Home WEATHER BRIEF There’s an app for that: weather in the palm of your hand

There’s an app for that: weather in the palm of your hand


A wealth of information is readily available on smartphones and tablets.

Aerovie’s EFB app, one of several comprehensive aviation software programs, gives pilots a vertical cross section of the weather they’re likely to encounter on their flight route.
By Karsten Shein
Comm-Inst Climate Scientist

While the junior pilot was driving to the airport, the senior pilot was letting his fingers do the flying from the passenger’s seat. A few swipes on his tablet, and he knew that they’d need to modify their flight plan to avoid getting caught in the midst of some nasty weather brewing between them and their destination airport.

By the time they parked the car, their new plan was in place with a tight deviation to skirt the weather system. The flight took off on time and needed only 10 extra minutes of flight time that the passengers didn’t even notice. In the beginning, it was simply a pilot versus whatever weather appeared in front of him.

Early aviators had little in the way of meteorological information to give them advance warning of impending weather that might make their flight uncomfortable or downright dangerous. Weather briefings and even flight plans were still a way off, and deviation decisions were made by simple gut feeling, with little other reliable information available to the pilot.

However, as aviation matured, so did the demand for weather products for pilots. Military squadrons and air carriers began to supply their pilots with printed weather maps, and they would post forecast updates in crew rooms so their pilots would have a heads-up about any weather they might encounter.

In the ever-evolving battle to keep pilots and passengers safe, it wasn’t much longer before pilots could call a meteorologist 24 hours a day and get a custom weather briefing for an impending flight.

And it took a few decades more before pilots could walk into an FBO or flight dispatch office and see the actual prog charts, surface analyses, and winds aloft, all displayed on a bulletin board in damp paper fresh off the digital fax machine.

There are dozens of apps that will provide near-real-time displays of ground-based radar information. Radarscope includes a variety of radar imagery from around the world, as well as offering pro subscriptions that include features such as lightning strikes.

Electronic evolution

When the Direct User Access Terminal System (DUATS) was inaugurated in 1989, it ushered in a new era in which not only could pilots file a flight plan through the emerging Internet, but they could also obtain weather briefings, and later even access current weather maps and charts.

Although DUATS officially shut its virtual doors last year, the legacy it left is nothing short of a paradigm shift that puts virtually every aspect of aviation weather at a pilot’s fingertips, literally.

What remained a major shortcoming was that the information available from these systems still could not be effectively carried with the pilot or updated easily while in flight. We still needed to talk with our dispatchers or with Flightwatch to get weather updates, and we had to do our best to visualize that verbal information in our decision processes.

If we were fortunate, we were flying an aircraft with an on-board weather radar system, or, at the very least, a Stormscope or Strike Finder to give us real-time updates of some weather conditions in front of us. The introduction and proliferation of tablet computers and other smart devices was the next logical evolution in technology for aviation.

Today’s smartphones and tablets have many times the computing power and file storage space of the desktop computers of just a decade ago.

Also, they are lightweight and easily stowed in a flight bag, and the programs (applications) they contain can – and often do – replace the many pounds of paper files (terminal diagrams, approach plates, weight and balance, manifests, and weather maps) that professional pilots used to lug aboard in thick flight cases.

Convenience of PEDs

The intuitive nature of capacitive touch screens and operating system layouts in portable electronic devices (PEDs) also transformed aviation by drastically reducing the time needed for search and retrieval of essential information, from checklists to radio frequencies for the alternate airport.

Instead of thumbing through a 200-page ring binder, a pilot could open a relevant app, tap the search icon, and within a few keystrokes the app would return the sought-after information.

Intelligent autocompletion has reduced the search times even further, listing possible results before finishing typing in a query. In a dynamic environment such as a cockpit during an approach into a busy major airport in heavy rain, anything that can shave a few seconds off a task that distracts from flying the plane is more than welcome.

Where once even the most experienced pilot might take a minute to make a calculation on their manual E-6B, an E-6B app can now spit out the desired answer in just a few seconds. What’s more, many apps now combine features that once were limited to expensive avionics, such as moving maps, 3-D synthetic terrain, and weather radar.

Although most pilots would be reluctant to rely on such apps over their dedicated and trusty panel avionics, these apps are a useful backup (or a primary, if the cockpit lacks such avionics). In many cases, because PEDs are easily upgraded for a few hundred dollars and software is frequently updated, they have become the go-to for many features that are too complicated or cumbersome to use easily on expensive, hard-wired avionics.

