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

24 December 2022

Bob Blog 25 Dec

Bob Blog 25 Dec 2022.
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 25 December 2022

FESTIVE GREETINGS EVERONE

Whilst the world media concentrate on the polar blast across North America
this Christmas
(www.theguardian.com/us-news/2022/dec/21/us-winter-weather-storm-cold-snap).
.

Cyclone DARIAN was named last week and is still traveling SE across the
Indian Ocean to SW of Jakarta.
It did a loop and intensified to Cat 5 on the Australian scale and Cat 4 on
the Saffir-Simpson hurricane wind system scale.

In the past few days another cyclone flared briefly. On Thursday it was
named ELLIE as Cat 1 off Darwin.
This reminded us of Cyclone TRACY that hit Darwin at Christmas 48 years ago
in 1974.
ELLIE made landfall as a Cat 1 system. It did NOT have enough time to grow
as much as TRACY over the open ocean,
however even as a CAT 1 system it has been very wet and did do some damage.

See
www.news.com.au/technology/environment/tropical-cyclone-ellie-declared-set-t
o-make-landfall-as-category-1-storm/news-story/b38bb5009b308ee695467dab2e002
16e

and
www.abc.net.au/news/2022-12-24/cyclone-ellie-displaces-homeless-residents/10
1806274
Ex-ELLIE moved inland on Christmas eve as seen at
www.bom.gov.au/australia/meteye/

In the map above there is a HIGH shown in the Aussie Bight, south of ELLIE.
This is travelling east and should build in the Tasman Sea on Boxing Day
making gusty NE winds for a quick start to this year's SYDNEY-HOBART yacht
race.
The tailenders are expected to encounter a passing trough on Wednesday
See
rolexsydneyhobart.com/news/2022/pre-race/2022-rolex-sydney-hobart-fleet-set-
for-downwind-start/

The tracker for the race is at www.rolexsydneyhobart.com/tracker/

MJO
The active part of the MJO is now travelling across Indonesia and north
Australia.
In the New Year there is an increasing chance of a cyclone forming in the
Coral sea area,

WEATHER ZONES
South Pacific Convergence Zone
The SPCZ is expected to have an active week across the Coral Sea to Fiji and
to the southeast.
A tropical low is expected to form in the Coral Sea by mid-week and then
travel SSW into the western Tasman Sea by end of the week.

HIGHS and LOWS
HIGH H1 building in Tasman Sea on Boxing Day and is then expected to travel
east across central Aotearoa NZ this week and then travel east along 40S.
After a month or so of passing troughs this is summer "coming at last" over
Kiwi land.

As usual this is a High between two lows.. L1 is expected to form between
Tonga and NZ on Boxing Day then travel southeast and peak in development
mid-week and then get steered to the SW as H1 travels east. Surfs up for
East coast North Island around New Years.
Low L2 is expected to form in the Coral Sea by mi- week and then travel
south towards Lord Howe by end of the week.
L2 may interfere with trans-Tasman sailing this week.

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

18 December 2022

Bob Blog 18 Dec

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 18 December 2022
GOOD OLD SCOTTISH ENGINEERING

To measure the air temperature, we need to put a thermometer in equilibrium
with an air sample. The air sample should be well shaded from sunlight but
in a box that is well ventilated with fresh air. Such a box was first
designed by Thomas Stevenson as reported in the June 1864 edition of the
Journal of the Scottish Meteorological Society. I wonder if the louvre
system was inspired by a Christmas Tree,

Thomas Stevenson spent his whole life in Edinburgh and watching waves around
the surrounding coast. His observations are written here
babel.hathitrust.org/cgi/pt?id=uc1.b4525127&view=1up&seq=54
stating that wave height =1.5 times square root of fetch.

He and his brothers Alan and David made great advances in the engineering
of electrifying LIGHTHOUSES. His brother-in-law, James Balfour, went to New
Zealand and became the first Marine engineer for Otago Province.
His youngest son, Robert Louis Stevenson, didn't follow in his father's
footsteps. Instead, he became a novelist and world traveller rather than an
engineer. Thomas was not amused.


TROPICS
There is a zone of potential development in the Indian ocean and around
Indonesia.
MJO
Over Christmas and New Year the active part of the MJO is expected to travel
from Indian Ocean to NW Australia.
In the New Year there is an increasing chance of a cyclone forming in the
Coral sea area,

WEATHER ZONES
South Pacific Convergence zone
The SPCZ is expected to have an active week across the Coral Sea to north
of Fiji , and over Samoa to east of Tonga. Another convergence zone is
expected to linger about and south of French Polynesia. An active trough is
expected to cross New Caledonia around mid-week. Avoid.

HIGHS and LOWS
HIGH H1 south of Tahiti is expected to travel slowly off to the northeast
this week.
This allows room for Low L1 now in the Tasman Sea to cross central NZ on
Thursday and Friday, followed by a weak ridge over the Christmas weekend
Low L2 is expected to travel across New South Wales late this week and into
the Tasman Sea this weekend and linger there until next week.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

11 December 2022

Bob Blog 11 Dec

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 11 December 2022

CONGRATULATIONS TO TOM ROBINSON

Tom Robinson is in the process of rowing across the Pacific Ocean and
yesterday made landfall in Penrhyn, Northern Cooks,
completing over half the trip. He hopes to be the youngest ever to row the
whole way solo. We wish him good speed for 2023.

MAKE YOUR OWN WAVES

This week I was introduced to an interesting " indoor ocean" wave-making
pool at youtu.be/pir_muTzYM8

How do they compute the virtual waves in movies and video games?

The answer is Fast Fourier Transforms and Oceanographic Spectra. To give you
a taste of this complicated topic
see the you tube at www.youtube.com/watch?v=kGEqaX4Y4bQ

And you can experiment with you own wave maker with a Google Play app at

play.google.com/store/apps/details?id=com.SimulationisEvolution.OceanWavesSi
mulation&hl=en_NZ&gl=US



TROPICS
Tropical depression Twenty Nine is moving away from Philippines. There is a
zone of potential development near Fiji.

MJO
The GFS ensemble outlook for the remainder of December shows enhanced
convection of the MJO is expected to build in the Indian Ocean.
This may point to a late start to the South Pacific Cyclone season.


WEATHER ZONES
South Pacific Convergence Zone SPCZ
The SPCZ is expected to have a very active week all the way from Solomona
Islands and especially active from Samoa to Southern Cooks.
One tropical Low L1 is tonight near southern Tonga and expected to go
southwest peak close to the NE of Aotearoa NZ by mid-week and then go
southeast and fade.

HIGHS and LOWS
HIGH over 1032hPa to east of NZ and south of Tahiti tonight is expected to
travel off to the east and be replaced by H1 from the southwest . These
highs are keeping a northeast flow from the subtropics onto NZ.

Low L2 is expected to travel across Tasmania on Monday and go southeast into
the South Tasman Sea, followed by another low that deepens in the Tasman on
Wed/Thursday and then crosses central NZ early next week.

Tropical low L3 is expected to form around the southern Cooks by mid-week
and then go SW /S/SE and finally push H1 off to the east, signalling a
change in pattern.

There may be a reasonable voyage from Fiji/Tonga to NZ after mid-week. If
trying to cross the Tasman be ready to divert around the fronts.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

04 December 2022

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 4 December 2022

THE ISOBARS OF NOVEMBER

REVIEW OF THE LAST MONTH (November 2022)
Here is a link to a YouTube clip giving an animated loop of the isobars and
streamlines in the South pacific at youtu.be/qgPsVkd_U5U

Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
The main pattern remains the same as since winter with the cool waters of La
Nina along the Eastern Equatorial Pacific surrounded by zones of warmer than
normal conditions in the north and south Pacific. The hot area that was off
Japan has relaxed. The rains over eastern Australian have run off and
produced a cool pool in the western Tasman sea .

