NIGERIAN COLLEGE OF AVIATION TECHNOLOGY, ZARIA

FLYING SCHOOL/GROUND STUDIES DEPARTMENT

METEOROLOGY PRACTICAL
 FLIGHT OPERATION OFFICERS
COURSE-ADVANCE
PRACTICAL METEOROLOGY
FOR DISPATCHERS’

INTRODUCTION:

Meteorological information necessary for the safe conduct of flight is usually

provided by the meteorological authority designated by each state. The
meteorological authority is responsible for provision of such services though it
may wish to arrange for the provision of the service by other providers on its
behalf. The services provided include briefing/consultation and flight
documentation.

Meteorological information refers to Meteorological reports, Charts, Forecasts

and any other statement relating to existing or expected meteorological
conditions. Such information originates or is available through the Meteorological
Agency or its offices.

Meteorological informations for airline operators are used for the following:
a) Pre-flight planning
b) In-flight replanning using centralized operational control of flight
operations
c) Use by flight crew before departure
d) Aircraft in flight

1.0 INFORMATION AVAILABLE FROM METEOROLOGICAL OFFICES

1.1 WEATHER REPORTS:

These are prepared at routine intervals and are available for aviation purposes
every hour or half hour. Selected or special reports are made when certain
phenomena occur between times of routine reports. These reports are called
Actuals and example of such are METARs and SPECI. METAR is
meteorological aerodrome report whereas a SPECI is an aviation selected weather
report. To issue a SPECI there must be improvements or deteriorations through
certain weather criteria. These would then supplement the routine reports.
TRENDS may also be issued for selected aerodromes if significant changes occur
during the two hpurs after the observation time. Runway state codes are included
into the METARs when applicable.

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1.2 AIR-REPORTS:
These are reports of meteorological conditions made by aircrew while an aircraft
is in flight and recorded on a form- AIREP form. This information forwarded to
the meteorological office concerned is made available for use to other aircrew
members.

1.3 SYNOPTIC CHARTS:

Analyzed mean sea level (MSL) synoptic charts show the surface weather
existing over specified areas. They are prepared for standard times. Also available
are prognostic MSL synoptic charts. These indicate the synoptic situation, as it is
expected to become 24 hours or later. Similarly, current and prognostic charts of
fixed pressure levels (i.e. upper levels) are available.

1.4 WARNINGS:
Warnings of gales, squalls, thunderstorms, fog, duststorms and other hazardous
are prepared for issue to listed recipients:

1.5 FLIGHT DOCUMENTATION AND FORECASTS:

These are written or printed information provided to flight crew, air traffic
services units and other recipients as required for flight operations. They include:
i. upper wind and upper-air temperature
ii. expected significant en-route weather phenomena
iii. aerodrome forecasts
iv. aerodrome reports in METAR and SPECI code form
v. SIGMET information and appropriate special air-reports and
vi. AIRMET information for low level flight

Flight documentation is presented in one or more of the following forms:

a) En-route information:

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 i. Chart form
ii. Tabular form
iii. Abbreviated plain-language text
b) Aerodrome information:
i. METAR, SPECI and TAF codes
ii. Abbreviated plain language (usually in tabular form)
(Refer to Appendix A to D at the end of this text)

1.6 INFORMATION FOR PRE-FLIGHT PLANNING AND IN-FLIGHT RE-

PLANNING

Meteorological information for pre-flight planning and in-flight re-planning shall

include the any or all of the following, as established by the meteorological
authority in consultation with the operators concerned.
a) current and forecast: upper winds, upper-air temperatures and
humidity;

b) tropopause height and temperature, and direction, speed and height

of maximum wind;

c) existing and expected significant en-route weather phenomena and

amendments thereto;

d) a forecast for take-off;

e) METAR and, where available, SPECI (including trend forecast)

for the aerodrome of departure, take-off and en-route alternate
aerodrome, the aerodrome of intended landing and destination
alternate aerodromes;

f) TAF and amendments thereto for the aerodrome of departure and

intended landing, and for take-off, en-route, and destination
alternate aerodromes;

g) SIGMET information and appropriate special air-reports relevant

to the whole of the routes concerned.

h) AIRMET information for low-level flights.

