Bob Blog 16 April

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 April 2023

Climate change

We've done it.. Reached the warmest daily average ocean temperatures since
reliable world-wise measurements began in the 1980s:
(as recorded at climatereanalyzer.org/clim/sst_daily/) The previous warmest
was during the El Nino of 2016.

Review of the Cyclone Season
The Madden Julian Oscillation MJO is a burst of tropical energy that travels
from the Indian Ocean to the Pacific Ocean. It takes a week or two to travel
across each region and is associated with the formation of tropical
cyclones. However, this association doesn't work every time.
As a proxy for following the MJO a good parameter is outgoing longwave
radiation as measured by satellites. This is high with clear skies and
lowest when clouds are thickest. The chart is from the Climate Prediction
centre website cpc.ncep.noaa.gov/ shows three MJO events during the cyclone
season.

In New Zealand we will long remember the damage from Cyclone Gabrielle
(payouts so far of $0.9billion), Cyclone HALE and the many downpours. On
Valentine's Day 14 February a national state of emergency was issued in New
Zealand and there were 10 storm-related deaths.
And yet, as cyclone seasons go, the South Pacific region had been somewhat
average with 5 (maybe 6) named storms and just one Category 5 (Kevin) and
one Category 4 (Judy)

In the Australian region, by the numbers they had they had an average
cyclone season too with 10 named storms and two reaching Cat 5 (Darian and
Ilsa)

We can see no real association in the South Pacific region this year between
cyclone occurrence and MJO, but there is a plausible association in the
Australian region, especially during MJO2 and 3.

TROPICS
Tropical Cyclone ILSA grew to Cat5 before making landfall near Port Hedland
over NW Australia and took a couple of days to fade inland. There is an
interesting tropical depression tonight over Loyalty Islands, but it seems
to have missed its chance to become a tropical cyclone. This phase of MJO is
now moving across the Pacific.

WEATHER ZONES
South Pacific Convergence Zone SPCZ
A burst of convection is expected to travel east along the SPCZ across Fiji
and Tonga this week.
It has already produced a Low L1 that is expected to cross Iles des Pins on
Monday and then go south into the Tasman Sea later this week. It is expected
to form Low L3 that may deepen over Southern cooks by end of the week and
then go southeast this weekend. Avoid
Also in the tropics, a convergence zone is expected around Galapagos.

Zonal traffic in the mid-latitudes this week.
High Hi built to 1034 over Chathams Islands with a squash zone on its
northern side between H1 and L1. It is expected to travel off to the east.
Low L2 crossed Tasmania today and is expected to cross New Zealand on
Tuesday night and Wednesday following H1 and followed by H2.

Panama to Marquesas: Still getting northerly winds at Panama for departure.
Doldrums between 2north and 3 south with active showers around Galapagos.

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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.
Contact is bob@metbob.com or txt 64 277762212
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