Transcript Relative humidity

WEATHER
The term weather describes the state of the air at a particular place and
time – whether it is warm or cold, wet or dry, and how cloudy or windy
it is.
AIR MASS
Air masses form above parts of the Earth that have similar
characteristics, such as an ocean, or a large forest. In order for an air
mass to take form, the air must remain above that location for at least a
couple of days, before moving on. In order for this to happen there
needs to be a high pressure system in the area.
FRONTS
Weather fronts are formed as the leading edge of two air
masses approach each other. The warmer air will always
slide over the top of the cooler air and usually brings
some sort of precipitation.
COLD FRONT
A cold front is defined as the transition zone where a cold air mass is
replacing a warmer air mass. Cold fronts generally move from
northwest to southeast. The air behind a cold front is noticeably colder
and drier than the air ahead of it. When a cold front passes through,
temperatures can drop more than 15 degrees within the first hour.
WARM FRONT
A warm air front is the place where a warm air mass replaces a cool air
mass. We already know that warm air overrides cold air. This is
because the air masses have different temperatures and
densities. Warmer tropical air is forced over the cooler polar air. This
forms a bulge on the front - called a warm front. If a warm front passed
overhead when you were standing outside, you would feel the air
warming up.
HUMIDITY
Humidity is a term for the amount of water vapor in air.
Relative humidity is the amount of moisture in the air compared to what
the air can "hold" at that temperature. When the air can't "hold" all the
moisture, then it condenses as dew.
HURRICANE
A hurricane or typhoon (sometimes simply referred to as a tropical cyclone, as
opposed to a depression or storm) is a system with sustained winds of at least
33 meters per second (64 kn) or 74 miles per hour (119 km/h).
A tropical cyclone is a storm system characterized by a large low-pressure center and
numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones
strengthen when water evaporated from the ocean is released as the saturated air
rises, resulting in condensation of water vapor contained in the moist air.
ISOBARS
A line drawn on a weather map connecting points of equal pressure is
called an "isobar“, and they are given in millibars.
LAND BREEZE
a coastal breeze blowing at night from land to sea, caused by the
difference in the rate of cooling of their respective surfaces.
SEA BREEZE
a wind from the sea that develops over land near coasts. It is formed by
increasing temperature differences between the land and water which create
a pressure minimum over the land due to its relative warmth and forces
higher pressure, cooler air from the sea to move inland.
SNOWFLAKE
Individual snowflakes are nearly unique in
structure.
WIND
air in natural motion, as that moving horizontally at any velocity along
the earth's surface: A gentle wind blew through the valley.