone. Ahead of a typical warm front in the northern hemisphere, winds are from the southeast and behind the front winds will shift to the southwest.
Explain Low pressure and High pressure symbols.
Low pressure with a number such as 99 means 999 mb and with 03 means 1003 mb. High pressure with a number such as 25 means 1025 mb.
Explain the term Extra-tropical low.
Extra-tropical low: A low pressure center which refers to a migratory frontal cyclone of middle and higher latitudes. Tropical cyclones occasionally evolve into extra-tropical lows losing tropical characteristics and become associated with frontal discontinuity.
Explain the term Low Pressure.
Low pressure: An area of low pressure identified with counterclockwise circulation in the northern hemisphere and clockwise in the southern hemisphere. Also, defined as a cyclone.
Explain the term High Pressure.
High pressure: An area of higher pressure identified with a clockwise circulation in the northern hemisphere and a counterclockwise circulation in the southern hemisphere. Also, defined as an anticyclone.
Explain the term "New" when referring to low and high pressure centers.
New: The term "NEW" may be used in lieu of a forecast track position of a high or low pressure center when the center is expected to form by a specific time. For example, a surface analysis may depict a 24-hour position of a new low pressure center with an "X" at the 24-hour position followed by the term "NEW", the date and time in UTC which indicates the low is expected to form by 24 hours.
Explain the term Rapidly Intensifying.
Rapidly intensifying: Indicates an expected rapid intensification of a cyclone with surface pressure expected to fall by at least 24 millibar (mb) within 24 hours.
With the use of a diagram draw the Common Weather Symbols.
Common weather symbols
Explain the term Squall
Squall: A sudden wind increase characterized by a duration of minutes and followed by a sudden decrease in winds.
With the use of a diagram show the symbols for Wind Speed and Direction.
Wind speed and direction
With the use of a diagram draw the symbols for Fog.
Explain the term Fog.
Fog: Over the marine environment the term fog refers to visibility greater than or equal to 1/2 NM and less than 3 NM. Fog is the visible aggregate of minute water droplets suspended in the atmosphere near the surface.
Explain the term Dense Fog.
Dense fog: Within the marine environment the term dense fog refers to visibility less than 1/2 NM. Fog is the visible aggregate of minute water droplets suspended in the atmosphere near the surface. Usually dense fog occurs when air that is lying over a warmer surface such as the Gulf Stream is advected across a colder water surface and the lower layer of the air mass is cooled below its dew point.
Explain the term Sea Fog.
Sea fog: Common advection fog caused by transport of moist air over a cold body of water.
Explain with the use of diagram the symbols for Freezing Spray.
Explain the term Freezing Spray.
Freezing spray: Spray in which super-cooled water droplets freeze upon contact with exposed objects below the freezing point of water. It usually develops in areas with winds of at least 25 knots.
Explain the term Complex gale or storm.
Complex gale/storm: An area in which gale/storm force winds are forecast or are occurring, but in which more than one center is the generating these winds
Explain the term Developing Gale.
Developing gale: Refers to an extra-tropical low or an area in which gale force winds of 34 knots (39 mph) to 47 knots (54 mph) are "expected" by a certain time period. On surface analysis charts a developing gale indicates gale force winds within the next 36 hours. When the term developing gale is used on the 48 hour surface forecast and 96 hour surface forecast charts, gale force winds are expected to develop by 72 hours and 120 hours, respectively.
Explain the term Developing Storm.
Developing storm: Refers to an extratropical low or an area in which storm force winds of 48 knots (55 mph) or greater are "expected" by a certain time period. On surface analysis charts a developing storm indicates storm force winds forecasted within the next 36 hours. When the term developing storm is used on the 48 hour surface and 96 hour surface charts, storm force winds are expected to develop by 72 hours and 120 hours, respectively
Explain the term Gale.
Gale: Refers to an extratropical low or an area of sustained surface winds (one minute) of 34 knots (39 mph) to 47 knots (54 mph).
Explain the term Storm.
Storm: Refers to a extratropical low or a area of sustained winds (one minute) in excess of 48 knots (55 mph).
Explain the term Small Craft Advisory.
Small Craft Advisory: Refers to areas within the coastal waters with sustained winds (one minute) of 18 knots (21 mph) to 33 knots (38 mph).
With the use of a diagram draw the symbols for Tropical Systems.
Explain the term Hurricane.
Hurricane: A tropical cyclone with closed contours, a strong and very pronounced circulation, and one minute maximum sustained surface winds 64 knots (74 mph) or greater. A system is called a hurricane over the North Atlantic, Gulf of Mexico, North Pacific E of the dateline, and the South Pacific E of 160E.
Explain the term Tropical Cyclone.
