Wicked Fast Jet Stream Meant Speedy Cross Country Flights

A schematic of the force of Tuesday's jet stream winds in the
United States from CBS News. The whitish shading over
the Northeast depicts record strong jet stream winds
of more than 200 mph.

Like everybody else, I don't like flight delays.

But I understand that weather, mechanical issues, staffing, coordination between airports and all kinds of other factors frequently conspire from letting you make your connecting flight on time.

Every once in awhile, you get lucky and your plane lands a little ahead of schedule. That happened a lot this week as what could be a record fast jet stream rocketed roughly west to east across the nation this week.

Eastbound flights got caught up in this jet stream and often made it to their destination in record time.

For instance, a Virgin Atlantic flight from Los Angeles to London landed at Heathrow 48 minutes early because of the boost given by the jet stream over the United States.

That plane was clocked at going 801 mph over Pennsylvania. Usually, cruising speed is around 560 mph. That 801 mph is faster than the speed of sound and airliners are generally not designed to go that fast. But nothing bad happened because the aircraft was being propelled by 200 mph jet stream winds and not by revved up plane engines.

That meant the air speed of the plane was 800 mph, but the ground speed - what the plane's engines could produce - was well below that.

In any event, most flights heading west to east across the nation in the past couple of day landed earlier than normal. Of course, planes heading in the opposite direction were a little late, because they either had to fight the jet stream head winds or detour around the jet stream.

Jet streams thrive on the contrast between the warm tropics and the cold Arctic. Because there's a bigger temperature contrast between the North Pole and the Equator in the winter, the jet stream is fastest in the winter.

The jet stream got an added boost this week because of a conspiracy of three different branches of the jet stream. A very fast stream coming across the Pacific zoomed into Mexico and the southwestern United States.

Meanwhile, the polar jet stream split, with one arm heading southeastward through the western states, then turning northeastward toward New England. The other branch of the polar jet stream made a beeline from Alaska to the Great Lakes.

All three of these jet stream branches merged over the northeastern United States. They combined their collective power and voila! A record fast jet stream was born over places like Pennsylvania.

The jet stream is 35,000 feet or so overhead. The incredibly fast winds of a jet stream don't usually translate to the surface and that's what happened this time.

Tuesday afternoon, the jet stream was screaming above our heads in Vermont at roughly 200 mph. Here on the ground, it was a delightfully sunny, calm winter day with wind speeds of less than 10 mph.

Jet streams do help steer weather systems. The southern jet stream is carrying moisture from the tropical Pacific, which helps explain why it has been snowing so hard in the Sierra Nevada mountains of California, and raining so hard in the Ohio and Tennessee River valleys this week.

The northern stream that approaches from the west is helping shunt the deeper moisture to our south, which explains why the precipitation with these storms has generally not been that heavy here in Vermont.

The jet stream has slowed down a bit overhead since yesterday but it is still wicked fast. The overall speed and orientation of it is expected to remain roughly the same as it has been the past couple of days, so the current general weather pattern will last that long, too.