Flight documentation should cover the whole of the route and comprise
information a), c), and e) to h), however for flights for two hours’ duration or less,
after a short stop or turnaround is normally limited to the information

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 operationally needed, but in all cases the flight documentation should at least
comprise information e), f), g) and if appropriate, h).
1.7 BRIEFING, CONSULTATION AND DISPLAY
Briefing and/or consultation shall be provided, on request, to flight crew members
and/or flight operations personnel. Its purpose is to supply the latest available
information on existing and expected meteorological conditions along the route to
be flown, at the aerodrome of intended landing, alternate aerodromes and other
aerodromes as relevant, either to explain and amplify the information contained in
the flight documentation or, if so agreed by the meteorological authority and the
operator, in lieu of the flight documentation.
The meteorological information used for briefing and consultation shall include
any or all of the information listed above (a to h).

2.0 NOTIFICATION REQUIREMENTS FROM OPERATORS

Notification from operators in respect of briefing, flight documentation, and other
meteorological information needed by them is normally required for non-
scheduled flights:
a) for flights up to 500 nm, at least two hours before the time of
collection;

b) for flights over 500 nm, at least four hours before the time of
collection.

It is in the interest of all concerned to give the maximum time possible. However,
circumstances may not allow even the minimum times detailed above. In such an
event it is unlikely that the briefing will be supported by documentation.
When the forecast is collected well in advance of the expected time of departure,
the briefing officer should be contacted shortly before departure to check that later
information does not necessitate an amendment to the original forecast.

Generally, request for meteorological information should include the following

details:
a) Aerodrome of departure and ETD
b) Destination and ETA
c) Route to be flown, ETA at and ETD from intermediate aerodrome(s)
d) Alternate aerodromes
e) Cruising level(s)
f) Type of flight, whether VFR or IFR
g) Type of meteorological information requested, i.e. whether flight
documentation and/or briefing or consultation

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 h) Time(s) at which briefing, consultation and/or documentation are
required.

3.0 METEOROLOGICAL INFORMATION AND THE DISPATCHER

As a dispatcher, it is necessary that you:

1. Always use the latest weather information.
2. Always check date and time of observation, forecast or significant weather
and upper air wind and temperature chart
3. Match weather information with other important information to dispatch
the flight eg.
i. check the health of the aircraft Minimum equipment List (MEL)
ii. check the Captains’ Ratings – Low-time captain – apply necessary
restriction
iii. plan ahead of weather, have an alternate plan should the flight be
delayed.
4. After dispatch, keep the flight crew updated on any changing weather
conditions.
5. If uncertain about a situation, solicit help from fellow dispatchers

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4.0 METARS AND TAFs

4.1 METAR AND SPECI CODES:

MEATER (MET Aerodrome Report) is a routine meteorological aerodrome
report, and contains information concerning actual conditions at the time of
observation.

SPECI is a special aviation weather report. It is issued when a significant change

in weather occurs between two routine reports.

Aviation weather reports (METAR and SPECI) form part of the VOLMET
broadcasts (A VHF plain language, continuous broadcast of selected aerodrome
reports for aircraft in flight). The elements reported are in the following
sequence:-

LOCATION
TIME
SURFACE WIND and significant VARIATIONS
VISIBILITY
RUNWAY VISUAL RANGE (RVR) when applicable and significant
variations
WEATHER
CLOUD
TEMPERATURE AND DEW POINT
QNH
SUPPLEMENTARY INFORMATION
TREND FORECAST.
METAR and SPECI FORMAT DECODE:
LOCATION: (CCCC) - ICAO four letter aerodrome indicator
TIME (GGggz) – Time of observation in hours and minutes UTC
0800Z - 0800 UTC, 0755Z – 0755 UTC
MPS

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 SURFACE WIND dddff(Gfmfm) KT dndndn V dxdndn
KMH
ddd - direction in degrees from True North
ff - wind speed
G - gust indicator (if necessary)

fmfm - maximum wind speed observed (if necessary)

MPS
KT - wind speed units used
KMH
dndndn V dxdndn - variation in wind direction measured in
clockwise
when there is change in:
i) direction of 60o or more; and
ii) wind speed of more than 3 kt

Note:- 1. If the surface wind has a variable direction, it is indicated thus:

VRB03.
2. Calm is indicated thus: 00000.

Examples: 31015G27 kt – 310oT at kt, gusting 27 kt.

