Download 21-1 Air Masses

21-1 Air Masses
Earth’s rotation causes differences in _______________, which in turn, creates wind patterns.
Fluids (including air) flow from _________ to _______ pressure.
Air mass-large body of air with similar ________________ and ______________ forms when a
mass of air moves ____________ or remain _________________.
Air masses (dry if formed over__________, moist if formed over ______________)
Source Region
Type of Air
Symbol
Continental
Maritime
Tropical
Polar
North American Air Masses come from six locations:
Air Mass
cP
Source Location
1.
Movement
Weather
Cold and dry
mP
Cold and moist
cT
2.
3.
4.
mT
5.
Warm and moist
Warm and dry
How is air over the ocean different from air over a continent? ________________
An air mass brings the weather of its ________________ but can change as it
____________________.
Air near the poles is _______. It ___________, and creates a ________ pressure area. Air near
the equator is ________. It __________, creating a _________ pressure area.
Air moves from ________ pressure to _________ pressure, or from ______ weather to
___________ weather.
Air generally flows from the __________ to the _____________.
Remember the Coriolis effect. It ________ winds to the __________ in the northern
hemisphere.
21-2 Fronts
Front: boundary between __________________ of different densities (fronts can be hundreds
to thousands of ___________________ long.)
Cooler air is ______________ and often does not mix with ________________ so a front forms.
Where cold air meets warm air, ____________ & _______________ often form.
Cold Front: A ____________ air mass moves into a ______________ air mass. It pushes
underneath the warm air &_______________ it. Lots of cold air ______________________.
Fast moving cold fronts often form ____________________ clouds…can result in short lived
violent ____________________. Cold front moves in: ___________________ rainstorm, then
temperature __________________. On a weather map, cold fronts are shown as
a_____________ line with ____________ pointing toward warmer air.
________________________: line of heavy thunderstorms that form ahead of a fast cold front.
Warm Front: warm air__________________ cold air…warm air rises as a _____________
slope. Clouds can form ___________________ the base of the front so warm fronts cause
_____________________over large areas. Warm front moves in: _________________rain,
then _________________ weather. On a weather map, warm fronts are shown as a
_____________ line with _____________________ pointing toward colder air.
______________________ Front: forms when two air masses move very slowly or not at all (or
air masses move parallel to each other). Symbol_______________ cold & warm front symbols.
______________________ Front: fast moving cold front completely overtakes a warm front
and lifts it off the ground completely.
______________________Front: In the main area of the US, between 60o and 30o N, weather
is mainly caused by the polar front between two large wind belts.
STORMS
______________________ Cyclones: Large, rotating _______________ often occur in the
____________ latitudes where the polar front meets warmer air. They are similar to
_________________, but much ________________ and less ____________.
________________________ often occur when cyclones do; they _______________ from a
high pressure area.
Thunderstorms: _________ stages, _________________, __________________ and
______________________. In the cumulus stage, warm moist air rises (_________________)
and forms a cumulus cloud. In the mature stage, the cloud becomes ______________________,
which can produce torrential _______________ and ______________. Air is dragged
_________________ with the precipitation. As the storm dissipates, the ________________
stop the rising air currents, and water vapor _________________________.
Lightning: (http://www.lightningsafety.noaa.gov/science/science-overview.shtml)
Lightning is an electrical ___________________ in the atmosphere, or between the
atmosphere and the ground. _____________________ is a stream of moving ______________.
_______ is an insulator that keeps electricity from flowing ________________. As particles of
ice and hail bounce around in the cloud, ______________ become positively charged and rise
to the top of the cloud, while _______________ becomes negative and drop to the bottom.
Lightning can occur within a cloud, between the ________________ bottom of the cloud and
the ground (negative lightning), or between the _________________ of the cloud and the
ground (positive lightning.) Lightning heats the air, which _____________ rapidly, producing
_______________.
______________________ lightning has farther to go; it happens less often but is much
stronger than negative lightning. So positive lightning starts _______________________, while
negative lightning ________________. Forestry departments have machines and people in
_______________ to record ____________________ and find ___________ early.
Hurricane: Most destructive storm that develops over _________________, has winds greater
than ___________ km/h that spiral in toward the intensely low pressure center. The hurricane
winds blow water toward the shore, causing huge ________________________.
Most hurricane deaths are caused by ____________________.
Warm, moist air over ocean ______________ rapidly & condenses. ___________ heat is
released in large amounts, and strengthens the rising air.
Thick _______________________ clouds spiral upward around a very low pressure center and
cause the ________________ winds to increase speeds. The _______ is clear, sinking air.
Rating hurricanes: Saffir-Simpson scale of 1 – 5; it uses pressure, wind speed, storm surge.
http://www.nhc.noaa.gov/aboutsshws.php has animation.
Hurricane Watch: ____________________________________________________________.
Hurricane Warning: __________________________________________________________.
Hurricane Andrew was a small category 5 hurricane which hit ___________________, south of
Miami in ___________. Hurricane Wilma was a large hurricane, category j5 when it hit the
_________________________________________; category 2 when it hit Weston in ________.
Tornadoes: destructive, rotating columns of _______ with VERY high wind speeds up to
________ km/h.. Forms when a thunderstorm meets high _________________ winds and
causes a narrow, ________________________-shaped extension that may or may not touch
the ground. If it touches the ground, it follows a haphazard (wandering) path
Most common in _______________________________.
Most deaths are from being _______________________ collapsing buildings and flying debris.
Tornado Watch: ____________________________________________________________.
Tornado Warning: __________________________________________________________.
A tornado hit __________________________ in northern Broward County on January 27, 2016.
21- 3 Weather Instruments
Lower Atmosphere:
Thermometer: Measures ________________________; liquid expands when heated.
Barometer: measures ______________________, which drops as a front approaches.
Anemometer: measures _________________________ with rotating cups.
Wind Vane: measures ___________________________.
Upper Atmosphere:
Radiosonde: Measures ___________________, _______________________ & __________________;
attached to a __________________________________________.
RADAR: Radio Detection and Ranging; uses _________________________________to determine
velocity and location of water in the atmosphere.
Weather Satellite: uses cloud sequence images to measure ___________________, measures
_______________ with infrared light detection. Also measures the ocean height & flow.
Computer: solves complicated ________________________________, also known as models.