Tips On Using SiriusXM Satellite Weather In ForeFlight

With the release of ForeFlight Mobile 8.1 you now have the opportunity to use the best portable en route weather system available courtesy of our partnership with SiriusXM Satellite Radio. The SiriusXM Pilot for ForeFlight subscription tier has been uniquely designed to provide all of the essential weather data during every phase of flight. In fact, within about 15 minutes of turning on the SXAR1 and connecting to the ForeFlight Mobile app, you’ll have seamless access to a comprehensive set of weather products well before you close the door on the cockpit and depart. Here are some of my tips to safely use this unique collection of weather data.

Hurricane Hermine

SiriusXM radar depiction of Hurricane Hermine as it approached the Florida coast in early September.

The SiriusXM source label

Knowing the source of the data you are using is paramount since weather data ages quickly. When connected to the SXAR1, you’ll see a SiriusXM label under the tappable timestamp button in the upper left of the Map view. Moreover, every weather product provided through the SiriusXM broadcast includes a source label in parentheses along with its relative age like the one depicted in the image below. This is similar to the ADS-B label shown when connected to Stratus. While connected to the SXAR1 in flight, always be sure to check for the presence of the SiriusXM label. Seeing this label will confirm that you are using the most current weather available.


Products received from the SiriusXM broadcast and displayed in ForeFlight will be labeled with a SiriusXM tag along side the product’s age as shown here for a terminal aerodrome forecast (TAF) for the Cape Girardeau Regional Airport.


During the warm season, lightning from ground-based sensors is perhaps one of the most critical weather elements to have available in the cockpit. Any area of weather that includes lightning means there’s a darn good chance you will encounter severe or extreme convective turbulence in and around that weather. While most of the serious thunderstorms will be included within the boundary of a convective SIGMET, not all thunderstorms will meet convective SIGMET criteria. Moreover, thunderstorms often occur outside of these areas, especially during a rapidly developing convective event.

Lightning is broadcast over SiriusXM every five minutes and provides pilots with a birds-eye view of where the truly nasty convective weather is located. Moreover, both cloud-to-ground (CG) and intracloud (IC) lightning are part of this broadcast. It’s quite important that both types are included since many severe storms are often dominated by IC lightning.

With SiriusXM not every lightning strike is broadcast. Instead, a single lightning symbol is shown anytime one or more strikes have occurred within a generous 0.5 nautical mile grid. So when you pinch-and-zoom way in on the ForeFlight map as shown below, you’ll notice the lightning bolt symbols are aligned in this 0.5 nautical mile gridded pattern. ForeFlight retains the most recent 10 minutes of lightning data which tends to align with the most recent radar depiction very well.

SiriusXM Lightning grid

A zoomed-in view of SiriusXM lightning reveals it’s gridded nature.

Lightning is detected even in regions where radar coverage is not present. This can be extremely useful when flying outside of the NEXRAD radar coverage area. You’ll see lightning depicted in regions over the Gulf of Mexico and Caribbean as well as the coastal waters of the U.S. in the western Atlantic and eastern Pacific Oceans. It will also include lightning in Canada, Mexico, Central America and the northern-most regions of South America. Although there is SiriusXM NEXRAD coverage provided around Puerto Rico and the U.S. Virgin Islands (using the base reflectivity from the lowest tilt), having lightning shown in other locations in the Caribbean will help pilots avoid the nasty tropical convection that occurs in these highly traveled areas where there isn’t NEXRAD coverage.


SiriusXM radar coverage is available using the base reflectivity layer from the lowest tilt around Puerto Rico and U.S. Virgin Islands. You will also see lightning depicted outside of the standard NEXRAD coverage area as far south as the northern portions of South America.

Storm attribute markers

Pilots have become accustomed to seeing echo top heights and storm track identification markers in ForeFlight. With SiriusXM you’ll get those same NEXRAD storm attributes. This includes a generic storm marker with an echo top height shown in 100s of feet in addition to cells that have signatures of hail, mesocyclone and tornadoes using the symbols shown below. Echo top heights are only shown for tops 20,000 feet and higher.


Storm attribute markers include hail, mesocyclone and tornadic vortex signature. Under the settings, these SiriusXM Storm Markers can be switched on and off as desired.

