Transcript presentation - Outback Air Race

Outback Air Race 2012
James Lannan
Bureau 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
Satellite Observations
 Satellites provide 24 hour information on development and
movement of weather systems
 Infra-Red Images – detect temperatures
Excellent 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
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Radar Locations
Combined Satellite and Radar
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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
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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
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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.
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
Code
Description
OBSC TS
Obscured thunderstorms
OBSC TS
Obscured thunderstorms
EMBD TS
Embedded thunderstorms
SEV TURB
Severe turbulence
FRQ TS
Frequent thunderstorms
SEV ICE
Severe icing
SQL TS
Squall line thunderstorms
SEV ICE FZRA
Severe icing due to freezing rain
OBSC TSGR
Obscured thunderstorms with hail
SEV MTW
Severe mountain wave
EMBD TSGR
Embedded thunderstorms with hail
HVY DS
Heavy duststorm
FRQ TSGR
Frequent thunderstorms with hail
HVY SS
Heavy sandstorm
SQL TSGR
Squall line thunderstorms with hail
VA
Volcanic ash
TC
Tropical cyclone
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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/
For More Information …
www.bom.gov.au
1. Weather & Climate information
3. Images & Charts
2. Capital City Forecasts
4. Aviation Weather Services
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