Tropical cyclone: A non-frontal, warm-core, low pressure system of synoptic scale, developing over tropical or subtropical waters with definite organized convection (thunderstorms) and a well defined surface wind circulation.
Explain the term Tropical Depression.
Tropical depression: A tropical cyclone with one or more closed isobars and a one minute max sustained surface wind of less than 34 knots (39 mph).
Explain the term Tropical Storm.
Tropical storm: A tropical cyclone with closed isobars and a one minute max sustained surface wind of 34 knots (39 mph) to 63 knots (73 mph).
Explain the term Typhoon.
Typhoon: Same as a hurricane with exception of geographical area. A tropical cyclone with closed contours, a strong and very pronounced circulation, and one minute maximum sustained surface winds of 64 knots (74 mph) or greater. A system is defined as a typhoon over the North Pacific W of the dateline.
Explain the term Combined Seas.
Combined seas: The combination of both wind waves and swell which is generally referred to as "seas".
Explain the term Primary Swell Direction.
Primary swell direction: Prevailing direction of swell propagation.
Explain the term Significant Wave Height.
Significant wave height: The average height (trough to crest) of the 1/3rd highest waves. An experienced observer will most frequently report the highest 1/3rd of the waves observed.
Explain the term Swell.
Swell: Wind waves that have moved out of their fetch or wind generation area. Waves generated by swell exhibit a regular and longer period than wind waves.
Explain the term the High Seas.
High Seas: That portion of the Atlantic and Pacific oceans which extends from 20 to 40 nm off the Western and Eastern US coasts and extends to 35W in the Atlantic ocean and to 160E in the Pacific Ocean. The area includes both the coastal and offshore waters.
Explain the term Offshore Waters.
Offshore waters: That portion of oceans, gulfs, and seas beyond coastal waters extending to a specified distance from the coastline, to a specified depth contour, or covering an area defined by a specific latitude and longitude points
Explain the term Convection.
Convection: Caused by local, solar or manmade heating. The air above will become heated, expand becoming less dense and thus rise in columns. The clouds formed will be cumuloform and can have extensive vertical development.
Explain the term Turbulence.
Turbulence: Occurs when moderate or strong winds are disrupted by the earth’s surface. The rising air currents will cool adiabatically and combined with heat loss to a cold surface forming low stratus form clouds with very low vertical development.
Explain the term Orographic Uplift.
Orographic Uplift: Occurs when air is forced to rise over a land obstruction such as a mountain slope or hillside. A sharp rise will cause cumuloform clouds while a lesser slope will cause stratus form both on the windward side. In certain situations turbulence may form above and to leeward possibly causing stratocumulus of a lense shape.
Explain the term Frontal.
Frontal: At a warm front the warm air climbs over the cooler air at a gentle angle resulting in stratoform clouds from Ns, St, As, Cs to Cu. At a cold front the warm air rises much faster forming cumuloform clouds with considerable vertical development.
Explain the term Convergence.
Convergence: Occurs when air comes together at a point or line. When airs warm and cold air blowing in nearly opposite directions the warm air will rise causing clouds similar to a warm front. Convergence clouds of cumuloform type are found in tropical revolving storms.
Explain the term Adiabatic Process.
As air rises the pressure on it falls, the air expands to equal the pressure of the air around it. As the same amount of heat is now in a larger area the temperature will fall as the number of air/heat molecules touching the thermometer will be less than before.
The process is a change of temperature within the air without there being any gain or loss of heat from the air.
Explain the term Stable Air Condition.
When the DALR and the SALR are greater than the ELR, a parcel of air pushed upwards will become cooler than the air around it which has not moved. Being cooler, and more dense, it will fall back towards its original level if and when it can.
Explain the term Neutral Air.
Neutral air occurs when the adiabatic lapse rate of the ascending or descending air is the same as the ELR so the air under consideration will always be at the same temperature as the air around it. Being the same temperature it will not continue its motion or try to return to its original level once the moving force is removed.
Explain the term Unstable Air.
When the DALR and the SALR are smaller than the ELR, a parcel of air pushed upwards will become warmer than the air around it which has not changed altitude. Being warmer and less dense it will keep on rising regardless of the effect of the force that started its movement.
Explain the term Conditional Instability.
Conditional instability exists when the ELR is between the DALR and the SALR of a parcel of ascending air. The air will be stable as long as it remains dry, if it becomes saturated it will sooner or later become unstable.
Explain the term Global Wind Patterns.
Global Wind Patterns wind belts of the general circulation The global wind pattern is also known as the "general circulation" and the surface winds of each hemisphere are divided into three wind belts:
Polar Easterlies: From 60-90 degrees latitude
Prevailing Westerlies: From 30-60 degrees latitude (aka Westerlies)
Tropical Easterlies: From 0-30 degrees latitude (aka Trade Winds)
Explain the term Global Surface Currents.
