NOUS41 KWBC 041815 AAA



Technical Implementation Notice 16-02 Amended

National Weather Service Headquarters Washington DC

315 PM EST Fri Mar 4 2016


To:        Subscribers:

           -NOAA Weather Wire Service

           -Emergency Managers Weather Information Network


           Other NWS Partners, Users and Employees


From:      Timothy McClung

           Portfolio Manager

           NWS Office of Science and Technology Integration


Subject:   Amended: Climatology Calibrated Precipitation

           Analysis (CCPA) Changes: Effective March 29, 2016


Amended to change the implementation date from Tuesday, March

22, 2016 to Tuesday, March 29, 2016


On or about Tuesday, March 29, 2016, beginning with the 1200

Coordinated Universal Time (UTC) run, the Climatology Calibrated

Precipitation Analysis (CCPA) product will be updated.


The upgrade in the CCPA production suite includes:


1. Update the regression coefficients with extended historical

training data sets of the NCEP Climate Prediction Center (CPC)

Unified Global Daily Gauge Analysis and the NCEP Environmental

Modeling Center (EMC) Stage IV 6-houly multi-sensor estimation

from 2002 to 2015.


2. Change the computation of weights used in downscaling from 6

hourly CCPA to 3-hourly CCPA, by using Stage II to replace Stage

IV data in CNRFC where the latter has poor quality.


3. Extend the CCPA look-back period following the Stage IV

update schedule in 2015 implementation of the RTMA/URMA upgrade.

The job makes additional reruns at 1/3/5/7 days past the valid



4. Add 2.5 km NDGD grid output. This grid analysis is generated

by interpolating from the HRAP grid to 2.5 km NDGD grid. The 2.5

km NDGD CCPA covers the same domain as the 5km NDGD CCPA, and it

is also available for both 3-hourly and 6-hourly accumulations.


Following the NCEP implementation standards, there will be

significant changes in CCPA product directory structure and

output file names.


Directory Changes:


CCPA files will be moved from the

gens/prod/gefs.YYYYMMDD/HH/ccpa directory structure to



Files will be available on external servers in the following






NCEP FTP server:



D/HH ,

where YYYYMMDD is the date and HH is the ending time (hour) of

the 6-hour accumulation period. 



File Name Changes:


All existing files named ccpa_conus_GRID_tXXz_LLh_gb2 will be

replaced by ccpa.tXXz.LLh.GRID.conus.gb2. Where GRID is the

spatial resolution, XX is the accumulation ending time, and LL

is the accumulation length.


There will be six files for each (XX,LL) pair corresponding to

the following six grids (GRID):

1. hrap: HRAP Grid (same as the Stage IV grid)

2. ndgd5p0: 5 km National Digital Forecast Database (NDFD) CONUS


3. ndgd2p5: 2.5 km National Digital Forecast Database (NDFD)

CONUS grid

4. 0p125: 0.125 degree CONUS latitude/longitude grid (Grid ID


5. 0p5: 0.5 degree latitude/longitude grid with data coverage

over CONUS only

6. 1p0: 1.0 degree latitude/longitude grid with data coverage

over CONUS only (Grid ID 3)

For specifications of Grid IDs 3 and 110, see


The timing of final data delivery will be delayed by this

implementation as some additional time will be needed to

generate the data at the 2.5km NDGD grid. The delay is expected

to be 7-8 minutes or less. Users are also advised to pay special

attention to additional updates with the extended look-back

periods: The rerun 1 day after the valid date may be delayed by

up to 7-8 minutes while the added updates 3/5/7 days after the

valid date will slightly improve the product accuracy.


A consistent parallel feed of both GEFS and NAEFS data will be

available on the NCEP server via the following URL:


Test data will be available at:


More information regarding the CCPA and its scientific

implementation can be found at:


Disclaimer:  NCEP would encourage all users to ensure their

decoders are flexible and are able to adequately handle changes

in content order, parameter fields changing order, changes in

the scaling factor component within the Product Definition

Section (PDS) of the GRIB files and also any volume changes

which may be forthcoming.  These elements may change with future

NCEP model implementations.  NCEP will make every attempt to

alert users to these changes prior to any implementation.


For questions regarding these changes, please contact:


    Yan Luo

    NCEP/EMC Global Modeling Branch

    College Park, Maryland

    Phone:  301-683-3778



For questions regarding the dataflow aspects of this data set,

please contact:


    Justin Cooke

    NCEP/NCO Dataflow Team

    College Park, Maryland

    Phone:  301-683-0567



NWS National Technical Implementation Notices are online at: