2014 Melbourne to Vanuatu Weather Outlook – Wednesday 25/6 Update

Four days until the start on Sunday and the prognosis is for this vigorous westerly airstream to continue until at least early next week. The westerly pattern kicked off with a bang on Tuesday, with passage of an intense cut off Low through Bass Strait.

As shown in the satellite pic and aviation sigwx chart updated from the weekend, the Low featured an upper cold pool and a classic hook in the polar jet, enhancing the intensification and delivering severe westerly gales along the Victorian coast. Seas in Bass Strait built up quickly, with the Port of Melbourne Wave Buoy near the Heads measuring significant wave heights of 5m and maximum wave heights of 7m from the southwest by Tuesday afternoon.

For this weekend the pattern sees southwesterly cold fronts lining up along the south coast of the continent in the classic ‘shark fin march’ much vaunted by skiers, which looks set to include a cold front on Sunday and possibly also Saturday, with cold and blustery west/southwesterly winds. The passage of the Sunday cold front is shown on the prognosis map below. A well developed seaway associated with this pattern can be expected in Bass Strait, a key consideration for safe negotiation of the Rip and legs across to the Prom and Gabo.  

Of interest is how fast and in what form the High behind the westerly airstream will migrate to the east towards the Tasman. Early indications from the ACCESS, ECMWF and GFS models (ACCESS for Wednesday 2 July shown below) are that this migration will be relatively slow and centred around 35 S latitudes, and likely to maintain a favorable southerly/southwesterly flow along much of the race track until at least midweek. Further to the west and the Low shown west of WA (on the Sunday prognosis) and south of WA (in the ACCESS Wednesday model) is also a feature to watch, particularly its development and potential for intensification as it moves east. On the weekend we will look at how these systems have changed or progressed enabling a better idea.

Current-wise, CSIRO-IMOS imaging of the eastern seaboard indicate that the East Australian Current is running relatively strong for this time of year, and featuring a number of jets and eddies setting in various directions between Flinders Island and Jervis Bay. Warm water temperatures are persisting off the southern NSW coast of around 20 C.

Andrew Roberts

2014 Melbourne to Vanuatu - Weather Outlook 7 days out

Thank goodness the start is not this Sunday as the short-term outlook would make for a very unpleasant Wilson’s prom to Gabo and most likely some sheltering would be prudent.  Available outlooks at present would seem to be better with a front passing just before the start.  

Perhaps  touch and go for the front in progress or into the southerly. This far ahead is bound to be somewhat different on the day, although 7 day accuracy is quoted as being around 75%+.  This a prognosis from weatherzone (www.weatherzone.com.au) who also have a nice chart showing jetstream influence.  Next is to compare this with a picture of 10am prognosis from the BOM Access model which shows the front should be just passed and a fairly stiff southerly in place for the trip to Blairgowrie. Good news for the overnight stay!

I suspect any route prediction models will have a fairly consistent outcome as the general pattern of highs is still fairly in the 35-40⁰ latitudes with fronts in between.  ie. The westerlies are not very prominent in our area yet as spinoffs from below the highs, although this week will see some action in Bass Strait.  Now let’s look at the southern hemisphere MSLP to get an idea of the general patterns circulating which is useful to see the broad scheme although it is modified before it gets to the race area.  Also is a general jetstream chart to guess which areas COULD be influenced.  Note this Southern Hemisphere map is an analysis and not a prognosis, therefore requiring to move it ahead a bit to match the others. Significantly, all the highs are lying in much the same latitude band. During next week, we will look at how these systems have changed or progressed enabling a better idea.

The jets are displayed in a convenient way for visualisation in this aviation sigwx chart. It does not show the vertical meanders which can give entry and exit areas.  It also uses heights in flight levels.  For instance FL400 would be standardised for aircraft 40,000ft and by studying the chart one can determine the upper and lower heights of the jet.  Entry and exit points are useful in determining where low intensification or formation areas could present and as such are better represented on 200 & 500 hpa maps. (Numerical prediction products BOM). Looking back at the sigwx (significant weather) chart one can see the confluence of jets under Perth which no doubt will be responsible for the complex low situation forecast next Tuesday and on. Note also that parts of the jets are very fast-up to 200 knots. Each solid feather represents 50 kts.

We will follow all this further next week.

Robin Hewitt

2014 Melbourne to Vanuatu Virtual Race

For the first time, "stay at home sailors" can join others from around the world to test their navigation skills in the virtual version of the ORCV's Melbourne to Vanuatu 2014.

Online sail-racing navigation simulation Sailonline.org is partnering with the Ocean Racing Club of Victoria, to bring a virtual version of the Melbourne to Vanuatu Race to armchair navigators around the world. Race start is at the same time as the real race on Saturday, 29^th June 2014 at 09:00 local time (Friday, 28^th June at 23:00 UTC) and follows the same course.

Sailonline.org is a non-profit, non-commercial sail-racing navigation simulation run entirely by volunteers. All races are free to join and each Soler (one who sails on Sailonline) gets exactly the same boat. The challenge is navigating through the weather. Sailonline uses almost real-time weather downloaded from NOAA every six hours and the boat physics are considered to be the most life-like of any online simulation.

The Beneteau First 47.7 is the boat chosen from the Sailonline fleet to compete against the actual yachts in the race.

To add to the realism, Sailonline.org has arranged with OceanTrackto overlay the positions of the real fleet onto the virtual race screen so armchair navigators can see how they are faring against the real yachts in the race as they make their way to Vanuatu.

Whether you are a seasoned old salt or a newbie, all are welcome and there is always someone willing to help with questions in the online race chatroom.

Registration for the virtual Melbourne to Vanuatu Race will open on Saturday 21^st June 2014 at 09:00 Melbourne time (Friday 20^th June 23:00 UTC) giving plenty of time to learn the ropes of armchair navigation before the race starts.

For more details please go to the links below:

http://sailonline.org/

https://www.facebook.com/pages/Sailonlineorg/151732058212110

http://www.orcv.org.au/

https://www.facebook.com/OceanRacingClub?fref=ts

http://www.orcv.org.au/index.php/sailing/races/long-distance-events/vanuatu

http://www.oceantracker.net/home/about-oceantrack

OCEAN RACING CLUB OF VICTORIA

NOTICE TO COMPETITORS

2014 MELBOURNE TO VANUATU RACE/RALLY

CHANGES TO SAILING INSTRUCTIONS

1. Appendix A1.5 for both the Race and Rally are modified to read;

“Satphone voice calls will be to +61 418 396 605 and text messages to +61 429 982 327.”

1. Appendices A7.2 (Race) and A 6.2 ( Rally ) are modified to read:

“Yachts are required to report their position by email or by satphone text message at 0800 and 2000 AEST daily. Reports must be sent to This email address is being protected from spambots. You need JavaScript enabled to view it. in the case of email or to +61 429 982 327 for text messages.”

1. Appendices A12.3 (Race) and A10.3 (Rally) are modified to read:

“Within two hours of arrival at a safe harbour, contact must be made with the Race Committee on +61 418 396 605 (voice) or +61 429 982 327 (text ).”

Ray Shaw

Rear Commodore ORCV