Download Precipitations

Precipitations
Name: __________________________________________ Period: _______ Date: ___________
Essential Question: How do snows, hail, sleet, and rain form?
One of the more common questions before a winter storm strikes usually centers
around whether your area will receive snow, sleet, freezing rain, or a combination of all three.
Meteorologist at the National Weather Service continually investigate atmospheric data and
computer model forecasts, to forewarn you of any or all of these hazards. But what is the
difference between freezing rain and sleet…and even snow? It all depends on the temperature,
not only here on the ground, but in the upper atmosphere as well. We get just rain when the
temperatures are above 32° throughout most of the air column above the surface. Snow is
produced when temperatures are cold both aloft and at the ground. The snow does not melt as
it falls, and temperatures at or below 32 degrees near the ground allow it to accumulate.
Sleet is formed when temperatures is slightly above freezing aloft produce rain that freezes to
ice pellets, as it falls into a cold layer of air. Sleet usually bounces when hitting a surface and
does not stick to objects. However, it can produce a “sandlike” accumulation like snow.
Freezing rain forms when warm temperatures aloft , generally several degrees above freezing,
produces rain that falls onto a surface with temperatures below 32 degrees. This causes the
liquid rain to freeze on impact to objects such as trees, power lines, cars and roads forming a
coating or glaze of ice. Even a small amount of freezing rain on roads can create a significant
travel hazard. ( aloft means great height )
http://www.crh.noaa.gov/eax/?n=pcpntype http://dfw.cbslocal.com/2013/11/22/freezing-rain-vs-sleet-vs-snow/
Clarifying Questions:
1. How do meteorologist at the National Weather Service investigate and predict the weather?
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2. Why do meteorologist take their job of investigating the condition of the atmosphere seriously?
Think! _______________________________________________________________________________
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3. What factors determines the type of precipitation?
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4. What condition/s results to rain as the type of precipitation?
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5. What condition/s results to snow as the type of precipitation?
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6. What condition/s results to sleet as the type of precipitation?
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7. How can sleet form “sandlike” accumulation like snow?
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8. What condition/s results to freezing rain as the type of precipitation?
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Analyze the figures on the left and answer the questions on the right.
9. Describe the temperatures from the upper troposphere to the
ground when the type of precipitation is snow.
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10. What is the freezing point of water? ( 0 F or 32 F )
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11. Describe the tilt of our planet in space when it is winter.
( Tilted away from the Sun or Tilted towards the Sun)
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12. Describe the temperatures from the upper troposphere to the
ground when the type of precipitation is sleet.
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13. What conditions make the type of precipitation sleet rather than
snow? Think!
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14. Describe the temperatures from the upper troposphere to the
ground when the type of precipitation is freezing rain.
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15. Which layer of the atmosphere do weather changes occur?
( troposphere or Stratosphere)
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16. Which layer of the atmosphere do we find the ozone layer?
( troposphere or Stratosphere )
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Weather processes such as wind, clouds, and precipitation are all the result of the atmosphere
responding to uneven heating of the Earth by the Sun. The uneven heating causes temperature
differences, which in turn cause air currents (wind) to develop, which then move heat from where there
is more heat (higher temperatures) to where there is less heat (lower temperatures
17. What causes weather processes such as wind, clouds, and precipitation?
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18. The uneven heating of our planet is because of Earth’s _________________ ( tilt on its axis, rotation)
that results to temperature ___________________ ( inversion, difference ), which in turn causes
______________________ ( gravity, wind ) to develop.