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 29 March

More on the Australian Flood
There was a blocking HIGH in the South Tasman Sea, and it took several days
for a Low to form over NW Australia and the finally travel southeast across
Australia and kick that HIGH away. This meant that there was a squash zone
of strong steady onshore winds onto the Australian East Coast, bringing rain
that showed up on the weather radar from Bundaberg to Melbourne for days.
One way of looking at this weather pattern is to plot a time-latitude plot
of the zonal winds along the 145 to 155E longitude band (basically the
Australian east coast) as can be done at psl.noaa.gov/map/time_plot/ from 14
to 26 March. It shows that the on-shore easterly winds peaked from 20 to 24
March.

And a grab from Marinetraffic.com shows that as I write this the container
ship EVER GIVEN is still stuck in the Suez Canal:

And here is some GOOD news: Fiji have agreed to extend their Blue Lane entry
permission to Savusavu from 1 April, see
www.fijitimes.com/savusavu-approved-as-port-of-entry-for-foreign-luxury-yach
ts/

The Tropics
It is another quiet weekend with no active cyclones.

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
SPCZ is rather broad and weak, stretching from Coral Sea/Solomons to Fiji/
Samoa with some convergence zones around French Polynesia.
Weak passing trough over New Caledonia on Tuesday 30 March.
Low is expected to form in the Coral sea by sat 3 April and should stay SW
of New Caledonia.
Lows are also expected to form near Austral Islands and south of Pitcairn at
end of the week, travelling off to the east.

Subtropical ridge (STR)
HIGH east of NZ is expected to travel off to the east along 40S.
New High is expected to travel into Tasman Sea from New South Wales on
Wednesday and reach northern NZ for the Easter weekend.

Aussie/Tasman/NZ troughs
Trough over central NZ tonight crossing North Island on Monday/Tuesday,
-stay put.
Low is expected to form in south Tasman Sea on Monday and travel east over
central NZ on Wednesday, followed by a southerly flow on Thursday/Friday.

Panama to Galapagos/Marquesas
Moderate northerly to NE/E winds to Galapagos this week, along with a good
tail current.
Path to take to Marquesas this week is via NORTH 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 bob@metbob.com or txt 6427 7762212

Bob Blog 21 March

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 21 March

The start of a new weather year
The March Equinox was 09:37UTC on 20 March and is a good point to start the
count of a new orbit around the sun (it starts the first month of the year,
Nisan in the Jewish calendar, Farvardin in the Persian Hijri calendar, or
Caitra in the Indian/Hindu calendar). The day-of-12-hours-sunlight or
equilux is a few days later in the southern hemisphere (because of
refraction of the sunbeams by the atmosphere as reported by MetService at
www.facebook.com/MetService/posts/4056722254389802

As a coincidental start to the new weather year an East Coast Low off
Australia has been giving the record-breaking conditions, with rain on the
radar from Bundaberg to Melbourne, as seen on windy.com, and with more to
come.
This system should weaken as it crosses the Tasman Sea, reaching Fiordland
on Friday.

Last Wednesday, on Saint Patrick's Day. Team NZ retained the America's Cup
in yacht racing in Auckland's Hauraki Gulf. The AIS from Marine Traffic
showed congestion as the winning yacht Te Rehutai (Ocean spirit) returned to
port.

World Met day is Tue 23 March, with theme: The Ocean, our climate and
weather, see
public.wmo.int/en/resources/world-meteorological-day/wmd-2021-the-ocean-our-
climate-and-weather

The state of the ENSO
La Nina is fading
When the Pacific trade winds are stronger than normal, they drag sun-warmed
sea surface to the west, encouraging upwelling from the cool depths around
the Galapagos. This has been going on for months giving us a "La Nina"
event. It has been shifting the subtropical ridge away from the equator.

The Ocean:
The sea surface temperatures in the equatorial eastern Pacific (area
Nino3.4) have been well into La Nina territory over the past few months and
are now relaxing and quickly returning to "normal" range.

The Atmosphere:
ENSO stands for "El Nino/Southern Oscillation". The main parameter we watch
is the Southern Oscillation Index SOI (30 day running mean) and this comes
from the weather map, summing up the whole weather pattern over the South
Pacific into one number. It counts the average number of isobars between
Tahiti and Darwin. The SOI has been more than plus one (standard deviation
from its mean) since late 2020, giving us a LA NINA event. It has now near
zero.

SOI can be seen at
www.farmonlineweather.com.au/climate/indicator_enso.jsp?c=soi&p=weekly
Trend in the Sea temperature anomalies, can be seen at
www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-sta
tus-fcsts-web.pdf

According to the International Research Institute of the Climate Prediction
Centre,
at iri.columbia.edu/our-expertise/climate/forecasts/enso/current/,
reviewing all of the different models for forecasting the future of this La
Nina, it has a 60% chance of transiting to normal in the next few months---
and a 40% chance of remaining much the same.

The Tropics
It is a quiet weekend with no active cyclones.

SPCZ=South Pacific Convergence zone.
SPCZ is rather broad and weak, stretching southeast from Coral Sea/Solomon
to Fiji/ Samoa then to southeast.

Subtropical ridge (STR)
BIG FAT HIGH 1036 in south Tasman Sea is expected to travel across southern
NZ around mid-week and then eastwards along 45S.
Another HIGH 1030 expected to cross Tasmania this weekend.

Aussie/Tasman/NZ troughs
Low over NW Australia expected to travel southeast and deepen rapidly off
New South wales coast by mid-week and then travel off to south-southeast
across south Tasman Sea. Avoid.

Panama to Galapagos/Marquesas
A period of variable winds in Panama mid-week, otherwise moderate northerly
winds for starters Light winds around Galapagos, turning southerly by end of
the week.
Good current to southwest then west between Panama and Galapagos. Path to
take to Marquesas this week is via NORTH of Galapagos.
There is a "mirror" ITCZ along approx. 3S from around 90W to 120W with a gap
ear 95W as seen on windy.com
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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 atweathergram.blogspot.co.nz.
Contact is bob@metbob.com or txt 6427 7762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bob Blog 14 March

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 14 March
The Tropics

TC HABANA is in South Indian Ocean.

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
SPCZ is stretching southeast from Coral Se/Solomon to Fiji/ Samoa then to
southeast.
Trough is expected to pass over Fiji and Tonga on Monday and Tuesday and
then turn into a LOW travelling southeast.

Subtropical ridge (STR)
HIGH 1032 to east of NZ is expected to travel east along 40 South.
Another HIGH 1030 expected to cross Tasmania on Tuesday and reach South
Island on Thursday and central NZ this weekend.

NZ/Tasman troughs
Trough is expected to cross South Island on Monday and North Island on
Tuesday/Wednesday.
America's Cup course in Auckland should have weak NE flow/cloudy periods/odd
shower on Monday, moderate NW flow on Tuesday, and the SW winds + possible
showers should ease by Wednesday afternoon, then light + dry easterly winds
for reminder of the week.

Panama to Galapagos/Marquesas
Good northerly winds in Panama until mid-week then light and variable. Light
variable wind flow over Galapagos. Good current expected going to southwest
between Panama and Galapagos. Path to take to Marquesas this week is via
NORTH 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 bob@metbob.com or txt 6427 7762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

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
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>