Average isobars for past month
The Antarctic High has continued to weaken and thereby weakening the
southern polar vortex. The Artic low has almost disappeared. The southern
Subtropical ridge has noticeably weakened , except in the South Atlantic.

Pressure anomolies for past month
The lows that started over south Australia is early spring extended to NZ by
late spring. Rising pressures over the Aleutians and Canada and another zone
over northwest Europe is making the northern hemisphere a 2-wave pattern.
The Southern hemisphere is clearly in a 3-wave mode.

Zooming into the NZ area
On the tropical side the 1010 has drifted south onto northern Australia,
typical of summer. However, on the southern side the 1010 has shifted north
from Campbell Island to Taupo, due to the numerous lows and lack of highs
travelling across the Tasman Sea. This is more like a spring pattern.

TROPICS
There are no named storms at present. There is a zone of potential
development north of New Guinea.

WEATHER ZONES
The SPCZ is active at present in the eastern Coral Sea/Vanuatu/ New
Caledonia area but this should clear off to the southeast . Convergence zone
has cleared off French Polynesia at present. A Convergence zone now near
Samoa is expected to drift southeast to Southern cooks.

HIGHS and LOWS
HIGH H1 over North Island is expected to travel off to the east along 35S,
with a squash zone on its northern side around 27S.
Low L1 south of NZ is expected to travel east along 50S.

Low L2 is forming west of New Caledonia and expected to travel SE and fade
near Northland on Wed/Thurs, followed by H2.

Low L3 is expected to travel slowly Se from Bass strait into the south
Tasman Sea by mid-week and then Northeast towards central NZ by end of week.
HIGH H3 should banana around south side of L3 and build east of the South
Island by end of the week.

Looking Ok to sail to NZ next ten days, just divert around the lows.

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

27 November 2022

Bob Blog 27 Nov

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 27 November 2022

LIGHTNING
Last week, between 16 - 25 November, the Aotearoa / New Zealand region saw
91,349 lightning strikes (Source: MetService), with around a 1/3 of those
situated over the land. All regions of the country have experienced
significant lightning activity, however of all the regions around the
country, the Waikato Region takes 1st place with 4,255 lightning strikes
over the period, followed by Westland (3,114) and Hawke's Bay (2,970).
Dunedin had the lowest recorded number of strikes, with 42 recorded over the
9-day period.

Lightning is the most damaging weather hazard for yachts. When you
anticipate it, the standard recommendation is to put some hand-held nav
instruments in the gally oven for protection for the duration, so if the
yacht is hit and losses its electrics, not all is lost.

When we have unstable air in the chimney of a shower cloud, rising water
droplets bash into sinking ice crystals and all that rubbing together rips
off electrons that float to the top, leaving an accumulating positive charge
at cloud base. Lightning occurs when the air between two electrically
charged regions can no longer keep them apart. The average discharge is
several gigajoules.

To put this in context, between the 9 days between 16-25th November
approximately the same amount of energy was discharged into the atmosphere
(or ground) as that either generated by the New Zealand National Grid or
consumed within all industry sectors in New Zealand (Source:
https://www.mbie.govt.nz/building-and-energy/energy-and-natural-resources/en
ergy-statistics-and-modelling/energy-statistics/electricity-statistics/
)


TROPICS
The latest cyclone activity report is at zoom. earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is from
www.ssd.noaa.gov/PS/TROP/TCFP/index.html

There are no named storms at present. There is a zone of potential
development in the China Sea.

WEATHER ZONES
South Pacific Convergence zone SPCZ
The SPCZ is somewhat quiet from Solomons to north of Fiji, then has an
active convergence zone/trough over southeastern parts of French Polynesia.

HIGHS and LOWS
HIGH H1 has been south of French Polynesia for a while is this week expected
to go off to the northeast.

HIGH H2 now between Fiji and NZ is expected to travel east along 30S.

HIGH H3 should stay slow-moving in the south Tasman Sea this week, and move
onto NZ at end of the week, breaking the spell of wet weather

LOW L1 formed over Wairarapa today, cancelling the Wellington Santa parade,
and is expected to travel off to the east southeast.

LOW L2 is forming around New Caledonia area and expected to deepen as it
travels southeast

LOW L3 should travel east across the south Tasman Sea.

LOW L4 is expected to deepen off Bundaberg and travel across the north
Tasman Sea late this week.

So, things are busy this week in the South Pacific, and changeable, but NZ
looks good for arrival from 3 to 6 December.

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

20 November 2022

Bob blog 20 Oct

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 20 November 2022

INSTABILITY AND 1012 THE MAGIC ISOBAR

The recent rains in Australia were brought about by the influx of air aloft
from the Antarctic. This cold air last week crossed the Tasman Sea bringing
with it thundery downpours that have recently reached New Zealand. When
colder than normal air resides aloft, meteorologists describe the air as
being "unstable", meaning that any rising pocket of air may be boosted
upwards by its own buoyancy. An interesting way to "defy" gravity. These
unstable clouds are the ones that produce downpours. CAPE is a good
parameter to measure instability

All clouds contain rising moist air but only a few produce rainfall.
Basically, there are three types of clouds: flat ones, wavy ones, and bubbly
ones. The factor that determines the type of cloud and any resulting
rainfall is 'upward motion'.

Flat clouds are the result of gentle large-scale upward motion created by
air rising slantwise along a slope such as a frontal boundary. These layers
of rising air have little and slow-changing buoyancy: a condition which is
called stable air. They produce rain.

Bubbly clouds are a sign of rapid upward motions which occur on a small
scale in time and space when the atmosphere has lots of triggered buoyancy,
and is called unstable. They produce showers.

Wavy clouds are produced when strong winds blow over a range of mountains on
a stable day. Supercooled cloud droplets form in the
lower pressure pockets that ripple downstream. These clouds, called
Altocumulus lenticularis, are usually dry.

In order to be able to share our cloud watching experiences with others, we
need to learn a few cloud names. The names we use were introduced in England
by chemist Luke Howard in 1802. The two main Latin words are 'Stratus' for
flat or stable and 'Cumulus' for lumpy or unstable. Combined, they describe
a flat low layer of cloud with a bumpy base as stratocumulus.

The word 'nimbus' indicates rainfall. It's used as a prefix for flat clouds,
as in 'nimbostratus' but has the suffix 'nimbus' as in cumulonimbus.

Height above the ground is divided into thirds as follows: 'Cirrus'
describes hairy looking clouds high in the sky, with the prefix 'cirro'
attached to other clouds so high that they are made of ice crystals. The
prefix 'alto' is added for middle clouds (the same meaning of the word is
used for the alto voices in a choir). Middle clouds are composed of liquid
droplets and some of these may have a temperature below zero Celsius
(supercooled). Low clouds carry no prefix and are distinguished by being
modified by the terrain or 'feeling the ground'.

Average atmospheric pressure on Planet Earth is 1013.25hPa. The nearest
isobar to this is the 1012, and indeed this is A MAGIC ISOBAR. It's the
dividing line; at any one time the isobars higher than 1012 will always be
balanced by those lower than 1012. Robert FitzRoy selected the word 'change'
to describe the 1000 to 1012 mean sea level pressure zone on a barometer.
Usually, the 1012 isobar is the straightest on the weather map. Isobars with
lower numbers are associated with cyclones called 'cyclonic'. Isobars with
high numbers are associated with anticyclones called 'anticyclonic'.
Usually, but not always, anticyclonic isobars are associated with stable
air, and cyclonic isobars are associated with unstable air.

