Welcome to ARPS

General Information

CAPS has served the meteorological community since 1997 by continuously providing real-time numerical analyses and forecasts, initially as part of a collaboration with American Airlines known as Project Hub-CAPS (Carpenter, et al., 1999). During Special Operational Periods, increased resolutions with more sophisticated configurations are often employed, making use of supercomputing resources at NCSA or PSC. The Advanced Regional Prediction System (ARPS) of CAPS and its data analysis system (ADAS) are used.

From mid-May to the end of June of 2002, ARPS ran in support of Internation Water Project (IHOP 2002), a major field experiment occurring over the US contral plain. Triple nested 27/9/3 km grids were employed, with the 27 km grid covering the CONUS domain. Up to 256 Compaq Alpha CPUs on the PSC Terascale Computing System and/or up to 512 processors of a Pentium III Linux cluster at NCSA were used. Data analyses was performed locally on a Pentium 4 Linux cluster.

In more recent years, CAPS has participated in spring experiments with the Storm Prediction Center, CASA, and VORTEX2.

Currently, the 20-km CONUS is run daily starting from 00 UTC and forecast for 84 hours. 00 UTC NAM run will be used for the initial-condition first guess and for providing the boundary conditions. The 9-km nested grid starts at 12Z and runs for 24 hours, getting its boundary conditions from the 20 km forecast. 3 km forecast starting at 00 UTC and runs for 6 hours. All forecasts use the OU Super Computer.

Guide to Interpreting the Products (not all products listed are available).

NOTE - Some information is out of date. Click on News for latest info.

Description of the Forecast System

Data Sources

Note: Consult the Data Status page of each forecast run to see how many observations of each data type were actually used.

Sample ARPS Configuration

ARPS Version 5.0 is used with the following options:

CAPS/wx Directory

Maintained by Kevin W. Thomas. Your comments, inquiries, problem reports, and suggestions are welcome.