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Forecasting Precipitation
scaffolding activity
Introduction:
Forecasting precipitation requires the consideration of many factors.
Sometimes simple mathematics can be an
effective tool for predicting when precipitation will occur,
however, this method alone is always reliable.
It is important to consider sources of moisture and lifting mechanisms
in the development of precipitation.
The purpose of this activity is to introduce some indicators that
useful for predicting when and where precipitation is going to occur.
Key words
throughout this activity link directly to helper resources that provide
useful information for answering the questions.
Key Components:
1)
Why is moisture necessary for precipitation
to develop?
2) What role do fronts play in the
development of precipitation?
3) Describe what happens as an
parcel of air rises
upwards through the atmosphere.
Forecasting Scenarios:
4) For the following weather scenarios, indicate if precipitation is
"likely" or "unlikely" to occur given the
conditions described in each scenario. Explain why.
| Weather Scenario |
| Precipitation? |
Example Scenario:
Boulder, CO, a city on the east side of the Rockies.
Downslope winds are expected.
| Unlikely |
Downslope winds (or wind blowing down the mountain) tend to be very dry,
warming as it descends, creating an
unfavorable environment for
the development of precipitation (since rising air in the presence of
downslope winds is unlikely).
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Scenario 1:
A cold front is approaching from the west, but the air both ahead of
and behind the front is very dry.
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Scenario 2:
A warm front is approaching and the air behind and ahead of the front
is very moist.
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Scenario 3:
Upslope winds are expected in Boulder, CO and
the air has been
very moist for the past couple of days.
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| Scenario 4:
The trend for the latest
batch of precipitation is a steady eastward movement of 30 miles/hour.
The latest position is roughly 700 west of here. Will precipitation arrive
within 24 hours?
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forecasting temps
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Teacher Guides
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