In most cases these storm attribute markers will also contain a direction and speed of the cell being tracked. Similar to the other storm tracks you will see depicted on the radar mosaic in ForeFlight, SiriusXM tracks will contain an arrow showing the direction of movement as well as the speed. If the cell is moving at a speed of more than 10 knots, you’ll also see two black dots depicted on the arrow that loosely estimates the position of that storm cell in 20 and 40 minutes based on the cell’s current speed and direction provided. The arrowhead represents the estimated location of the cell in 60 minutes.

Confusing Storm Attribute Markers

During a rapidly developing convective event or when thunderstorms are dissipating, it’s quite common to see the storm tracks for adjacent cells point in opposite direction.

While these markers provide additional information about a storm cell, keep in mind that there will be times when the storm tracks for adjacent cells may provide conflicting information as you can see in the example shown above. It’s unlikely these cells are actually moving toward each other. This typically occurs during the initial stage of thunderstorm evolution especially when there’s an area of rapidly developing convection. Animating the radar is perhaps the best way to note the direction of movement of an area of weather.


Shown here are several storm attribute markers to include mesocyclone circulation and tornadic vortex signatures from Tropical Storm Hermine as it passed off the coast of South Carolina.

Radar layers

The SiriusXM composite reflectivity and base reflectivity from the lowest tilt have the same 2 km horizontal resolution as you may have experienced with the regional radar broadcast provided by ADS-B. On the left is the regional composite reflectivity mosaic broadcast by ADS-B using the Stratus 2 receiver. On the other hand, the right side is the SiriusXM mosaic just a minute earlier. While the mapping of dBZ levels to color may be a little different for the two composite reflectivity sources, the overall spatial resolution is the same.


Regional composite reflectivity from ADS-B shown on the left and composite reflectivity from SiriusXM shown on the right. Both have a similar resolution.

There’s no doubt that the overall qualitative glance value is practically the same between the two radar depictions above. You’ll find, however, that the latest SiriusXM broadcast will be about 5 minutes fresher on average than what you get through ADS-B.

Partial radar refresh

You may occasionally notice that both of the radar mosaics may take a short period of time to completely refresh the Map view for the entire radar coverage area when a new NEXRAD broadcast is being processed. During the refresh, it will be common to see “Radar not available” briefly depicted over regions where coverage is normally provided as shown below for the base reflectivity mosaic from the lowest tilt.

Partial refresh

Partial updates to both the composite reflectivity and base reflectivity from the lowest tilt should be expected when the newest radar broadcast is being processed.

This is because radar data received by the SXAR1 rarely comes as a continuous frame of data. Often this data is broadcast in blocks over a short period of time. This is especially true for the base reflectivity mosaic from the lowest tilt. To avoid holding back the entire radar mosaic until every single byte is received, we decided to provide the newest radar in pieces as it arrives. Whether or not this occurs and how long it takes to provide a complete picture, depends on the amount of radar echoes throughout the entire coverage area. During times of high convective activity or large-scale precipitation, expect the refresh to be a bit slower, typically 20 to 30 seconds.

If you believe in Murphy’s Law, this refresh delay will rear its ugly head at the most inopportune time. If the refresh takes uncomfortably too long while in flight, you can always switch to the other radar depiction in the short term.

Also includes Canada

Unlike ADS-B, the SiriusXM radar depiction from the lowest tilt does include Canadian Doppler radar information as well (Canadian radar is not included in the composite reflectivity mosaic). You won’t see any storm tracks or echo tops depicted by Canadian radar data, but this does extend the radar coverage to the southern most part of Canada for those pilots that fly to this area frequently. In addition to radar, you will see winds and temperatures aloft depicted in Canada as well as METARs, TAFs and PIREPs.

Winds and temperatures aloft

The winds aloft layer is populated by model-based winds (not observations) from the SiriusXM broadcast. These are an accurate representation of the current winds at 3,000 ft MSL up to FL480 at 3,000 ft intervals. This is a similar presentation to what you will find with the winds aloft layer when connected to the Internet. Tapping on any wind barb will provide the wind direction, wind speed and temperature at the altitude selected.


While in flight, you will see updates to the current winds once each hour. At this time there are no forecasts of winds aloft provided through SiriusXM valid beyond the current time. Consequently, the SiriusXM winds are not used in performance calculations, so you should anticipate using the pack feature to have an estimation of winds aloft along your route while in flight.

ForeFlight HD 3.8 with Terminal Procedure Printing, Offline NOTAMs, and Improved Airway Support

ForeFlight Mobile HD version 3.8 is now available for your iPad and iPhone! Download it today from the App Store and grab the latest update to the user manual.

