Introduction to Weather Forecasting Cliff Mass Department of Atmospheric Sciences University of Washington The Stone Age Prior to approximately 1955, weather forecasting was basically a subjective art, and not very skillful.
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Department of Atmospheric Sciences
University of Washington
Vilhelm Bjerknes in his landmark paper of 1904 suggested that NWP--objective weather prediction-- was possible.
One such equation is Newton’s Second Law:
F = ma
Force = mass x acceleration
Mass is the amount of matter
Acceleration is how velocity changes with time
Force is a push or pull on some object (e.g., gravitational force, pressure forces, friction)
Using observations we can determine the mass and forces, and thus can calculate the acceleration--giving the future
Using a wide range of weather observations we can create a three-dimensional description of the atmosphere…
Weather forecasting skill has substantially improved over the last 50 years. Really.
National Weather Service
Cleveland Abbe (“Ol’ Probabilities”), who led the establishment of a weather forecasting division within the U.S. Army Signal Corps.
Produced the first known communication of a weather probability to users and the public in 1869.
Professor Cleveland Abbe, who issued the first public
“Weather Synopsis and Probabilities” on February 19, 1871
The Thanksgiving Forecast 2001
42h forecast (valid Thu 10AM)
SLP and winds
But you can have too much of a good thing…