At high latitudes during the winter months, the air at altitudes used by passenger and cargo aircraft can reach temperatures cold enough (-65°C) such that the jet fuel used by the aircraft can begin to freeze. Currently, aviation forecasters rely on a combination of isolated aircraft reports, a sparse network of radiosondes, and global model fields for identifying and characterizing these cold air hazards. Satellite information can help fill in the spatial and temporal gaps in the current observations. In particular, temperature and moisture retrievals from the NOAA-Unique Combined Atmospheric Processing System (NUCAPS), which combines infrared soundings from the Cross-track Infrared Sounder (CrIS) with the Advanced Technology Microwave Sounder (ATMS) to retrieve profiles of temperature and moisture. NUCAPS retrievals are available in a wide swath of observations with approximately 45-km spatial resolution at nadir and a local Equator crossing time of 1:30 A.M./P.M. enabling three-dimensional observations at asynoptic times.
For forecasters to best use NUCAPS observations, the soundings must be displayed in the National Weather Service’s decision support system, the Advanced Weather Interactive Processing System (AWIPS). NUCAPS profiles are available operationally AWIPS as point observations that can be displayed on Skew-T diagrams. NUCAPS data are also now available as an experimental gridded visualization within AWIPS developed by a multi-organization research-to-operations team through the Joint Polar Satellite System (JPSS) Proving Ground. The Gridded NUCAPS visualization enables views of plan-view horizontal maps and vertical cross sections, which gives forecasters additional tools for diagnosing the three-dimensional extent of Cold Air Aloft (CAA) events.
From December 2016 to March 2017, forecasters at the National Weather Service (NWS) Anchorage Center Weather Service Unit (CWSU) collaborated with the Gridded NUCAPS development team on a targeted assessment to determine the operational viability of these products for the CAA forecast challenge. This abstract will discuss the transition-to-operations process and results of this assessment, including case study examples where the Gridded NUCAPS products influenced forecast decisions.