280V350 - variation between 280oT and 350oT
00000 - Calm

VISIBILITY: VVVV(Dv)(VxVxVxVxDv) or CAVOK

- minimum horizontal visibility in metres and direction
(eight points of Compass) where required: followed by significant
variations at different directions when:
i) minimum visibility is less than 1500m, and
ii) maximum visibility is more than 5000 m.

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 Examples: 4000 decodes as 4000 m
9999 “ “ 10 km or more
1400SW 6000N – Min. vis. = 1400 M TO Southwest
- Max. vis. – 6 km to North

RUNWAY VISUAL RANGE (RVR): RDrDr/VrVrVrVri,

or RDDrDr/VrVrVrVr V VrVrVrVr
- Runway Visual Range with direction or location, and significant changes upwards
or downwards in RVR during the previous 10 minutes.

Example: R24/P1500 - On RWY 24, RVR is more than 1500 m

R24/M0050 - On RWY 24, RVR is less than 50 m

PRESENT WEATHER W’W’ - See Table next page

CLOUDS: NsNsNshshshs(CC) or VVhshshs

NsNsNs - Cloud amount expressed as:-

FEW – few for 1 to 2 oktas
SCT - scattered for 3 to 4 oktas
BKN - broken for 5 to 7 oktas
OVC - overcast for 8 oktas

hshshs - Height of base of clouds in units 30 metres or 100 ft

(CC) - Cloud types; only CB (cumulonimbus) and

TCU (towering cumulus are indicated)

VVhshshs - When sky is obscured, vertical visibility is reported

Examples: 1. VV002 = Vertical vis = 60m or 200ft

2. VV/// = Vertical vis. = unavailable

Note:- 1 When there are no clouds and CAVOK is not appropriate, the
cloud
group is replaced by SKC = Sky Clear.

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 w’w’ - SIGNIFICANT PRESENT, FORECAST AND RECENT WEATHER

QUALIFER WEATHER PHENOMENA

Intensity of Descriptors Precipitation Obscuration Other
Proximity 2 3 4 5
1
- Light MI Shallow DZ Drizzle BR Mist PO Well
Moderate BC Patches RA Rain FG Fog Developed
/no qualifier/ DR Drifting SN Snow FU Smoke Dust/sand
+ hevy BL Blowing SG Snow grains VA Volcanic ash Whirls
VC/In the SH Shower(s) IC Diamond Dust DU Widespread dust SQ Squalls
vicinity/ TS Thunderstorm PE Ice pellets SA Sand FC Funnel
FZ Freezing/ GR Hail HZ Haze Clouds/
Supercooled GS small hail or Tornado or
Ice/snow Water spout/
pellets SS Sandstorm
DS Duststorm

2. CAVOK = Cloud and Visibility OK.

It replaces visibility, RVR, present weather and cloud if:-
i) Visibility is 10 km or more;
ii) No CB or no cloud below 1500 m or 5000 ft;
iii) No precipitation, thunderstorm, sandstorm, duststorm,
shallow fog or low drifting dust, sand or snow.

AIR TEMPERATURE AND DEW POINT: TT/TdTd

- Air temperature and dew point temperature in whole oC
(if below 0oC preceded by M).
Example: M01/M03 - Air tempt. = Minus 1oC
Dew point tempt. = Minus 3oC

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ALTIMETER SETTING PRESSURE: QPHPHPHPH
QNH in whole hectopascals (HPA) or inches, tens-ths and hundred
ths of an inch depending on indicator. If the indicator is:
i) Q then QNH isin HPA
ii) A then QNH is in inches

Examples: Q0995 - QNH is 995 hpa

Q1014 - QNH is 1014 hpa
A2994 - QNH is 29.94 ins.

SUPLEMENTARY INFORMATION: RE w’w’ WS TKOF RWYDrDr

Or
WS LDG RWYDrDr

This information is added at the end of the METAR and it is limited to

information on:-
i) Recent weather since last routine report of operational significance
ii) Low level Wind Shear along Take-Off and/or Landing runway

Example: RETS WS TKOF RW 24

i) Recent weather (RE) - Thunderstorm
ii) WS TKOF RW 24 – Wind Shear along take-off runway 24.

