A Systematic Error Comparison Between the ECMWF and NMC Prediction Models

Abstract

The 24 systematic forecast errors in the 50 mb geopotential height from the ECMWF and NMC operational prediction models are compared and analyzed. During the winter of 198 the error patterns from the two models over the Northern Hemisphere were remarkably similar. The error signatures within composites of selected dates, which were chosen according to the character of the flow regime over the Rocky Mountains, were also very similar, indicating that improper orographic forcing may represent one deficiency common to both models. The general similarity of the patterns in each composite, however, does not rule out the existence of yet another important common deficiency.