Transcript File - Mr. LaFranca`s Earth Science Class

Notepack 38
Aim: How do we read and create weather
station models?
Do now: Where does she get her information
from?
Weather Measuring Instruments
Anemometer
measures wind speed
Wind Vane
measures wind direction
Barometer
measures air pressure
Psychrometer
measures relative humidity
The Weather Station Model p14
Draw a Station Model
Get accompanying notes here
©Steve Kluge 2007 Some images from the NYSED Earth Science Reference Tables
Temperature
• Temperature measures the amount of heat that is in
the air.
• Important!! Weather stations models use F. You may
need to convert from C or convert to C to find dew
point or Relative humidity.
Back to the Station Model
Back to the Station Model
©S. Kluge 2007
Visibility
• This refers to how far a person
can see during the daytime.
• It is measured in miles.
• The larger the number, the
farther you can see. (Clear day)
• The smaller the number, the
less you can see. (foggy or
hazy)
Back to the Station Model
Dewpoint
• The temperature in F were the water vapor in
the air begin to condense.
• Important!!! Remember the Dew Point Chart is
in C degree. You may need to covert F to C or C
to F.
Back to the
Back
Station
to theModel
Station Model
Wind Speed
• Wind Speed tells you how fast the air is moving.
• The number of lines or feathers represent the speed.
Long lines are 10 kts and short lines are 5 kts.
• A small triangle is 50kts.
• The more lines, the faster the wind is.
Back to the Station Model
Now You Try It
15kts
45kts
20kts
30kts
40kts
25kts
35kts
Back to the Station Model
Wind Direction
•This symbol tells you in which direction does the
wind come from.
•NOT WHERE IT IS GOING!!!
• You use the direction on a compass. Where the
feathers point is the direction the wind is coming
from.
N
NW
NE
E
W
SW
SE
S
Back
to the Station Model
Back to the Station
Model
NE at 25 Knots
E at 5 Knots
SE at 10 Knots
Back to the Station Model
©S. Kluge 2007
Precipitation
• Precipitation is any type of water that falls from
the sky. (rain, snow, sleet).
•This number records how much precipitation has
fallen.
•The bigger the number, the more precipitation has
fallen.
Back to the Station Model
Back to the Station Model
Cloud Cover
•This measurement describes how much clouds
are in the sky or how much of the sum is being
blocked by clouds.
•The circle is colored by ¼’s.
Back to the Station Model
Back to the Station Model
Barometric Pressure
• The barometric pressure measures the
pressure or density of air.
•Warm air has a lower density than cool
air.
•It is measured in millibars.
Back to the Station Model
Decoding the Coded Pressure
Example: 196
19.6
Insert a decimal point to the left of the last digit
Put a “9” and a “10” in front of the result
919.6
1019.6
Test the results against the range of normal atmospheric pressures
919.6 is below the range of normal pressures…. REJECTED!
1019.6 is within the range of normal pressures…. ACCEPTED!
Coded pressure
196= 1019.6
Decode these coded pressures: 002
1000.2
mb
993
280
000
999.3
1028.0
1000.0
Encoding the Pressure
1013.5
10135
Remove the decimal point
Report the last 3 digits
135
Pressure
1013.5 = 135 encoded pressure
Encode these pressures: 1032.7
327
987.3
1012.2
873
122
1000.1
001
Back to the Station Model
©S. Kluge 2007
Barometric Trends
• As the barometer rises, cooler and dryer air is
moving in. The “+” sign is used.
• As the barometer decreases, warmer and
wetter air is moving is. The “-” sign is used.
Back to the Station Model
The Barometric Trend
+ 19 /
+ means “Higher now than it was 3 hours
(- means “Lower now than it was 3 hours ago”)
ago”
19 means the pressure has changed by 1.9 mb
/
means the pressure is currently rising
( means the pressure is currently falling)
\
What was the pressure 3 hours ago?
Here?
1003.5
1017.7
Back to the Station Model
©S. Kluge 2007
Draw a Station Model for These Conditions:
Temperature= 45F
Dewpoint= 32F
Wind NE at 20 knots
Overcast
Visibility= 1.5 miles
Rain Showers
Pressure Now= 997.3 mb
Pressure 3 hrs. ago= 1000.2mb
Barometer Falling
Precipitation in last 6 hrs.= .53 in.
Back to the Station Model
©S. Kluge 2007