Bobgram 26June

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.

Compiled Sunday 26 June 2022

The Winter Solstice migration
A series of active fronts across the Tasman Sea NZ area for the first half
of June delayed departure for many yachts in NZ wanting to get to the
tropics. Then, around the shortest day/winter solstice last Tuesday, the
weather pattern became OK for departure and a large cluster of yachts set
forth.

Passage Planning
A regular yachtie around the Pacific is Richard West on SV Legacy. He is
currently in New Caledonia and looking at a good weather pattern for sailing
to Goldstone in Queensland. He has generously decided to take time out and
record the thinking process he uses to evaluate when to depart and what may
be encountered on this voyage. These videos are useful for anyway doing
weather passage planning and goes thru the tools that are available. His
comments on how to use the new boat handling parameters now available of
Predictwind are also very useful. This new hydrodynamic tool uses the wave
polars of your vessel to compute the three axes of motion, what I call the
roll, heave and slam of the waves.

You can find these videos at
twoatsea.com/weather-planning-for-passages-video-series/

He also looks at the steepness factor as mentioned in one of my previous
blogs metbob.wordpress.com/2019/02/17/bob-blog-17-feb/
The Steepness factor was introduced by Dr. Dilip Barua at
widecanvas.weebly.com/nature/waves-height-period-and-length

TROPICS
CELIA is travelling west northwest in the northeast tropical Pacific. Areas
of potential development are around the Philippines and central America.

WEATHER ZONES

SPCZ=South Pacific ConvL1ergence zone and STR (Sub tropical ridge).
The SPCZ stretches across the Coral Sea to northern Vanuatu to Fatuna.
A convergence zone/trough is expected to trave east across New Caledonia on
Tuesday and Fiji on Wednesday then travel further east.
It looks ok to sail from Tahiti to Tonga this week.

HIGHS and LOWS
High H1 east of Chathams is expected to travel slowly along 40S this week
maintaining steady trade winds Low L1 is expected to form in the trough that
crossed NZ on Saturday and travel SE on western side of H1.
Low L2 is expected to form on the northwest side of a trough crossing South
Island on Monday.
Another trough is expected to cross the South Island on Thursday and the
North Island on Friday followed by a cold southerly.
HIGH H2 is expected to form over NSW on Tuesday and move slowly east across
the Tasman Sea reaching central NZ early next week.
Wait until after L2 for an Ok pattern to travel north from NZ or west from
Noumea.
. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more detail for your voyage, then check metbob.com to see
what I offer.
Or Facebook at /www.facebook.com/metbobnz/ Weathergram with graphics is at
metbob.wordpress.com (subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at weathergram.blogspot.co.nz.
Contact is bob@metbob.com or txt 64277762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>