Scenario: So, this morning, you checked the weather forecasts for LAX and JFK and all’s clear. You leave your last meeting, head right to the airport and find…a four hour weather delay. WHAT??
A line of thunderstorms developed in western Pennsylvania slowed the flow of planes into the Northeast. Your flight is rerouted around the thunderstorms by flying over Atlanta to the Northeast. This means farther distance (remember Great Circle Routes), less favorable winds (jet streams are farther north in thunderstorm season), and fitting your flight into the heavy Florida to Northeast traffic flow. This all adds up to lengthy delays even though destination weather is good.
I’m Chief Forecaster-Surface Meteorology and it’s my job to keep Delta’s Operational Control Center aware of any weather problems. Delta and Northwest are the only airlines to have in-house forecasters. Safety is our number one concern.
We make forecasts based on computer models that run on some of the fastest computers in the world at the National Weather Service. (It still takes four hours to run our best model.) We get the model forecast and interpret the results and communicate how the weather affects the operation.
The models are great for large scale winter storms. Not as good on air mass thunderstorm. For tropical systems, they run special models since these are only fair for the physics of the tropics. Our forecasts have improved tremendously as the computers become faster, enough to run the better models. And that should help you next time to get to your destination.
Michael
Chief Forecaster - Surface Meteorology
November 29th, 2007 at 12:40 pm
Michael - thanks for the explanation of what you do. It seems especially timely after that silly Apple iPhone commercial where the pilot (theoretically) uses his iPhone to bypass a weather delay. I just have a few questions - why did Delta decide to have its own in-house forecasters? Why do you think that gives Delta an advantage? How does the information you generate get to the airports when there are delays? Thanks!
November 29th, 2007 at 1:33 pm
Regavqueen,
Delta has a two part weather department. I do weather forecasting but others here do turbulence forecasting, trying to keep airplanes out of the bad turbulence. They are constantly receiving pilot reports on what flight levels are smoother and where the icing conditions are. They do a very good job.
As for us weather guys, we give four briefings a day to various operations about the weather so that they can be prepared for the weather. A small part is a frost forecast for ATL. By alerting the de-icing people 24 hours ahead when we expect frost the next morning, they can have everything set up, including extra people, to de-ice the airplanes so there aren’t any delays.
For major storms, the airline will need to cancel flights. The reservations people can call ahead of time and try to get the customers re-booked on other flights, either earlier or later. The flights will be cancelled based on our forecast of what time and what type of weather is expected. I can tell you that is a lot of pressure.
I can give you an example. I grew up in Philadelphia. There was a charter for a football team going into Philly for a playoff game. The team was worried because of snow forecast in Philly. I told them that the charter had to be on the ground by a certain time or it might not get in at all. I am told they moved up the charter and landed exactly at the time I specified and the first flakes fell as they landed. I was very lucky but there are a lot of these kind of events going on all the time.
Michael
November 29th, 2007 at 4:41 pm
How does Delta recover from a large-scale snow storm? Best case scenerio.
November 29th, 2007 at 6:44 pm
#3 Tristar_Fan
The best way to recover is to never get involved in a snow storm. Let’s say a nor’easter is moving up the east coast and threatening the major cities. The first thing that we do not want to do is to leave airplanes on the ground at any of these airports overnight so we will fly them out early the night before. If you leave them and no one can get to the airport or dig out after the storm then that plane is wasted. I go back to the 1993 Superstorm when flights were diverted all over the place and some planes were not available for over a week.
After that, it depends on the airport’s ability to clear the snow, the amount of traffic trying to get into the airport, and the safety of an operation into difficult conditions. We have limits on the amount of time that an airplane has to get off the ground after it has been de-iced since the snow will build up weight and change the planes aerodynamics. Airports will close sporadically for an hour or two during a storm to clean runways. If all the international operations are trying to land at JFK within a two hour span, that leads to problems. So their are a lot of factors. If we can cancel a flight and consolidate the passengers with a later flight that would help the overall operation.
We can usually operate in snow at the smaller airports in snow belt areas since they are used to it. If it snows in Charleston SC, they are not going to have the equipment to handle it and the operation is less safe. If it snows in a busy airport, there is no way that they can de-ice all the flights so some flights have to be cancelled.
There are a lot of different strategies based on the type of the precip and the airport involved. We can’t take off if moderate freezing rain is falling. Period. No operation.
Hope this answers some of your questions.
Michael
November 29th, 2007 at 7:50 pm
Interesting topic. On the photo it shows a map for the US, but do you also forecast for the intercontinental flights? I just flew last Tuesday night on the red eye from Atlanta to London. As we were around the Washington and NY area there was quite a bit of turbulence, even so much so that the captain requested the cabin service to be suspended temporarily.
