Turbulence on a flight from Tampa to Nashville

July 20th, 2022 |
GOES-16 True Color imagery from 1841 – 1956 UTC on 20 July 2022 (Click to enlarge)

An Embraer 175L took off from Tampa shortly before 1900 UTC on 20 July 2022. About an hour into the smooth flight (as shown here, i.e., around 1945-1950 UTC), turbulence injured about 7 passengers that resulted in a diversion to Birmingham AL (news article; Here is the flight path). The animation of true-color imagery, above, taken from the CSPP Geosphere site (link), shows the region of turbulence, a region of strong convection developing west-to-east along a boundary just inland from Gulf Coast from Mississippi to Florida.

The CIMSS Turbulence site (link) shows probabilities of Moderate-of-Greater (MOG) Turbulence. This machine-learning product was developed using satellite imagery and NOAA/NWS Global Forecasting System (GFS) model output as well as observations of Eddy Dissipation Rate (EDR) on board large aircraft (Here is a training video on the product). MOG Probability fields over North America — along with EDR observation points and Pilot Reports of turbulence — from 1750 to 2140 UTC on 20 July 2022.

MOG Turbulence probabilities, 1740 – 2140 UTC on 20 July, along with Pilot Reports (PIREPs) of turbulence (Click to enlarge)

The CIMSS turbulence site also includes a Midwest sector that shows the Gulf Coast region; MOG Probability contours and observations are revealed for this event with more clarity. The turbulence was observed in between two different regions of higher probability. This matches an observed feature of this product as noted in the training: We notice that often turbulence occurs on the edge of a predicted feature, not in the center. This indicates that an aircraft that skirts just around a known feature is not “in the clear”. That was the case on this day.

MOG Turbulence Probabilities, along with Pilot Reports (PIREPs) of turbulence and EDR observation points, 1920 – 2000 UTC on 20 July 2022 (Click to enlarge)

GOES-17 IFR, Low IFR, and MVFR Probability fields over South Alaska

June 7th, 2022 |

IFR (Instrument Flight Rules) Probability estimates the likelihood that IFR conditions are occurring by fusing GOES-17 satellite data with model output. The satellite-derived products give output of low IFR, (LIFR), IFR, and Marginal Visual Flight Rules (MVFR). In aviation, the difference between these classifications is generally:


Low Instrument Flight Rules (LIFR): Ceilings are less than 500 feet above ground level and/or visibility is less than 1 mile.


Instrument Flight Rules (IFR): Ceilings are 500 to 1,000 feet and/or visibility 1 to 3 miles.


Marginal VFR (MVFR): Ceilings are 1,000 to 3,000 feet and/or visibility is 3 to 5 miles.

An example of GOES-17 IFR, Low IFR, and MVFR Probability fields along with the red visible channel (0.64 microns) over South Alaska on 07-June-2022 from 16:00 to 17:50UTC. Note how flight rules probability changes as cloud cover (seen from the visible imagery in the bottom right panel) changes [click to enlarge].

CIMSS Turbulence Fields changed

May 27th, 2022 |
GOES-17 Band 8 (“Low-level water vapor”) Infrared (6.19 µm) fields, 1910 UTC on 27 May 2022, along with derived Turbulence Probability for 30-33 kft, 34-37 kft, 38-41 kft (Click to enlarge)

At the request of AWC and WFO HNL, the turbulence probability fields for AWIPS have been changed (the website — here — is unaltered as of now). The turbulence probability is split into 3 layers that are each 3000 feet thick: 30000-33000 feet ; 34000-37000 feet; 38000-41000 feet. The AWIPS plugin used to display the information has also been changed, so that contours are drawn, as shown above. This will affect AWIPS performance if you are displaying the full disk imagery (because there are so many contours to draw!)

High-altitude turbulence over the Southern Plains

May 25th, 2022 |

GOES-16 Upper-level Water Vapor (6.2 µm) images, with pilot reports of turbulence (cyan) — with and without contours of RAP40 model Maximum Wind Speed (yellow) [click to play animated GIF | MP4]

GOES-16 (GOES-East) Upper-level Water Vapor (6.2 µm) images with pilot reports of turbulence — with and without contours of RAP40 model Maximum Wind Speed (above) showed an anomalously-deep 500 hPa trough over the Southern Plains, where there was an anomalously-strong 250 hPa jet streak developing along its forward (eastern) edge. A number of pilot reports of moderate to severe turbulence were seen within the exit region of this jet streak.

In GOES-16 Upper-level Water Vapor images with and without an overlay of a Turbulence Probability product (below), higher probability values were apparent in the area near/along the axis of the 250 hPa jet streak (and the related pilot reports of turbulence).

GOES-16 Upper-level Water Vapor (6.2 µm) images, with pilot reports of turbulence (cyan) — with and without an overlay of Turbulence Probability [click to play animated GIF | MP4]