Issued 29 January 2012
Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world of weather maps, so please fine-tune to your place. Dates are in UTC unless otherwise stated.
La Nina's indicators are now levelling out after relaxing over the last month. The Southern Oscillation Index was 2.3 in late December, and eased to 1.16 by 21 Jan, and 1.01 on 29 Jan.
A new MJO cycle of enhanced convection is making its way across Australia and towards the Coral Sea. TC IGGY has been named offshore of West Australia and is likely to wander slowly south this week, hopefully staying well offshore.
The South Pacific Convergence zone SPCZ was very intense last week across Papua New Guinea Vanuatu and Fiji and less intense further to the southeast. It has been carrying rain heavy enough to produce landslides in PNG and Fiji. The zone is shifting around a bit this week but, with a new MJO cycle approaching it is likely that we are now moving towards the "business part" of this cyclone season over the next few weeks. Best to stay put.
It is likely that the LOW now around Vanuatu may deepen over next few days and do a clockwise loop towards New Caledonia by the end of the week. Also another LOW may form in west or central Coral Sea by mid to late week, Avoid.
SUBTROPICAL RIDGE STR
Good news for haymakers over northern NZ. The HIGH that is tonight over the North Tasman Sera should cross the North island on Monday and then be deflected back again by a passing southern front on Tuesday/Wednesday and then fade away in much the same place by the end of the week.
The high that is now in the Aussie bight should stretch eastwards along 50S on Tuesday and build over Chathams on Wednesday and Thursday and then spreading off to the east of NZ. A squash zone of enhanced East to NE winds is likely to remain between this high and the Lows over Coral Sea Vanuatu--- avoid the north Tasman Sea this week.
TASMAN SEA/NZ AREA
A Low over Tasmanian and associated front is expected to slide southeast across the south Tasman Sea during Monday, followed by a weakening trough on Tuesday to Thursday and then a northerly flow on Friday to Saturday. This should help some of the hot air over Australia to reach southern NZ by next weekend.
A cold front is likely to cross southern NZ on Sun/Mon 5/6 Feb, relaxing the winds over New Zealand for their Waitangi Day KIWI day holiday.