outback air race 2012 james lannan bureau of meteorology
TRANSCRIPT
Outback Air Race 2012
James LannanBureau of Meteorology
Perth to Darwin…via the rest of Australia…
Perth to Ceduna: – Mid latitude weather.
Ceduna Charleville Darwin– Mid latitude weather initially– Tropical weather (~ North of Longreach, QLD; ~23.5ºS)
Darwin Perth– Tropical weather initially.– Mid latitude weather to finish (~South of Newman; ~23.5 ºS.
This boundary will be discussed later).
Mid Latitude Weather: Covered mostly in the “Flying the Southwest”
Tropical Weather: Covered by the “Flying the Tropics”
What should you expect?
Mid Latitude Weather: Southern Australia (~South of 23.5ºS; ~ South of Alice Springs)
– Cold fronts/Low pressure systems.– Turbulence.– Fogs.– Thunderstorms.– Fires (mostly controlled burns)
The Tropics: Northern Australia (~ North of Alice Springs)– Will still be dry season. Well timed!– Bushfires/Burning off programs.– Dust.– Possible turbulence.– Fogs and Thunderstorms possible but unlikely.
Winds: August Mean – 300ft
Winds: August Mean – A050
Winds: August Mean – FL100
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Satellite Observations
Satellites provide 24 hour information on development and movement of weather systems
Infra-Red Images – detect temperaturesExcellent for viewing broadscale weather patterns in motion
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Weather Radar Observations
Images provide warnings of major weather events such as thunderstorms, tropical cyclones and areas of heavy rainfall
Radar Locations
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Combined Satellite and Radar
Cold Fronts – Southern Aus Mainly affect southern half of Australia, however can trigger
weather further north. Hazards:
– Thunderstorms and showers, hail possible– Low cloud and low visibility in rain.– Strong winds– Fog the night or two after a frontal passage.
Northwest cloud bands: - Entire route.
Warm moist tropical air moving southeast over continent. Large systems, often associated with a cold front. Large vertical and horizontal extent of cloud.
Hazards:– Low cloud.– Embedded thunderstorms– Fogs.– Rain
Turbulence/Nocturnal low level jets.
Low-level jets – Wind shear– Inland tropical areas during winter. Eg: Mount Isa, Tennant
Creek, Halls Creek.– Occur mainly below 3000ft above ground level.– Wind speeds typically ~25 knots, 50kt possible.
Turbulence– Thermals
– Rough guide: if surface temperatures >30º– Any hilly/mountainous areas can contain turbulence, ie: Perth
escarpment, McDonnell Ranges. – Cold Fronts can contain strong wind shear/turbulence.
Fogs/low cloud
Mainly form in coastal areas, however if a northwest cloudband or cold front has passed through, central areas susceptible as well.
Sea fogs common around Gulf of Carpentaria coast. Clear by mid-morning.
Dust Storms
Usually observed in inland areas during the dry season. Generally in the order of 6-8km width. Visibility may be <300m. Often linked to a cold front passing over southern Australia. Dust devils also possible, visible vortices with small diameter
(<100m). May extend up a few thousand feet. Take-offf/Landing hazard.
Smoke Dry season = Burning off season. Controlled burns. Low visibility in thick smoke. Sentinel – Geoscience Australia.
Morning Glory cloud Quite rare, but would be incredible to see! Often form in the late dry, commonly near Burketown. Prevailing SE’ly wind mixes with sea breeze off Gulf of
Carpentaria. Wind squall/wind shear often present.
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Aviation Forecasts & Warnings:Aerodrome Forecast (TAF)
Forecast weather is expressed using the following abbreviations:
Weather Descriptor
MI shallow DR drifting FZ freezing
BC patches BL blowing TS thunderstorm
PR partial
Weather Phenomena
DZ drizzle SS sandstorm PO dust devil
RA rain DS duststorm SQ squall
GR hail GS small hail/snow pellets FC funnel cloud
SN snow FG fog VA volcanic ash
SG snow grains BR mist IC ice crystals
DU dust FU smoke PL ice pellets
SA sand HZ haze
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Aviation Forecasts & Warnings:SIGMET
SIGMETs are issued to advise of the occurrence or expected occurrence of the following phenomena:
Code Description
OBSC TS Obscured thunderstorms
EMBD TS Embedded thunderstorms
FRQ TS Frequent thunderstorms
SQL TS Squall line thunderstorms
OBSC TSGR Obscured thunderstorms with hail
EMBD TSGR Embedded thunderstorms with hail
FRQ TSGR Frequent thunderstorms with hail
SQL TSGR Squall line thunderstorms with hail
TC Tropical cyclone
Code Description
OBSC TS Obscured thunderstorms
SEV TURB Severe turbulence
SEV ICE Severe icing
SEV ICE FZRA Severe icing due to freezing rain
SEV MTW Severe mountain wave
HVY DS Heavy duststorm
HVY SS Heavy sandstorm
VA Volcanic ash
Please ensure you…
Obtain the latest aviation observations, forecasts, warnings and charts from the briefing system
Telephone the Bureau for a more elaborative briefing, when appropriate
Pay attention to media weather presentations and reports.
A useful site for looking up ongoing fires burning around the country:
http://sentinel.ga.gov.au/acres/sentinel/
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For More Information …www.bom.gov.au
1. Weather & Climate information
2. Capital City Forecasts
3. Images & Charts
4. Aviation Weather Services