In New Zealand flat, wavy, and bubbly clouds often co-exist, especially near
the mountains. Even when the weather map and large-scale clouds indicate a
stable day, a fresh breeze blowing onto a range of mountains from the sea
can produce cumulus clouds and showers on the windward slopes. Stability can
change during the day, often reflected in the clouds: a day may start with a
flat deck of stratocumulus which has a lumpy underbelly, and by afternoon
the cloud deck may have changed to a flat underbelly, indicating a change to
unstable air. The clouds may then burn off and break up into cumulus clouds
with lumpy tops. These changes add to the fascination of cloud watching.

Judging stability by reading weather maps and/or watching clouds is both an
art and a science.

TROPICS

There are some lows in the China Sea and southwest of Jakarta producing
near-equatorial westerly winds across Indonesia, but no named storms
tonight.

WEATHER ZONES

The SPCZ South Pacific Convergence Zone is somewhat quiet from Solomons to
north of Fiji, then has an active convergence zone/trough over southeastern
parts of French Polynesia.
The active trough between Fiji and NZ is expected to weaken in a few days.

HIGHS and LOWS
HIGH H1 east of Aotearoa NZ is still a blocking High, staying put and
helping maintain a strong subtropical ridge westwards to Australia
LOW L1 is expected to travel across the south Tasman Sea.
Around Tuesday night/Wednesday its trough should cross NZ, avoid.
And then it should travel east.
The simple zonal pattern this week makes for simple voyage planning.
Traveling from tropics to NZ means crossing the variable subtropical ridge
--- a zone of fickle winds.

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

13 November 2022

Bob Blog 13 Nov

Bob Blog 13 Nov
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 13 November 2022

BLOCKING
The high east of Aotearoa NZ has been a blocked high with little wind in the
steering field above it.
As is normal with a blocking high, lows keep forming on outs NW shoulder
between Tonga and NZ , and this has been making it difficult to form a good
voyage from Fiji southwards recently.

TROPICS
Cyclone YAMANEKO has developed in the NW Pacific and there is the potential
for formation this week to SW of Jakarta.

WEATHER ZONES
South Pacific Convergence Zone
The SPCZ is somewhat quiet from Solomons to north of Fiji, then active from
Samoa to the Australs.
Tropical Low L1 is expected to form between Tonga and NZ on Monday and
deepen as it travels south. Its associated front is expected to cross Tonga
on Monday and Tuesday.

HIGHS and LOWS
HIGH H1 east of Aotearoa NZ has been a blocked high with little wind in the
steering field above it.

HIGH H2 between New Caledonia and NZ is expected to travel east and weaken.
There should be OK voyages on the western side of this high for travel from
New Caledonia to NZ from Tuesday, and from Fiji to NZ by mid-week.

Late in the week a combination of L2 and L3 is expected to blossom into a
large low in the Tasman Sea worth avoiding . This low should then weaken and
travel south at the end of the week.

Next front crossing Northland is expected on Wed 23 Nov.

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

06 November 2022

Bob Blog 6 Nov

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 06 November 2022

REVIEW OF THE LAST MONTH (October 2022)
Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
The warm waters between New Guinea and the north of New Zealand have
intensified. Otherwise, the main pattern remains the same as in September
with the cool waters of La Nina along the Eastern Equatorial Pacific
surrounded by zones of warmer than normal conditions in the north and south
Pacific.

Average isobars for past month (below)

The Antarctic High has weakened considerably, weakening the southern polar
vortex. The Siberian high has intensified as has the Artic low increasing
the polar westerly winds over northern Europe.

Pressure anomolies for past month (below)

There has been a notable deepening of the lows over southern Australia which
has had a very wet October. Lowers pressure over the Arctic and higher
pressures over Asia and the Aleutians show there are strong westerly winds
over northern Europe.

Zooming into the NZ area
The 1015 Isobar has shifted southwards from Fiji to south of New Caledonia
and the subtropical ridge has moved off central Australia, indicating an
early trend to summer conditions.

TROPICS
Finally, a quiet week. There is a tropical depression in the south Indian
ocean well southwest of Jakarta, and another in the North Atlantic between
the Bahamas and Bermuda, but no named storms.

WEATHER ZONES
The SPCZ is increasing in activity and active from new Guinea to Vanuatu/New
Caledonia, with another convergence zone in an arc from Samoa to French
Polynesia.

Tropical Low L1 over Society Islands is traveling off to the southeast,
leaving behind a convergence zone that is expected to weaken and travel
north.

HIGHS and LOWS
HIGH H1 east of Aotearoa NZ is expected to travel steadily ENE, allowing Low
L# in the Southern Ocean to be drawn to the NE in the wake of H1.
HIGH H2 is expected to stall in the South Tasman Sea until mid-week as a
trough on the front end of L3 then travels northeast out of the Southern
Ocean bringing a southerly change to South Island. in north Tasman Sea is
expected to travel east along 30S and weaken.
This movement of H2 blocks L2 from travelling southeast so it is expected to
go south taking wind and swell with it.

This opens an avenue of light wind between Fiji and New Zealand, but within
this is a zone of squally NE winds and frontal zone associated with L2 .
AVOID.
This zone is expected to extend as far north as Minerva and reach there on
Thursday night (local). It should affect norther NZ on Friday and Friday
night and, finger's crossed, clear in time for the World Cup Rugby on
Saturday night.
AVOID arriving in NZ on Friday/Saturday 11/12 Nov and 18 to 21 Nov.

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

30 October 2022

Bob Blog 30 Oct

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 30 October 2022
The pre cyclone season migration can be seen on PredictWind/tools/AIS today
The climax of their voyage was the passing trough last night
As seen at www.meteo.nc/nouvelle-caledonie/observations/images-satellite
This trough has vented a lot of moisture from the South Pacific convergence
zone and has been built on the western should of a BFH (big fat High)
As seen on weather map from metservice.com
This relay of energy from the tropics to the mid-latitudes may have been
triggered or helped by a recent active part of the MJO into the Pacific,
albeit a weak one.

MJO stands for the Madden Julian Oscillation, a wave of extra energy in the
tropics that travels along equatorial latitudes from the Indian Ocean to the
Pacific Ocean. Each MJO takes around 30 to 60 days to make this trip, and
around a week to cross a region.
A good method to track the MJO is to watch the bubbly blue zones in an OLR
(out-going longwave radiation)map, as shown at
www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foregfs.shtml
This map shows a blue sone moving into the Coral sea in the last few days,
then forecast to fade.
It seems that this MJO might not trigger a tropical cyclone , and since they
are a month or more apart , we may be bold enough , perhaps, to suggest that
there may be no tropical cyclones in the South Pacific until the next MJO
in December. This shouldn't be taken as a forecast or outlook and has as
much merit as "reading tea leaves", so treat it with caution.
As we enter into the nominal start of the this new cyclone season on Tuesday
I shall mention the research predictions from the New Caledonian
meteorologist at www.meteo.nc/nouvelle-caledonie/cyclone/coin-des-experts

TROPICS
NALGAE travelled across the Philippines last week with a death toll of 72
from slips and flooding, see
www.theguardian.com/world/2022/oct/29/storm-nalgae-floods-and-landslides-in-
philippines-kill-at-least-72


WEATHER ZONES
SPCZ The South Pacific Convergence zone
The SPCZ is weak across the Solomon Islands and north of Vanuatu and active
in patches from Fiji to French Polynesia.
The patch over Fiji tonight is expected to weaken and the patch over
southern cooks may deepen into a low by end of the week. Avoid.
HIGHS and LOWS
HIGH H1 east of Aotearoa NZ is a BFH (Big Fat High) and should stay put all
week.
HIGH H2 in north Tasman Sea is expected to travel east along 30S and weaken.
Trough between H1 and H2 is on its western shoulder has been active with
lightning for the past day and is expected to travel slowly east being
pushed by H2.
Low L1 in Australian Bight is expected to travel east across South Tasman
Sea mid -week and across South Island by end of the week, preceded by a
vigorous NW to Westerly flow and followed by a southerly flow and H3 from
central Australia.
After that trough has cleared Fiji it should be Ok to set sail for NZ.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

23 October 2022

Bob Blog 23 Oct

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 23 October 2022

The "SUCKER PUNCH" pattern
Friday 21 October, and a cold front went past Auckland in the morning
followed by showers in a southwest onshore flow from the Tasman Sea.

During the day locals watched the western horizon to time these showers.

By afternoon, the skies were clearing, and people started planning an
evening BBQ to celebrate the start of their only spring long weekend (thanks
to Labour Day Monday). Just as they gathered outside a sucker punch of wind
and rain arrived from the eastern horizon. How can this happen?

The "sucker punch" is a reasonably common Auckland weather pattern and is
explained by its position north of the main mountain ranges of Aotearoa.
At 7am the weather map shows the passing front is leading in a HIGH
crossing the south Tasman Sea.
At 1pm air is diverted northwards along the eastern side of the main
mountain ranges, and this creates a zone of falling pressure in the lee to
west of Taranaki
Then at 7pm the air that has freshly arrived in the Bay of Plenty and still
has the angular momentum it had when south of the mountains is finally free
of the mountains and gets kicked to the left by Coriolis and sucked in
towards that zone of falling pressure. The sucker punch.
TROPICS
The latest cyclone activity report is at zoom.earth and tropic.ssec.wisc.edu
and Tropical Cyclone Potential is from
www.ssd.noaa.gov/PS/TROP/TCFP/index.html

Depression Twentyfive is approaching Vietnam and Cyclone Roslyn is moving
on-to Mexico.

WEATHER ZONES
The SPCZ stretches from Coral Sea/ New Caledonia/ Vanuatu to Fiji then
across Tonga to Sothern Cooks. Tropical Low L1 is forming over Vanuatu and
expected to travel east across Fiji on Tues/Wed. Another tropical Low L2 is
forming between Southern Cooks and Austral islands and expected to travel
SE. Avoid these.
After L1 has cleared Fiji should be Ok to set sail for NZ.
HIGHS and LOWS
A southerly change travels northeast across NZ on Monday, followed by HIGH
H1 on Tuesday. H1 then is expected to travel off to the east along 35S.
Low L3 has formed offshore of Bundaberg and is expected to travel south
along the East Aus coast to Eden by mid-week and then southeast across the
south Tasman sea.

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

16 October 2022

Bob Blog 16 Oct

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 16 October 2022

The waning moon of October---- its Palolo season again.
Palolo (in Fijian: Balolo) is the edible portion of a worm that grows in
shallow coral reefs.
The mating season of the palolo follows the lunar cycle - typically on the
seventh night after the October full moon (the one after the equinox)
Under this waning moon the palolo worm will detach its lower half, where its
reproductive organs are, and this "tail" floats to the surface of the water
and releases eggs or sperm in a mass synchronised spawning event spread by
this special tide.
This South Seas caviar tastes like a combo of abalone and oysters. It
deteriorates quickly in sunlight, so gatherers need to collect it in the
pre-dawn hours. "It's the early bird". Many social traditions are triggered
by this event
One of the traditional things triggered by the Palolo season is the annual
pondering about the coming cyclone season. In the island people try and link
what they can observe at this time with what might come in the next few
months. So, if it's a great mango season that may be taken as an indicator
of a possible nasty cyclone season.

This year the boffin at BoM (Australia's Bureau of meteorology) are saying
MORE
The full report is at www.bom.gov.au/climate/cyclones/australia/
They say this is linked to the current La Nina. And that the first cyclone
this season may be "early" and occur in November.
MetService NZ and Fiji Met Service issue the official cyclone warnings over
the South Pacific, and they have joined with NIWA of NZ to issue the
following maps.
The full report is at
niwa.co.nz/climate/southwest-pacific-tropical-cyclone-outlook/southwest-paci
fic-tropical-cyclone-outlook-october-2022

They also point the finger at La Nina, which typically shifts the
subtropical ridge southwards and thus shifts the cyclone risk westwards,
towards the Coral Sea.
They do note that this La Nina is expected to weaken and may be neutral late
in the season, and that can change things.
During the cyclone season there are usually quiet spells and then bursts of
energy. The Madden Julian Oscillation can help us identify the energy bursts
a week or more ahead, and I'll comment more on that in a few weeks,

TROPICS
The latest cyclone activity report is at zoom.earth and tropic.ssec.wisc.edu
and Tropical Cyclone Potential is from
www.ssd.noaa.gov/PS/TROP/TCFP/index.html

Cyclone NESAT is approaching Vietnam and expected to peak on Tuesday.


WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Vanuatu to north of Fiji.
This thins out then thickens into a convergnc3 zone hovering around the
Society islands.
A passing trough is expected to travel eastwards to south of Tonga by
mid-week

HIGHS and LOWS
High H1 east of Aotearoa NZ tonight is travelling away to the ENE.
A showery low L1 tonight in the Tasman Sea is expected to cross North
Island on Monday and wander off to the east connected to the trough south of
Tonga.
HIGH H2 is expected to travel east across the Tasman Sea and fade there late
in the week.
Low L3 is expected to travel late this week from south of NZ to east of NZ
bringing a cold southerly in its wake on Friday. Avoid.
Then High H3 is expected to travel east across the central Tasman Sea and
reach central and northern NZ for the long weekend.
H2 and H3 offer good opportunities for sailing from tropics to NZ and
Australia.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

09 October 2022

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 9 October 2022

Back in August I talked about Blaise Pascal's famous experiment showing how
air pressure changes with altitude at
metbob.wordpress.com/2022/08/29/bob-blog-28-aug/
During the 18th century barometers become useful as a tool for forecasting
weather on sailing ships
and then in the 19th century…. Robert FitzRoy introduced weather
forecasting to newspapers

Born 1805, Robert FitzRoy
Fourth Great-grandson of Charles II
Protégé of Francis Beaufort
Age 12: joined Navy Academy
Age 19: passed Royal Naval exams, first ever to achieve 100%.
Age 23: Made Captain of "The Beagle"
Age 26-31: Skipper of BEAGLE with Charles Darwin's famous voyage to
Galapagos
1843-1845 2nd Governor of NZ
1853: First International Meteorological Conference at Brussels
1854: Meteorological Statist to the Board of Trade.
1857: Christophorus Buys Ballot shows mathematically
that wind circulates around air pressure centres.
1859: Storm sinks the "ROYAL CHARTER".
"Origin of Species" published
Age 55: Rear-Admiral FitzRoy
Daily weather maps in 'The Times"
Age 58: Publishes "The Weather Book"
1865: decommissioned and takes own life

.TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html
Cyclone JULIA is about to travel from the Atlantic to the Pacific. Cyclone
BALITA is the second named storm of the 2022/23 South Indian Ocean season
which usually starts around 15 November. These cyclones have been confirmed
by scatterometer.

WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Vanuatu and briefly visits
Fiji and Tonga. A low L1 is forming tonight south of Tonga and expected to
travel SE this week. Another Low L2 is expected to form near Vanuatu by
Wednesday and travel SE to be to NE of North Island by weekend. Avoid.

High H1 east of NZ tonight is travelling away to the ENE.

