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The Air Up There Podcast

Convective Weather and How it Could Affect Your Flight

Season 2, Episode 8
Published: Friday, April 16, 2021

Inclement weather conditions are, by far, the largest cause of flight delays in the United States. In an average year, inclement weather — including convection — is the reason for nearly 70 percent of all delays.

In this episode, we'll hear from two professionals on convective weather, flight delays, and the work that FAA does to get ahead of severe weather and minimize delays.

Read the show notes on our blog.

Convective Weather and How it Could Affect Your Flight

Convective Weather and How it Could Affect Your Flight

Transcript

Allen Kenitzer:
Welcome to The Air Up There, a podcast about the wide world of aviation and aerospace. I'm Allen Kenitzer.

Dominique Gebru:
And I'm Dominique Gebru. Today we're going to look at how the FAA and partnering agencies keep flights moving safely and efficiently during severe weather events, especially thunderstorms. You're probably aware that snow storms can lead to airline flight delays, but snow isn't the only kind of weather that can affect air traffic.

Allen Kenitzer:
That's right Dominique, while all kinds of weather present flying challenges, perhaps the most disruptive are the convective storms that strike in the summer. And thunderstorm season is right around the corner for much of the United States. These storms typically form, grow and move swiftly to cover large swaths of airspace.

Dominique Gebru:
And our air traffic professionals have their hands full to minimize delays while routing planes around these huge weather systems. We're going to hear from one of our air traffic management experts at the FAA, who will explain how that symphony works. But first, we're going to take a listen to Allen's interview with a meteorologist from the aviation weather center, who explains what convective weather is, and how NOAA aviation weather specialists collaborate with FAA traffic management specialists.

Allen Kenitzer:
One of the most common reasons for flight delays is weather. And it just so happens that I'm here today with Jonathan Leffler, a meteorologist from NOAA's Aviation Weather Center. Jonathan, welcome.

Jonathan Leffler:
Thank you, good to be here.

Allen Kenitzer:
Can you tell our listeners what you do and how you decided on this specific field within meteorology?

Jonathan Leffler:
Sure, so I'm the domestic operations branch chief at the Aviation Weather Center. I lead a team of 24 meteorologists who forecast over the continental United States and coastal waters. I've been a meteorologist since 1997 and I've focused on aviation for almost my entire career. I've always had a fascination with weather and clouds, and you'd probably get the same answer from about 99% of meteorologists. I started my career as a weather officer in the United States Air Force, and I focused a lot on aviation, which is primarily keeping air crews safe, as well as protecting the base. I also had neighbors who were pilots, so it made the forecast a lot more meaningful when they came into the office for a briefing.

Allen Kenitzer:
Fascinating. For our listeners, Jonathan, can we start with the basics? What is aviation weather?

Jonathan Leffler:
Sure, no problem. I would say that aviation weather is meteorology that's focused on safeguarding aviation travel to include commercial airlines, business jets, and general aviation. The conditions that we forecast and monitor include, low clouds and visibility, mountain obscuration, icing, freezing levels, high and low turbulence, wind shear, strong surface winds and convection. It's also important to note that we keep awareness on satellite imagery, radar, pilot reports, surface observations, airport forecast, basically anything that could impact the safety of flight.

Allen Kenitzer:
Okay, so going back to the title of this podcast, Jonathan, what is convective weather?

Jonathan Leffler:

Convective weather is the vertical transport of heat and moisture in unstable environment, which is real technically speaking, basically a thunderstorm or developing clouds, such as towering cumulus. We normally talk about convective weather in the warm season, but it could also happen in the cold season, depending on synoptic conditions. Sometimes you could have low top thunderstorms develop in the winter if you've got a real strong low pressure system moving through and you've got the right conditions with the air masses.

Allen Kenitzer:
So what you're saying is that the weather at 35,000 feet can be a lot different than the weather on the ground?

Jonathan Leffler:
That is true. I would say that the biggest difference is the change in temperature. The surface will have large fluctuations depending on the amount of sunshine or the type of air mass that we're in, if we're in a cold front or a warm front, et cetera. The winds are almost always much stronger at altitude with the presence of the jet stream. And if there's any type of precipitation at 35,000 feet, it would be ice where the ground would see all types of precipitation such as liquid, rain, or freezing rain, or frozen snow, or hail.

Allen Kenitzer:
So then how does weather of this sort impact the flight of the average traveler?

Jonathan Leffler:
So in the cold season, turbulence is a lot more predominant, so that would mean less comfortable rides. Also, a very strong jet stream could either accelerate or slow down the amount of time needed to get to your destination, and this is obviously contingent on if you're flying with the wind or against the wind. In the warm season, thunderstorms are the most predominant feature and they pose all sorts of problems for travelers. That could be bumpy rides, it could be delays, maybe even a divert if things really aren't working out well. And certainly aircraft safety is a number one priority when dealing with thunderstorms.