TREND FORECAST 2 Hrs from time of Observation:

TTTTT TTGGgg MPS VVVV
Or dddff(Gfmfm) KT OR
KMH CAVOK
w’w’ NsNsNshshshs

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 Or or
NSW SKC
This group covers changes in Surface Wind, Visibility, Weather and Cloud. These are
described by:-
i) the change indicators: BECMG = Becoming
TEMPO = Temporary
NOSIG = No significant change
ii) the time indicator for the change: FM - From
AT - At
TL - till

Example: BECMG TL 1200 9999 NSW

- Becoming Till 1200 UTC
Visibility = 10 km or more
NSW – No significant weather

4.2 TAF DECODE:

A TAF is a terminal aerodrome forecast and contains an estimate of the

conditions which are expected to prevail during the period of the forecast.

TAFs are written in the METAR code with minor differences. The Temperature,
Dew Point, QNH and supplementary information are omitted.

The time group covers a period (i.e. 1018 means 1000 UTC to 1800 UTC not
1018 UTC)
Indicators for changes are only limited to two terms only:-

i) BECMG, and
ii) TEMPO

When necessary, the group immediately following the indicators will specify the
period to which the changes refer.

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 Example: BECMG 0509 = Becoming between 0500 UTC and 0900 UTC
TEMPO 1012 = Temporary between 1000 OTC and 1200 UTC

Note:- In order to distinguish METAR and TAFs in the Bulletin print-outs,

Prefix letters are used as follows:-
SA - indicate METARs, and these are normally re-issue every ½ hour
FC - indicate standard 9 hours TAF’s and they are normally re-issue
every 3 hours
FT - indicate extended TAF’s covering a period of 18 hours in UK, and
24 hours in the USA

TAFs are primary weather forecast source for the dispatcher to predict weather
conditions at the destination and alternate aerodromes at the planned arrival times.

METAR AND TAF EXECISES:

Decode the following weather reports:-

Frankfurt Main: EDDF

SA201720 03015KT 8000NE FEW045 SCT250 14/10 Q1016 NOSIG
SA201650 03011KT 6000NE SCT042 BKN250 15/10 Q1015 NOSIG
FC201500Z 201601 04010KT CAVOK
FT201600Z 210018 04015KT 3000HZ BKN030 BECMG 0709 06018G30KT
CAVOK

Geneva: LSGG
SA201720 06004KT 4000NE -RA SCT009 BKN040 OVC080 13/11 Q1012
NOSIG
SA201650 05004KT 5000N -RA SCT009 BKN040 14/12 Q1012 NOSIG
FC201500Z 201601 04008KT 7000 SCT020 BKN025
FT201600Z 210018 03005KT 5000 OVC020 TEMPO 1118 BKN030

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Zurich: LSZH
SA201720 04005KT 7000 SCT016 OVC022 12/08 Q1013 NOSIG
SA201650 04008G19KT 7000 SCT016 SCT022 BKN040 12/08 Q1012
NOSIG
FC201500Z 201600Z 210018 05005KT 6000 SCT013 OVC028 BECMG 2124
2500 BR OVC010
FT201500Z 210018 05005KT 2500BR OVC010 TEMPO 0008 1500 BR
BECMG 0811 04010KT OVC015 PROB30 TEMPO 1218 BKN020

Milan: LIML
SA 201720 00000KT CAVOK 16/14 Q1007 NOSIG
SA 201650 00000KT CAVOK 16/15 NOSIG
FC 201700Z 201803 VRB05KT 8000 SCT025 TEMPO 3000 -RA
FT 201600Z 210018 VRB05KT 5000 SCT030 TEMPO 0206 0900 PRFG
BKN008 BECMG 1218 +RA BKN020

Rome: LIRA
SA 201720 00000KT 9999 FEW015 SCT017CB BKN025 16/16 Q1006
SA 201650 00000KT 9999 FEW015 SCT017CB SCT025 17/16 Q1005
FC 201600Z 210018 VRB05KT 9999 SCT025 SCT070 TEMPO 1218
SCT015CB

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5.0 WEATHER CHARTS

INTRODUCTION

The visual presentation of weather to be expected en route is an important part of this

course. Significant weather and tropopause/maximum wind velocity charts are prepared
by World Area Forecast Centres (WAFCs) and disseminate same to users via Regional
Forecast Centres (RAFCs) via satellite. WAFCs are components of the World Area
Forecast Systems (WAFS). The WAFS consist of two WAFCs – London and
Washington. RAFS charts are issued at 6-hourly intervals to be available to the user at
least nine hours before the time of validity.

