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

8

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

9

Weather Radar Observations

Images provide warnings of major weather events such as thunderstorms, tropical cyclones and areas of heavy rainfall

Radar Locations

11

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.

19

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

20

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/

22

For More Information …www.bom.gov.au

1. Weather & Climate information

2. Capital City Forecasts

3. Images & Charts

4. Aviation Weather Services