Bobgram

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 29 Mar 2026

Cyclone NARELLE formed on Saint Paddy's Day and continued to PALM Sunday
Reminds us of another waltzing Matilda -type cyclone called STEVE in the
year2000:

The WMO released their latest "State of the Climate" report to mark WORD
METEOROLOGY DAY WMD last Monday (I celebrated WMD with a toast to
meteorologists everywhere-the weather knows no boundaries).
wmo.int/publication-series/state-of-global-climate/state-of-global-climate-2
025

The main statement in this report is that our planet now has an energy
IMBALANCE -it is trapping more energy from the sun than it is emitting, and
this imbalance is increasing.




TROPICS

NARELLE and last week's tropical depression near Vanuatu have reduced that
cyclone formation potential from the South Pacific Convergence zone There
are no named cyclone on the weather map tonight. However, there is an
interesting zone of high cyclone formation potential now near the Southern
Cooks

WEATHER ZONES

The remains of NARELLE are now moving off to the southeast into the Southern
Ocean.
L1 and its associated fronts developed last few days as an east coast low
off Sydney and is crossing New Zealand tonight and Monday then moving off to
the southeast followed by High H1 bringing NZ a good start to easter.
At the same time High H2 brings a settled Easte to Southeast Australia.
Note that H2 is expected to move inland for a while--- previous highs have
been taking the summer path across the Australian Bight. but now that we
have had the Equinox , the nights over the Australian deserts are longer
than the days. leading to cooler denser air which can support the higher
hectoPascals.
After a brief trough over NZ on Saturday and Easter Sunday, High H2 brings
NZ some more settled "Indian Summer" weather just after Easter.
Lurking in the tropics is another Low L2 forming during Easter between
Vanuatu and Fiji/New Caledonia. The models are still differing about its
future scenarios. more about that next week


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Bobgram

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 22 Mar 2026
EQUINOCTUAL CYCLONES
The Equinox was yesterday morning (New Zealand time).

Cyclone NARELLE formed west of Vila last week and since then has been
travelling west.

We now have depression 98P forming in the same place, and it is forecast to
go south this week


TROPICS


Cyclone Narelle spun up over the northern Coral Sea and intensified to cat 4
when making landfall over Cape York peninsular and cat 5 in Gulf of
Carpentaria and is expected to build again in warm seas off northwest of
Australia.
98P is expected to deepen to below 985hPa when it enters the central Tesman
sea by Thursday. This is a good recipe for lowering pressure. take warm
moist air (low density) from the tropics and send it into cooler conditions
(denser air). The less dense air gets raised up high and vented off by
strong winds aloft. when the conditions for this are set up, air is removed
from the system so that its surface pressure lowers (more isobars) and that
squeezes the isobars togethers. more wind.

WEATHER ZONES
Cyclone NARELLE is expected to continue around Aussie coast and deepen again
when over the sea. I suggest that you save its track-a lot will be written
about it in the future.
L2 comes out from the north end of a southern trough. Its associated
convergence zone is expected to bring squalls mainly between Samoa and
Tahiti this week.
HIGH H1 has given a period of "Indian summer" weather to New Zealand with
sunny afternoons but overnight dew or mist. It is moving away and fading
next few days.
L1/98P is expected to bring a period of wet/windy weather to the North
Island on Tuesday night to Thursday as it travels south, and to South Island
on Friday--- possibly with a secondary low forming east of Sydney bringing
them a southerly buster.
H2 is expected to slowly travel east across the Aussie Bight reaching
Tasmania this weekend.

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If you would like more details about your voyage, check metbob.com
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(subscribe/unsubscribe at bottom).
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Contact is bob@metbob.com or text 64277762212.
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Bobgram

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 15 Mar 2026
Outlook for April
The internet is abuzz with several commentators reporting that there may be
a switch to an extreme El Nino later this year. For now, relax.
Indications are that, during April and into May, the Tasman Sea /New Zealand
area weather is likely to be close to normal.

Our friends at tropical tidbits.com mainly watch tropical cyclones. They
also give access to some climate models which show outlooks for the month of
April based on current trends.
These are called anomalies and they indicate how this April may vary from
normal.

The map has isobars which show the averaged weather forecast for April. In
April, on average, the west-southwest winds of winter reach as far north as
Cook strait, and a High centred near the Australian Bight noses a ridge of
relatively light winds onto the Bay of Islands. Daily weather pattern
shuffle around this idea.
The anomalies show expected difference from a normal April. Papua New
Guinea is above normal --- but only by small amounts. And between Solomons
and Tonga are below normal. Since these are over a low-pressure area (the
South Pacific convergence zone) and this is expected to be accentuated in
April.

Indeed, when we look at the forecast rain anomalies for April:
New Guina highlands are pointing to extremely dry condition. And from the
Solomon Islands to Tonga there is an accentuated South Pacific convergence
zone. A dry zone over Tasman Sea and New Zealand indicates this area may
have light winds and sunny skies that linger in autumnal anticyclones (an
Indian summer).





TROPICS

It has been a quiet week with no named storms.
There OLR trend shows that, for the south Pacific, the next few weeks may be
sunnier than normal (yellow) and so the risk of cyclone formation may be
lower than normal.


