ADDS Turbulence Help

Disclaimer and Labeling

GTG is generated operationally at NOAA/NCEP which is supported 24 hours a day, 7 days a week. Its use is unrestricted (meteorologists, dispatchers, GA and commercial pilots, ATC, etc).


The Turbulence page contains depictions of the Graphical Turbulence Guidance product, version 3.0 (GTG), which forecasts turbulence from the surface to FL 450, with 0, 1, 2, 3, 6, 9, 12, 15 and 18 hour lead-times, driven by, and synchronized with NOAA's "Rapid Refresh" of RAP forecast model with a horizontal grid spacing of 13.5km and 50 vertical levels. GTG-3.0 provides computer-generated four-dimensional forecasts of information related to the expected intensity of atmospheric turbulence relates to Clear-Air Turbulence (CAT, mountain wave turbulence (MWT, and low-level terrain and thermally-induced turbulence sources. It is not intended to predict turbulence associated with convection and thunderstorm clouds, but may provide some guidance in areas of properly predicted thunderstorms when the convection is widespread. The product provides forecasts for the 48 contiguous United States, and much of Canada and Mexico. Although the GTG product has been verified against thousands of turbulence pilot reports and in situ EDR data, users should also be aware that turbulence is a highly dynamic phenomenon and in case of rapidly changing conditions the product may not accurately convey a significant hazard. Further, the GTG-3.0 graphics available on ADDS are "snapshot" graphics, intended to depict forecasted turbulence conditions at the valid time (for example, at 1200Z), not for a valid time range (for example, from 1200Z to 1300Z). The graphics suite is automatically produced with no human modifications.

ADDS is operationally supported 24 hours a day, 7 days a week by the AWC. However, due to the processing time of the model data, the GTG-3.0 will normally be released about 50 minutes after the valid time of the RAP data set. The longest update cycles occur at 00Z and 12Z due to additional data ingest and processing. GTG-3.0 will normally be released 100 minutes after the valid time of the RAP data set at 00Z and 18Z. ADDS is configured so the composite graphic with the most relevant valid time should display when you initially select the GTG-3.0 product, but all graphics in the GTG-3.0 suite are available for viewing via the valid time and altitude selection interface.

NOTE: Users should pay close attention to the valid time of individual graphics due to the delay caused by RAP update cycles required for the GTG-3.0.