The captain then did something I have not heard a lot in my 20 years of global frequent flying. He made announcements about descending, then later climbing again to find smoother air, including by how much he was going to descend or climb. We eventually found smoothness again. I suppose your turbulence guys were busy reading the data and listening in to other flights in the area.
Other question: is it true that there is an unofficial competition between pilots on who can get from gate to gate in the shortest time on certain routes? Jet streams can be quite helpful for these kind of things.
I think my record for NY - Ams was once 6 hours and a little bit, on a 747. The pilot announced it was his quikest trip ever for him. He then overshot the position on the stand and because it was so early it took a full 30 minutes before there was a tractor to push us back that little bit we needed to connect to the walk way… Talk about overzealous
Another time from Tokyo to San Fran we were so early that San Francisco International Airport (can I emphasise “International”!!) was not open to international flights yet as there were no border control people to check our passports. We sat on the plane at the gate for 45 minutes, and the border opened at 7AM…
The joys of flying
November 30th, 2007 at 3:35 pm
malbarda
Getting in early can be pretty bad too. All our flights try to find the best winds. I used to do that 30 years ago but now the computer and the weather models pick the fastest winds (or slowest head winds).
There used to be (25 years ago) pilots who would try to set a speed record between cities but I don’t think that happens too often anymore with the high cost of fuel. If you get in on a short time, you have to send the data to an organization in Paris and they will validate it and send the pilot a plaque but it costs a couple of hundred dollars so it may not be worth it.
I don’t know about your particular flight but the turbulence forecasters do at times recommend a lower altitude for smoother air and then climb again to avoid another area of turbulence. It gets kind of complicated with different jet streams and tropopause heights. The pilots are also monitoring the radio in the immediate area trying to find smoother air. They don’t like turbulence either.
The turbulence guys do forecast for most of the world now that we fly to so many destinations. As usual, with less data and farther distances, your forecasts are less accurate. But the computer model of the winds is pretty good around the world.
Michael
December 2nd, 2007 at 1:39 pm
Michael - this is great info and really interesting. One question I’ve always had is how airlines consider weather patterns when selecting their “hub” airports. ATL (Delta) is affected all summer by thunderstorms. ORD & MDW (United, American, Southwest) are always hit with snow in the winter. In your opinion, is there an airport in the US somewhere that has ideal weather patterns year ’round in terms of having minimal ATC delays that are weather related? Thanks!
December 5th, 2007 at 5:37 pm
Michael,
Thanks for the great post! Is there any system now or in the works that could give travelers a good risk percentage that their flight will be delayed based on weather. I know there are several commercial sites out there that do something like this but I would really like to see it tied to my upcoming travel so I don’t have have to leave the Delta site.
Also I think you guys should have your own blog to tell us about what changing weather situations.
Wes
December 6th, 2007 at 9:56 am
Micheal,
I am submitting a post similar to the one by WesNSpace. My wife and I start our long awaited vacation tomorrow and mother nature is brewing up another winter storm in the rockies. We will by flying directly into Aspen, but the forecast are not looking to good. What are our chances that our flight on Dec 7th will be cancelled? I understand that it is hard to say until it actually happens, but what are the ingredients(visibility, wind,etc..) necessary for Delta to cancel if it is snowing? Any feedback will be great and thanks again.
Kenny
December 6th, 2007 at 12:20 pm
Great topic!!!
What about the predictable weather patterns - like summer storms in ATL just about every afternoon. Does Delta alter its schedule to reduce the number of flights scheduled for the predictable bad windows?
December 6th, 2007 at 8:34 pm
jb colonel
As far as I know, hubs spring up more for their gographical/population base than for weather conditions. I remember a study from the early 90’s that ranked the hubs as best weather to worst for airplanes. You guessed it, ATL came in worst. TSTM, low clouds/fog, and the occasional snow/ice storm leaves a lot to be desired at ATL.
The best hubs are in the West…PHX, LAS, LAX because they don’t get too many TSTM and little snow/ice.
Michael
December 6th, 2007 at 8:39 pm
WesNSpace,
I like your thinking–my own weather blog.
As far as delays goes, most times we do have a pretty good idea based on the weather and experience when and where the delays are going to occur. I don’t know of any program that predicts that but if Delta were planning something like that, I wouldn’t know of it. But there are all kinds of entrepreneurs who hope to make money.
Michael
December 6th, 2007 at 8:45 pm
Elpontiff,
I am sorry I didn’t answer your posts sooner for your flight. You’re right. There is a middle sized storm developing in the rockies. Most of the energy goes to the southern Rockies though. But there is plenty of moisture from the Pacific. So I would say ASE should get several inches of snow and quite a bit in the mountains.
