CPC Experimental Degree Day Product.


The Climate Prediction Center issues a forecast for population weighted monthly total degree
days for 9 regions within the conterminous U.S, as well as for all lower 48 states combined. 
Forecasts are issued together with the CPC Long Lead Outlook and are based on the monthly and
seasonal temperature outlooks.  

Product description
   This tabular product gives values of population weighted heating and cooling degree days that
are expected to be exceeded 90% and 10% of the time, together with the expected mean value for
various regions of the country.   Degree days are accumulated for the given calendar month and
are in degrees Fahrenheit with base 65 F.

Product generation            

  The product is formed by first disaggregating the CPC forecasts for seasonal mean temperatures
into a series of forecasts for the monthly mean temperature (the first month's forecast is obtained
from the 30-day outlook).  Predictions for monthly means at CPC forecast divisions are
downscaled to obtain forecasts for NCDC climate divisions.  A statistical relationship between
mean temperature and mean daily degree days for given months and climate divisions is then
used to obtain a forecast distribution for monthly heating and cooling degree day totals from the
forecast temperature distributions.  A weighting factor is formed from the proportion of the
population of the NCDC climate division to the population of the entire region.  The product of
the degree day count and population weighting factor is summed for each NCDC climate division
within a given region to obtain the population weighted forecast for heating or cooling degree
days. 

Format of each group of data   

Line 1     Region of the country , Postal Code of states in region in parenthesis. (See
          accompanying table).
Line 2    Table header
Lines 3-14     Column 1 Year of forecast valid time
          Column 2 Month of forecast valid time 
          Column 3 Forecast value of heating degree days expected to be exceeded 90% of
               the time.
          Column 4 Forecast mean value of heating degree days
          Column 5 Forecast value of heating degree days expected to be exceeded 10% of
               the time.
          Column 6 Forecast value of cooling degree days expected to be exceeded 90% of
               the time.
          Column 7 Forecast mean value of cooling degree days
          Column 8 Forecast value of cooling degree days expected to be exceeded 10% of
               the time.
 

Table.    Regional definitions.
Region                                States                                                                                    

New England         Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island,
                    Vermont                  
Mid Atlantic        New Jersey, New York, Pennsylvania
East North Central  Illinois, Indiana, Michigan, Ohio, Wisconsin
West North Central  Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, South
                    Dakota
South Atlantic Delaware, District of Columbia, Florida, Georgia, Maryland, North
               Carolina, South Carolina, Virginia, West Virginia
East South Central  Alabama, Kentucky, Mississippi, Tennessee
West South Central  Arkansas, Louisiana, Oklahoma, Texas
Mountain       Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah,
               Wyoming
Pacific        California, Oregon, Washington