While not rare, it is a pleasant surprise to see a fairly quiet radar mosaic stretching from coast to coast. Unless you are specifically looking for nasty weather, a tranquil radar usually means decent flying weather, outside of cold clouds, in most locations that are not reporting low ceilings and reduced visibility due to a radiation fog event. This also means you may not see some of the other familiar markers you’d normally expect to be displayed on the Map with the radar layer on. One of these markers that is often missing is the echo top heights.
Overall, a fairly benign radar with the most significant returns in southern California.
First, let’s get one thing out of the way; echo tops are not the same as cloud tops. Cloud tops are always higher. Second, echo tops represent the mean sea level (MSL) height of the highest radar echo of 18 dBZ or greater. Third, echo tops heights are added to the NEXRAD mosaic in ForeFlight only when the echo tops consistently exceed 20,000 feet MSL. In other words, you won’t see an echo tops report of 15,000 feet, for example. So it’s understandable for customers to believe echo tops may be “missing” from the radar mosaic when the radar is fairly benign. Moreover, there may be some intense-looking echoes in various locations, even some with storm tracks and mesoscale circulations shown, but no echo top heights anywhere to be found. Let’s take a look at a recent example.
In the image above, notice that most of the U.S. is enjoying an early evening free of any significant weather. A few light echoes in southeast Arizona, some light snow in Montana and Idaho, showery precipitation in western Washington and probably the most intense area of weather in southern California. Zooming in on that area below, there are some areas with reflectivity values greater than 40 dBZ (yellow and orange) indicating moderate precipitation. But there’s not a single echo top height displayed even though there are several storm tracks identified. The storm tracks are there since the cellular structure and the relative high reflectivity of the echoes has triggered the NEXRAD algorithms to generate one. However, this algorithm is completely independent of the echo top height.
Cellular returns indicate showery precipitation. A few cells have storm tracks defined, but despite their intensity, no echo tops are shown.
Despite the intensity of these cells in southern California, the echo top heights are likely below 20,000 feet. Since cloud tops are higher than echo tops, let’s examine the cloud top height in this area. The best way to determine the height of cloud tops is to examine the satellite imagery in ForeFlight like the color-enhanced infrared satellite image shown below. This satellite image shows the cloud top temperature. Notice the pale green colors within the black circle where the most significant returns are located. Using the color bar at the top of the image, these solid pale green colors equate to a cloud top temperature of about -20 degrees Celsius.
The color-enhanced infrared satellite image shows the temperature of the surface of the earth or temperature of the cloud tops. In this case, clouds in southern California have cloud top temperatures of -20 degrees Celsius.
Once the cloud top temperatures are known, it’s a simple process to compare this cloud top temperature against the temperatures aloft using ForeFlight. Below are the Winds and Temperatures aloft for Bakersfield near one of the more intense cells at this same time. This clearly shows at 18,000 feet MSL the temperatures were -6 degrees Fahrenheit or -21 degrees Celsius. So cloud tops in this region were definitely below 20,000 feet.
The ForeFlight Winds and Temperatures aloft show a temperature of -6 degrees Fahrenheit (-21 degrees Celsius) at 18,000 feet MSL over Bakersfield.
If you were paying close attention to the radar loop, you may have noticed that one lone echo top height marker appears (pointed to by the red arrow below) of 201 indicating an echo top height of 20,100 feet in this cell. So when you see a lack of echo tops reported, it just may be that those tops are below 20,000 feet.
A single echo top height of 20,100 feet MSL did pop up on the radar loop bolstering the idea that most echo tops were below 20,000 feet.
For those of us with significant flight experience, transitioning from a paper logbook to a digital one can seem like a daunting task. We know total time is not the only stat that requires accuracy. Day, Night, and IFR currency should be considered, as well as the ability to report on aircraft category, class, and model over time periods. How about turbine time? Retract? Let’s look at a few simple steps to “catch up” in ForeFlight Logbook, allowing you to obtain accurate totals for insurance forms, potential employers, or the FAA.
Step 1: Assess your flying.
Are you a career pilot? Weekend warrior? Own and operate a turbine Grumman Goose (if so let’s talk…)? What does your next year in aviation look like? Your style and frequency of flying dictates how much detail you’ll need to get out of your logbook.
Step 2: Choose a resolution.
Total Time Only—If you’ve only flown one plane, or even just one type, this could be all you need. You know every hour you’ve flown is in your Cessna 182 RG, so there’s no need to break down your flight time further.
