Turbulence Guidance

This post will highlight some of the turbulence guidance being used and evaluated in the testbed during the experiment.  The valid times are 13 Feb 21Z - 14 Feb 09Z.

The first two images below are guidance that is available on our operations floor.  To get a general idea of the pattern, the 300 hPa heights, winds and isotachs are plotted.  The second image shows the Ellrod-Knox Turbulence Index for the same period, which is highlighting a region of enhanced turbulence along the east coast developing along the shear zones of the ridge.

13 Feb 12Z NAM forecast of 300 hPa heights and winds.

13 Feb 12Z NAM forecast of 300-400 hPa Ellrod-Knox Turbulence Index.

For the experiment, we have been looking at several different high-resolution forecasts of turbulence.  The first is a probabilistic forecast of turbulence from the AFWA ensemble between 25,000 and 30,000 feet.  The second is an explicit prediction of Turbulent Kinetic Energy (TKE) from the WRF-NMM run at 00Z and 12Z for the Storm Prediction Center.  Plotted is the maximum value over the previous hour in the layer between 200 and 500 hPa.

13 Feb 00Z AFWA forecast of probability of turbulence for FL250-300.

13 Feb 12Z SPC WRF-NMM forecast of hourly max TKE between 200-500 hPa.

Looking at these different solutions, all have the ribbon of turbulence along the east coast jet, but the location of the maximum differs depending on the predictor.  A loop of water vapor imagery for this period is shown below.  Overlaid on this loop are automated aircraft observations of Eddy Dissipation Rate (EDR), which are an objective measure of turbulent eddies in the atmosphere, as well as subjective Pilot Reports (PIREPs).  Toward the end of the period, a Turbulence SIGMET was issued off the New England coast.

GOES-East Water vapor imagery with EDR observations from aircraft and Turbulence SIGMETs.