× 1,000 = 3,180 feet AGL Quiz

PDF page 300: Middle clouds form around 6,500 feet AGL and extend up to and usually produce hazardous weather phenomena, such 20,000 feet AGL. They are composed of water, ice crystals, as lightning, hail, tornadoes, gusty winds, and wind shear. and supercooled water droplets. Typical middle-level clouds These extensive vertical clouds can be obscured by other include altostratus and altocumulus. These types of clouds cloud formations and are not always visible from the ground may be encountered on cross-country flights at higher or while in flight. When this happens, these clouds are said altitudes. Altostratus clouds can produce turbulence and may to be embedded, hence the term, embedded thunderstorms. contain moderate icing. Altocumulus clouds, which usually form when altostratus clouds are breaking apart, also may To pilots, the cumulonimbus cloud is perhaps the most contain light turbulence and icing. dangerous cloud type. It appears individually or in groups and is known as either an air mass or orographic thunderstorm. High clouds form above 20,000 feet AGL and usually form Heating of the air near the Earth’s surface creates an air mass only in stable air. They are made up of ice crystals and pose thunderstorm; the upslope motion of air in the mountainous no real threat of turbulence or aircraft icing. Typical high regions causes orographic thunderstorms. Cumulonimbus level clouds are cirrus, cirrostratus, and cirrocumulus. clouds that form in a continuous line are nonfrontal bands of thunderstorms or squall lines. Clouds with extensive vertical development are cumulus clouds that build vertically into towering cumulus or Since rising air currents cause cumulonimbus clouds, they cumulonimbus clouds. The bases of these clouds form in are extremely turbulent and pose a significant hazard to flight the low to middle cloud base region but can extend into high safety. For example, if an aircraft enters a thunderstorm, altitude cloud levels. Towering cumulus clouds indicate areas the aircraft could experience updrafts and downdrafts that of instability in the atmosphere, and the air around and inside exceed 3,000 fpm. In addition, thunderstorms can produce them is turbulent. These types of clouds often develop into large hailstones, damaging lightning, tornadoes, and large cumulonimbus clouds or thunderstorms. Cumulonimbus quantities of water, all of which are potentially hazardous clouds contain large amounts of moisture and unstable air to aircraft.

PDF page 300: Middle clouds form around 6,500 feet AGL and extend up to and usually produce hazardous weather phenomena, such 20,000 feet AGL. They are composed of water, ice crystals, as lightning, hail, tornadoes, gusty winds, and wind shear. and supercooled water droplets. Typical middle-level clouds These extensive vertical clouds can be obscured by other include altostratus and altocumulus. These types of clouds cloud formations and are not always visible from the ground may be encountered on cross-country flights at higher or while in flight. When this happens, these clouds are said altitudes. Altostratus clouds can produce turbulence and may to be embedded, hence the term, embedded thunderstorms. contain moderate icing. Altocumulus clouds, which usually form when altostratus clouds are breaking apart, also may To pilots, the cumulonimbus cloud is perhaps the most contain light turbulence and icing. dangerous cloud type. It appears individually or in groups and is known as either an air mass or orographic thunderstorm. High clouds form above 20,000 feet AGL and usually form Heating of the air near the Earth’s surface creates an air mass only in stable air. They are made up of ice crystals and pose thunderstorm; the upslope motion of air in the mountainous no real threat of turbulence or aircraft icing. Typical high regions causes orographic thunderstorms. Cumulonimbus level clouds are cirrus, cirrostratus, and cirrocumulus. clouds that form in a continuous line are nonfrontal bands of thunderstorms or squall lines. Clouds with extensive vertical development are cumulus clouds that build vertically into towering cumulus or Since rising air currents cause cumulonimbus clouds, they cumulonimbus clouds. The bases of these clouds form in are extremely turbulent and pose a significant hazard to flight the low to middle cloud base region but can extend into high safety. For example, if an aircraft enters a thunderstorm, altitude cloud levels. Towering cumulus clouds indicate areas the aircraft could experience updrafts and downdrafts that of instability in the atmosphere, and the air around and inside exceed 3,000 fpm. In addition, thunderstorms can produce them is turbulent. These types of clouds often develop into large hailstones, damaging lightning, tornadoes, and large cumulonimbus clouds or thunderstorms. Cumulonimbus quantities of water, all of which are potentially hazardous clouds contain large amounts of moisture and unstable air to aircraft.

PDF page 300: Middle clouds form around 6,500 feet AGL and extend up to and usually produce hazardous weather phenomena, such 20,000 feet AGL. They are composed of water, ice crystals, as lightning, hail, tornadoes, gusty winds, and wind shear. and supercooled water droplets. Typical middle-level clouds These extensive vertical clouds can be obscured by other include altostratus and altocumulus. These types of clouds cloud formations and are not always visible from the ground may be encountered on cross-country flights at higher or while in flight. When this happens, these clouds are said altitudes. Altostratus clouds can produce turbulence and may to be embedded, hence the term, embedded thunderstorms. contain moderate icing. Altocumulus clouds, which usually form when altostratus clouds are breaking apart, also may To pilots, the cumulonimbus cloud is perhaps the most contain light turbulence and icing. dangerous cloud type. It appears individually or in groups and is known as either an air mass or orographic thunderstorm. High clouds form above 20,000 feet AGL and usually form Heating of the air near the Earth’s surface creates an air mass only in stable air. They are made up of ice crystals and pose thunderstorm; the upslope motion of air in the mountainous no real threat of turbulence or aircraft icing. Typical high regions causes orographic thunderstorms. Cumulonimbus level clouds are cirrus, cirrostratus, and cirrocumulus. clouds that form in a continuous line are nonfrontal bands of thunderstorms or squall lines. Clouds with extensive vertical development are cumulus clouds that build vertically into towering cumulus or Since rising air currents cause cumulonimbus clouds, they cumulonimbus clouds. The bases of these clouds form in are extremely turbulent and pose a significant hazard to flight the low to middle cloud base region but can extend into high safety. For example, if an aircraft enters a thunderstorm, altitude cloud levels. Towering cumulus clouds indicate areas the aircraft could experience updrafts and downdrafts that of instability in the atmosphere, and the air around and inside exceed 3,000 fpm. In addition, thunderstorms can produce them is turbulent. These types of clouds often develop into large hailstones, damaging lightning, tornadoes, and large cumulonimbus clouds or thunderstorms. Cumulonimbus quantities of water, all of which are potentially hazardous clouds contain large amounts of moisture and unstable air to aircraft.