Here is a rundown of the new features and bug fixes in 3.8:

  • Print Instrument Procedures with iOS 4.2 AirPrint (iPad only).  Only a small number of printers are supported now, but Apple is working to add more in the future.
  • NOTAMs are saved to your device after viewing.
  • Native city- or airport name-based search – no internet connection required. Put quotes around multi-word queries like “San Diego”.
  • Redesigned N-number/aircraft search with improved Aircraft views.
  • Soft-lock on procedures view now locks rotation on iPad, since the iPad lock-switch is now a mute switch in iOS 4.2.
  • iOS 4.2 compatibility with better fast-app switching support for iPad.
  • Improved airway support
    • Detection of intersection automatically when two airways put side by side
    • Automatically uses closest VOR on airway as exit/entry point when airport is adjacent to an airway in a route
    • Better support for joining airway to SID/STAR
  • Improved SID/STAR support (e.g. fixed issue where some waypoints would repeat).
  • Better performance in flight plan filing form on iOS 4.2 and fix for possible crash when exiting form on iPhone.
  • Fixed bug where BYOP procedures are not accessible from Favorites and Recents.
  • Fixed bug where maps would get clipped after rotating iPad on another view.
  • Fixed location tracking bug.
  • New settings (see ForeFlight section in iPad Settings app)
    • Change type of aircraft shown on Maps when in motion.
    • Disable auto-hide of toolbar in full screen approach plate viewer.
  • Fixed issue preventing a tap of the top status/time bar from scrolling to top of view in Airport details (iPhone).

The Pilot’s Guide to ForeFlight Mobile

We’ve updated our user manual, the Pilot’s Guide to ForeFlight Mobile HD.  Click here to get the latest version of the manual.

How to Get 3.8

New to ForeFlight?  Download ForeFlight Mobile HD today from the App Store!

Already have the app?  Follow these instructions for updating the app on your iPad or iPhone.

Need a group plan or backup subscription? View group pricing here.

Announcing ForeFlight File: iPhone Flight Plan Filing

Today we’re proud to unveil ForeFlight File, our latest iPhone aviation app. If you haven’t been ready to take the plunge into our more full-featured iPhone aviation application, ForeFlight File is a great way to get an inexpensive peek at one of the many features available in the ForeFlight Mobile suite.

iPhone Aviation

ForeFlight File is a simple flight plan filing utility for pilots designed for iPhone and iPod touch. File can submit flight plans without any special setup requirements, or you can file plans using your DUATS Access Code and get the extra assurance some pilots prefer. File was designed with the same attention to detail that ForeFlight customers expect, including such user interface gems as our Intelligent Aircraft Color Picker, altitude corrections for VFR and IFR flight plans, detailed email confirmations, detailed status messages when a flight plan fails to file for any reason, and a Fix feature for correcting flight plans that could not be filed for any reason.

Finally, a simple iPhone flight plan filing utility designed for pilots, by pilots!

Other features include:

  • Intelligent Altitude Selector sets the proper altitudes based on type of flight plan filed
  • iPhone-style pickers for time en route, fuel aboard, departure time, and cruise altitude
  • Previous and Next buttons to quickly progress from field to field
  • Complete history of all flight plans filed
  • A copy function to file a new flight plan from an existing flight plan
  • A delete function to remove old flight plans
  • Email confirmations that include a flight plan summary, flight plan details, current and forecast weather observations, and ForeFlight confirmation codes

ForeFlight File is available for purchase in the iPhone App Store for $4.99. All of the functionality in ForeFlight File can be found in the Flight Plans tab inside ForeFlight Mobile, so existing customers of ForeFlight Mobile need not purchase ForeFlight File.

Visit our web site to explore features and learn more about the latest addition to the ForeFlight family.

Night Flights & Sunny Runways: Developing iPhone Aviation Apps

By Adam Houghton, Principal Developer

Mobile applications are powerful because they are so portable. Devoted iPhone and Blackberry owners carry their devices everywhere. I’ve been known to forget my keys and I accidentally drove most of September without a license, but I never leave home without my iPhone. The emergence of location-aware, carry-everywhere mobile devices is ushering in the next great computing platform. The Internet on my desk is occasionally useful; the Internet in my pocket is always useful.

But for a mobile software developer, portability brings a new set of challenges. Traditional desktop applications like Quicken or iPhoto are run on big screens in homes and offices with a user’s undivided attention. iPhone users don’t sit at desks – they’re more likely to launch apps while waiting for a taxi on a rainy street corner. And whether it’s powered by RIM, Apple, or Android, a phone’s screen is highly reflective and usually smaller than a deck of cards.

