Tuesday is a beautiful day in the northeast. Temperatures near 40 in New York, light winds coming from the north 5 to 10 mph, and the sun flowing from one wall to the other sound like a quiet day, especially in February. But at the top of the atmosphere, it's a different story.
The jet stream, a high-altitude airflow along which storms move, is furious. The river of air was recorded at over 230 mph over Long Island on Monday. This measurement comes from the 250 millibar pressure level, which means that it was at a height greater than 75% of the mass of the atmosphere. It sets the record for the fastest wind speed of 250 millibars ever recorded in New York and probably the country.
The level of 250 millibars tends generally between 30,000 and 35,000 feet. It's about the same height as commercial aircraft. Unsurprisingly, the jet stream can have a big impact on the speed of planes reach their destination.
With a maximum speed currently over central Pennsylvania, planes crossing the jet will be either accelerated or slowed down, depending on the direction in which they are heading. It's like the mobile gateway of the airport. You have your own speed of advancement, but if you continue this speed in a moving environment, it can propel you at an impressive speed.
The Virgin Atlantic flight from Los Angeles to London culminates in a huge 801 mph Monday night at 35,000 feet above Pennsylvania. "[N]never seen that kind of tailwind in my professional pilot life, " tweeted Peter James, jet captain.
It seems like a record for the Boeing 787-9 jet, which once flew at speeds of up to 776 mph. The normal cruising speed of a Dreamliner is 561 km / h, with a maximum propulsion of 587 km / h. Any increase in speed achieved through this is due to Mother Nature's helpful help.
Although the plane did not stay long in the "jet train" – the maximum wind zone integrated into the jet stream – it still arrived 48 minutes earlier. And you may notice something suspicious about reading at 801 mph – it is higher than the speed of sound (767 mph). However, the breaking of the sound barrier in the case of air travel depends on its speed, and not on its ground speed.
Ground speed is the speed of an airplane relative to a ground point. We can see how fast the shadow of the plane moves on the surface. Speed, on the other hand, is the difference between ground speed and wind speed.
"On a perfectly immobile day, the speed is equal to the speed on the ground", NASA explains. "But if the wind blows in the same direction as the aircraft, the speed will be lower than the ground speed."
In other words, a speed above the speed of sound has not been reached. Commercial aircraft are generally not designed to fly at supersonic speeds.
In addition to the ground speed of 801 mph scheduled on Monday, several other particularly high speeds have been recorded.
A LAX-JFK Delta flight on Monday night reached a ground speed of 678 mph at 39,000 feet over the Ohio Valley, while a 737 between Chicago and New York exceeded 700 mph at 8:43 am Eastern Tuesday morning.
Similarly, the Dallas-Boston flight times were lowered below the three-hour mark on Tuesday, while a two-plane Embraer ERJ-190 aircraft hit 739 mph in the series of jets.
In the future, connections between Chicago and New York / Boston will be shortened to 1 hour and 24 minutes Wednesday instead of the usual two hours of flight.
But it is very likely that if you fly to the west, you will not find the jet stream useful. Flights from New England and the New York area will likely require an additional 20 to 30 minutes of travel time, either slowed by jet drag or forced to change direction.
For the jet stream to be so successful, it takes a big storm to get ready somewhere, is not it?
Surprisingly, it's the opposite (one of the biggest storms occurs Tuesday in the western Gulf of Mexico). Storms bend the jet-stream into a ridge and dive into the waves that pass through the Lower 48. Just like twisting a garden hose, the flow rate decreases. In the absence of large-scale weather systems, a west zoning jet is free to gain considerable speed, a little in the way of reaching the fastest speeds on freeways.
Jet streams generally can not reach speeds as high as in winter, as temperature differences between north and south are maximized. On Tuesday, temperatures ranged from minus 10 to minus 20 in eastern Canada, but reached 80 in Florida. These large differences in temperature (and pressure) feed the wind.
Editor's note: This story has been updated to clarify the difference between ground speed and speed based on reader feedback.