The National Weather Service Unified Surface Analysis

For many decades, various offices within the United States Weather Bureau and the current National Weather Service (NWS) each composed surface analyses over different parts of the world to satisfy their operational needs and serve their respective customers. These analyses usually overlapped and led to a duplication of effort by the offices—and brought confusion to users who would see features analyzed differently from office to office. To remedy this redundancy, the National Centers for Environmental Prediction (NCEP) Office of the Director proposed that the various analysis centers—the Hydrometeorological Prediction Center (HPC), the Ocean Prediction Center (OPC), the National Hurricane Center (NHC), and the Honolulu Weather Forecast Office (HFO)—limit their analyses to their respective areas of expertise. Each individual map is merged to create one seamless Unified Surface Analysis covering almost 70% of the Northern Hemisphere. This effort was intended to make the entire analysis process more efficient and to allow each center to use its expertise to focus on particular regional and meteorological features within their area of responsibility. The seamless surface analysis was initiated in 2002 by HPC, OPC, and NHC, with HFO joining the collaboration effort in 2003.

The purpose of this presentation is to advertise the mechanics and logistics of the Unified Surface Analysis. Many users, including other NWS offices, may not be aware that the Unified Surface Analysis is a collaborative effort between four different offices, each of which must contend with meteorological features and patterns unique to their area of responsibility. Conflicting opinions often arise over the analysis of features due to historical traditions or “schools of thought” at each center—or simply due to the non-definite nature of the science of meteorology. In the end, respect for the analysis expertise of each center prevails and facilitates the creation of one seamless and comprehensive NWS Unified Surface Analysis. Hopefully over time, the seamless surface analysis process will cause the principles of all four centers to merge into a more consistent analysis ideology.