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

13 December 2015

Bob Blog 12 Dec 2015



Issued 13 December 2015

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.


A wonderful occasion for Planet Earth (and there is no Planet B) —190 nations agree to the COP21 in Paris in 13 Dec 2015.  It’s good to be alive during such an historic occasion.

This day may indeed go down in history as being a turning point.  Good way to start the festive season. See for a FAQ about this.

To mark this occasion there is a very large storm affecting Aleutian Islands (you can see it at


El Nino

There are signs in the data that this El Nino may have peaked, or at least plateaued The NINO 3.4 index which measures the warmth of the sea sin the target area dropped last week, and the SOI index (based on barometers in Darwin and Tahiti) seems to be relaxing.

Latest data can be seen at .


Tropical Cyclones

The 28th numbered storm of the northwest Pacific’s tropical cyclone season developed this week rapidly east of the Philippines.

MELOR should be just south of Manila by Wednesday. It marks the first time in recorded history that a named storm has dotted the Philippines region every month of a calendar year, from Mekkhala in January to Melor now.

There is also BOHALE in the south Indian Ocean


The Weekly rain maps show an easing of rain in the South Pacific.

They also show an interesting stream of continuous moisture stream from China across the Pacific Ocean to Washington state in USA.

These rain maps may be seen at



SPCZ=South Pacific Convergence zone.

The SPCZ is rather weak and spread out between 5 and 15S from 180 to French Polynesia.

Another branch of the SPCZ seems to be redeveloping in the northern Coral Sea.

SO it looks like a relatively quiet week in the tropics this week.


STR= Sub-tropical Ridge

High that is SE of Tonga tonight should continue travelling east along 30 to 35S.

High that is in the north Tasman Sea tonight is expected to fade away where it is by Wednesday.

Another HIGH is expected to cross Tasmania on Monday and then travel NE across the Tasman Sea during the week and northern NZ on weekend of 19/20 Dec.


Over NZ/Tasman:

Disturbed west to southwest flow.


See my yotpak at for terms used.

See my website for information on tailor-made voyage forecasts–

Feedback to Tell anyone you like that to subscribe they should email me.

Weathergram text only (and translator) is at

Weathergram with graphics is at, click FOLLOW at bottom right to subscribe.

To unsubscribe,  send a reply email saying LEAVE.



No comments:

Blog Archive