Allen Kenitzer:
How do you and your colleagues monitor weather at altitude and then how do you get that weather information to pilots?

Jonathan Leffler:
We monitor pilot reports, or we call them PIREPs. And that's the most common way for us to know the, quote unquote "ground truth", of what's happening at altitude. We also use advanced satellite technology and radar data to help us assess the environment and decide what impacts there might be based on our education and experience. We usually disseminate our information via the web and other communication systems that the FAA uses. Additionally, pilots can self-brief, they can get weather from dispatch, or they can call for flight weather briefings.

Allen Kenitzer:
So how does the Aviation Weather Center partner with the FAA?

Jonathan Leffler:
AWC partners with the FAA primarily at the command center, which is in Warrenton, Virginia. We have six meteorologists who work at the national level to help planners and decision makers keep the national airspace system, or NAS, safe and efficient. The national weather service also has meteorologists at the regional level, these are the air route traffic control centers across the country. And we work with those meteorologists to coordinate forecasts and warnings, and really ensure that the weather message is consistent between our office and their office.

Allen Kenitzer:
Jonathan, I'm sure that some people are wondering why can pilots fly through some clouds or some types of bad weather, but not others? And then when is it decided that a flight will have to divert around a specific weather system, and then of course causing a potential delay in my arrival time?

Jonathan Leffler:
Well, that's a really good question. I think the decision to fly or not fly through an area is really up to the pilot. The pilot's going to work closely with the controllers to understand the situation, understand what's going on, and then he or she is going to make the call on proceeding if the route ahead is safe. We want pilots to avoid convection as much as possible, given the inherent dangers of turbulence, and icing, and wind shear, and hail, everything that you run into with a thunderstorm. The Aviation Weather Center issues convective SIGMETs, these are aviation warnings to help increase that threat awareness for the pilots. And the FAA planners and controllers may adjust routes of flight to move aircraft around expected thunderstorm areas, and that route change could delay your arrival time.

Allen Kenitzer:
Jonathan, is there anything new in this field, technology wise? Are we getting better at forecasting this weather?

Jonathan Leffler:
The Aviation Weather Center has been leveraging the web to deliver a graphical forecast and data sets to the aviation community. We do this through a couple of tools, first one is the graphical forecast for aviation, which we call GFA. And the second one is the helicopter emergency medical services tool, which we call HEMS. I think the old days of teletype and text-based products are being phased out in favor of these graphical formats, which really paint a more complete picture for the pilot. We're also exploring different types of data delivery, so users can tailor what information they'd need to see. As far as being good at forecasting the weather, I believe the weather service is very good in aviation and convective forecasting. We work really hard to assess conditions accurately, issue timely forecasts, and ensure that the aviation message is consistent with our FAA partners.

Allen Kenitzer:
Thank you again. We've been talking with Jonathan Leffler, a meteorologist from NOAA's Aviation Weather Center.

Dominique Gebru:
Thanks Allen. Now that we know more about aviation weather and convective weather, let's hear what the FAA does to actually plan and prepare for thunderstorms in the busiest airspace in the country. Our field reporter, Chris Troxell interviewed New York district traffic management officer, Mike Porcello. Mike's a veteran of traffic management in the busy Northeast Corridor. We also hear more from Mike on the FAA-NOAA collaboration and how those two agencies use tools to accurately predict aviation weather.

Chris Troxell:
Hi, this is Chris Troxell with FAA communications. I'm here with Mike Porcello, the traffic management officer for the New York District. Mike helps to manage the flow of traffic in the busiest and most complex airspace in the world. Mike, thanks for being here today. Mike, can you start by telling us a little bit about yourself and how you got into the air traffic control field?

Mike Porcello:
So I'm the traffic management officer for the New York District. My responsibilities include delay mitigation and analysis, as well as the strategic planning for managing the flow of traffic in the Northeast. My entry into the field is not a spectacular one, I visited LaGuardia Tower and was completely captivated. And that is how I got started.

Chris Troxell:
How long have you worked in New York TRACON and what is it like working at the busiest control facility in the world?

Mike Porcello:
So I've been in the agency for almost 32 years, I've spent about 22 of those at the New York TRACON, and it's amazing. The busiest and most complex airspace in the world presents challenges like no other, it is an awesome place to be.

Chris Troxell:
And I've heard that it's challenging even on a good weather day. Badder thunderstorms, and other types of weather add to the complexity of the Northeast Corridor.

Mike Porcello:
Oh you're correct Chris, it is challenging on a good weather day, we have capacity issues just based on the volume of traffic coming out of New York metro area. We like to tell people that New York metro area is roughly the equivalent of Chicago O'Hare and LAX combined, in terms of the amount of volume it generates. Thunderstorm season typically starts at the busiest time of year. Airline schedules increase significantly in the summer, as you would expect, and being in the Northeast, the overwhelming majority of our traffic is going West, or Northwest, or Southwest.