Global wind-driven surface currents for a typical January. Warm currents are shown in red and cold currents are colored blue. Note the similarities and differences between large-scale ocean current and wind patterns.
Explain all aspects of Waves. (length / height / speed / period / crest / trough / breaking.
The length (D) of a simple wave is the horizontal distance, measured in meters, between two (2) consecutive wave crests.
The height (C) of a simple wave is the vertical distance, measured in meters, between the top of crest and the bottom of the trough on either side of the crest.
The speed of a wave is expressed in knots or meters/sec. It is the speed at which the individual wave is advancing.
The period of a wave is the time interval measured in seconds required for the passage of successive crests to pass a fixed point.
The crest (A) of a wave is the highest point that the water will rise to without losing solid contact with the body of water below it.
The trough (B) of a wave is the lowest the water descends to, in the oscillation of the water.
The breaking of a wave is the crest pushed by wind until it collapses (breaks).
Explain with the use of a diagram Wave Characteristics.
Explain the term Tsunami.
A tsunami (pronounced tsoo-nah-mee) is a wave train, or series of waves, generated in a body of water by an impulsive disturbance that vertically displaces the water column. Earthquakes, landslides, volcanic eruptions, explosions, and even the impact of cosmic bodies, such as meteorites, can generate tsunamis. Tsunamis can savagely attack coastlines, causing devastating property damage and loss of life.
Explain the term Occluded Front.
The union of two fronts, formed as a cold front overtakes a warm front or quasi-stationary front refers to a cold front occlusion. When a warm front overtakes a cold front or quasi-stationary front the process is termed a warm front occlusion. These processes lead to the dissipation of the front in which there is no gradient in temperature and moisture. At an occluded front there will always be a wedge of warm air aloft above the cold airs at the surface (sometimes called a trowel in Canada).
Explain the term Warm Occlusion.
When a warm front overtakes a cold front or quasi-stationary front. This often results in the dissipation of the front until there is no temperature or moisture gradient.
Explain the term Cold Occlusioin.
A cold occlusion forms when air blowing in behind the occlusion is colder than the air ahead so the warm air is lifted similar to a cold front.
Explain the term Warm Front.
Leading edge of relatively warmer surface air mass which separates two distinct air masses where the temperature and moisture gradients are maximized.
A warm front will travel at 60% of the geostrophic wind ahead of the warm front.
Explain the movement of a Depression.
If it has a well defined warm sector the center of the low will move in the same direction as the line of the isobars in the warm sector. The speed at which it moves is determined by the geostrophic wind in the warm sector (Frontal).
When there is no well defined warm sector, the depression will move in the direction and speed of the strongest winds around it (Non-Frontal).
Depression tends to move towards the isobaric low where the pressure is falling faster.
Secondary depressions move cyclonically around their primary.
Explain the various types of Depressions. Thermal / Vertical Instability / Oragraphic Uplift / Polar Front
Thermal (Non –frontal): Locally, inland and sea breezes are a small thermal depression.
Vertical Instability (Non-frontal): Tropical revolving storms form in the same air mass.
Orographic Uplift (Non-frontal): Form at a mountain barrier on the lee side.
Polar Front (Frontal): Warm, cold and occluded fronts form where two different air masses meet.
Explain the term Secondary Depression.
A secondary depression may form on the cold front where the isobars are elongated or “V” shaped behind the primary depression. Secondary depressions tend to circle cyclonically around the primary and tilt it more towards the pole. They frequently follow the primary depression path and “swallow” it as it occludes, slows down and starts to fill. This secondary will now become the primary if it spawns a secondary of its own, on its cold front. As the secondary may produce its own secondary there may develop a family of depressions which may be up to seven depressions before very cold polar air forces its way towards the equator and cuts off the generation of more centers. The weather conditions around the secondary are often more violent than those found on the primary.
Explain with the use of a chart Frontal Depression Weather Changes.
Explain the safe sector of a TRS in the Northern Hemisphere.
Area A is the most dangerous section of the safety sector and should be avoided at all costs.
Area C would be dangerous, especially close to the path where the eye will pass.
Area B would be dangerous in 6 to 18 hours time because it is likely the eye and dangerous quadrant will pass through here.
Area D will be hazardous if the storm curves to the left.
Opposite applies for the Southern Hemisphere
Explain the TRS seasons globally.
Explain the TRS seasons.
Name and explain the Seven (7) Fundamental Isobaric Patterns.
Explain the key points for the the 7 Isobaric Patterns.