PDF page 299: fog is less than 20 feet thick, it is known as ground fog.

PDF page 299: When a layer of warm, moist air moves over a cold surface, nuclei are important because they provide a means for the advection fog is likely to occur. Unlike radiation fog, wind moisture to change from one state to another.

PDF page 299: is required to form advection fog. Winds of up to 15 knots

PDF page 299: also increases drag, which when combined with lowered lift Steam fog, or sea smoke, forms when cold, dry air moves over production, can adversely affect the ability to take off. An warm water. As the water evaporates, it rises and resembles aircraft must be thoroughly cleaned and free of frost prior smoke. This type of fog is common over bodies of water

PDF page 299: Fog is a cloud that is on the surface. It typically occurs when Ice fog occurs in cold weather when the temperature is the temperature of air near the ground is cooled to the air’s much below freezing and water vapor forms directly into ice dew point. At this point, water vapor in the air condenses and crystals. Conditions favorable for its formation are the same becomes visible in the form of fog. Fog is classified according as for radiation fog except for cold temperature, usually –25 to the manner in which it forms and is dependent upon the °F or colder. It occurs mostly in the arctic regions but is not current temperature and the amount of water vapor in the air. unknown in middle latitudes during the cold season.

PDF page 299: the wing and can drastically reduce the production of lift. It

PDF page 299: the ground, buildings, and other objects like cars and aircraft. Upslope fog occurs when moist, stable air is forced up sloping This moisture is known as dew and sometimes can be seen land features like a mountain range. This type of fog also on grass and other objects in the morning. If the temperature requires wind for formation and continued existence. Upslope is below freezing, the moisture is deposited in the form of and advection fog, unlike radiation fog, may not burn off with frost. While dew poses no threat to an aircraft, frost poses a the morning sun but instead can persist for days. They can definite flight safety hazard. Frost disrupts the flow of air over also extend to greater heights than radiation fog.

PDF page 304: Cold fronts move more rapidly than warm fronts, progressing the skies usually clear rapidly, and the front leaves behind at a rate of 25 to 30 mph. However, extreme cold fronts gusty, turbulent winds and colder temperatures.

PDF page 304: Comparison of Cold and Warm Fronts Warm fronts and cold fronts are very different in nature as are the hazards associated with each front. They vary in speed, composition, weather phenomenon, and prediction. Cold fronts, which move at 20 to 35 mph, travel faster than warm fronts, which move at only 10 to 25 mph. Cold fronts also possess a

PDF page 305: Cold fronts are fast approaching with little or no warning, Occluded Front and they bring about a complete weather change in just a An occluded front occurs when a fast-moving cold front few hours. The weather clears rapidly after passage and drier catches up with a slow-moving warm front. As the occluded air with unlimited visibilities prevail. Warm fronts, on the front approaches, warm front weather prevails but is other hand, provide advance warning of their approach and immediately followed by cold front weather. There are two can take days to pass through a region. types of occluded fronts that can occur, and the temperatures of the colliding frontal systems play a large part in defining Wind Shifts the type of front and the resulting weather. A cold front Wind around a high-pressure system rotates clockwise, while occlusion occurs when a fast moving cold front is colder low-pressure winds rotate counter-clockwise. When two than the air ahead of the slow moving warm front. When high pressure systems are adjacent, the winds are almost in this occurs, the cold air replaces the cool air and forces the direct opposition to each other at the point of contact. Fronts warm front aloft into the atmosphere. Typically, the cold are the boundaries between two areas of high pressure, and front occlusion creates a mixture of weather found in both therefore, wind shifts are continually occurring within a front. warm and cold fronts, providing the air is relatively stable. Shifting wind direction is most pronounced in conjunction A warm front occlusion occurs when the air ahead of the with cold fronts.

PDF page 306: warm front is colder than the air of the cold front. When this and instability are present, the clouds continue to increase is the case, the cold front rides up and over the warm front. If in vertical height. Continuous, strong updrafts prohibit the air forced aloft by the warm front occlusion is unstable, moisture from falling. Within approximately 15 minutes, the weather is more severe than the weather found in a cold the thunderstorm reaches the mature stage, which is the most front occlusion. Embedded thunderstorms, rain, and fog are violent time period of the thunderstorm’s life cycle. At this likely to occur. point, drops of moisture, whether rain or ice, are too heavy for the cloud to support and begin falling in the form of rain

PDF page 301: referred to as rain. Rain that falls through the atmosphere but evaporates prior to striking the ground is known as virga. Freezing rain and freezing drizzle occur when the temperature of the surface is below freezing; the rain freezes on contact with the cooler surface.