Essentials of the U. S. Navy's numerical frontal analysis model, employing special second derivatives of the potential temperature field, are reviewed. The scheme is extended to include frontal-prognosis problems, visual presentation of numerical fronts, and application of the new approach to other areas of interest in meteorology and oceanography. The difficulties of accurately depicting baroclinicity for surface frontal analysis are also discussed.
A limited evaluation of the surface, 1000- and 850-mb numerical frontal analyses relative to manually analyzed fronts for six synoptic times in February 1965 over the western part of the Northern Hemisphere is presented. Average departures of numerical frontal positions from U. S. Weather Bureau analyses are about 100 n mi and are less than 50 per cent of the mesh length used by the Fleet Numerical Weather Facility. Merits and deficiencies at each of these three levels are enumerated and discussed.