33WAF/29NWP Sub-seasonal to Seasonal (S2S) Impact-based Decision Support Services (IDSS): Adding Local Value to the Climate Prediction Center’s 8-14 Day U.S. Hazards Outlook

National Weather Service Weather Forecast Offices (NWS WFOs) generate forecasts of various weather related parameters and associated products on timescales of 0-7 days, while the Climate Prediction Center (CPC) is responsible for periods beyond seven days. Most forecast information from the NWS WFOs is deterministic, but this has begun to change in recent years with the inclusion of more probabilistic messaging. This dovetails better with outlooks from the CPC, which are probabilistic in nature. One of these CPC products is the 8-14 Day U.S. Hazards Outlook, which serves to alert stakeholders of the probability for impactful weather conditions during the 8-14 day period. Recent extreme weather events such as excessive heat, extreme cold, and heavy precipitation that affected the Tennessee Valley were included in these outlooks. However, messaging in the Hazards Outlook includes the use of “Much Below” and “Much Above” terminology, which may leave the user guessing about specific temperatures and precipitation amounts that could occur. This made it evident that increased visibility of the products by NWS WFOs, while including relevant details about temperatures and precipitation amounts, could be beneficial for stakeholders. The local Huntsville WFO climate team collaborated with the Alabama Office of the State Climatologist (AOSC) in developing a Jupyter Notebook file that extracts important percentiles threshold data in the 30-year climatological dataset used by the CPC for the Hazards Outlook. The resulting values, when used in conjunction with other CPC tools such as the Week-2 Global Probabilistic Extremes Forecast Tool, can allow for the inclusion of important temperature and precipitation information in local Seasonal-to-Subseasonal (S2S) Impact-Based Decision Support Services (IDSS) messaging.

This presentation will include information about this new S2S IDSS initiative, along with a demonstration of the Jupyter Notebooks file developed by the AOSC, and examples of associated local products and services to support decisions for the general public and our stakeholders such as emergency management and agricultural partners.