FORECAST SIGNIFICANT WEATHER AND WIND CHARTS

In addition to the surface isobaric chart, there are a number of additional met charts that
are generally available for weather briefing. There are two basic chart types: Weather
charts and wind charts.

WEATHER CHARTS

Weather information is presented for overlapping layers of the atmosphere:

● Low Level Weather Forecast (Metform 215): Surface – 15 000ft AMSL

● Significant Weather Chart: medium level and High Levels

Europe - FL100 – FL450

North Atlantic - FL250 – FL630

Middle and Far East - FL250 – FL630

Africa - FL250 and above

Caribean/South America covering - FL250 and above

Examples of each type of chart are presented on the following pages.

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 Fig. 1 UK Low Level Forecast (FORM 215)

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 Fig. 2 UK Low level Spot Wind Chart (Form 214)

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 Fig. 3a Upper Level Significant Weather Chart

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 Fig. 3b. Upper Level Significant Weather Chart

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 Fig. 3c. Upper Level Significant Weather Chart

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Low Level Significant Weather - Decode

Forecast Weather Below 15 000ft Chart

Introduction

The form comprises a fixed time forecast weather chart covering the period from 3 hours
before until 3 hours after the forecast time. A separate outlook chart show the expected
position of the principal synoptic features 9 hours after the time of the forecast chart, with
separate text describing the main weather developments during the period.

Main forecast weather chart and text:

● A fixed time weather chart shows the forecast position, direction and speed of
movement of surface fronts and pressure centres for the time shown on the chart legend.
The position of highs (H) and lows (L) are shown by the symbols ‘O’ and ‘X’,
accompanied by the pressure values in hPa. Arrows and figures give the direction and
speed of movement (in knots) of fronts and other features. Speeds of less than 5 knots
are shown as ‘SLOW’. All features are given identifying letters to enable their
subsequent movements to be followed on the outlook chart

● Freezing levels (0oC) are shown as figures for thousands of feet in boxes at appropriate
places on the chart

● Continuous scalloped lines enclose zones of distinct weather patterns, each zone being
identified by a number within a circle. The forecast weather conditions (visibility,
weather, cloud) during the period of validity, together with warnings and any remarks,
are given in the text underneath the charts, each zone being dealt with separately and
completely
● In the text surface visibility is expressed in metres (m) or kilometers (km), with a
changeover at 5km. Weather is described in plain language, using well-known and self
evident abbreviations to shorten the text. Cloud amount, in oktas and type, with the
height of base and top, is given, with all heights in feet AMSL. Warnings and significant
changes and the expected occurrence of icing and turbulence, are given in plain language,
using standard abbreviations where possible. The height of any sub-zero layer below the
main level is also given. Hill fog is not used, but cloud covering hills’ is thought to be
more informative and implies visibility <200 m

Outlook chart and text

● An outlook chart to the right of the forecast chart shows the expected position of the
main synoptic feature at the end of the outlook period. No weather zones are given on
the outlook chart. Surface isobars are shown

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● The outlook text, following the main forecast text, describes the principal weather
changes expected during the 6-hour outlook period

Upper Level Significant Weather - Decode

Charts (See fig.3a, 3b and 3c)

Symbols

Significant Weather charts share a number of symbols with the surface chart. These
symbols, together with abbreviations used, are outlined in table 1.

In accordance with the WMO and ICAO, high level significant weather prognostic charts
are provided for the en-route portion of international flights. The significant weather
elements to be depicted are defined by WMO and ICAO. High level charts are issued
four times a day with valid times of 000Z, 0600Z, 1200Z and 1800Z.

The charts are formatted on Mercator or Polar Stereographic projection background

maps.

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 Table 1. Symbols for Significant Weather Chart

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Decoding the Chart

Fronts are shown using standard symbols. Tropopause heights are given by a three digit
number in a box 350 sometimes accompanied by an L, e.g. 260
L

to indicate a local tropopause low centre, or an H, e.g

H
370

to signify a local tropopause high centre.

The main purpose of the chart is to define significant weather areas and zones of (Clear
air turbulence). The significant weather zones shown by scalloped boundaries indicate
the amount, base, and top of clouds, together with associated turbulence and airframe
icing, e.g. ISOL EMBD CB 350/XXX means that there are individual embedded
cumulonimbus present giving moderate to severe turbulence and airframe icing from
below the specified chart level to FL350.

