SC.912.E.7.5 Predict future weather conditions based on present observations and conceptual models...
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SC.912.E.7.5 Predict future weather conditions based on present observations and conceptual models and recognize limitations and uncertainties of such predictions.
SC.912.E.7.5 Predict future weather conditions based on present observations and conceptual models and recognize limitations and uncertainties of such
SC.912.E.7.5 Predict future weather conditions based on present
observations and conceptual models and recognize limitations and
uncertainties of such predictions.
Slide 2
Earth Systems and Patterns The scientific theory of the
evolution of Earth states that changes in our planet are driven by
the flow of energy and the cycling of matter through dynamic
interactions among the atmosphere, hydrosphere, cryosphere,
geosphere, and biosphere, and the resources used to sustain human
civilization on Earth.
Slide 3
questions Some thunderstorms are caused by convection resulting
from the collision of two air masses. Which describes the collision
involved in this type of thunderstorm? A. Two cold fronts collide.
B. Two warm fronts collide. C. A cold front moves into an area with
warm air. D. A warm front moves into an area with cold air.
Slide 4
CHAPTER HOME Meteorologists must gather huge amounts of data in
order to make their predictions. They rely on sensing instruments
and on computer models to provide the information they need.
CHAPTER SECTION OUTLINE VOCABULARY 20.5 Forecasting Weather Weather
Visible Satellite Image - Ohio Infrared Satellite Image - Ohio
station model
Slide 5
CHAPTER A compact expression of weather information for an
area, including temperature, dew point, weather conditions, wind
speed and direction, barometric pressure, and cloud cover.
VOCABULARY station model Weather station model
Slide 6
CHAPTER HOME Meteorologists use the data to make surface
weather maps and forecasts. CHAPTER VOCABULARY 20.5 Forecasting
Weather Weather Surface Weather Map station model SECTION
OUTLINE
Slide 7
Lightly draw lines connecting identical values of sea level
pressure. Remember, these lines, called isobars, do not cross each
other. Surface Air Pressure Map
Slide 8
Isobars can be used to identify "Highs" and "Lows". The
pressure in a high is greater than the surrounding air. The
pressure in a low is lower than the surrounding air. Label the
center of the high pressure area with a large blue "H". Label the
center of the high pressure area with a large red "L".
Slide 9
High pressure regions are usually associated with dry weather
because as the air sinks it warms and the moisture evaporates. Low
pressure regions usually bring precipitation because when the air
rises it cools and the water vapor condenses.
Slide 10
Where should we expect rain or snow? Where should we expect dry
weather? How could we tell if it was rain or snow
expectations?
Slide 11
Slide 12
Surface Temperature Map You will draw lines connecting the
temperatures, much like you did with the sea- level pressure map.
However, you will also need to interpolate between values.
Interpolation involves estimating values between stations which
will enable you to properly analyze a map.sea- level pressure
map
Slide 13
Isotherms are used to identify warm and cold air masses. Where
is the region with the lowest temperatures? Where is the region
with the warmest air?
Slide 14
Dewpoint Temperature Map This map shows the dewpoint
temperature for various locations over the conterminous U.S. The
values are in F. Recall, dewpoint is the temperature to which, if
the air cooled to this value, then the air would be completely
saturated.
Slide 15
Isodrosotherms are used to identify surface moisture. The
closer the temperature and dewpoint are together, the greater the
moisture in the atmosphere. As the moisture increases so does the
chance of rain. Also, since moist air is lighter than dry air, the
greater the moisture, the easier for the moist air to lift into the
atmosphere resulting in a better chance for thunderstorms.
Typically, dewpoint 70F or greater have the potential energy needed
to produce severe weather. What will this information, combined
with our previous data sea pressures and temperatures, tell us? Can
we predict the actual temperature and precipatation in all areas
exactly?
Slide 16
Slide 17
Surface Pressure Change Map This map shows change in surface
pressure (in whole millibars) during the past three hours at
various locations.
Slide 18
Draw lines connecting equal values of pressure change for every
two millibars. These lines are drawn for the -8, - 6, -4, -2, 0,
+2, +4, +6, +8, etc. values. Remember, like isobars, these lines
(called isallobars) are smooth and do not cross each other. Using a
blue colored pencil, beginning at any +2 value, lightly draw lines
connecting equal values of the +2 millibars pressure change.
Remember, you will need to interpolate between values to draw your
lines correctly. Draw the remaining "positive" pressure change
value(s) at two millibars intervals. Using red colored pencils
lightly draw a line connecting equal pressure change values of less
than zero (0). Finally, using black, draw a line connecting the
zero (0) line.
Slide 19
Slide 20
Cold fronts are often located in areas where the pressure
change is the greatest. The front represents the boundary of
different air masses. Cold air is more dense than warm air so when
a cold front pass your location, the pressure increases. We analyze
for pressure change to look for these boundaries. We can also tell
where high pressure and low pressure systems are moving by looking
where the greatest change is occurring. Cold air Warm air
Slide 21
Analyzing maps with the current weather conditions is an
essential part of the entire forecast process. Basically, if we do
not know what is currently occuring, it is near impossible to
predict what will happen in the future. Computers have been able to
analyze maps for over 20 years. However, computers cannot interpret
what they analyze. There is no substitute for the hand analysis.
Analyzing maps by hand causes the forecaster to study every detail
in the weather and enables him/her to discern the continuity or
"flow" of the weather.
Slide 22
Great forecasts, the ones that save lives and property, begin
with the careful analysis of the current conditions. Conversely,
based upon post- analysis, "bad" (or busted) forecasts, the ones
most remembered by the public, could have been improved if one did
a careful analysis in the beginning. Map analysis is not too unlike
drawing in a dot-to- dot coloring book. Just as one would draw a
line from one dot to the next, analyzing maps is similar in that we
will draw lines of equal values between dots representing various
elements of the atmosphere.
Slide 23
Slide 24
compare, and comment on, the direction the wind blows around
high and low pressure (based upon the arrows they drew) compared to
the direction of the staffs on the surface map.
Slide 25
compare, and comment on, the cloud cover under the areas of
high and low pressure.
Slide 26
what type of present weather they see plotted on this map. What
type of past weather do the students see?