LONG LEAD FORECAST DATA SET FORMAT
DATA SET NAME cpcllft.dat ,cpcllfp.dat
DESCRIPTION:
These two datasets contain the official CPC long lead forecasts
interpolated to 102 climate regions (prior to 1999) or 126 locations
(102 forecast divisions and 24 Alaskan stations) after Jan 1 1999.
Data begin with the forecast
issued in December 1994 and continue through the present. Each
forecast is identified by a header record that describes the data
used for the forecast, and its lead time. Two groups of data follow;
the first contains the forecast values for the probability of the
below normal class, and the second contains the forecast probability
of above normal. The forecast probability for the near normal class
is one minus the sum of the two given classes. Each group consists of
the forecast value for 102 climate regions based on NCDC's climate
division data. The data order and location are described in climate
region dictionary file. The last record is a blank, with year
(IY)=9999, and a record of data, all equal to a missing indicator
of -9.999.
FORMAT:
Line type 1: IY,IM,IH,NSTA
FORTRAN FORMAT(5I5)
KYR, KMO = Year (ie. 1997) and month (1=Jan ... 12=Dec) that the
forecast was issued. An official
forecast is typically made about ten days after the
last complete month of data and is issued around the
15th of the month KYR, KMO.
KP = Lead time for this forecast (in months). This is the lead
time between the latest data used (the month prior to,
KYR,KMO) and the start of the valid time of the forecast.
NSTA = Number of data locations in the each of the two data groups.
KID = Data identifier, 950 (951) = Forecast probabilities for
seasonal temperatures (precipitation).
KFL = Data flag. This location is reserved for data identification
purposes. It is used to label any procedural factor that may
affect forecasts. 0= interpolation from Intergraph software and
"borrowing" rules used to define non-favored categories.
1 - Manual interpolation with "borrowing" rules used for non-
favored categories
2 - interpolation from NTRANS software. Transformed-normal
distribution with skill contraction used to integrate distribution
to obtain non-favored categories.
Line type 2: (PB(I),I=1,NSTA)
FORTRAN FORMAT(9(12(F6.3)/))
PB(I) = The forecast probability that the 3 month season that
begins KP months after KYR,KMO will be in the lowest third
of the climatological distribution of that element in
region I. The valid time can be computed by adding KP+1
to KMO, adjusting for any year change. So, for example,
if KYR=1994, KMO=11 and KP=2 then the valid time is:
KMO + 2 + 1=14. Since 14>12, the year must be adjusted,
(+1) and the month becomes 14-12=2 indicating that the
valid period begins on the first day of February (month 2)
1995, and extends through the last day of April (FMA 1995).
Line type 3: (PA(I),I=1,NSTA)
FORTRAN FORMAT(9(12(F6.3)/))
PA(I) = The forecast probability that the 3 month season that
begins KP months after KYR,KMO will be in the highest
third of the climatological distribution of that element
in region I.