Learning
g Goals
Winds Aloft
ds Aloftt Explained
Wind
w
on a long flight and found
d strong un-expecte
ed headwin
nds that made
m
Ever went
you thiink twice about
a
your fuel plan
nning? Eve
er faced un
n-expected
d tailwinds
s that
just ma
ade your day
d
joyful?
? Well, surrprises no more! It is time to get more
precise
e and accu
urate in predicting th
hese winds
s. It’s time
e to be fam
miliar with
h the
wind aloft.
b
nd. The wo
ord aloft means
m
up in the air, or high
Let’s sttart with a general backgroun
in the sky.
s
Anoth
her name for the winds aloft is Enroute Winds, so
o both poin
nt to
the sam
me meanin
ng.
The pro
ocess of in
nterpreting
g these wiind reports
s is quite simple
s
and
d you will find it
pretty easy in th
he end that you will not miss a flight witthout chec
cking the winds
w
aloft, that being said, let’s
s get right into it.
a TWO types
t
of wind aloft reports:
r
There are
1- Reports prresented in a graphical format (Wind alloft charts). They arre
published for the wh
hole world
d.
mat. These are usua
ally issued
d in and fo
or the
2- Reports prresented in text form
a
airports
off the Unite
ed States of
o America
a. Howeve
er, occasio
onally you may
f
find
some text reports for airp
ports outs
side of the U.S. but tthey will fo
ollow
t
the
same pattern.
Oka
ay then lett’s start with the mo
ore popula
ar format, the Wind aloft Charrt.
To obtain
o
the
e current wind
w
aloft chart
c
you will need to open th
he followin
ng link:
http
p://aviatio
onweather.gov/ifdp//
Onc
ce opened here are the steps to follow:
1- Choose th
he area inttended to fly.
f
For ex
xample if your
y
flight is going to be
w
within
Eurrope or Afrrica choose area “C””
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Paage 1 of 6 2- Once the wanted
w
arrea is open
ned you will be welc
comed by a nice big bulky
t
table
with lots of nu
umbers in it; these numbers
n
in
ndicate the chart Identifier
o numberr.
or
• the column on the left named "V
VALID" rep
presents th
he forecastt time.
6 ho
ours, 12 hours,
h
18 hours
h
etc..
• Win
nd inforfma
ation data
a is issued at 00:00U
UTC and 12:00 UTC while
the wind charrt may be created at a later tiime
• The
e PREVIOU
US (PREV) chart prov
vides inforrmation from 12 hou
urs
ago
o.
• The
e CURRENT
T (Curr) ch
hart provid
des inform
mation for the curren
nt time
period
3- So which number do
o I choose
e? Well it depends
d
on your tim
me of flightt and
f
flight
level.
Let’s assume we are
e going to fly now frrom HESH to HECA at FL240. It's
g
going
to be
b a short flight so we
w choose the most accurate current wiind
f
forecast
chart which
h lasts 6 hours:
h
Cha
art nr. 290
05
4- Once you open the chart you are going to be gre
eeted by a similar look as
f
follows:
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Page 2 of 6 a
Seems complicatted, well not
n at all once
o
you finish this document
d
t. The first thing
otice are th
he many liines that appear
a
on the chart.. There lin
nes tell you
u the
you no
wind sp
peed and direction. The techn
nical term for these lines is Wind Barbs.. The
followin
ng picture
e shows yo
ou how to determine
e the speed of the w
wind from the
t
line.
As shown above the picturre tells us some crucial inform
mation:
1234-
The
T
T
The
T
The
T
The
small lines reprresent 5 kn
nots
long lines repre
esent 10 knots
black triangles represent 50 knots
circle with the dot
d in its center
c
represents ca
alm winds..
So now you have
h
figure
ed out the
e speed of the wind you now n
need to
dete
ermine its
s direction.
The
e process of
o doing so
o is not that precise
e thus it is only an estimate. All
A you
hav
ve to do is look at th
he line and
d assume that
t
there is a comp
pass in you
ur
han
nds pointin
ng towards
s the north
h. Now loo
ok where the
t
wind lines are po
ointing
on the
t
chart.
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Paage 3 of 6 Let’’s work at an examp
ple.
The REDciircle indica
ates a wind of aboutt 15knots and it is a
almost looking
1- T
t
towards
easterly dirrection so the winds
s are blowiing from the WEST (270)
t the Eas
to
st (090). As
A a result winds in the
t
red cirrcle are wiinds of abo
out
270/15 kn
nots.