CAT zones surround jetstreams and are indicated by a bold chain dotted line e.g. - - - -
Each zone is numbered in a square box, e.g. 2 The type of turbulence is then read off in
a supplementary table – CAT Areas placed in one of the corners of the chart, eg. 2
360/290 indicates moderate turbulence from FL290 to FL360 in CAT zone 2.

With layered cloud it is assumed that the turbulence indicated will be experienced
throughout the cloud but the degree of icing will only be experienced in the cloud above
the freezing level. With cumulonimbus, however, it is assumed that moderate/severe
turbulence and icing will be experienced throughout the cloud.

The level of the 0o C isotherm is indicated on the 700 to 150 hPa chart by a small chain
dotted line indicted thus; ---------------0o: FL130 ----------------

Wind/Temperature Chart

Spot winds and temperatures are available for a number of standard levels. The
presentation of this information can be in one of two formats.

● Lower Wind and Temperature Chart Information for all standard levels from 1000ft to
24000ft is presented in tabular form (fig. 2 – Met Form 214)

● Upper Wind and Temperature Chart (fig. 4a and fig. 4b)

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 fig 4a. Upper Wind/Temperature Chart

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 fig 4b. Upper Wind/Temperature Chart

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Separate charts are produced for a number of specific flight levels.

Lower Wind and Temperature Decode

Charts Metform 214 (See fig. 2)

Lower wind charts are produced for various heights above mean sea level (altitude). The
selected altitudes are at 1,2,5,10,18 and 24 thousand feet. The winds and temperatures
for these altitudes are shown in a box with the lat/long to which it refers shown at the top
of each box. The sector wind and temperature are calculated by extracting all the
relevant winds and temperatures from the boxes along the route and averaging them as
single wind and temperature, as shown below:

Referring to fig. 2, the winds and temperature from EGJJ to LFPG at 7000 ft would be:

10 250/45 -07
05 270/15 +02 262/27 -02

276/27 - 02

10 290/35 -06 290/26 -02

05 290/20 +00

The sector wind temperature used in planning would be 276o/27 kt, -02oC.

Upper Wind and Temperature Chart Decode

Upper wind charts are produced for particular pressure levels expressed as flight levels.

The standard levels are:

850 hPa (FL050)

700 hPa (FL100)
500 hPa (FL180)
400 hPa (FL240)
300 hPA (FL300)
250 hPa (FL340)
200 hPa (FL390)

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Wind speed and direction at appropriate latitudes and longitudes are shown by arrows,
using the same symbols as those used for surface wind on a synoptic chart. Temperatures
are also shown with positive air temperatures indicated with the prefix ‘PS’ e.g. PS12.

The sector wind and temperature are calculated by extracting all the relevant wind and
temperatures on the route and averaging them as a single wind and temperature, as shown
below:

Lets consider fig. 2, the winds and temperature from LONDON (N51 28 W000 28) to
COLOGNE
(N50 10 E007 30) would be:

270/110 -30
260/95 -36 265/103 -33

265/89 -33

270/90 -31 265/75 -33

260/60 -35

The sector wind and temperature used in planning would be 265/89kt -33oC.

In the Medium and High altitudes Chart, they are issued every 6 hours and are valid for
the time specified. It is necessary to interpolate between issue times to extract relevant
information.

To find the wind and temperature at a position other than that at a lat/long intersection,
some careful interpolation is required. To find an average wind for a whole route you
must split the route into a number of sections, say 10 o of latitude or longitude (depending
on the direction) find the wind & temperature for each section and find a mathematical
average. If the winds found vary through 360 o, you will have to take care eg. The
average of the two winds 310/20 and 010/30 is 340/25 and not 160/25!

To find the wind component, the average W/V will have to be applied to the mean track
for the route using a representative TAS and the navigation computer. (For normal
subsonic jet transport aircraft flying between 30,000 and 40,000ft, 480 kt is reasonable
figure).

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 APPENDIX A - AERODROME FORECAST
 TABULAR FORM

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 APPENDIX B AERODROME FORECAST
- TAF Code form

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 APPENDIX C. TABULAR FORECAT OF EN-ROUTE CONDITIONS
- LOW LEVEL

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