On Monday, a Virgin Atlantic flight from Los Angeles to London reached speeds of 801 mph at 35,000 feet over Pennsylvania. Though the weather was calm across the Northeast this week, up in the atmosphere, the jet stream was clocked at more than 230 mph over Long Island on Monday, setting the record for the fastest 250-millibar wind speed ever recorded over New York and, possibly, the country.
The 250-millibar pressure level, which is at a height above 75% of the atmosphere's mass, is approximately at 30,000 feet to 35,000 feet, which is the same height at which commercial planes fly. Therefore, the jet stream has a significant impact on how fast aircraft can travel. Depending on their direction of travel, airplanes passing through the jet stream will either be sped up or slowed down.
Virgin Atlantic’s Boeing 787-9 twin jet broke its previous record of 776 mph on Monday. The average cruising speed of a Dreamliner is 561 mph, with a maximum propulsion of 587 mph. The plane didn't fly though the jet streak, a region of high speed wind within the jet stream, for very long. However, it did arrive 48 minutes early.
Meanwhile, an LAX-JFK Delta flight reached 678 mph at 39,000 feet over the Ohio Valley, while a 737 from Chicago to New York hit 700 mph. Chicago to New York/Boston routes were expected to be shortened to 1 hour, 24 minutes today rather than the usual two-hour flight time. Also, flight times from Dallas to Boston were under three hours, with an Embraer ERJ-190 twin jet reaching 739 mph in the jet streak.
Those traveling in the opposite direction will need additional flying time. Planes flying west from New England and New York will probably take an extra 20 or 30 minutes, either delayed by the jet streak or forced to travel around it.
Despite the strong winds, no storm is forecast. The closest developing storm yesterday was in the western Gulf of Mexico. In fact, storms tend to decrease the flow of the jet stream. Jet streams usually only reach speeds this high in winter because temperature differences between the north and south are greater. Yesterday, temperatures were around minus-10 to minus-20 in eastern Canada, though well into the 80s over Florida. These differences in temperature and pressure tend to power the wind.