Pilots are finding a myriad of uses for their tablets. Apps exist for everything from weight and balance to filing flight plans and even tracking flights for later review. So, naturally, there are a wide variety of apps that bring current and forecast weather right to the pilot’s fingers. Some of these are stand-alone weather apps, while others are designed specifically for aviation, and integrate weather information into the features they offer.

Given the relative ease with which an app can be developed by a competent programmer, it is no surprise that many air carriers and charter operators have developed their own bespoke programs for their pilots. However, such apps are tailored to the needs of those company’s operations, and are generally only available to the company’s pilots.

Most pilots, professional and recreational, will rely on the many off-the-shelf apps available in Google Play for Android devices, or Apple App Store for iOS gadgets. Electronic flight bags Electronic flight bags (EFBs) are a class of app that seek to replace most, if not every aspect of what pilots used to do with paper and a calculator – and then some.

This includes functions historically handled by panel-mounted avionics. Various screens will calculate weight and balance, perform route planning, and even let you fill in and file your flight plan entirely electronically. A big part of these EFBs is their access to weather, both in terms of preflight planning and in-flight updates.

While not specifically designed for aviation, Windy is an app with a graphical display of current and forecast (up to 240 hours ahead) wind speeds and directions that can help with flight planning and routing.

There are several popular EFB apps available to pilots, including FlyQ EFB, Appareo Electronic Flight Bag, Garmin Pilot, ForeFlight Mobile EFB, and AOPA GO. While they all differ in the way the information is displayed, and some offer more features than others, all these apps provide fairly comprehensive access to a suite of weather planning products such as surface analyses, prog charts, metars and tafs, convective forecasts, and map layers such as freezing levels, satellite and radar imagery, and turbulence and icing forecasts.

In terms of aviation weather, EFBs generally lead the pack – primarily because they package weather information together with other features important to pilots. For example, EFBs generally include legal weather briefings supplied from a common and trusted source with current and forecast conditions displayed in both text and graphical formats.

In addition to preflight weather planning and briefings, these EFB apps are generally also designed to work in the cockpit to provide near-real-time weather information when it is most needed. Many of them offer ADS-B compatibility to deliver FIS-B weather data, and the ability to integrate that weather information into other displays such as flight routes, virtual attitude indicators, and even terrain/synthetic vision.

To receive weather data in flight, the tablet is normally linked via Bluetooth to an ADS-B or satellite weather receiver, such as the Sentry ADS-B or Sirius XM SXAR1. It is worth noting that many of these EFB apps are built on a tiered subscription revenue model where different features are available at different subscription levels.

For example, ForeFlight makes digital ATIS (D-ATIS) data available to pilots who subscribe to the Performance Plus and Business Performance plans. Those subscribed to lower tiers will see only the most current metar report for a given airport. In most cases, however, essential aviation weather information and functions are available to all at any subscription level.

Aviation weather apps

Most EFBs require monthly or annual subscriptions to pay for the comprehensive services and convenience they provide, and reviews on the app outlets suggest that most pilots feel it is money well spent. Of course, there are also free or inexpensive apps that deliver weather information, some of which are general weather apps, while others are specifically tailored to pilots.

There are aviation weather apps focused solely on weather, while others, such as FlyGo Aviation Weather Route Planner, combine weather with other information, like map tracking and airport information. Nearly all aviation weather apps focus on delivering current metars and tafs, and many also include airmets, sigmets and weather radar.

Some, such as Sky MET are map-based, allowing a pilot to simply scroll and zoom around a map to see the current weather. A few of the more popular aviation weather apps include Easy Aviation Weather-WX, NOAA Aviation Live Sky Weather, and NOAA AWC Aviation Weather.

MyRadar app screen grab of a tornadic squall line moving across the Nebraska/South Dakota border (the blue dot is the device’s current position). Many free and low-cost radar apps stream the most current radar imagery, which can help pilots avoid flying into severe weather.

Other weather apps

Of course, weather is so important to so many people and industries that many of the best weather apps are not designed specifically for aviation. Of these, there are dozens – if not hundreds – of options, ranging from professional-level weather products to rudimentary options for connecting to backyard weather stations.

On the negative side, this means that you’ll need to try a lot of apps before you find the ones you really like and use. On the positive side, most of them are free, or at most cost a few dollars.

And, with the painless ability to install them, try them and delete the ones you don’t like with just a tap of the finger, there is little point in recommending any specific apps. With few exceptions, just like the EFBs and aviation weather apps, all weather apps use the same weather information, gleaned from the exact same official sources.