But, because of the variable conditions at mountain valley airports, most of the time the airplanes will load up and take a shot at landing. If it doesn’t get in then they usually land at another nearby airport and bus the passengers in. The problem is that the valley airports need higher minimum visibility and clouds than normal airports because of the mountains around it.
Safety first.
Michael
December 6th, 2007 at 8:52 pm
travelling mommy
No. The pattern is not as reliable as you think. Even though it seems that there are TSTM around ATL every afternoon, the airport itself is only impacted about one in five days and I can’t tell which day that will be when the schedules are made.
Most of the schedules are made for customer demand. For example, nearly all the European flights leave in the afternoon to get to Europe around sunrise so that the passengers can have a full day of sightseeing before paying for a hotel. The airlines would gladly offer flights arriving in the afternoon but there wouldn’t be enough passengers.
But sometimes, weather is very punctual. Like a sea breeze that was forcing our Dubai flight to take off on a less favorable runway until we changed the schedule 45 minutes and everything was fine. Or our arrival into Quito was scheduled for the morning fog time. By moving the arrival back an hour the flight got in on time. So there are some things we can do.
Michael
December 7th, 2007 at 7:51 pm
Michael
Is your team responsible for the forecasts for all the Delta flights? How does each aircrew get its briefs? I know that the Air Force moved towards Aircrew Briefing Terminals that allowed Aircrews to request and receive briefings without interfacing directly with the weather forecasters.
December 9th, 2007 at 8:38 pm
It seems to me that certain Hubs do better handling snow than others. Salt Lake does a great job on the runways and ramp, where Denver does not. Maybe because there is more real estate to cover there. Dallas is a mess when it snows, but it doesn’t do that there very often so they don’t have the equipment needed. When you have to divert a flight to another airport because of weather, do you consider where it is diverted and what the weather impact is there? For example sending a Salt Lake flight to Vegas rather than Boise because Vegas is probably going to have better weather.
December 11th, 2007 at 8:41 pm
Williams75
We do the forecasts for our largest cities and hubs. And we are on call for any bad weather in any other place we fly to, including Africa and South America.
Pilots get a printed metro briefing for every flight. If you are at the airport before a flight, you might see a printer spewing out tons of paper. That is the metro briefing. The computer gathers all the information..observations, forecasts, NOTAM (airport notices to airmen about something different at the airport), SIGMET (SIGnificant METeorological information like icing or TSTM) and all our forecasts too.
If the pilot has any questions about the weather and metro briefing, he/she may call us anytime of the day or night for clarification. We frequently get cell phone calls from the pilot (through the dispatcher) when they are sitting on the tarmac waiting for a TSTM to pass and the pilot wants to know what’s going on with the weather.
We work at the general office complex in ATL so we are not at the airport for a face to face. But the pilots have monitors at the airport that they can check radars and satellite pictures for their flight. And they can call us.
Michael
December 11th, 2007 at 8:57 pm
rc video
You got it. Places where it snows a lot put a lot of resources into de-icing and snow removal. SLC has this great car wash system that works tremendously. But the southern airports don’t because it isn’t economical to tie up a lot of resources for one or two days a year. You can ususally say the same thing about ciites and their street cleaning operations. Usually, if you don’t get a lot of snow, you don’t have the equipment or manpower and it takes a lot longer to accomplish what one of the northern cities would laugh about.
There is also a space problem. De-icing airplanes takes a big area and the older, more crowded airports just don’t have enough space. They may have to designate a parking area or a taxiway for de-icing. And where do you put all that snow that you remove from the runway? Some airports just dump it into the ocean at the end of the runway but others need to pile it up somewhere.
We try to take into account weather when diverting. Most diversions are a result of TSTM affecting the airport for 30+ minutes. So if there is a line, we don’t want the plane with TSTM between where you divert and your destination. You would really like to put the plane behind the TSTM. Say TSTM hitting ATL and we have 10 diversions, you can’t put all 10 into Birmingham behind the TSTM because they don’t have the room so you need to spread them out. But you try not to put too many east where they will need to come back through the TSTM to get to ATL.
Michael
December 11th, 2007 at 9:34 pm
Thanks Michael.
It was not too long ago I was getting those PMSV calls from crews on the runway, anxious to know when the tstms would move away or the fog would lift. I retired from Air Force Weather a couple of years ago so when I saw the blog with you and the surface chart it definitely caught my attention. Those pictures brought back memories of my days at Air Force Global Weather Center and a number of bases across the country and overseas. I guess I haven’t gotten weather totally out of my blood!
December 12th, 2007 at 8:49 pm
williamsd75
You never do!
We still hand analyze a surface chart when we first start shift. I think that it is important to jump into the data and get your hands dirty.
Thanks for your service.
