NOUS41 KWBC 281900


Public Information Statement, Comment Request

National Weather Service Headquarters, Washington, DC

300 PM EDT Thu Jun 28 2012

To:†††††††† Subscribers:

††††††††††† -Family of Services

††††††††††† -NOAA Weather Wire Service

††††††††††† -Emergency Managers Weather Information Network

††††††††††† -NOAAPORT

††††††††††† Other NWS Partners, Users and Employees

From:†††††† Geoff DiMego

††††††††††† Chief, Mesoscale Modeling Branch

††††††††††† NCEP/Environmental Modeling Center

Subject:††† Soliciting Public Comments through August 12, 2012,

††††††††††† on Removal of the Obsolete RUC Surface Analysis

The National Centers for Environmental Prediction (NCEP) is

seeking comments through August 12, 2012, on discontinuing the

legacy analysis system known as Rapid Update Cycle Surface

(RUCS), also known as RUC Surface Assimilation System (RSAS). All

output products from this system would also be discontinued.


This system is based on old technology and analysis grids of

equal or better resolution and quality are readily available (see

below). In addition, NCEP wants to conserve resources, not only

the compute resource, but also the personnel resource needed to

port the code to the new Weather and Climate Operational

Supercomputing System.

The RUCS analysis uses optimum interpolation in 2-Dimensions to

update its hourly products.This is done multiple times each

hour with the latest result overwriting the previous result.

Output products are for 12 surface parameters on four grids with

15, 40, 60 and 80 km spacing.The 15 km grid is polar-

stereographic, covers North America and is GRIB grid #88.The

40 km grid is Lambert conformal, covers the Contiguous United

States (CONUS) and is GRIB grid #212.The 60 km grid is polar-

stereographic, covers CONUS and is GRIB grid #87. The 80 km grid

is Lambert conformal, covers CONUS and is GRIB grid #211.


Three operational systems within the NCEP production suite

produce similar analyses of surface parameters using the state-

of-the-art Gridpoint Statistical Interpolation (GSI) analysis

scheme. These systems are:


1. North American Mesoscale (NAM) at 12 km, including NAMís CONUS

nest at 4 km, NAMís Alaska nest at 6 km, NAMís Hawaii nest at 3

km, and -NAMís Puerto Rico nest at 3 km;

2. The 13 km North American Rapid Refresh (RAP), which replaced

the CONUS-based Rapid Update Cycle (RUC) in May 2012

3. Real Time Mesoscale Analysis (RTMA) at 2.5 km over CONUS,

Hawaii, Guam and Puerto Rico, and at 3 km over Alaska.


Both the RAP and RTMA are updated hourly, and both RAP and NAM

use GSI in 3-Dimensions.


The RUCS output is disseminated via the NWS and NCEP FTP servers.

No RUCS products are sent on NOAAPORT. Details about the exact

RUCS files and the products they contain that are being

considered for removal can be found at


More information about the NAM, RAP and RTMA products that are

available as replacements can be found at


NWS will evaluate all comments to determine whether to proceed

with this change. If approved, a TIN will be issued containing

implementation dates.

Send comments on this proposal by August 12, 2012 to:

Geoff DiMego

NWS/NCEP Environmental Modeling Center

Camp Springs , MD


Rebecca Cosgrove

NWS/NCEP Central Operations

Camp Spring, MD

National Public Information Statements are online at: