Graphical Turbulence Guidance Nowcast (GTGN)

Graphical Turbulence Guidance Nowcast (GTGN)

Project Tabs - GTGN

Example of a GTG turbulence forecast as it appears on the Operational Aviation Weather Center web site.
Example of a GTG turbulence forecast as it appears on the Operational Aviation Weather Center web site.

Since it is a forecast product, the GTG is most useful for route planning, i.e., strategic avoidance of turbulence. However, given the rapidly evolving character of turbulence, for tactical avoidance it is more useful to have a rapidly updated nowcast system. This system, called GTGN (N for nowcast), is currently under development at RAL and is primarily driven by the most recent available turbulence observations (in situ EDR measurements, turbulence pilot reports, NTDA output, and satellite–based turbulence inferences) merged together with a GTG short–term forecast. The product updates every 15 min.

Example GTGN output (lower right) showing modifications from the GTG input (upper right).
Example GTGN output (lower right) showing modifications from the GTG input (upper right).

The GTGN procedure uses GTG short–term forecast grids which are modified on a point–by–point basis to provide better agreement with the latest observations. The observations used include PIREPs, in situ EDR data, and NTDA EDR measurements. The gridded output is EDR. An example of the adaptive procedure is shown in the figure above.

GTG-N is a gridded turbulence nowcast product developed at the National Center for Atmospheric Research (NCAR/UCAR) and has satisfied the requirements and been approved by the Federal Aviation Administration (FAA) Technical Review Panel (TRP) and the Safety Review Management Panel (SRMP).

NCAR/UCAR is producing GTG-N output that can be made available through a license agreement to interested users. More information about the data feed and GTG-N data output is included in this document: User's Guide. If you are interested in receiving GTG-N data, please submit the contact information form below and we will contact you to set up the license agreement.

NOTE: NCAR/UCAR is not a 24x7 facility. We do not guarantee that GTG-N output is always available.

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Graphical Turbulence Guidance Nowcast (GTGN)

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