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

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) as shown here in Science in Oct 1988


Robert FitzRoy

As a teaser for my upcoming blog of Robert FitzRoy I have been reading:” This Thing of Darkness” by Harry Thompson (thanks for the tip from one of my regular readers) and here is a quote from it after FitzRoy encounters a period of strong westerly winds off South America


Sea temperature anomaly, taken from



The latest cyclone activity report is at and Tropical Cyclone Potential is from


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


Maximum winds of NANMADOL next 5 days from


Weather Zones Mid-week GFS model showing isobars, winds, waves (purple), rain (red), STR (Subtropical Ridge), SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone) and CAPE (lime)


CAPE maps from EC and GFS for mid-week as see by, note the difference between models.


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


Rain Accumulation next five days from

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.


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.


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