Mike Porcello:
We have complicating factors, for instance, Boston is close enough to us to generate a fair amount of competition for routes out of the Northeast. What normally happens, typically, convective weather will develop West and or South of us and then gradually move toward our area. As this happens, usually the system will increase in severity, close routes and airways along the way, and then in most cases, what follows are thunderstorms at the terminals. Well, we may be experiencing delays and stops due to weather hours before the system actually shows up in our airspace or in the vicinity of an airport. In some cases, it does not show up at all. Prior to all this happening, the FAA will deploy a severe weather avoidance plan, or SWAP as we call it, and we refer to thunderstorm season as SWAP season.

Chris Troxell:
Can you talk a little bit more about SWAP and planning of procedures that you have in place for weather events?

Mike Porcello:
Strategic planning for SWAP season starts immediately after the previous season has ended. We review events to see what worked, what didn't, and then also, if anything new has materialized that warrants our attention. In season planning starts the afternoon before with a call for all stakeholders, so that would be the airlines, facilities, there's other entities in there as well. And that's conducted by the Air Traffic Control Command Center located in Virginia. Weather and traffic information will be presented at that time and airlines and all traffic facilities will provide recommendations for mitigating impacts.

Mike Porcello:
The day of the event we'll have telecoms every two hours. We will also open a hotline for all effected facilities and airlines and work on route strategies to avoid weather. A well forecast event will be disruptive, but with enough time, airlines may be able to avoid having customers come to the airport to wait it out. It's more likely to occur with a developing or developed system with a somewhat predictable path. Reroute plans are disseminated early enough for dispatchers to act, and even though there's delay, it is somewhat manageable. Pop-up thunderstorms however, occur during unstable air mass events or in areas of limited convection, and they're very difficult for us to predict and plan for.

Chris Troxell:
Is it true that weather in one part of the country can delay flights that are not even departing from or arriving to airports in that area?

Mike Porcello:
Absolutely. That's true. Well for us, a good example would be convective weather that builds in the middle of the U.S., Tornado Alley, for instance, Kansas City area that causes reroutes to already congested areas or longer routes that add delay. For us, it's typical to avoid the Midwestern SWAP season, especially in the afternoon and early evening, by going through Canada. The Delmarva, the peninsula where Delaware, and Maryland, and Virginia come together as another area of a concern. Frontal storms may stall over that area or unstable air masses develop in that region. When that happens in that specific area, it shuts down several routes at once, that serve as popular destinations like Charlotte, Atlanta, Orlando, and Miami.

Chris Troxell:
Interesting. And so how do you explain that to an air traveler without the knowledge and experience of a controller or a pilot who fully understand that like you?

Mike Porcello:
So a big part of that explanation is you need to include an overview of flight hazards that are contained within thunderstorms and why it's so important to avoid them. A thunderstorm will contain almost every known hazard to aviation, from hail and heavy rain, to turbulence and downbursts. Now, the high volume of traffic that the New York metro area generates, makes rerouting aircraft away from this weather difficult. We are typically moving traffic to all the routes that are operating at or close to capacity.

Chris Troxell:
Do you see new tools emerging to help controllers enhance efficiency and throughput during thunderstorms and other weather events?

Mike Porcello:
One of the things that has really improved over the last, I would say, four to five years, predictive tools by NOAA. And these are tools that were typically used for predicting tornadic activity in the middle of the country, but are now being used to forecast thunderstorms by aviation weather specialists. And they've actually provided us with good products, makes our forecasting and planning a lot better than it had been. Additionally, we have traffic management programs that provide real-time analysis and performance, as well as airport surface viewers, so we can maintain situation awareness of surface congestion and delays. There is a lot of automation in place today, to help us in the decision-making process, but ultimately it's the humans in the loop that are responsible for making decisions based on that information.

Chris Troxell:
Thanks so much Mike, we really appreciate you taking the time to be here today.

Mike Porcello:
Thank you Chris.

Dominique Gebru:
It's amazing to learn what goes on behind the scenes to keep our air travelers safe, and we hope this episode helped pull back the curtain for our listeners. Be sure to tune in to our next episode, coming to your airwaves soon.

Allen Kenitzer:
Dominique, before we wrap up this episode, I'd like to remind listeners that the FAA does not cancel flights — airlines do. So if you're ever curious how severe weather may affect your travel plans, we encourage you to check with your airline.

Dominique Gebru:
If you liked today's episode, remember to subscribe and share it with someone else. You can find the FAA on social media. We're @FAA on Facebook, Instagram, and LinkedIn, and @FAANews on Twitter and YouTube. Oh and one more thing, I'm really excited to share that FAA administrator, Steve Dixon, is also on social media now. You can find him on Twitter @FAA_Steve and on LinkedIn by searching Steve Dixon.

Allen Kenitzer:
Thanks for listening.