What it boils down to then is simply how the developers have chosen to present that information to the user. In that, your choice of weather apps is largely a matter of personal preference. Do you like the interface, the color scheme, ease of navigation, combination of features…? I tried out about a dozen “radar” apps – all of which tap into and deliver NOAA and European data – before I found one that became my go-to radar app.

I kept one other for a few unique features I liked but didn’t use that often, but deleted the rest. Of course, other pilots may try this app and decide it doesn’t feel right to them. They’ll use a different one, but ultimately get the same information from it. There are a few weather apps, such as Dark Sky, Weather Underground, or AccuWeather, that deliver their own forecasts, but, again, they receive and use the same weather data that everyone else does.

While such forecasts may indeed, as their developers claim, be more accurate than those from official sources, aviation regulations remain clear that such information should not be used for decisional purposes. What to look for Although the look, feel, and functionality of an app – in other words, its usability – are primary deciding factors in which app to add to your tablet’s precious real estate and storage, when it comes to weather, not all apps are created truly equal.

Weather data sources such as NOAA, the UK Met Office, and others, all produce their data and products on certain schedules. Good apps will have update cycles that ensure the latest information is delivered within 1–2 minutes of its availability from the source. Some apps may cache downloaded information and display it on future use of the app if it cannot retrieve the most current data.

Others may update the information at a rate slower than the source updated it. In addition, in the world of apps, more is not necessarily better. There is so much weather information available these days, that pushing it all into a single app can degrade its usability. Pilots should know what an app delivers to them and that such information is easy to obtain.

For example, a radar app I used to use was lean and clean. I could zoom in and out, and it loaded and updated quickly. After the developers added other things such as multiple map layers, satellite images, surface observations, etc, the app’s size ballooned, loading slowed, and much of the information I used the app for (radar returns) was buried under other information.

Again, however, this is a matter of personal preference. While some pilots would prefer and be better served by having a suite of weather apps on their device, with each one providing some information, other pilots will fare better with all of the weather information they need under the menu of a single app.

Moreover, most of the apps that provide aviation and even general weather information are available as free or low-cost “lite” versions, and either they provide in-app purchases to upgrade functionality, or they offer a parallel “pro” version that enables additional features that the developers are confident users will wish to have access to.

Developers want to earn a living building apps and the lite version is simply a means of attracting users. They generate revenue by selling space on the app for ads, and by enticing users to upgrade. For many, though, the lite version is good enough, and it is worthwhile to investigate what the paid features are and whether you may need or want them.

Several EFB software platforms, such as ForeFlight here, are specifically designed to work across computer platforms, allowing pilots to plan on a desktop computer and continue to follow a flight from a tablet or smartphone from in the cockpit.

Getting info to your apps

On a final note, every weather app depends on retrieving and delivering weather observations and products derived from those weather observations. Despite being well into the digital age, where information travels at the speed of light, there remains some delay in getting information from an AWOS, satellite, or radar to an app in the cockpit.

Each and every official observation must be transmitted to central computers. Some of those transmissions still happen over dial-up phone lines. Once received, the data are run through processing algorithms, compiled, and staged for dissemination. When you’re receiving and processing thousands of observations every second, these programs can take some time to run.

Once the data are staged at the source, the app’s servers must retrieve and package the data for the app. Finally, the app itself communicates with its servers to request and retrieve the packaged data. Depending on the connection speed, that process can take several minutes.

For example, NEXRAD radar data is often up to 5 minutes old by the time it becomes available in ready-to-use form, FIS-B only transmits most data every 5–10 minutes, and radar data every 2.5 minutes. So, by the time pilots see the “latest” ground-based radar image on their apps in the cockpit, it may already be 10–15 minutes old. In a dynamic convective situation, a lot can change in that time.

There’s no real-time weather info What’s more, the US national radar composite image is only updated every 30 minutes, forecast models produce output only a few times (often only once) each day, satellite agencies release imagery once per hour, upper air soundings are taken once or twice a day, and many of the weather maps and charts that are created from the weather observations are 1, 3, or 6-hourly.

So, despite the best efforts of weather providers, there really is no such thing as real-time weather delivered from the ground to the cockpit except for when you’ve dialed in the local ATIS or asked the tower controller for his appraisal of the fog covering the airport.

Regardless of which weather app you use to plan or conduct your flight, no app (at least none that the authorities approve of) will make weather decisions for you. The weather-based decisions you make, even if they are informed by information presented by an app, remain your own.

Karsten Shein is co­founder and science director at ExplorEiS. He was formerly an assistant professor at Shippensburg Univer­sity and a climatolo­gist with NOAA. Shein holds a commercial license with instrument rating.