The "Climatology" Technique
 a forecast that is based on "climatology" or average weather
 example:
 Lets say the
climatological records show that it rains
only 1 day out of 100 during the summer
months in LA.
 Then, if you forecast
"no rain" for any day in July
and August, the probability you will be
wrong is 1/100.
 Therefore, the probability
you will be right is about 99%
 NOTE: precip forecasts are usually
given as probabilities
 ex: "there is a 60%
chance of rain today"
 this means that there is a 60%
chance of measurable precip at any random place
in the forecast area

Accuracy and skill in forecasting
 What is an accurate forecast?
 your forecast for tonights
min temp is 0°F
 if the actual min was
1°F, is in inaccurate?
 if the actual min was
10°F, is in inaccurate?
 Accuracy (in forecasting) is arbitrary
and relative  it's not clearly,
objectively defined
 How does a forecast show skill?
 must be more accurate than
utilizing persistence or climatology
 persistence is "hard
to beat" on a time frame of minutes
to hours
 skill is often shown on
time frame of hours to a few days
 Beyond 10 days, forecasts
are generally no better than those
generated by climatology
QUESTION FOR
THOUGHT:
Climatology shows that the skies over Vancouver,
Canada are cloudy 327 days a year. If you were to forecast cloudy skies
for every day of the year, how accurate will your forecasts be? Do your
forecasts show skill? Explain. 