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Note: HRES and Ensemble Control Forecast (ex-HRES) are scientifically, structurally and computationally identical.  With effect from Cy49r1, Ensemble Control Forecast (ex-HRES) output is equivalent to HRES output shown in the diagrams.   At the time of the diagrams, HRES had resolution of 9km and ensemble members had a resolution of 18km.


 

Fig8.1.14-5: IFS forecast vertical profile within the red circle shown in Fig8.1.14-4, DT 00UTC 21 May 2024, VT 06UTC 21 May 2024.  This  The hodogram supports CAT above and around the outflow associated with deep convection.  There is weak stability in the upper troposphere and a wind maximum in the vertical which supports breaking strong gravity waves.  IFS CAT accounts for this which is an important contribution in the tropics. 

Note: HRES and Ensemble Control Forecast (ex-HRES) are scientifically, structurally and computationally identical.  With effect from Cy49r1, Ensemble Control Forecast (ex-HRES) output is equivalent to HRES output shown in the diagrams.   At the time of the diagrams, HRES had resolution of 9km and ensemble members had a resolution of 18km.

An example of gravity wave turbulence

Image Added

Fig8.1.14-6: Example of Severe Turbulence

 An Airbus A330 encountered severe turbulence while flying over the eastern coast of Greenland on 14 Nov 2024.  This lay ahead of a sharp upper trough and was likely driven by mountain waves triggered by Greenland’s rugged orography.  Extreme vertical accelerations (decent -6800fpm and ascent 3800fpm) occurred and an in-flight shutdown of an engine was necessary followed by a return to Copenhagen.  The IFS turbulence index forecast (colour shading) correctly identified the hazardous area with lead time of 16 hours.Also shown are IFS forecast wind trajectories for the flight level, also altitude and vertical speeds experienced by the aircraft.. Forecast VT16UTC 14 Nov 2024; DT00UTC 14 Nov 2024

Note: HRES and Ensemble Control Forecast (ex-HRES) are scientifically, structurally and computationally identical.  With effect from Cy49r1, Ensemble Control Forecast (ex-HRES) output is equivalent to HRES output shown in the diagrams.  

Additional Sources of Information

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