2014 Vanuatu Race - Weather Outlook Sunday 29 June 2014

ORCV resident weather gurus Robin Hewitt and Andrew Roberts provide the following outlook (scroll to the bottom to see all 5 weather maps with comments). 

29Jun14-BoM 4 Day Forecast Issued 28 June2014 

Sunday and we are now seeing moderation in the westerlies that peaked overnight ahead of the southwest change, which also saw thunderstorms and plenty of rain dumping on southern Port Phillip and the Peninsula.

The Nepean wave buoy peaked Sunday morning with Sig Wx of 4m, Max Wx of 7m, and is now trending downwards along with the winds for the start on Monday. The strong High of 1035 over the continent which is moderating the current weather is shown on the 4-day map as slowly weakening to 1030 by late Wednesday as it approaches the NSW coast and into the Tasman Sea. 

Further to the west and we see another the low forming off the WA coast and vacillating up and down before deepening and sliding SE to join the familiar progression of deep lows and strong fronts on their march eastwards. This suggests the system drivers are still active. Keeping an eye on this next front and the system with it in order to see if the high is strong enough to tempt the lows further south will be an informative indicator. Hopefully all entrants will be at or around Gabo by this time with options to progress further north.

The previous wild weather Vic experienced also gave Sydney a pasting. 

In the Tasman Sea and the ACCES BOM model suggests a weak low forming just off the NSW coast Thursday AM as the high weakens with lighter winds and the front Friday about noon, perhaps not too strong. SW tending NW 20kts off Sydney and I doubt if anyone will be around Gabo by then, but 30Kts S-SW behind the front which at present gives up further north.



29Jun14-ACCESS-Global 06UTC 04-Jul-14


 BoM Win Forecast 4pm Friday 04-Jul-14.



29Jun14-Jet Stream


The southwards wave and large amplitude of the jet at 35000 ft would appear to me as responsible as a driver west of Perth and seems to have persisted for some time remembering it is the boundary between cold air and more northerly warmer air. The next southerly wave and velocity of 180 kts over NZ confirms Vanuatu as more desirable. 

 29Jun14-WeatherZone-ACCESS MSLP 1200 07-Jul-14  

This ACCESS model for Monday 7 July shows the low off the NSW coast moving into mid-Tasman and persisting with some tighter isobars on the system’s west side, along with rotating winds of south-southeasterlies on the western side, north- northeasterlies on the eastern side. Note the colours represent rainfall not wind.


29Jun14-WeatherZone-ACCESS Wind 1200 07-Jul-14

This next map is for wind. These maps will undoubtedly change closer to actual time but nonetheless are in order of 70-80% confidence. With the European EC model also showing formation of a low in the Tasman Sea next weekend, this potential development should be a key focus of the fleet looking further ahead on the race course. Maps show the usual temperature increase northwards of Gabo and Eden. The low should be a high for usual weather patterns, but when has weather ever been usual?



By Robin Hewitt and Andrew Roberts