Bob McDavitt's ideas for sailing weather around the South pacific

16 June 2014

BobBlog issued 16 June 2014

Issued 16 June 2014

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.

Todays edition is a day delayed (I was out for dinner last night :)

There was a full moon on Friday 13th and a perigee of the moon on Sun 15th,
so that spring tides this month are larger than normal. Data of the actual
sea level for Whitianga (on the Coromandel/east coast of the North Island)
shows a storm surge (SS) of 0.6 metres in the NE gale last Tuesday night
(morning of 11th) and this has eased to 0.2 metres since then. Just as well
the air pressure has been around normal in the past week here so that there
was little to no Inverse Barometer (IB) affect.
This Storm surge (SS) and Inverse Barometer (IB) effect on sea level data at
Whitianga for the past week can be seen at

There is a tropical depression off the North America coast (CRISTINA) but
nothing much to report.
The Indian Monsoon was about a week behind schedule this time last week, and
is now about 5 days behind schedule.
Tropical rain maps over the past two weeks show that the convergence zones
are starting to get closer than normal to the equatorthere is a huge bulge
of monsoon rain, but it is lagging to the SW of India.
Brazil is remaining mainly dry (and warm) for the Football/Soccer World Cup.
For the average statistics of rain and temperature for Brazil cities during
the cup try reading

SPCZ= South Pacific Convergence Zone
This continues to be weak or non-existent over much of the South Pacificand
is hugging close to the equator north of Papua New Guinea and north of its
normal position.

STR= Sub-tropical Ridge
The STR has in the last week reverted to its normal latitude range between
30 and 40S. High that was over northern NZ over the weekend is travelling
east along 30S and has a zone of enhanced easterly winds along 10to15S in
the tropics.
Next HIGH is expected to moves from Australian mainland into the western
Tasman Sea on Thursday and then onwards to northern NZ this weekend,
followed quickly by another high over southern NZ on Sunday 22 June

Departing from NZ to the tropics
Large trough is crossing Tasman Sea and NZ over next few days, the cold
front is expected to get east of NZ by Tuesday, and then there are several
waves of showery SW wind changes.
After a brief lull on Wednesday, a very strong burst of S /SW winds is
expected on Thursday, bringing large swells to the east coast. After the
high crosses northern NZ on Friday/Saturday, a low is expected to form in
the Tasman Sea by Sunday 22 June bringing northerly winds to northern NZ.
SO Best day this week to depart northwards from Northland may be Wednesday,
but if you would like a spirited departure with plenty of offshore wind then
look at a Thursday departure. A Friday departure may end up getting caught
in the weekend High.

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