Time by Type (make + model)—This would suffice for most pilots. Aircraft type generally implies other variables we need for currency, such as category and landing gear type.
Time by Aircraft ID—You may want to track hours in each specific aircraft you’ve flown. Whether for financial reasons, rental requirements, or simply reminiscence, this method provides the most detail without entering every flight.
Step 3: Choose a timeframe.
How far back will you start logging individual flights?
3 or 6 Months Ago—This will cover General, Night and IFR currency (part 91).
12 Months Ago—Your aviation insurance agent will ask for your time in make and model over the last 12 months, so you may want to enter each flight for the last year.
Other timeframe—You may fly under another authority apart from the FAA, or your employer’s record-keeping requirements may come into play here.
With these decisions made, it’s time to take a trip down memory lane. Sit down with your logbook, calculator, and a notepad. Create a new ForeFlight Logbook entry for each grouping. For example, one each for C172, P28R, and BE58. While you’re at it, take time to remember all the adventures in your flying career, knowing that your history will be stored safely in the ForeFlight cloud for you to access anywhere, anytime.
Login to plan.foreflight.com and tap on the Logbook tab to download the ForeFlight import template.
If you already have your own spreadsheet, you can use our web import tool on ForeFlight Web. Log in to plan.foreflight.com with your ForeFlight app credentials, click the Logbook tab, and then drag/drop your file into the box. You can also download our spreadsheet template if you are starting from scratch.
We are thrilled to deliver ForeFlight Logbook in our final release of the year. In addition, insightful Area Forecast Discussions are now built-in to airport weather views.
Simplicity, Utility, and Security with ForeFlight Logbook
Logbook is seamlessly integrated into the ForeFlight app, making it easy for pilots to manually and automatically log flights, track hours, review currency, record certificates and ratings, receive electronic instructor endorsements, and generate experience reports. In addition, your Logbook data is automatically and securely stored in the ForeFlight Cloud. ForeFlight’s servers regularly backup the logbook when changes or additions are made, delivering a new level of security and assurance for digital pilot logbook data. ForeFlight’s Sync platform seamlessly synchronizes your logbook information across all of the devices on your account.
Get the Whole Weather Story with Area Forecast Discussions
As Scott Dennstaedt says in his blog article on the topic, with ForeFlight 7.5 “you’ll have the ability to peer into the minds of forecasters.” Well, close. You can now access Area Forecast Discussions (AFDs) in ForeFlight.
Area Forecast Discussions are now provided for all US airports with their associated TAFs. These are issued by forecasters at the National Weather Service and provide important insights into forecast conditions, acting as a complement and explanation for recently issued TAFs.
The AFDs can be found in ForeFlight by tapping on a station in the Maps view, then tap Forecast in the pop-over. Also in the Airport view, tap the Weather tab then Forecast Discussion.
Check out Scott’s article where he walks through how AFDs can be routinely used in your flight planning. Do you know the size of the terminal area that is considered when a forecaster issues a TAF? Read Getting Into The Forecaster’s Head to find out.
New Subscription Plans Bring Added Features and Value
Coupled with the introduction of Logbook, we are also announcing new subscription plans for individual pilots that are designed to give you even more value from your ForeFlight experience. Logbook is an essential part of your flight bag and so we made it a standard feature in both of the new plans.
The new Basic Plus plan includes everything in the current Basic plan plus Logbook and Weight & Balance for $99.99/year.
The new Pro Plus plan includes everything in the current Pro plan plus Logbook and Synthetic Vision for $199.99/year.
If you are pleased with the plan you have now, you can still purchase or renew the existing Basic and Pro plans. You can manage this by logging in to foreflight.com/manage with your ForeFlight app credentials or by using our build your own plan link on foreflight.com/pricing.
As the old saying goes, in so many ways, a picture speaks a thousand words. By now you have probably seen the chilling photo like the one shown in this media report of Delta Flight 1889 parked safely at the gate after diverting to Denver International Airport. This was the result of a nasty encounter with hail at 34,000 feet while en route from Boston to Salt Lake City last Friday evening. It makes little sense with today’s proven technology that any commercial aircraft should ever encounter such a hazardous situation and risk the lives of those on board. The crew of this Airbus A320 did an admirable job getting the aircraft safely on the ground after this encounter, but there’s another side to the story that got them into trouble in the first place. A few simple pictures in the cockpit may have made all the difference in the world to avoid putting these passengers through such a harrowing experience.