A trough tonight in the Tasman Sea is expected to weaken as it travels east
across Aoteroa NZ on Mon and Tuesday and linger over the north on Wednesday.

HIGH H2 is expected to follow this trough across the Tasman Sea on Tuesday
and cross the South Island on Wed and Thu, to then be to south of L2, with
enhanced easterly winds onto Coromandel/Gisborne. Avoid

L1 and L2 make travel between Fiji and NZ hazardous until after 14 October.

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

02 October 2022

bob blob 2 oct 2022

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 2 October 2022

REVIEW OF THE LAST MONTH (September 2022)

Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
The main pattern remains the same as in July with the cool waters of La Nina
along the Eastern Equatorial Pacific surrounded by zones of warmer than
normal conditions in the north and south Pacific.

Average isobars for past month
From www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
This pattern is much the same as at the end of August.

Pressure anomolies for past month (below)
The main change in the past month has been the appearance of lower than
normal pressures over and around North America.

Zooming into the NZ area
The subtropical ridge is slightly weaker east of Aotearoa NZ otherwise the
pattern is very similar. .

.TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html
Cyclone IAN made historically damaging landfall over Florida last week with
a death toll over 20 and still rising.
Here is a clip showing four vessels drifting down along a street at Fort
Myers on the SW tip of Florida twitter.com/i/status/1575213169001127936
Tonight ORLENE is about to make landfall on west coast of Mexico and ROKE is
moving away from Japan.

WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Vanuatu and to a trough that
lingers over the Fiji area this week and may form a low L2 northwest of Fiji
by end of week.

HIGHS and LOWS
High H1 lingering south of Tahiti and slowly travelling East along 30S.
Low L1 crossing Aotearoa NZ tonight followed by a cold southwest flow for a
few days, with a trough extending back to Fiji.
HIGH H2 over 1030hPa travelling northeast across southern Tasman Sea and
central Aotearoa from Wed to Sat, with a squash zone of enhanced easterly
winds o its northern side.
Low L2 is expected to form northwest of Fiji this weekend as H2 moves off to
east of Aoteroa.

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

25 September 2022

Bob Blog 25 Sep

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 25 September 2022

TC FIONA
After devasting Puerto Rico, Tropical Cyclone Fiona travelled north and did
an extra-tropical transition with cold air wrapping around and squeezing off
the warm core. It then made land fall over Port aux Basques in Nova Scotia,
Canada, with a measured baro of 913hPa, a new Canadian record.
twitter.com/i/status/1572761254153920512
twitter.com/i/status/1573776053453164552
twitter.com/i/status/1573539748466999296
twitter.com/i/status/1573582481026162700
twitter.com/i/status/1573534734805868546

The storm surge washed away houses:
twitter.com/i/status/1573659603417579522

TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

We are having the late September flush with 6 cyclones.

IAN is approaching Florida, while GASTION and HERMINE are also in the
Atlantic and NEWTON is in the eastern Pacific. NORU is moving onto the
Philippines.


WEATHER ZONES
SPCZ=South Pacific Convergence zone
The SPCZ stretches from Coral Sea. L2 is forming east of Fiji and expected
to go to Tonga. Avoid.

HIGHS and LOWS
Low L1 in mid Tasman Sea is expected to go southeast to south of Aotearoa
NZ.
Low L3 east of Aotearoa NZ is expected to travel off to the northeast
followed by H1.
Low L4 is expected to form over New South Wales by mid-week and then travel
towards North Island by early October. Avoid.

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

18 September 2022

Bob blog 18 Sep

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 18 September 2022
Origin of the terms El Nino and La Nina
The locals in Peru are keen observers of ups and downs in their food stocks
over the years. They like to gather anchovies that can be easily collected
just offshore thanks to the strong upwellings of nutritious water in the
Humboldt current. Around Christmas in most years a current brings in warmer
seas from the north and a bounty of extra food, and Peruvian fish gatherers
called this event" El Nino" naming it after the birth of the Christ child.
The first published reference of this was in 1891 by Senor Dr Luis Carranza,
then President of the Lima Geographical Society, see
faculty.washington.edu/kessler/occasionally-asked-questions.html#q2
So, what about the origin of the term "La Nina"? Well, the locals in Peru
didn't have a term for a non-bounty period and when the term "El Nino" was
adopted for a warm event over the eastern equatorial Pacific, various terms
were used to describe its opposite. One was "Anti El Nino", but that can be
translated as antichrist and was only used once or twice.
So it was that S. George Philander of Princeton introduced the term "La
Nina" (Girl) for the "cold event". But some wanted to use "El Viejo" (old
man).

TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

FIONA is in the Caribbean and MADELINE is off west of Mexico
TC NANMADOL is tonight making landfall across Japan.
Two million people have been asked to shelter from this rare and very
dangerous

WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Samoa and fades further east.
A trough in the Coral Sea is expected to deepen into a Low (L4) mid-week and
that then fades over New Caledonia by end of week. Avoid.
HIGHS and LOWS
HIGH H1 east of Aotearoa NZ expected to travel east-southeast from 35S to
40S.
A warm front is expected to travel south across Aotearoa NZ on Monday and
then a broad meridonal trough by midweek with lows L1 at 43S and L2 at 23S.
Low L1 expected to travel southeast across central Aotearoa NZ on Monday
followed by strong southerly flow on Tuesday with rough seas.
High H2 is expected to travel across the Tasman Sea on Wednesday followed by
L3 on Thursday and Friday, avoid.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

11 September 2022

Bob Blog 11 Sep

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 11 September 2022

La Nina or not?

El Nino and La Nina are opposite ends of the swing of an identifiable
tropical influence on our seasonal weather.

The La Nina, caused by cooler than normal sea surface temperatures along the
equatorial eastern pacific, (STEEP), shifts the subtropical ridge away from
the equator and strengthens the trade winds.

The El Nino, with warmer than normal seas, draws the subtropical ridge
closer to the equator, weakening the trade winds.

Their comings and goings can last several months, maybe years, and so their
status can be used to help forecast the weather for the coming season.

Isobars
ENSO = El Nino/Southern Oscillation. The main parameter we watch from the
atmosphere is the Southern Oscillation Index SOI (30 day running mean) as it
sums up the whole weather pattern across the South Pacific into one number,
based on the number of isobars between Tahiti and Darwin, The SOI is the
normalised Tahiti minus Darwin barometer reading. When this is more than
plus one there is usually a La Nina event.
See www.bom.gov.au/climate/enso/wrap-up/

LA NINA EVENTS: We had it strong from Dec 20 to March 21, weaker peaks
July/Aug 2021, and Nov 21 to Jan 22, and a strong again May to July 22. We
are now "in-between events" with the SOI hovering around plus one. The SOI
has been mostly positive since Aug 2020, and some meteorologists are
wondering what this means --- see www.nature.com/articles/d41586-022-01668-1
and reliefweb.int/report/world/el-ninola-nina-update-august-2022

The Ocean:
The sea surface temperatures in the equatorial eastern Pacific have been
cool for a while but are currently mixed with a warm tongue between
Galapagos and Peru.

In passing, the warm seas in the northern hemisphere are remarkably red.
territory.

The warmer than normal ocean between Indonesian and Australia is a NEGATIVE
IOD (Indian Ocean dipole). This is associated with a wet Spring for eastern
and southern Australia and usually tugs the monsoon eastward off India (but
maybe not at present).

Sea temperature anomaly is at psl.noaa.gov/map/clim/sst.shtml

NINO3.4 is the parameter mostly used from the ocean for watching ENSO and
recently this has been hovering on the threshold,

Other factors now considered are the sub-surface temperature, the height of
the sea, cloudiness, and the trade winds. The combination of several
parameters and models are then summarised into a forecast for NINO3.4 for
the months ahead. The trend is looking neutral. See
www.bom.gov.au/climate/enso/wrap-up/

TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

EARL has wandered along the Gulf stream to the North Atlantic. MUIFA is
travelling north to east of Taiwan and FIFTEEN is also in the NW Pacific.

WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Samoa and fades further east
by southeast. A trough in the Coral Sea is expected to deepen into a Low
(L2) over New Caledonia by mid-week and then travel southeast towards
Northland by Saturday. Avoid arriving in NZ around 23/24 Sep.

HIGHS and LOWS
HIGH H1 east of Aotearoa NZ expected to travel east-northeast from 40S to
35S.

Low L1 expected to travel southeast across central Aotearoa NZ on Monday
followed by strong southerly flow on Tuesday with rough seas.

High H2 is expected to travel along 45s into Tasman Sea by mid-week and then
across southern Aotearoa NZ by end-of-week, with a squash zone of easterly
winds with L2 on its northern side.

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

04 September 2022

Bob Blog 22Sep

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 4 September 2022
Monsoon 2022

U.N. Secretary-General Antonio Gutteres said Pakistan's flooding, caused by
weeks of unprecedented monsoon rains and compounded by glacial meltwater
running down from the mountains, were a signal to the world to step up
action against climate change.

"Let's stop sleepwalking toward the destruction of our planet by climate
change,"
he said in a video message to an Islamabad ceremony launching the funding
appeal.

"Today, it's Pakistan.

"Tomorrow, it could be your country."

REVIEW OF THE LAST MONTH (August 2022)

MetService issue a tropical analysis of the South Pacific with isobars and
streamlines at www.metservice.com/warnings/tropical-cyclone-activity

I am now saving one image a day from this page and here is an animation of
last month's weather at this link: tinyurl.com/PacificAug2022

Between 15 and 20 August a strong "atmospheric river" brought flooding to
parts of Aotearoa NZ open to northerly winds, as a HIGH over 1040hPa south
of Tahiti stalled fronts in the Tasman Sea.

Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml


The main pattern remains the same as in July with the coo waters f La Nina
along the EEP Eastern Equatorial Pacific surrounded by a C shaped zone of
warm waters

Average isobars for past month
The subtropical ridge in the northern hemisphere has weakened. Otherwise
there hasn't been much change.

Pressure anomolies for past month (below)
The lower pressure zone that was over Canada has shifted west into the north
Pacific. And the low zone that was over Australia has relaxed.A Higher than
normal pressure zone persists from south of Australia across NZ into the
Pacific, encouraging the southern hemisphere's subtropics .

Zooming into the NZ area
The subtropical ridge around NZ has shifted north, and intensified,
increasing the trade winds. High centres have intensified to over 1025 in
Indian and East South Pacific Ocean.


TROPICS

After a quiet August, things are ramping up in September with Danielle and
Earl in the North Atlantic, Javier west of Mexico and Hinnamnor still
affecting east of Asia.

WEATHER ZONES

The SPCZ stretches from PNG across Solomons to Samoa and fades further east
by southeast. A trough in the tropics is expected to visit New Caledonia on
Monday and get eats to south of Fiji/Tonga by mid-week followed by southerly
swells to 3m. Avoid.

HIGHS and LOWS

Low L1 in mid Tasman deepening to 988 over Northland by Monday night/Tuesday
while a cold southerly blast cover N, combining to produce up to 7m swells
on its backside. Avoid

The trough associated with L1 is expected to brew L2 to SE of Niue by
Thursday and then off to the southeast for a few days.

High H1 should spread into South Tasman Sea by Wednesday and across NZ on
Thursday then travel east along 45S and should be useful for sailing.

A trough following H1 is expected to cross the Tasman and NZ this
weekend/next Monday.

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

28 August 2022

Bob Blog 28 Aug

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 28 August 2022

Monsoon 2022

August rainfall in Pakistan has been between 2.5 and 5 times the 30years
norm, with a death toll currently around 937. At least 184,000 people have
been displaced to relief camps.


Why are they called hectoPascals?
Barometer is coined from Greek words, Baros for "weight" and metron for
"measure".

When the MKS system of units was drawn up in 1960 PASCAL was chosen for the
name for a unit of pressure (a Newton per square metre) as a commemoration
of Pascal's pressure experiment described below. And so, isobars are now
labelled in hectoPascals. The prefix of hecto is from the Greek word hekaton
for "hundred". So 1010hPa means 101,000 Pascals or 101,000 Newtons per
square metre- that's about a tonne per square metre , same as an elephant.
Yes, for a diver, that's the pressure exerted by about 32 feet or 10 metres
of (sea) water.

Pascal was a Frenchman and his experiment was conducted in 1648….

FRANCE, mid seventeenth century:

This was the time celebrated by Alex Dumas in the Three Musketeers. Louis
XIII was King, but the ominous Cardinal Richelieu was in charge, and did
things his way.

You may recall in my blog on 31 July
https://metbob.wordpress.com/2022/08/01/bob-blog-31-july/ I described how in
1642 Evangelista Torricelli, a student of Galileo, produced the first
barometer to make a vacuum. Now Marin Mersenne was a French Priest who
earned the title "the post box of Europe" for he travelled a lot, had many
contacts around the scientific word and was great at making connections. He
visited Italy in 1644 and Torricelli showed him the barometer. He returned
to Paris with a choice collection of writings, including Torricelli's paper.
These he shared in 1646 at the Paris Book Club that included Etienne and
Blaise Pascal.

Back story: Blaise Pascal was born in France in June 1623, the son of
Etienne Pascal, a lawyer. His mother died when he was three. He was educated
by his dad and proved to be a child prodigy in anything mathematical. At the
age of eight the family moved to Paris. When Blaise was 15 Cardinal
Richelieu (then Prime minister of France) imposed some harsh fiscal measures
which his dad opposed and for that had to go into hiding. The following year
his sister Jaqueline (then 17) appeared in a play given before Richelieu and
after a "fine performance" the Cardinal rewarded Jaqueline with a pardon for
Etinenne plus a job offer to the post of Tax collector for Rouen. Side note:
Jaqueline was a child prodigy writing a five-act comedy when she was 11.

The following year young Blaise wrote an article on solid geometry which
drew the attention of Rene Descartes (the main French mathematician at the
time). Descartes couldn't believe such an article could have been written
from anyone so young. The two developed a special relationship.

In 1642, when he was 19, he started work on a calculating machine to help
his dad count those taxes - the first ever digital calculator, called a
Pascalaline, akin to the ones that were popular in the 1940s.

Blaise Pascal's life as a mathematician went on to produce the Pascal's
triangle which is a triangle of numbers starting with 1 and then extending
down left and right with each number equalling the sum of the numbers above
left and right. It gives the values of the polynomial coefficients, useful
in algebra and differential calculus.


Philosophical Disagreements
Blaise was intrigued with these vacuums and spent a few years reproducing
Torricelli's experiments and trying out different liquids such as water
versus red wine. In 1647 he wrote some papers on the properties on the void
at the top of barometer (Expériences nouvelles touchant le vide).
Then he and Rene Descartes have some long chats about this topic. Descartes
could not believe that a void or vacuum existed or that a barometer was
really measuring air pressure. He supported the explanation by Greek
philosopher Aristotle that this space was filled with a substance called
aether, which was extremely tenuous and able to flow through tiny pores in
the glass tube and fill in the space left by the receding water. The aether
was also used by Aristotelians to explain how light from far-away stars
reaches us by travelling through a substance. Things came to a pretty pass.

