Evolution of a Graphical Prediction Technique Incorporating Ageostrophic Effects

Abstract

Experience with a surface prognostic technique developed by Reed revealed some systematic defects, which were corrected subjectively in practice. In hopes of eliminating the defects, a forecast equation is derived here in a manner slightly different than the derivation of Reed, but which may still be used in a simple forecast scheme. This new equation is applied to a three-day period during January 1964, with fairly successful results. However, an ageostrophic correction, computed from thickness advection patterns, had to be applied to obtain a reasonable position forecast for a cold front in advance of a strong polar outbreak.