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 12 October 2025

The coming cyclone season

NIWA of NZ have issued their annual outlook for the coming cyclone season.

The main tropical climate driver at work is a "weak La Nina" pattern. Thia is likely to be augmented by the recent Stratospheric warming which may bring more wind to the Tasman Sea area until December, perhaps leading to stronger shearing forces in the tropics, which tend to prevent tropical cyclones from "winding up".

Here is NIWA's Cyclone forecast-- fewer cyclones than normal.
Greatest risk is in the Vanuatu /New Caledonian area with 3-4 cyclones likely.

SOLAR POWER IS NOW CHEAPEST

Solar energy is now so cheap it costs as little as €0.023 to produce one unit of power, a new study has found.

Solar energy has been branded the "key driver" in the world's transition to clean, renewable power due to its ultra-low cost.

A new study from the University of Surrey named solar energy the cheapest source of power, outranking other renewables such as wind, as well as coal and gas.

Researchers found that, in the sunniest countries, solar costs as little as €0.023 to produce one unit of power.

Even in the UK, which sits 50 degrees north of the equator and is infamous for its dreary weather, solar came out victorious as the cheapest option for "large-scale energy generation".

Due to the price of lithium-ion batteries falling by 89 per cent since 2010, the study also found that making solar-plus-storage systems is now equally as cost-effective as gas power plants.

See www.euronews.com/green/2025/10/08/

TROPICS


One named storm is active tonight

In the past week….

•Hurricane Priscilla lashed western Mexico with pounding surf and strong winds before its remnants drenched northwestern Mexico and the southwestern United States.

• The northern Philippines and far southern China were lashed by Typhoon Matmo.

• Category-4 Halong passed just off eastern Japan.

• The Leeward Islands were brushed by strengthening Hurricane Jerry.

• Category-1 Cyclone Shakhti churned the northern Arabian Sea.

WEATHER ZONES

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

Rain accumulation this week from Windy.com below shows well defined SPCZ between Solomon Islands and Samoa and another convergence zone between Loyalty Islands and Fiji.

Wind accumulation from windy.com below shows some squash zones in the tropics one between New Caledonia and south of Fiji.

LOWS and HIGHS

HIGH H1 at 35S south of French Polynesia is moving off to the east allowing a procession of weather systems to flow eastwards this week.

Front associated with LOW L1 in this procession is crossing North Island on Tuesday and then travelling off to the southeast.

Another Low is expected to travel from Southern Ocean to the NE in wake of L1, reaching Chathams area by Friday, and maybe bring a brief southerly change to Northland next Sunday night.

HIGH H2 should cross northern NZ on Thursday to Saturday bringing a lull along 30S S

Next front across Northern NZ is expected on Tuesday or Wednesday 21 or 22 October.

One model is starting to have the idea of forming a tropical trough in the Coral Sea late this week and taking this to northern NZ mid next week. So far this is only an idea, but it might grow to be a threat so is a risk.

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