Scientific experimental evidence
Blaise understood the power of experimental evidence and so he then built a
portable barometer using a glass tube of mercury inverted into a dish of
mercury. Because he had weak knees, he asked Jaqueline's then husband Florin
Périer, to do the hard bit - carry this device up the Puy de Dôme, a
conspicuous mountain in Rouen familiar to Blaise from his childhood, and
take a series of measurements. Sure enough, the height of the supported
mercury column got less with increasing altitude. The amount of fluid in the
tube was responding to changes in air pressure. So, it was air pressure that
was responsible for the height of the column, rather than the size of any
void left over at the top. This experiment was carried out on 19 September
1648 and verified Evangelista Torricelli's original hypothesis about
atmospheric pressure on the equilibrium of liquids.

Le Puy de Dôme in central France, site of famous PASCAL experiment

The Puy de Dôme experiment became famous in the world of science for finally
putting an end to the Aristotelians aether theory, and the principle it
proved became known as Pascal's Law.

Pascal's barometers quickly became the best tool for measuring altitude,
proving accurate enough to give good measures of the depth of coal mines. It
wasn't long before barometers were also adopted by sea-captains to help show
the dropping air pressure that precedes wet windy weather. To this very day,
even though we measure temperature, wind, rainfall, and humidity as well as
pressure—it is the PRESSURE LINES that we draw on weather maps that are
accepted as capturing and showing the weather pattern.

TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

HINNAMNOR is storm force near Iwo Jima. There are zones for potential
developments west of Mexico and across the central Atlantic.

WEATHER ZONES
SPCZ=South Pacific ConvL1ergence zone and STR (Sub tropical ridge).

The SPCZ stretches from PNG across Solomons to Samoa and is expected to
drift south to Fiji/Tonga late this week. Avoid.
Low L1 to south of Tahiti is expected to drift to southwest and then to
southeast.

HIGHS and LOWS
High H1 above 1034 over NZ is expected to slowly shift to Chathams by
mid-week then speed off to the east and fade.
Low L2 over Victoria tonight is expected to weaken as it moves into south
Tasman Sea by mid-week then over NZ on Friday. This one looks tame from
Tuesday.
Models are picking L3 to deepen off Queensland at end of the week and move
onto NZ next week. Avoid.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

21 August 2022

Bob Blog 21 Aug

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 August 2022

Another reason to hate a HIGH
Back in the 1990s when I wrote my MetPack notes, still available at
about.metservice.com/our-company/learning-centre/mariners-met-pack/

I included a section listing nine reasons to Hate a High.
Last week over New Zealand has been a perfect example of reason number nine
"The bigger they are the slower they move, blocking fronts that are trying
to follow them."
I mentioned that L2 and L3 2ould bother Aotearoa NZ (AoNZ) from Tuesday to
Friday last week, and indeed they did. This is because a large High grew to
well over 1040hPa east of AoNZ and south of FP.
Notice how there was a convergence zone of tropical moisture feeding the
frontal rain stalled over AoNZ , this was referred to in the popular media
as a "hosepipe" to help convey the picture.
As a result the rain accumulation was record breaking and very damaging


TROPICS
There are zones for potential developments west of Mexico and across the
central Atlantic.

WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Samoa. Early in the week a
convergence zone from around Niue to Southern Cooks is associated with L1, a
low further south that is expected to go to the southwest and fade. OK to
travel from Tahiti to Tonga this week.

HIGHS and LOWS
Last week's High over 1040 has now moved off to the east.
The next High H1 is around 1024 and more mobile. It starts the week in the
Tasman sea and travels east along 30S crossing northern NZ around Wednesday
and getting south of FP by week=end.
L2 in the Tasman Sea is expected to cross North Island on Monday night and
then go off to the southeast.
L3 is expected to form off Coffs on Wednesday and then travel southeast
crossing NZ on Friday, followed by a southerly flow.
H1 offers a brief opportunity of OK weather...it doesn't satisfy any of
those nine ways that make nasty Highs..

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
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>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

14 August 2022

Bob Blog 14 August

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 August 2022

Tides of New Zealand
Ahh.when we start moving out of the depths of winter my first reminder that
summer and brighter times are coming is the annual arrival of the new
edition of the NZ Nautical Almanac (thanks to Boat Books). It is online now
(and the astronomical data is at
www.linz.govt.nz/sea/nautical-information/astronomical-information) but
serious boats have a place on board for their own hard copy.

When the almanac arrives, it reminds me also of the time back in the early
1970s when I was doing a course in oceanography as part of my meteorological
degree at Victoria University in Wellington and we were given as homework
the task of studying the tidal movement in Wellington harbour as an example
of the application of Coriolis forcing (things that move around the southern
hemisphere feel a tug to the left).

What impressed me at the time was that the "tug to the left" from Coriolis
should cause the water in an oceanic basin in the Southern Hemisphere to
spin clockwise, but the tides around the NZ Coast rotate counter-clockwise.

The tide at Onehunga is around three and a half hours after that at
Westhaven. If ever a canal is built between these two harbours, it could be
a perpetual power station but would need locks for vessels.

The combined attraction of the Moon and the Sun generates ocean tides.
Calculating tides is not easy. Distance and angle of separation of the Sun
and Moon keep changing, and the shape and size of ocean basins complicate
the calculation, and these keep changing too. Each component has a cycle
with its own amplitude and period (a sine wave) and these are each
calculated then added back together. The main component in our area is M2
(the moon-twice-a-day component) due to the attraction of a 'virtual' Moon
placed on a perfectly circular orbit in the Earth's equatorial plane. It has
two high and two low tides per day (semi-diurnal wave). The K1 wave, with a
diurnal period, reflects declination variations of the Moon and Sun. In
certain areas, a hundred components have to be added together to obtain a
precise forecast.

An animation of M2 looks like (note that it repeats in 12hr and 25mins) is
at
/en.wikipedia.org/wiki/File:Global_surface_elevation_of_M2_ocean_tide.webm

There is a Tidal nodal point or amphidromic point (Greek for around running)
over the mainland near central New Zealand
The nearest bay to this point has been Oteranga Bay near Cook strait but now
that the centre of NZ has shifted since the Kaikoura earthquake in 2016, I
wonder if this too has changed?

Maupiha'a (also known as Mopelia) and Maupiti in the Society Islands west of
Borabora in western French Polynesia, are very close to a Tidal null point
or amphidromic point.

Although the lunar component of their tide is almost nil, there is still a
solar component, so slack water is around noon each day. There are also
ever-changing weather components. Whenever the lagoon water drains out to
sea it does so in a rush. These are NARROW PASSAGES and If a STRONG CURRENT
encounters an opposing wind or swell then a vigorous short chop results.

Maupiti's lagoon passage is on the south side of the island and may be
unsafe for several days whenever there a southerly swell.

Maupiha'a has a pass on its northwestern side. The pass can have up to a 9
knot continual outflowing current with a wall of breakers across the
entrance. In 1917 the German raider Count Felix von Luckner's three masted
schooner Seeadler was wrecked in these breakers.

Here is a link to a video of SV KOLOHE exiting from the passage on NW side
of Maupiha'a on a day when the surrounding swells where 3 to 3.5 significant
metres. The current was an estimated 5kt and encountered waves up to 2m. See
drive.google.com/open?id=1a8TWsADTKPYChc9o7YYneyEVjLUcScJG


TROPICS
Cyclone Ten is off the Mexican west coast, going NW. MEARI is fading near
Korea.

WEATHER ZONES
The SPCZ stretches from PNG to New Caledonia and from Vanuatu to Samoa. A
convergence zone/Trough from Samoa to Southern Cooks is expected to travel
northeast to FP by mid-week and then go westwards and form a low over the
Niue area by weekend. Avoid.