Michael
December 13th, 2007 at 10:50 pm
Thanks Michael
Although the Air Force always got a full days work from me I think I received much more than I gave. I totally agree with the idea of doing a hand analysis of the surface chart. Nothing get you to think about what is going on and why like drawing isobars.
Unfortunately, today most forecaster are responsible for larger areas and by necessity have gone away from doing hand analysis.
Thanks for the insights on how you provide weather support to Delta. Please let me know if you guys ever do an “open house”. Would love to see your operation.
December 14th, 2007 at 2:56 pm
Michael:
Just a note to thank you for fantastic insight to your position at DL. Besides a mechanical on the plane, I cant think of any other headache for the traveling public which is delays due to the Wx. Keep the good stuff coming.
December 14th, 2007 at 4:40 pm
Michael,
I used to work at NASA’s Dryden Flight Research Center at Edwards AFB. The most never wracking weather forecasting I ever heard was from Kennedy Space Center and the Spaceflight Meterological Group waiting to give a go or no-go for a Space Shuttle landing there. It can be so fickle. You would listen on the loops and hear, “Weather this is Flight. What’s your call?” It is always a multi-million dollar question if they have to stay up in space or come out to California. You could almost hear that guy sweat sometimes. Of course we in California always wanted bad weather in Florida so we could get a landing.
It is almost always sunny at Edwards.
Thanks for all you do for Delta to keep flying! Great article!
DeltaMD-90Flyer
December 20th, 2007 at 11:33 am
Michael,
Are all your forecaster positions full time or do you have part-timers that help to round out your evenings and weekend?
December 21st, 2007 at 11:30 am
Williamsd 75
Open house sometimes with the local chapter of AMS. Stephie, our boss, is this year’s president.
All positions are full time. Try the Weather Channel. They used to have part-time positions.
Michael
December 21st, 2007 at 11:41 am
DeltaMD-90 Flyer,
I met a couple of those guys. I think they work at Patrick Air Force Base. At least, they can look outside and see what the sky looks like.
It is a big gut call when you are calling a situation that will affect thousands of passengers and cost the company millions. If ATL forecast is for frozen precipitation, then the company will cancel hundreds of flights because it would be impossible to de-ice the entire operation. But ATL is always on the border with temperatures close to freezing or the precip ends before the temps drop or the dewpoint is dropping so how low will the wet bulb temperature go. It can be a killer.
Several years ago, we forecast about an inch of snow in the morning with cold air coming in from the northeast and an upper system coming in from the west with moisture. Well, we had the timing right but the moisture from the west met the cold/dry air from the northeast and the snow ended about 30 miles west of ATL. Workers driving in from the western suburbs had cars with a couple of inches of snow on their cars. We had cancelled hundreds of flights and all we got were mid level clouds.
Well, the vice president kept asking when the snow would get here and we kept saying about two hours. He was a little concerned. But it never did snow that day and we had a big bust. But that’s the way it goes in this business.
Later in the year, we can talk about TSTM busts.
Michael
December 21st, 2007 at 11:42 am
Everyone,
Have a happy Winter Solstice tonight.
Michael
December 21st, 2007 at 11:29 pm
Thanks Michael. Happy Holidays.
December 23rd, 2007 at 12:08 am
Hi Michael, I’m new to this site and actually found it while looking for info on flying and snow. Question for you….My family is flying out Monday (x-mass eve) morning from MCO to SLC, arriving about 10:30 Utah time. I noticed that there is a strong snow storm warning for that day. I know you’re not a fortune teller…but if it’s clear in Orlando when we leave at 7:15am, what are the chances of a cancelled flight into SLC if it’s snowing there with winds at 13mph? The storm is supposed to get worse in the afternoon…should we be okay for the morning flight? Are winds of 13mph dangerous to land in? What about the snow? Thanks in advance for any info!
December 27th, 2007 at 6:41 am
zshever,
Again, I’m late to give you advice but SLC is a great place even with snow. They are in the mountains so the moisture is generally limited and a 3-4 inch snowfall is common with cold front and upper storms there. And SLC can usually handle snow with little problem since they have a car-wash type de-icing system and lots of experience.
The only exception is when the air is very cold (-10C at 700mb/10,000ft) and the wind direction is off the Great Salt Lake. Then you get into a lake effect snow and could get up to 8 inches of snow.
But a wind of 13mph would be no problem to land in. Even if it’s blowing across the runway. I don’t know the crosswind limits for SLC but since it is in a valley and oriented in a unique direction the wind usually blow from the NNW or the SSE and that’s the way the runways are lined up.
I hope you enjoyed your vacation.
Michael
December 31st, 2007 at 8:30 pm
Thanks Michael,
We just got back…no problems landing in SLC or leaving to come home today. Thanks,
Zvia