AOPA Pilot Magazine - January 2020 - 76

meteorologists can preview sigmets about to
be released, correct errors, highlight urgent
reports, and discuss tweaks to the outlooks.
"We issue six-hour forecasts for highlevel turbulence," he says. "Flight Level
180 and above. And a forecast for lowlevel turbulence. Low-level wind shear.
Surface winds. Any sizeable area of sustained 30-knot winds at the surface."
The data come from observations,
numerical models, satellites, and radar.
"Pireps are very important. But anything we
can get our hands on," Sego says. Model data
is verified by experience-a lot of experience.
"When you have dealt with a scenario before,
you get a feel for what the telltale signs are.
If you were to sit down
with every person here,
you would see different things up on their
screens. There is no
single template we use.
We all know it's the little details that matter."
Lead Meteorologist
Jesse Sparks works the
Traffic Flow Management Convective Forecast Desk, or TCF. "The
TCF is a four-, six-, and eight-hour forecast
for convection across the whole country. It's
used by the FAA to plan all the day's flight
routes. You want to put flights where there's
no convection," he explains. "And you want to
plan that before you even get flights in the air."
What does planning mean? If the
weather in Chicago, for example, is forecast to develop strong storms to the south,
arriving and departing traffic is routed
to the north. Flights from the west coast
heading toward Detroit or Pittsburgh
might be shifted north or south, or held at
a higher altitude longer to avoid the turbulence. Based on the work in Kansas City,
the FAA may change what is called the
rate-the number of airplanes that arrive
or depart from an airport. Eighty or 90 or
100 airplanes an hour may show up at a
major airport during a morning or afternoon push. Maybe the FAA will put in a
ground delay program, or alter the distance
between aircraft, which is called miles in
trail. This helps the controller de-conflict
airplanes and also get around the weather.
In other words, a decision made by the
FAA in Virginia, about an airplane flying from
Seattle to Houston, may begin in Kansas City.
76 | AOPA PILOT January 2020

"For example," Sparks says, "we have
a big system coming out of the west
today." He points at a monitor showing
water vapor and high-level wind fields,
showing a wave that goes from Idaho
down through Colorado and into Arizona
and New Mexico. "It's a pretty deep
trough axis for May," he says. "You usually don't see something this deep coming
out in May. This is more like a January
or February type of feature." He points at
another lobe that goes from Portland to
Salt Lake City. "A lot of strong dynamics
come out of these, and that's why we're
expecting lots of severe weather in the
Plains the next few days."

At the international desk for the
Southern Hemisphere, Aviation Meteorologist Amanda Martin is working on
high-level significant weather charts, drawing out the speeds and directions and flight
levels of the jet streams. She's just finished
her turbulence forecast and is about to begin
a forecast for convection. She's also monitoring three volcanoes. "That's actually very,
very low," she says. "There are usually quite
a few more." In a short while she'll participate in an online chat with her colleagues
in Brazil, New Zealand, Australia, Taiwan,
Canada, and England, just to make sure
everyone is thinking the same way.
PIREP LOVE

At nearly every desk, one monitor shows
the airspace over the continental United
States and the North Atlantic Ocean.
Over the ocean, with a little flag for every
pilot report, it looks like a college party,
everyone talking at once. There are only
a handful of pireps over the Pacific, and
almost none over the lower 48.
"That's how we get visibility on
what's going on," Leffler says. "Which
is why pireps are absolutely important
to us. I can't know for sure what's going

What should be in a pirep?
Tips for sharing insight

According to Jonathan Leffler, a warning coordination meteorologist at the
Aviation Weather Center in Kansas City,
a pirep should include as much information as possible, reported as accurately
as possible. There is a difference, for
example, between chop and turbulence.
Chop is a nuisance; turbulence is a
threat. If you report light and occasional
moderate chop, it's uncomfortable but
it's not really a danger. If you report
light to moderate turbulence, now it's
becoming a safety of flight issue.
YouTube videos put out by the FAA
emphasize how important pireps are
and how much they want pilots
to file them. The example in the
pireps section of the FAR/AIM
reads: "One zero miles southwest of Appleton VOR; time 1516
UTC; altitude eight thousand five
hundred; aircraft type BE200;
bases of the broken cloud layer is
six thousand five hundred; flight
visibility 3 miles with haze and
smoke; air temperature 20 degrees Celsius; light turbulence."
However, don't get hung up on protocol for the information. Just give the
information. In fact, the FAR/AIM reads,
in part: "Although the pirep should be as
complete and concise as possible, pilots
should not be overly concerned with
strict format or phraseology. The important thing is that the information is
relayed so other pilots may benefit from
your observation. If a portion of the
report needs clarification, the ground
station will request the information."
Airline pilots give their pirep information to ATC. But what about GA fliers
down low? If you're not already in contact with ATC, call up Flight Service on
your radio via the nearest VOR. A specialist will take the information and get
it into the system as well. "If pilots are
not able to make pireps by radio," the
FAR/AIM says, "reporting upon landing
of the inflight conditions encountered
to the nearest FSS or Weather Forecast
Office will be helpful."
-WSO

The AOPA Air Safety Institute's new
SkySpotter Safety Advisor, optimized for
mobile and online viewing, gives information on giving and interpreting pireps.
airsafetyinstitute.org/safetyadvisors/
pireps
http://www.airsafetyinstitute.org/safetyadvisors/pireps http://www.airsafetyinstitute.org/safetyadvisors/pireps
AOPA Pilot Magazine - January 2020

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