HIGHS and LOWS
High H1 east of Northland expected to travel southeast along 35 to 40S to
around 160W and then intensify and become slow-moving. Squash zone expected
to north of H1 from mid-week.

L1 near Tasmania expected to travel southeast across the south Tasman Sea
and fade away by mid-week.

L2 is expected to form over New Caledonia on Monday and travel southeast
crossing NZ on Tuesday to Thursday followed by another low L3 on Friday

H2 is expected to standby over eastern Australia until after L3 and then
cross the Tasman Sea this weekend.

Not a good week for departing NZ

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more detail for your voyage, then check metbob.com to see
what I offer.
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at bottom).
Weathergram archive (with translator) is at weathergram.blogspot.co.nz.
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>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

07 August 2022

Bob Blog 7 Aug

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 07 August 2022

Thanks to Phillip Duncan of Weather Watch for sharing an interesting link
about NZ Tides at tinyurl.com/NZtidalnode explaining bout why there is a
tidal node, or amphidromic point, over mainland NZ and why the tides spin
counter-clockwise around NZ (where the Coriolis effect alone would have them
go clockwise).

REVIEW OF THE LAST MONTH (July 2022)
MetService issue a tropical analysis of the South Pacific with isobars and
streamlines, it is NOT available from their home page but from their severe
weather page (which can sometimes be otherwise empty) or at
www.metservice.com/warnings/tropical-cyclone-activity
I am now saving one image a day from this page and here is an animation of
last month's weather at youtu.be/C8x77I9Hzy8
It shows a series of six big lows forming in the Tasman Sea then crossing
NZ. Aotearoa New Zealand had their wettest July on record.

Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml show
This shows a further relaxation of the cool zone that makes up La Nina. The
surrounding C shaped ring of warm water has intensified over the North
Pacific and is strong from New Guinea to southeast of Tahiti. The Antarctic
convergence zone shows clearly. There is a marine heat wave around the north
and east coast of Russia. The Tasman Sea warmer reading shave relaxed.


Average isobars for past month (
The subtropical ridges in both the northern and southern hemisphere have
intensified. Otherwise there hasn't been much change.

Pressure anomolies for past month
The main change on this month's anomaly map is the lowering of pressure over
Canada. There has been an intensification of the High between French
Polynesia and South America. The low zones in the southern hemisphere have
all shifted east. Despite all those lows seen in the daily weather maps over
NZ, the Tasman sea is only slightly below normal here.

Zooming into the NZ area
Maps show that the subtropical ridge around NZ has shifted north, and
pressures have relaxed around the equator, relaxing the trade winds. Highs
have intensified to over 1025 in Indian and East South Pacific Ocean and
isobars over the Tasman Sea /NZ area have dropped around 5hPa.

TROPICS

The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

clip_image012

Cyclone Nine is off the Mexican west coast, going NW. There are also areas
of potential development around China Sea. Micronesia, and central Atlantic.


WEATHER ZONES

SPCZ

The SPCZ stretches from PNG across northern Vanuatu then weakens further
east, but also stretches from near Samoa to near French Polynesia. This
branch CZ is expected to travel north until mid-week and then form a low L3
to south of Tahiti and then L3 and CZ should travel to SW. Best time to
depart Tahiti is mid-week.

Trough over New Caledonia today expected to travel east onto Fiji area by
Wednesday and towards Southern Cooks by weekend.

HIGHS and LOWS

High H1 expected to stay quasi stationary somewhat south of Tahiti and east
of NZ. Squash zone expected between H1 and L3 from mid-week.

Wintry low L1 to west of South Island is expected to travel NE across
northern NZ by Tuesday and then off to the southeast.

L2 is expected to form near Norfolk Island around Wednesday and travel east
along 30S.

H2 is expected to travel east across Tasmania by Wednesday and onto NZ by
weekend followed by a trough early next week.

L2 may help foe sailing from Aus to Noumea from mid-week.

For good voyage from Opua may need to wait until after L2.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more detail for your voyage, then check metbob.com to see
what I offer.
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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
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

31 July 2022

Bob Blog 31 July

Bob Blog 31 July
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 31 July 2022

Nature abhors a void "Horror Vacui"

This was the level of understanding prior to Galileo who in 1632 published
his Dialogue Concerning the Two Chief World Systems
(en.wikipedia.org/wiki/Dialogue_Concerning_the_Two_Chief_World_Systems)

The following year this book was condemned by the Vatican but praised by
Evangelista Torricelli, one of his young students (then 25 years old).

Evangelista was the son of some poor textile workers, and was sent as a lad
to his uncle, a monk, for training. At age 16 his father died, and his uncle
sent him to Rome under the tutelage of Benedictine monk Benedetto Castelli.
Castelli was a student of Galileo and also entrusted by Pope Urban VII with
hydraulic experiments. This combination is what led him to the invention of
the barometer in 1643. His name lives on in the naming of the metric unit
for absolute pressure TORR.

Here is how Torricelli invented the barometer. Galileo observed that a
common suction pump could not raise water to a greater height than about 10m
(32 ft). He considered that the "abhorrence" was limited to 32 ft and
discussed this with Torricelli. After Galileo's death in 1642 Torricelli
asked what if we live in a "sea of air" that has weight and exerts pressure
like water. The suction pump lifts water up a tube - the piston closes off
access to air pressure at the top of the tube, but the air still pushes down
on the surface of the water outside the tube. This push causes the water to
rise until the weight of the lifted water equals the weight of the air push.

Now Evangelista had access to large vats of mercury in the lab basement
collected by students heating local rocks with Bunsen burners. He knew the
weight of mercury is 13 times heavier than water so that would reduce the
height of the lifted column from 10m to 76 cm. He asked a glass maker to
produce a glass tube about a quarter of an inch in diameter and 4ft. long,
and hermetically sealed one of its ends; he then filled it with mercury and,
applying his finger to the open end, inverted it in a basin containing
mercury. When he released his finger, some mercury sank into the basin, but
a column remained in the tube nearly 76cm (30inches) above the surface of
the mercury in the basin. Also, at the top of the tube was a vacuum, the
first ever humanly produced sustainable vacuum, which is now called the
Torricellian vacuum. This experiment is sometimes known as the Torricellian
experiment.


The following year he wrote up this experiment in a letter to Cardinal
Michelangelo Ricci that "We live submerged at the bottom of an ocean of air"

He died 3 years later maybe from typhoid.

A thorough write up on this experiment can be found at
galileo.imss.firenze.it/vuoto/eprota.html
(Original is in Italian but has an English translation).

Stay tuned to see how this led to the barometer and then to weather
forecasting.

TROPICS
FRANK and GEORGETTE are west of Mexico and SONGDA is near Korea.

WEATHER ZONES
The SPCZ is active in the Coral Sea to Vanuatu.
Convergence zone slow-moving near Fiji on Monday and Tuesday.
A convergence zone CZ is expected to linger between Samoa and Just south of
French Polynesia.
A passing trough is expected to form over New Caledonia on Tuesday and then
travel east forming L1 between Fiji and NZ on Wednesday. L1 then moves SE
and fades. Avoid L1. Associated trough crossing Fiji/Tonga at weekend.
OK to travel from Tahiti to Fiji this week but take a northern path to avoid
the heavier swells in the south, and maybe aim to cross that CZ near Samoa.

HIGHS and LOWS
High H1 across northern NZ on Monday expected to travel east along 35S with
a squash zone at around 25S.

L2 is deep in Australian Bight early this week and expected to travel east
along 45S reaching southern NZ by end of week. Constant moist NW winds for
NZ Alps this week, strong until mid-week.

H2 forming in Tasman Sea by mid-week is expected to cross northern NZ this
weekend.

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

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