Transcript 20.5 Forecasting Weather - Mrs. Plough`s Classroom

20.5
Forecasting Weather
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Objectives
Compare and contrast the different
technologies used to gather weather data.
Analyze weather symbols, station models, and
weather maps.
Describe how weather forecasts are made.
Introduction
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Forecasting weather is a
complex process that requires
the cooperation of countries
around the world
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Gather weather information
for their regions
Send this information too
computer centers
Compile information and use
it to create weather maps and
forecasts
Local forecasters modify the
forecasts to reflect local
conditions
Gathering Data
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Huge amounts of data are
necessary for weather
forecasting
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Satellites
Instruments attached to balloons
Weather stations
Weather radar
Airplanes
Ships
Satellites
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Provide weather
information about
every spot on Earth
2 basic types of satellite
images
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Visible
Infrared
Visible Satellite Images
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Uses light to create images
Black-and-white picture of
Earth
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White = sunlight reflected off
clouds or snow cover
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Brighter the white = thicker
the clouds
Gray = land
Black = water
Visible Satellite Images (cont’d)
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Can
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Estimate wind speed and
direction
Track storms
Estimate the stage and
severity of hurricanes
Aren’t available at night
Infrared Satellite Imagery
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Uses temperature to create
pictures
Can be taken day or night
Bright areas represent cold
temperatures
Darker areas are warmer
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Represent lower clouds
Lack or clouds
Infrared Satellite Imagery (cont’d)
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Temperatures of cloud tops
to determine how tall the
clouds are
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Taller the cumulus clouds
= more severe the
thunderstorms produced
Estimate wind speed and
direction at different
altitudes
Provide images of water
vapor in the air
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Determine temperature
and humidity at different
altitudes
Radiosondes
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Instrument package
attached to a balloon
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Carries it up into the
atmosphere
Transmits weather
information to
computers on the
ground
Radiosondes (cont’d)
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Measure the temperature, pressure, and humidity of air at different
altitudes
Estimate air stability and the likelihood that cumulus clouds and
thunderstorms will develop
Maps show the shape and intensity of the jet stream
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Important in determining the movement of air masses and storms
Surface Observations
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Only by analyzing data from
weather stations can
meteorologists diagnose
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Where in a storm it is
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Raining
Snowing
Where fronts and lows are
located
Surface Observations (cont’d)
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Most weather stations
are at airports
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Can easily retrieve
data from commercial
jets with automatic
weather recorders
Surface Observations (cont’d)
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Information on conditions over
the oceans comes from ships and
from automated stations on
moored buoys
Weather stations typically report
conditions every hour
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Temperature
Dew point
Barometric pressure
Wind speed and direction
Visibility
Precipitation
Height of clouds
Amount of cloud cover
Station Model
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Station model: Includes information on temperature, dew point,
weather conditions, wind speed and direction, barometric
pressure, and cloud cover
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Can be read by the meteorologists of any country
Making a Surface Weather Map
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Essential tools that give
weather forecasters the “big
picture” of current weather
conditions
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Made every 3 hours by the
National Center for
Environmental Prediction
(NCEP)
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Silver Spring, Maryland
Making a Surface Weather Map
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Steps to make a surface map
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Computer draws a map showing
station models
Draws isobars every 4 millibars
and identifies highs and lows
Forecasters draw in the fronts
A) 3 types of data from the station
model to find fronts
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Temperature
Wind direction
Dew point
Making a Surface Weather Map (cont’d)
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Rules to locate fronts
Wind direction changes
behind front
Temperature changes
sharply across fronts
Dew point changes sharply
across fronts
Forecasting
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Modern-day weather forecasts
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Based on computer weather
models
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Large computer programs
containing mathematical
equations designed to simulate
atmospheric processes
Many different models are used
to make forecasts
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Some are used to predict the
weather up to 2 days in
advance
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Run 4 times per day
Provide info up to 10 days in
advance
Forecasting (cont’d)
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Models begin with observed current weather data
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Temperature
Humidity
Wind at various levels of the atmosphere
Forecasting (cont’d)
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Transfer data into
mathematical equations and
predict future state of the
atmosphere
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Temperatures
Winds
Sea-level pressure
Precipitation
Configurations of the jet
stream
Forecasting (cont’d)
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Different models may
produce different
predictions
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Meteorologists decide
which model to use as a
basis for a forecast
Forecasting (cont’d)
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Subtle factors not included in the models can have a large impact on the weather
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Urbanization
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Plays a large role in the intensity of heat waves
Local effects
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Too subtle for models to predict
Forecasters use their knowledge of local weather patterns to modify the predictions they
receive from models
20.5 Review
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Kahoot
Exit Ticket
Activity
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Forecasting weather