Case Study: ForeFlight Checklist

At ForeFlight, we develop iPhone aviation apps. Pilots use ForeFlight Mobile, our flagship app, to check the weather report for the day’s flight during breakfast or file a flight plan from the airport terminal. In September, we introduced our second iPhone application: ForeFlight Checklist – Intelligent Aviation Checklists for Pilots.

Before releasing Checklist, we took it on quite a few test runs, constantly redesigning and tweaking the user interface to make it a natural fit in a pilot’s workflow. ForeFlight Checklist 1.0 received a fantastic reception, and as pilots have started using it out in the field, we’ve heard some great suggestions for new features. Two items in particular kept coming up, and illustrate the wide variety of environments and usage scenarios for mobile applications.

Scenario 1: Sunny Runways

The common use case for ForeFlight Checklist is running through a preflight checklist out on the runway. Each aircraft type has a customized list with dozens of items to check, such as verifying the tires are inflated and the fuel vent is unobstructed. Here is a preflight checklist for a Cessna 152 as seen in ForeFlight Checklist 1.0:

Preflight checklist for Cessna 152 in ForeFlight Checklist 1.0

ForeFlight Checklist 1.0: Cessna 152 preflight checklist

You can check an item by tapping it directly, or by tapping the green ‘Check’ button on the bottom. Pilots can consciously skip an item by tapping the yellow ‘Skip’ button. The table automatically scrolls the active item to the center and highlights it with a yellow background (“Fuel shutoff valve”). This, along with clearly defined indicators once a list is complete, keeps you from accidentally missing an item on the list.

After using Checklist out on the runway, a few pilots emailed us with an observation: the selected item was hard to see on a sunny day because the yellow background got drowned out. If you were wearing polarized sunglasses (a common scenario for pilots), it was even harder to see.

The solution for this was easy: change the background of the selected item to provide better contrast. We already had written code to special-case the background color, so we changed the color to blue (the standard iPhone color for indicating selections) and lightened the text color. Here is the same screen in ForeFlight Checklist 1.1, with a better contrasting background on the selected item, “Fuel shutoff valve”:

Cessna 152 preflight  checklist

ForeFlight Checklist 1.1: Cessna 152 preflight checklist

Scenario 2: Night Flight

Another handful of pilots emailed us with feedback on an opposite problem: when using Checklist in the evening, the app’s white background shone super brightly and was hard on the eyes. Even with the iPhone’s brightness setting turned all the way down, it was too bright.

To help out these pilots, we created “night mode“, a new color scheme available in ForeFlight Checklist 1.1. Inspired by the excellent Bloomberg iPhone app, night mode uses a black background with orange, gray, and white text. To ensure it’s easy on the eyes, while writing the code for this feature we actually turned off all the lights in the office and worked in the dark! Here’s a screenshot of the same Cessna 152 preflight checklist under night mode:

Night Mode in ForeFlight Checklist 1.1

Night Mode in ForeFlight Checklist 1.1

To toggle between night mode and the classic look (now called “day mode”), we added a new sun/moon icon on the bottom-right of the main screen:

Day mode vs night mode

Day Mode vs Night Mode in ForeFlight Checklist 1.1

If a checklist item has additional notes, a right arrow indicator is shown (e.g. “Rudder gust lock” and “Control surfaces” in the screenshots above). Tapping the arrow brings up the item detail screen, as shown below. Unfortunately, when creating night mode, this screen presented a challenge. Under day mode, the screen uses the iPhone’s “Grouped Table View” style, with floating white cells on a blue background. (This is familiar to anyone who has used the iPhone’s Contact app.) Unfortunately, this can’t be styled with a black background – it has to be white on blue. Instead, we created a new screen using the iPhone’s “Plain Table View” style, which doesn’t have floating cells and allows for a great deal more customization. (This style is used by Apple’s Mail app and Phone app, and is also the primary table view used elsewhere in Checklist.)

Here is the detail view under day and night mode for checking the Cessna’s RPM lever:

Detail view in ForeFlight Checklist 1.1

Detail view in ForeFlight Checklist 1.1

Creating night mode took quite a bit of work, but we’re very pleased with the outcome. Everyone on the ForeFlight team now uses it as their primary interface for Checklist – even during the day!

Know the Environment

When creating mobile applications, it is important to know your users. Whether it’s a sunny runway or a foggy afternoon, an iPhone app should feel at home in any environment.