The BLUE circle shows winds pointing to about a heading o
of 165 so, winds
2- T
a blowin
are
ng from 34
45/20 kts.
3- The
T
GREEN circle sh
hows winds of aboutt 270/50 kts.
k
As you
y
can allso notice there are numbers written arround the lines. These are
SAT
T's (Static air tempe
eratures) in NEGATIV
VE. This means
m
thatt :
•
•
•
around
d the red circle.
c
Tem
mperature is about -20C.
around
d the blue circle. Tem
mperature
e is about -7C.
around
d the green
n circle. Te
emperaturre is about -6C.
Eas
sy isn’t it? Once you practice trying
t
to re
ead some yourself y
you will fin
nd it
prettty simple
e too and itt will be an invaluab
ble informa
ation that you will need
n
to
look
kup during
g your flight planning, especia
ally as mos
st of today
ys airplane
e FMSs
require the wind
w
aloft to
t be entered for mo
ore accura
ate fuel calculations..
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Paage 4 of 6 Now le
et’s have a look at th
he winds aloft
a
in TEX
XT format.
DATA BASED ON
O 140000Z
e me it’s not
n that ha
ard let’s go
o over it line by line
Believe
1st line: Indicates that the data is ba
ased on fo
orecast ma
ade at 000
00Z at day
y 14 of
the currrent montth
2nd line says thatt the follow
wing data is valid from time 1200Z
1
at d
day 14 of the
t
currentt month. The
T
data can
c
be issu
ued and us
sed from 0
0900Z to 1
1500Z, an
nd
temperratures are
e negative
e above FL
L240
3rd line:
e This line
e describes
s the flightt levels for which th
he wind is reported and
a
the
word “FT” is an indication of the loca
ation of th
he report. But not th
he location
n itself.
4th line
e: This is the forecas
st itself. So
o “EMI” (K
Kansas City, MO). Th
he 3,000 foot
f
wind is
s forecast to be 240 degrees at
a 26 knotts. The 6,0
000 foot w
wind is fore
ecast to
be 270
0 degrees at
a 26 knotts and the
e air tempe
erature is forecast to
o be -9 de
egrees
Celsius
s. The 30,0
000 foot wind
w
is fore
ecast to be
e 270 deg
grees at 55
5 knots with the
air tem
mperature forecast to
o be -50 degrees
d
Ce
elsius.
A
Altitude
Code
winds
Temperature
3000
2807
28
80 @ 07 kno
ots
-
6000
2715-07
27
70 @ 15 kno
ots
-7 °C
9000
2728-10
27
70 @ 28 kno
ots
-10 °C
12000
2842-13
28
80 @ 42 kno
ots
-13 °C
18000
2867-21
28
80 @ 67 kno
ots
-21 °C
24000
2891-30
28
80 @ 91 kno
ots
-30 °C
30000
7
751041
1)
250
0 @ 110 kn
nots
-41 °C
34000
771150
1)
270
0 @ 111 kn
nots
-51 °C
39000
790855
1)
290
0 @ 108 kn
nots
-55 °C
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Paage 5 of 6 1. for
f winds 100 knots
s or greate
er
btract 50 frrom the first 2 numbers to ge
et the wind
d heading
• sub
• add
d 100 to th
he 3rd and
d 4th number to gett the winds
speed
2. If the wind
d speed is
s forecast to
t be 200 knots or greater,
g
th
he wind grroup is
c
coded
as 199
1
knots. For exam
mple, "779
99" is deco
oded as 27
70 degrees
s at
199 knots
s or greate
er.
3. W
Wind direc
ction is coded to the
e nearest 10 degree
es. When tthe forecas
st
s
speed
is le
ess than 5 knots, the coded group is "9
9900" and read, "LIG
GHT
A
AND
VARIIABLE."
INTER
RPOLATIO
ON:
n the winds
s aloft be?
?
Now what to do if we wantt to fly FL 260..what will then
use the interpola
ation meth
hod between the hig
ghest and lowest ava
ailable datta.
he table we
w see:
from th
FL 240
FL 300
wind
ds 280 @ 91 knots
wind
ds 250 @ 110 knots
s
winds at
a FL260 will
w be:
280 + ( 250-280
0 / 300-24
40 ) * (260
0-240) = winds
w
270
0
91 + ( 110-91 / 300-240 ) * (260-2
240) = win
ndspeed 97.3
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Paage 6 of 6