Cloud tops information can be seen or inferred using the:
- Cloud Tops Layer on the Map when connected to ADS-B or XM
- Graphical (HTML) briefing
- Clouds map layer (Included in Pro Plus, Performance Plus, and Business Performance plans.)
- Infrared Satellite Imagery.
Cloud Tops Layer on the Map (ADS-B or XM)
In flight, if ForeFlight is receiving XM or ADS-B weather through an external receiver, a Cloud Tops layer will be available on the Maps view.
Cloud tops on the Map via XM.
Graphical (HTML) Briefing
ForeFlight's Graphical (HTML) briefings include a set of Cloud Coverage images. To view them, open the briefing and tap Forecast > Cloud Coverage in the sidebar. These images display forecast cloud tops, along with cloud bases and any icing and mountain obscuration AIRMETs.
Cloud coverage forecast chart in a Graphical (HTML) briefing with tops shown.
Clouds Map Layer
On the Maps view, the Clouds map layer displays a global view of forecast cloud coverage at a selectable altitude (using the altitude slider on the right) and time (using the time slider at the bottom). The forecast depicts the forecast percentages of cloud cover using different shades of gray. The Clouds map layer is included in Pro Plus, Performance Plus, and Business Performance plans.
To view this map layer, on the Maps view, select the drop-down in the upper left and select the Clouds map layer.
The Clouds map layer shows forecast clouds by time and altitude.
PIREPs provide another source of cloud tops. To see PIREPs on the Maps view, select the PIREPs map layer from the drop-down in the upper left. Then tap on a PIREP icon to see the PIREP details.
PIREPs often have cloud top reports.
Infrared Satellite Imagery
Infrared satellite images provide cloud-top temperatures. The colder the cloud top, the higher the clouds. You can infer the altitude of cloud tops by calculating a standard temperature lapse rate. Additionally, you can compare the temperature shown at a point on ForeFlight’s Infrared Satellite imagery with the temperature shown in the winds aloft table reported for an airport in that area. The temperature in the winds aloft table will have a corresponding altitude, which will be close to the cloud tops over that area. This method is an approximation and not precise.
To use Infrared Satellite imagery to infer cloud tops over the USA, follow these steps:
- Tap More > Imagery.
- In the Regions menu, select USA.
- In the USA imagery menu, scroll down to the Satellite group and tap Infrared.
- Tap the Infrared Satellite thumbnail for the appropriate region.
- In the full-screen image, find the coloration for the area in question and note the temperature indicated at the bottom of the image.
- Next, tap Airports in the navigation toolbar and open the appropriate airport.
- Tap Weather > Winds.
- Find the altitude that corresponds to the temperature noted on the Infrared Satellite image.
Use the IR satellite image to find the temperature at cloud top for a particular area.
Use the Winds Aloft information at an airport near the area of interest to find the altitude of the temperature seen on the IR imagery.