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Don Paul: How meteorologists help you fly safely

Raise your hand if you’re a nervous flier.

OK, even mine is slightly raised.

No doubt, nasty weather adds to those fears whether down on the ground or up in the air. What do airlines, their meteorologists, government meteorologists and the FAA do to enhance your weather safety on a routine basis? More than you might think, though there is space here to discuss only a few measures.

Most of you know the vast majority of the lower 48 states are monitored by sophisticated Doppler radars from the National Weather Service, augmented by the Department of Defense Dopplers, and some shorter range, high resolution Federal Aviation Administration/FAA terminal Dopplers. Here is a national radar composite of NWS radar reflectivity.

Individual radars present far more information and detail on thunderstorms, squalls, snow, hail and heavy rain. Doppler radar also can monitor the wind velocities at many layers of the atmosphere, and help to detect vertical motions associated with turbulence, which is of key importance on takeoffs and landings.

The terminal Doppler radars have much shorter range and send their signal on a different, more sensitive band than the longer range NWS Dopplers, because they are tasked to monitor close-in conditions to the airports where they are situated. Note the comparison between the more pixelated zoomed image of the NWS 88-D on the left and the higher resolution zoomed image from the Milwaukee terminal Doppler on the right. The hook echo of a tornado is far better defined closed to the airport on the right. (“RFD” stands for rear flank downdraft, but don’t let’s worry about that, okay?)

Buffalo does not have a terminal Doppler. However, we are fortunate to have our NWS Doppler right at the airport, and NWS meteorologists here alert the FAA tower to hazardous situations including wind shear. Terminal Dopplers are especially important where NWS radars are located far from major airports, as is the case near New York City. The NWS Doppler is in Suffolk County, eastern Long Island, far from the New York City-area airports. At that distance, the NWS radar beam passes over JFK, LaGuardia and Newark airports higher in the atmosphere, incapable of detecting low level wind shear. The beam travels in a straight line while the horizon curves.

The airlines have been equipping their aircraft with more and more sophisticated weather radars which enable pilots to find safer flight paths in terms of turbulence and hail. Here is an aviation radar image from a flight manual, though newer aircraft now are equipped with far more sophisticated radars.

Pilot training includes extensive classwork and simulator practice in aviation meteorology. Pilots are instructed on where dangerous updrafts and downdrafts are most likely to be found in a storm cell, and what indications present hail hazards. For several decades, the networks of Doppler radars here and in most industrialized countries have been detecting dangerous wind shear – sudden changes in wind direction and speed which can radically reduce lift for aircraft wing surfaces – which used to be associated with aircraft disasters.

In 1983, President Reagan’s plane missed by six minutes what would have been a likely fatal “microburst” (violently descending winds in a mature thunderstorm) at Andrews Air Force Base, in the pre-Doppler era when conventional radars could not detect these features. The fascinating details are in this short Washington Post article by my colleague Jason Samenow.

While pilots generally make decisions on whether to take off or land, the FAA plays a critical role when the scale of weather hazards and their impacts become sufficiently large.

“Ground stops” can be imposed by the FAA which, while notorious for causing scheduling snafus, improve avoidance of exposure to hazards for hundreds of aircraft. There can also be "ground delays" and "severe weather avoidance plans." Wind shear alerts can be issued to pilots by air traffic control based on supplied meteorological information, in order that airliners either stay on ground until the shear has passed or avoid landing during the shear event. Air traffic control centers will assist pilots in avoidance of growing squall lines, with planes “vectoring” around hazardous cells.

With the improved training and more sophisticated radars, there are far fewer cases of pilots mistakenly flying into the most hazardous parts of storms, and it has become easier for pilots to find “weaknesses” in lines of storms for a safe passage.

As for lightning strikes, this Washington Post article by famed weather writer Jack Williams nicely details why aircraft are generally safe even when struck.

"Clear air turbulence" remains one of the most difficult aviation weather forecasting challenges. It is virtually invisible to the eye as well as radar and, if not forecast, can catch pilots quite unaware. That is why it is simply foolish to leave your seat belt unfastened when flying.

Generally, when pilots encounter significant turbulence, they report it promptly so pilots in the vicinity are made aware of the bumpy air. Aviation meteorologists are aware of what conditions favor more CAT, and ongoing research is bringing incremental improvements in the forecasting of CAT. All pilots and meteorologists have access 24/7 to the FAA’s Aviation Weather website, which provides a wealth of information to pilots making their flight plans. For example, this somewhat technical chart projects the ongoing turbulence at 6 p.m. EDT during an active period on Thursday, May 3.

If you scan the legend, you’ll see there are a few spots where severe turbulence has been detected.

Most passengers feel like moderate turbulence is severe, especially infrequent, nervous fliers. True severe or extreme turbulence is much less common, but there was some when this chart was generated. Two things to keep in mind: aircraft are well engineered to withstand severe turbulence, and your cockpit crew knows how to read this chart. Finally, your pilot will always get an aviation forecast before they take off. They know their aircraft can take the rough stuff, but they also know that makes for unhappy passengers, and for those not strapped in, endangered passengers.

In cars, “Buckle Up” is the law. In planes, it’s simply common sense.

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