It’s truly a shame that a pilot flying a single engine Cessna 172 can have significantly more weather information available to them in the cockpit than the crew of this A320 had. We woulda, coulda, shoulda this crew’s decision to fly into this developing area of convection, but that’s not the point. The simple fact is, aircrews flying paying customers today are not equipped with matured technology that will provide them with valuable weather data to make timely decisions during any phase of flight to avoid these kinds of encounters.
Think big picture
Sure, these aircraft are equipped with onboard radar and the crews they carry are highly trained and experienced pilots who know how to make use of that radar. Even when properly used, onboard radar has limitations. It is a real-time snapshot of what’s occurring right now out in front of the aircraft, and this is critical data for tactical decisions, but is simply a microcosm of the overall energy in the atmosphere. In events like this, it is the macro picture of what’s unfolding 100 or more miles away that is often just as important. This large-scale view is better suited to help make the proper strategic decisions, especially when it comes to a developing area of severe thunderstorms. But that information needs to get to the pilot-in-command.
The view from above
Air crews can and do get help from air traffic controllers. Controllers can tout about a “hole” that the last five aircraft recently traversed. But that doesn’t necessarily tell you how fast that hole is closing up and whether or not it will still be there when you arrive. The crew may also have access to their company’s dispatchers, but in the end, the captain may not have the complete picture in his or her head…and that’s where these strategic decisions are made.
This color-enhanced infrared satellite image (also available in ForeFlight Mobile) valid at 0045 UTC shows two distinct areas of convection. Dark purple and white areas denote very cold cloud tops likely from strong updrafts. Flight path of Delta 1889 taken from Flightaware is shown in black.
The squeeze play
Even before Delta Flight 1889 departed Boston’s Logan Airport, two areas of convection started to blossom in Colorado, one in northeast Colorado and the other in southeast Colorado. At 0045 UTC, you can see two distinct systems on the color-enhanced infrared satellite image shown above. As the Airbus crossed over the Mississippi River (black line is the aircraft’s approximate track taken from Flightaware) around the time this satellite image was taken, both areas of thunderstorms had been designated as severe. Nevertheless, there’s clearly a gap between these two convective systems and that appears to be where the crew was headed.
This color-enhanced infrared satellite image valid at 0115 UTC shows the gap between these two areas of convection beginning to quickly fill in with a rapidly developing line of severe thunderstorms.
The gap shrinks on satellite
By 0115Z, that severe line of thunderstorms to the south moved into western Kansas. A line of storms developed on the northern extent of this area of severe thunderstorms bridging the gap shown very clearly in the infrared satellite image above. At this point the flight was still in southwest Iowa just about to cross the Nebraska State line. Even if this image didn’t become available for at least 15 to 20 minutes later at 0130Z, it was plenty of time to notice this explosive area of convection was quickly filling this gap.
About 20 minutes before Delta Flight 1889 penetrated this line of storms, the gap had completely closed with the color-enhanced infrared satellite image showing very cold (high) cloud tops along the route of flight.
The gap is all gone
About 20 minutes before the crew diverted to Denver at 0205 UTC, the image above shows the gap is now completely gone as these two areas of severe convection continue to mature and merge into one mesoscale convective system (MCS). Unfortunately, the crew of this Airbus A320 did not have access to critical weather data such as this. A simple three hour loop of this color-enhanced infrared satellite image could have given the pilots enough information to recognize the gap was closing and choose a better route to prevent this kind of encounter from occurring.
The view from the ground
The local ground-based NEXRAD that is updated every five minutes had even more details that might have suggested the gap would quickly disappear. Once again, this kind of strategic weather information is not available in the cockpit of these aircraft. The 2.5 hour 0.5 degree base reflectivity loop shown below is from the Goodland, Kansas WSR-88D NEXRAD Doppler radar. The loop ends right about the time the crew diverted to Denver, shortly after being pelted by hail.
This is a loop of the 0.5 degree base reflectivity out of Goodland, Kansas. This loop shows how the gap between these two convective systems begins to quickly disappear. Radar site is in the center of this image. Source: UCAR.
At the beginning of this loop, notice a crescent-shaped area of low reflectivity returns appears out of the northern edge of the southern-most area of severe storms. This is called an outflow boundary. According to meteorologist and thunderstorm researcher, Dr. Charles Doswell, III, “Cold, stable air is the ‘exhaust’ of deep, moist convection, descending in downdrafts and then spreading outward like pancake batter poured on a griddle. After spreading outward, the leading edge of this outflow – a ‘gust front’ – which often has ascent associated with it, can develop new storms.”
