GROUND SCHOOL

1
GROUND SCHOOL

• METEOROLOGY
• METAR/TAFs

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METAR

• Aviation Routine Weather Report

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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
CYWG Code letters of reporting station (CYWG
means Winnipeg)
4
METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
172000Z Date and time of observation (17 means
17th day of the month 2000Z means 2000 UTC
co-ordinated universal time
5
METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
30015G25KT Wind and gust information (winds
from 3000 True _at_ 15 KTS Gusting to 25 KTS)
25 15 10 KT
GUST FACTOR?
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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
3/4SM Prevailing visibility (3/4SM means ¾
statute mile)
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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
R36/ 4000 FT/D Runway visual range (R36 means
runway 36 / 4000 FT/D means visual range is
4000 feet and is decreasing)
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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
SN BLSN Present weather (-SN means light snow
BLSN means blowing snow)
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SKY CONDITIONS

• SKC
• FEW
• SCT
• BKN
• OVC

• Sky clear (No cloud present)
• Trace to 2 oktas (2/8)
• 3 to 4 oktas (3/8 to 4/8)
• 5 to 7 oktas (5/8 to 7/8)
• 8 oktas (8/8)

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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
BKN008 OVC040 Sky condition (BKN means broken
cloud cover _at_ 800 feet OVC040 means overcast _at_
4000 feet)
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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
M05/M08 Outside Air Temperature and Dewpoint
(OAT/DPT) M is for Minus
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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
A2992 Altimeter setting (A2992 means altimeter
setting of 29.92 inches of Hg)
Hg mercury
13
METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
REFZRA Recent weather (REFZRA means freezing
rain was reported since the last scheduled report
but is not present at the time of
this Observation)
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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
WS RWY36 Windshear (WS means windshear was
reported on runway 36)
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METAR
METAR CYWG 172000Z 30015G25KT 3/4SM R36/ 4000
FT/D SN BLSN BKN008 OVC040 M05/M08 A2992 REFZRA
WS RWY36 RMK SF5NS3 SLP134
METAR EXPLAINED
RMK SF5NS3 SLP134 Remarks (SF5 means 5 oktas of
stratus fractus cloud NS3 means 3 oktas of
nimbostratus cloud SLP134 means sea level
pressure of 1013.4 hPa
1 mb (millibar)
1 hPa (hecto Pascal)
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TAFs

• Aerodrome Forecast

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TAF
TAF CYOG 011640Z 011717 28015KT P6SM SNRA FEW015
OCV040 TEMPO 1700 2SM SNRA BR OVC015 FM0000Z
28015KT P6SM BKN030 BKN250 TEMPO 0003 SHRA FM
1000Z 30015KT P6SM SKC
TAF EXPLAINED
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TAF
TAF CYOG 011640Z 011717 28015KT P6SM SNRA FEW015
OCV040 TEMPO 1700 2SM SNRA BR OVC015 FM0000Z
28015KT P6SM BKN030 BKN250 TEMPO 0003 SHRA FM
1000Z 30015KT P6SM SKC
TAF EXPLAINED
Forecast for Windsor issued on the 1st day of the
month _at_ 1640 UTC and valid from 1700 UTC (on the
1st) to 1700 UTC (on the 2nd)
Wind from 2800 true _at_ 15 KTS, visibility greater
than 6 SM, light snow and rain, few clouds _at_
1500, overcast _at_ 4000
24 HOUR FORECAST
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TAF
HOURS
HOURS
TAF CYOG 011640Z 011717 28015KT P6SM SNRA FEW015
OCV040 TEMPO 1700 2SM SNRA BR OVC015 FM0000Z
28015KT P6SM BKN030 BKN250 TEMPO 0003 SHRA FM
1000Z 30015KT P6SM SKC
TAF EXPLAINED
A temporary fluctuation between 1700 UTC and 0000
UTC will bring visibility of 2 SM, light snow and
rain, mist, overcast _at_ 1500
TEMPO is only used when the modified forecast
condition is expected to last less than one
hour the total period of the modified condition
will not cover more than half of the total
forecast period.
When the modified forecast condition is expected
to last more than one hour, either FM or BECMG
must be used.
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TAF
HOURS
MINUTES!
TAF CYOG 011640Z 011717 28015KT P6SM SNRA FEW015
OCV040 TEMPO 1700 2SM SNRA BR OVC015 FM0000Z
28015KT P6SM BKN030 BKN250 TEMPO 0003 SHRA FM
1000Z 30015KT P6SM SKC
TAF EXPLAINED
From 0000 UTC, the wind will be from 2800 true _at_
15 KTS, visibility greater than 6 SM, broken sky
cover _at_ 3000, broken _at_ 25000
FROM indicates a ______ forecast.
NEW
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TAF
TAF CYOG 011640Z 011717 28015KT P6SM SNRA FEW015
OCV040 TEMPO 1700 2SM SNRA BR OVC015 FM0000Z
28015KT P6SM BKN030 BKN250 TEMPO 0003 SHRA FM
1000Z 30015KT P6SM SKC
TAF EXPLAINED
A temporary fluctuation between 0000 UTC and 0300
UTC will bring light rain showers.
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TAF
TAF CYOG 011640Z 011717 28015KT P6SM SNRA FEW015
OCV040 TEMPO 1700 2SM SNRA BR OVC015 FM0000Z
28015KT P6SM BKN030 BKN250 TEMPO 0003 SHRA FM
1000Z 30015KT P6SM SKC
TAF EXPLAINED
From 1000 UTC, the wind will be from 3000 true _at_
15 KTS, visibility greater than 6 SM, sky clear.