WEATHER ZONES
For the New Zealand area: On Monday and Tuesday High H1 travels across
central areas. On Tuesday, Low L1 is expected to form on a trough crossing
Tasmania and then travel southeast on Wednesday past southern New Zealand.
From Wednesday to Saturday Low L2 is expected to deepen over the Kermadecs
and then travel off to the SE sideswiping east coast of North Island. After
Saturday the next High from the Australian Bight is expected to travel
across central New Zealand.


In tropical areas, the SPCZ os expected to be active between the Solomon
Islands and to south of Fiji.
A tropical low L3 may form on Thursday in the Coral Sea and then travel
west into the Gulf of Carpentaria.
Another low L4 may form off west Australian coast and fade as it goes
south.


In my illustrated edition is a diagram that shows a week of rain
accumulation around the equator.

Normally the ITCZ sits between 3N and 10N, but during March another
convergence zone forms south of the equator. I call this a mirror ITCZ. I
think it forms because during March these of the latitudes of the direct
overhead Sun. This month the sun will be directly overhead the equator at
Friday 20 March at 14:46 UTC (early Saturday for Fiji and New Zealand).

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If you would like more details about your voyage, check metbob.com
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(subscribe/unsubscribe at bottom).
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Bobgram

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 08 Mar 2026

The rate of global warming jumped in 2013.
A recent publication in  Geophysical Research letters as at
agupubs.onlinelibrary.wiley.com/doi/10.1029/2025GL118804
by G.Foster and  S.Rahmstorf   have removed from the temperature records the
three main natural variable factors ( El Nino, volcanism and solar
variation) 
to produce smoother trends. This smoothed data shows there has been an
acceleration in warming with a notable jump around 2013.

There is an observable increase in the Earth's energy imbalance,
as detected by the CERES project and published at
berkeleyearth.org/global-temperature-report-for-2023/

TROPICS
Cyclone Urmil passed over the open waters of the Pacific, well to the south
of Fiji and Tonga. • An unnamed tropical storm formed south of Java.

WEATHER ZONES
For the New Zealand area: On Monday, the front attached to L1 is expected to
be followed by cold southerly conditions.  Then Tuesday to Thursday should
have light winds with the passage of H1 .  Then another front on Friday
attached to L3 followed by SW winds.

For Northern Tasman Sea and Queensland to Kermadecs: That tropical Low L2 is
expected to track steadily from 20S to 30S with strong winds and heavy rain.
Avoid.

For other tropical areas: this is expected to be a relatively quiet week.

For South half of Australia:  That monsoonal trough last week combined with
that front attached to L1 and brought heavy rain to Adelaide area.   This
week's front is expected from Tuesday to Thursday attached to L3 and is
expected to be followed by strong SE winds and 3m swells as far north as
Lord Howe by Friday 13/Sat 14 March.  Then High H3 should spread across
Aussie Bight bringing easterly flow to Australia.  

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If you would like more details about your voyage, check metbob.com
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Contact is bob@metbob.com or text 64277762212.
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Bobgram

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 22 Feb 2026
A review of last month's weather
Here is a link to a YouTube clip giving an animated loop of the isobars and
streamlines
For the month of January is at youtu.be/dF205bOjbXI
New Zealand had damaging weather on 14 to 16 February.

The 500hPa heights and anomalies shows that prolonged upper low over Tasman
sea late in the month
From http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.shtml

Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
The waters over eastern equatorial Pacific are now near normal.
The warm patch between Tonga and New Zealand is relaxing.
The cool (dry) zone in the mid Indian Ocean is moving onto western
Australia.

Average isobars for past month (below)
From http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
Apart from that deep depression over New Zealand during mid February, the
remainder of the month was close to average. Overall the monthly isobars
show a return of the subtropical ridge to normalcy.
The low pressure band over the Aleutian Islands has also relaxed.


Pressure anomalies for past month (below)
From https://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
The anomaly pressure pattern for last month shows a weakening of the
negative anomalies over Australia and New Zealand. Also the replacement of
Highs between Australia and Antarctica with lows.
The 1015 isobar has reurned to the Tasman Sea.





TROPICS
URMIL is now south of Fiji and moving off to the southeast. The area of
high potential placed over the South Atlantic looks to be an erroneous
artifact.
Cyclone Horacio underwent unprecedented intensification in the Indian Ocean
while narrowly missing the island of Rodrigues. It went from a tropical
storm to a Category-5 cyclone in less than 24 hours, producing sustained
winds of 161 mph as the year's most intense storm so far.

WEATHER ZONES

The remains of URMIL (or L1) are expected to continue SE and then south
whilst a cold front and southerly change spread north on Monday forming L2
east of North Island by mid-week and the L1 and L2 should move off to the
east.

High H1 is then expected to travel northeast then east across New Zealand,
whilst High H2 travels east across the Aussie Bight.

In the tropics further lows are expected to form. L3 may move from Coral
Sea onto Cairns late this week. Low L4 may move to southwest off the
northwest end of Australia.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
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 text 64277762212.
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