This is a perfect description of what transpires next. This boundary continues to push north-northeast and helps to initiate a new line of thunderstorms that rapidly blossoms into a convective barrier in extreme southwest Nebraska leaving the crew little choice but to use their onboard radar to tactically locate and penetrate the “softest” part of this line.
The crew of this Airbus didn’t have any ground-based radar loop such as this available to them in the cockpit. Even so, most of the in-cockpit radar mosaics that general aviation pilots use every day is a volume product constructed from a composite of all elevation angles of the radar. Composite reflectivity tends to mask out important details such as these outflow boundaries. Unfortunately, most in-cockpit weather providers have chosen not to broadcast the 0.5 degree base reflectivity product like the one shown above. This includes the radar mosaic that can be received through the FIS-B (ADS-B) broadcast with Stratus or through the Baron Mobile Link for XM-delivered satellite weather.
Vertically integrated liquid or VIL is another volume product that can show the truly nasty part of the storm. This loop clearly shows how quickly the gap disappeared between these two convective areas. Source: Plymouth State Weather Center.
More is better
Furthermore, there are other NEXRAD products that can be very useful in flight. This includes another volume product called vertically integrated liquid (VIL) shown above. As mentioned earlier, composite reflectivity looks at all elevation angles of the radar for a particular volume scan and shows the highest reflectivity return in the column. VIL is similar, but is a summation of the reflectivity in the column. VIL is often an indicator of the storms’s updraft strength and has a strong link to observed hail size.
At 0055 UTC, two convective SIGMETs were active each describing an area or line of severe thunderstorms. Source: NOAA.
Severe weather and aircraft don’t mix
You might say hindsight is 20/20, but this isn’t about second guessing a pilot’s decision. Instead, it’s a plea that aircrews should have more information available to them to make better informed decisions. There’s no doubt this was a risky choice; not only a risk of hail damage, but the threat of dangerous convective turbulence. The weather on both sides of the flight path consisted of severe thunderstorms. At 0055 UTC, the Aviation Weather Center (AWC) had issued two convective SIGMETs (WSTs) covering both areas of severe thunderstorms. Whether thunderstorms are severe or not is determined by the local weather forecast offices, but was echoed in the text of these convective SIGMETs. Both advisories suggested the potential for hail up to 2 inches in diameter as shown below.
The southern most convective SIGMET was issued for a line of severe thunderstorms with hail up to 2 inches in diameter with tops above FL450. Source: NOAA.
It’s time to end this madness
It’s the middle of the second decade of the 21st century and no airplane should end up flying into a thunderstorm and encounter hail and turbulence like that of Delta Flight 1889. Was this just a case of being in the wrong place at the wrong time? Not likely. Perhaps a bit of bad timing, but it was not some kind of surprise encounter that removed the paint and dented the nose cone of this A320. Not only that, but the hail nearly shattered the pilot and co-pilot’s front windscreen making it look like something you’d see in a Hollywood movie. As Stu Ostro, a senior meteorologist at The Weather Channel, commented: “hail shafts aren’t like lightning bolts from the blue shooting way out the side of a storm.”
It’s time to start requiring commercial aircraft to have unlimited access to weather information in the cockpit – more than just onboard radar. Many aircraft equipped with Wi-Fi could easily connect to any number of ground-based weather sources and display it on a mobile device such as an iPad. Even with a device like a Stratus, the FIS-B data broadcast is still lagging way behind the available technology. So it’s time to start providing pilots with more than just basic weather data that mimics the heavy textual weather of the 1980s. There’s no doubt that getting more graphical weather data in the cockpit along with some focused training will keep professional aircrews from flying blindly into a hailstorm. Fortunately for those on board Delta Flight 1889, this flight ended well.
However, right now airlines are stuck in this information-age purgatory. Is this due to cost? Probably, but there’s no encouragement by the FAA for airlines to equip pilots with this potentially live-saving guidance. This encounter should be a wakeup call to those stakeholders in aviation safety to allow, if not require, pilots to have unfettered access in the cockpit to whatever weather data is necessary to make every flight an uneventful one. What is it going to take to make this happen? Hopefully it will not be an event that has a tragic ending. But that’s usually the way it works.