NOTICE ABOUT UPCOMING CHANGES

14 June 2013:

On 16 Jul 2013, NCEP will transition from the current operational Central Computing System (CCS) to the Weather and Climate Operational Supercomputing System (WCOSS). WCOSS does not have a "compress" function, so all Stage II/Stage IV files will be compressed with "gzip", and the file names shall be changed from file.Z to $file.gz ("gunzip" can be used to uncompress both types of files).

Note that 16 Jul is the projected date of the transition, and if that day turns out to be a critical weather day, the transition will occur earlier, before the start of the critical weather period. If you have a script that automatically grabs the data from NCEP's ftp site, you might want to make appropriate changes now. E.g. if you script currently has "mget ST2ml*.Z", you might want to change it to "mget ST2ml*"; if you have "uncompress ST2ml*", consider changing that to "gunzip ST2ml*".

For more information about the transition, please see http://www.nco.ncep.noaa.gov/pmb/changes/docs/wcosseval.shtml.

18 June 2013:
A set of sample Stage II/IV files produced on WCOSS have been placed on ftp://ftp.emc.ncep.noaa.gov/mmb/precip/st2-st4_wcoss_sample.20130616/.

Stage II: NCEP National Multi-sensor Hourly Precipitation Analysis

Generated at NCEP, from hourly radar precipitation estimates and from hourly gauge reports. Generated at ~35 minutes after the top of the hour, and again at T+6h and T+18h. No manual QC.

Stage IV: Mosaicked from the regional multi-sensor analyses generated by the RFCs

Mosaicked into a national product at NCEP, from the regional hourly/6-hourly multi-sensor (radar+gauges) precipitation analyses produced by the 12 River Forecast Centers (RFCs) over CONUS. Some manual QC done at the RFCs. Mosaic done at NCEP within an hour of receiving any new hourly/6-hourly data from one or more RFC.

Precipitation for the RTMA

Questions and Answers

Stage II/IV Comparisons(left panel is Stage II):

• Snapshot from T-12h (T is current time)
• 12h loop from T-12h
• 24h loops (there is a 2-day lag in image production)
• 24h accumulation (12Z-12Z) comparison: Go to the model daily precipitation verification page. Select a day, go to the bottom of that day's page, where the Stage II/IV analysis are compared to the 1/8-degree daily precipitation analysis (produced by CPC, based on the 7,000-8,000 daily gauge reports)

References

emc.external.helpdesk@noaa.gov

NCEP/EMC Mesoscale Modeling Branch

GAPP/GCIP Project at NCEP/EMC