Climate Perspectives: A Web-based Tool for Assessing the Unusualness of the Weather

Humans are becoming increasingly vulnerable to climate variability and change, especially the occurrence of extreme events. And this has increased the need to assess the rarity or extremeness of a recent or ongoing weather episode. Among other things, it useful to compare this event or period of anomalous weather with similar events or periods in the past and to assess whether they are occurring more or less frequently with time. In response to this need, the NOAA Southeast Regional Climate Center (SERCC) has developed a web-based routine, Climate Perspectives (CLIMPER) that allows the user to flexibly investigate unusualness of a weather event or recent streak of unusual weather. CLIMPER (http://www.sercc.com/perspectives/) ingests current and past weather data from the Regional Climate Center's Applied Climate Information System (ACIS) and provides a rich mix of climatological information over a range of time periods. These climate perspectives provide a synopsis of recent temperature and precipitation patterns in terms of how they depart from what is normally observed. The daily updated climatological information allows the user to readily assess the extremeness of an ongoing weather event or regime (e.g. exceptionally hot, cold, or wet conditions) over the prior days, weeks, or months by seeing how it compares with historical record during the same calendar period. Unlike traditional climatologies, the information on this site is not bound by the artificial boundaries imposed by calendar months. Weather departures are identified over time periods that can cross months, thus the identification of a time period with the most extreme departure from normal is not constrained to one calendar period such as a given month, season, or year. The user can select from a wide variety of stations in the Southeast region and from stations for all larger cities across the continental United States. Specifically, they can develop climate perspectives for minimum, maximum, and mean temperature as well as precipitation. In addition, they can see what city across the United States has the most similar temperature based on its climatological normals. A daily maximum temperature of 22 F in Greensboro, NC, for example, might be identified as being closest to the temperatures typically experienced in Minneapolis, MN on a given date in January. A user can also identify events or periods in the past record in which similar weather conditions were observed.