Meteorology 5Meteorology 5

– SURFACE and UPPER CHART comparison– JET STREAM– METAR– TIME ZONES– WINDS, VISIBILITY & WEATHER– OBSCURATION & SKY CONDITION– FD’s, SIGMET, PIREP– GFA or Area Forecast

Surface Chart / Surface Chart / note fronts & isobarsnote fronts & isobars

STANDARD PRESSURE SURFACESSTANDARD PRESSURE SURFACES

• 850 mb 5000 feet asl

• 700 10000

• 500 18000

• 400 24000

• 300 30000

• 250 34000

• 200 40000

• 150 45000

• 100 53000

Upper chart/ note no fronts. Also, Isobars are replaced by contour lines

STEEP PRESSURE GRADIENT GIVES HIGHER WIND SPEEDS

JET JET STREAMSTREAM

Pg 12-11

Pg 12-13

Low Level Nocturnal JetLow Level Nocturnal Jet

40 KNOTS Pg 11-13

METARMETAR

METAR CYVR 222200Z CCA 18018G35 1SM R24/5000FT/D –SN BLSN BKN010 OVC050 M05/M11 A2992 REFZDZ WS RWY24 RMK SF6SC2 VIS ½ TO W SLP122

TIME ZONESTIME ZONES

•DAYLIGHT SAVINGS TIME WOULD BE ONE HOUR LESS

•SPRING FORWARD AND FALL BACK

•INVENTED BY A CANADIAN

WIND AND GUST GROUPWIND AND GUST GROUP

WIND DIRECTION VARIATION is coded into remarks if:– 60O OR MORE AND 3 KNOTS OR MORE OF WIND FOR LAST 2 MINUTES ie. 240V320

– A VARIATION OVER THE LAST 10 MINUTES PRIOR TO THE OBSERVATION WOULD BE REPORTED PROVIDED 60O AND 3 KNOTS OR MORE

Changing WindsChanging Winds

• GUST - 5K higher than 2 minute average

- Highest peak must be at least 15 k

• SQUALL - 15K higher than 2 minute mean average

- I minute mean of at least 20 k- After max must decrease by 5 k

• SHIFT - 45O change or more

- Change in less than 15 minutes- Average at end of wind shift at least 10 k

Wind GustWind Gust

VISIBILITYVISIBILITY

FLIGHT VIS FLIGHT VIS vs vs

GROUND VISGROUND VIS

FLIGHT often worse vis than

GROUND

PRESENT WEATHERPRESENT WEATHER

PRESENT WEATHERPRESENT WEATHER

PRESENT WEATHERPRESENT WEATHER

OBSCURING PHENOMENAOBSCURING PHENOMENA

VC = 5 statute milesVC = 5 statute miles

REPORTED REGARDLESS

SKY CONDITIONSKY CONDITION

REMARKSREMARKS

Pressure tendency usually in remarks.Pressure tendency usually in remarks.

SKY CONDITIONSKY CONDITION

– Clear: SKC 0/8

– Few: FEW trace, 1/8 to 2/8

– Scattered: SCT 3/8 to 4/8

– Broken: BKN 5/8 to 7/8

– Overcast: OVC 8/8

CEILINGCEILING

– Broken: BKN 5/8 to 7/8

– Overcast: OVC 8/8

TORONTO BUTTONVILLETORONTO BUTTONVILLE

METAR CYKZ 251700Z 03008KT 10SM BKN050 OVC250 M08/M15 A2982 RMK SC6CI2 SLP114

METAR CYKZ 251800Z 35009KT 9SM BKN050 OVC240 M08/M13 A2977 RMK SC5CI3 SLP095

METAR CYKZ 251900Z 01009KT 7SM BKN040 BKN240 M08/M13 A2977 RMK SC5CI2 SLP095

TAF CYKZ 251630Z 251705 05005KT P6SM SCT025 BKN250 TEMPO 1719 5SM HZ BKN020 BECMG 1921 35012KT FM0300Z 35015G25KT P6SM SCT025 BKN120 TEMPO 0305 BKN025RMK NXT FCST BY 23Z=

Change TermsChange Terms

• PROB is only used for 30 or 40% probability.

FDs - low levelFDs - low level

FCST BASED ON 251200 DATA VALID 251800 FOR USE 17-21 3000 6000 9000 12000 18000

YAM 0117 3613-19 9900-21 9900-26 2408-35

note the backing winds in the descent over Ottawa

YOW 0720 0814-13 1109-12 1614-15 1934-22

YQG 3309 3109-14 2707-16 2313-20 2232-28

YVV 0606 0305-15 9900-17 2016-20 2039-28

YYB 0406 9900-16 2009-17 2020-20 2043-28

YYZ 0410 0506-13 9900-13 1909-17 1927-25

ACTUAL LAPSE RATEACTUAL LAPSE RATE

• METAR CYKZ 251900Z 01009KT 7SM BKN040 BKN240 M08/M13 A2977 RMK SC4CI2 SLP095

• FCST BASED ON 251200 DATA VALID 251800 FOR USE 17-21 3000 6000 9000 12000

YYZ 0410 0506-13 9900-13 1909-17

6000 -13

650 -08

Lapse is roughly 1o/1,000 ft

SIGMETSIGMETWSCN31 CWTO 250430SIGMET A1 VALID 250430/250830LN TSTMS 30NM WIDE MAX TOPS 400 OBSRVD AT 0400Z FROM LONDON-TORONTO-PETERBOROUGH. LN MOVG SWD ABT 20 KTS AND INTSFYG. TSTMS MOVG OUT OF AREA BY 0730Z.

Significant Meteorological Report

PIREPPIREP

UA/OV CYHM 1235 FL050/

TP C172/SK 030 OVC 045/

TA -04/WV 240016/TB LGT/

IC LGT/RM FROPA 10 MI W

PIREP report Mixed IcingPIREP report Mixed Icing

GFAGFA

• Issued at 2330Z, 0530Z, 1130Z and 1730Z• Covers 12 hours with a 12 hour IFR outlook• Country covered with 7 GFA areas• Heights are feet above sea level• Section 3 of MET in AIP• Minimum of 5k to have speed be indicated • CU, TCU, CB and ACC will be indicated• Winds less than 20 k usually not shown• Amended GFA shows CCA, etc in title box

VALID

1800Z