Automated jet streams on significant weather high level charts at WAFC Washington

An outstanding consistency and efficiency issue in the production of Significant Weather High Level Charts at WAFC Washington at the USA's Aviation Weather Center (AWC) is the drawing of jet stream maxima worldwide. The drawing and labeling of approximately 50 jet stream maxima can consume approximately an hour, leaving less time for meteorologists to analyze, forecast, and add value to turbulence and convection forecasts.

AWC has developed an automated jet stream tool which provides forecasters with worldwide jet stream maxima which are input into our jet stream production. The tool uses a new AWC developed algorithm that extends the zero relative vorticity jet algorithm graciously provided to AWC by the UKMET Office. Using the USA's Global Forecast System global model, the AWC algorithm: 1) determines where the wind speed is greater than 80 kt on the 300, 250, 200, 150, and 100 hPa isobaric levels, 2) locates wind speed extrema at those levels, 3) sorts the wind speed extrema points from 300 to 100 hPa using the maximum wind speed field to determine one level of maximum wind speed points, 4) determines the flight level of the jet stream maximum points, and 5) draws jet stream maxima streamlines through the jet stream maximum points.

The resulting automated jet stream maxima lines compare favorably with those produced by human forecasters in most cases. Detailed comparisons between the automated jet stream maxima lines and those produced by AWC forecasters will be shown. Suggestions for future algorithm development will be discussed. In addition, the potential for collaboration between WAFC Washington and London to improve consistency between the respective centers' products will be explored.