The Surface Station Model and Surface Charts

C D

B

H A

G

F

I

J

E

Surface Weather Observation Station Model

C D

B

H A

G

F

I

J

E

• A = Total Cloud Cover

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C D

B

H A

G

I

F

J

E

B = Wind Direction The barb points into the station model from the direction the wind is blowing (in this example the wind is from the northwest)

C D

B

H A

G

I

F

J

E

C = Wind Speed – A half-barb = five knots; – A full barb = 10 knots; – A flag = 50 knots » (a knot is approx. 1.15 mile)

C D

B

H A

G

F

I

J

E

D = Temperature –Depending upon the station the temperature can be given in degrees Fahrenheit or Celsius

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C D

B

H A

G

F

I

J

E

E = Dewpoint –Like temperature dewpoint can be expressed in degrees Fahrenheit or Celsius

C D

B

H A

G

F

I

J

E

F = Current Weather – Symbols are used to explain the weather at the time of the observation

C D

B

H A

G

F

I

J

E

G = Visibility –This is the average distance the observer can see, horizontally

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C D

B

H A

G

F

I

J

E

•

H = Sea-level Pressure –Given in millibars (the first number of the pressure is left off (9, 10) because surface pressure is commonly around 1000 millibars

C D

B

H A

G

F

I

J

E

•

I = Pressure Change during the last 3 hours –indicated with a + or - and a millibar value

C D

•

B

H A

G

F

I

J

E

J = Pressure Tendency in the last 3 hours – a line indicating a rise, a fall, or steady surface pressure

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Surface Chart • The “Typical” Surface Chart • Station models • Isobars – Lines of equal pressure

• High and Low Pressure Centers • Frontal Position

Surface Station Models

Station Models, Isobars, High and Low Pressure Centers, and Frontal Positions

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Surface Chart • Other Types of Surface Charts • Specific variable charts – – – – – –

Temperature Dewpoint Moisture Convergence Wind Direction and Speed Cloud Cover ETC….

Temperature

Dewpoint Temperature

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Wind Speed (knots) and Direction

Surface Chart • Items to be aware of when examining a surface chart • Location of High and Low Pressure Centers • Frontal Locations (convergence zones) • Surface Moisture

The Surface Station Model and Surface Charts

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