Bob Blog

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 7 March

REVIEW OF THE LAST MONTH (February 2021)
La NINA (the cool eastern equatorial Pacific) seems to be weakening. Also,
the warm blob south of Tahiti is easing. Everything else is much the same as
last month.
The Siberian HIGH has weakened. The subtropical ridges have sifted north a
little, and the (east) Pacific/ Marine HIGH has intensified. Otherwise,
everything is much the same as it was at end of January.
Australia and the Tasman Sea have switched from about normal to below normal
pressure (has become a place frequented by LOWS and TROUGHS), and New
Zealand has switched form "troughy" to "ridgey".
Zooming into the NZ area, the 1015 isobar has expanded over the Northland to
Chatham Islands area and the 1010 Isobar has shifted a little north over
the South Island. The Antarctic High has strengthened.

The Tropics
South Pacific has had a busy week. A 7.1 quake near East cape on Friday
early morning produced a Tsunami of around half to one metre as measured by
the GNZ tide gauge at east Cape. Then there was a 7.4 quake which produced a
tsunami at the Raoul island tide gauge. And around an hour later an 8.1
quake cut the power supply on Raoul Island and its tsunami arrived a few
hours later at the Northeastern NZ tide gauges (and Chatham Islands)
reaching around half to one metre in places.
NZ Tsunami gauge network is at http://www.geonet.org.nz/tsunami
Then, on Saturday, TV NIRAN's eye zipped by to the south of New Caledonia
causing extensive damage from wind gusts up to 220 km/hr.

TC NIRAN continues going east-southeast across open waters in the South
Pacific.
TC MARIAN continues going south across the South Indian Ocean.
TC HABANA is also travelling southeast across the South Indian Ocean.

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
SPCZ is stretching southeast from Coral Se/Solomon to Fiji to Samoa to
Tahiti.
TC NIRAN is expected to weaken but remain as a LOW.
The rain accumulation map shows a convergence zone along 5 degrees South.
This is an annual system that is sort-of-a-mirror-image of the ITCZ, due to
the noon day being directly overhead 5 degrees South latitude this week. Now
that it has formed it may linger for a few weeks.

Subtropical ridge (STR)
HIGH 1016 in Tasman sea expected to intensify to over 1020 over northern NZ
on Tuesday and Wednesday and then travel off to the southeast to east of NZ.
Another HIGH expected to cross Tasmania on Wednesday and reach South Island
on Friday.

NZ/Tasman troughs
Trough is expected to cross Tasman Sea on Tuesday and NZ on Wednesday then
linger east of North Island on Thursday/Friday.
Start of America's Cup in Auckland is scheduled for Wed 10 March, and this
trough may bring some 20+ knot winds late on Wednesday----followed by a week
or so of light winds.

Panama to Galapagos/Marquesas
Good northerly winds in Panama until mid-week then light and variable. Wind
flow over Galapagos is expected to briefly be southerly on 11 march then
light and variable. Good current expected going to southwest between Panama
and Galapagos. Path to take to Marquesas this week is via south of
Galapagos.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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 mailto:bob@metbob.com or txt 6427 7762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>