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 June 2025
SOLSTICE and the state of Greenland Ice melt
The Solstice this weekend marked the longest day of the year in the northern hemisphere and the shortest in the southern.
At this time of the year the Pleiades cluster is visible in the eastern sky just before sunrise (so long night light is not swamped by a full moon). This is taken by Polynesians in the southern hemisphere to be the start of a new year. Their name for that cluster is MATARIKI. In New Zealand we celebrated MATARIKI with a Friday holiday and long weekend. Tahiti will celebrate its first Matari'i National Public Holiday in 2026. In Hawaiian culture, the star cluster is known as Makahiki and its rising is also considered the start of the new year for agricultural purposes.



After the solstice there is a thermal lag until ground temperatures reach their annual minimum. For the next six weeks we can say that when the "days get longer the cold gets stronger". In the northern hemisphere a similar heat lag occurs, and ground temperature do not reach their annual PEAK until "the dog days" when the dog star Sirus rises just before dawn. When stargazing, if you can find Orion's belt then look left and up to find Sirus and then look right and down almost twice as far to find Pleiades/Matariki/Matari'I/Makahiki.

So, we are just beginning to move into the period of maximum ice melt in Greenland.
Sadly, the data shows that we are already forming new maximum melt recordings.

See https://nsidc.org/ice-sheets-today
During a May heat wave Greenland's ice sheet melted 17 times faster than normal, according to a new report by World Weather Attribution. In Iceland, temperatures soared past 79 degrees, breaking records and straining infrastructure not designed for such warmth on the island.


TROPICS
Typhoon Wutip left at least six people dead in Vietnam from downpours and flooding. The storm also damaged crops on China's island province of Hainan. * The most active region for tropical cyclone development continues to be off Mexico's Pacific coast, with Tropical Storm Dalila passing offshore and Eric striking Acapulco as a Category-2 hurricane.

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

Rain accumulation this week from Windy.com shows a well-defined South Pacific Convergence zone from Solomons to Samoa.

Wind and rain accumulation this week from Windy.com show a storm on the back side of a low east of NZ. They also show an active squash zone between Niue and Tonga and then a tropical trough forming over Southern cooks after mid-week. Avoid.
LOWS and HIGHS
LOW L1 tonight has a 990hPa centre east of Auckland and south of Niue with gale winds near its centre. It is expected to move off to the SE.
HIGH H1 in central Tasman Sea is expected to also travel SE across north Island next few days mid-week. A squash zone of enhanced trade winds is expected between Niue and Tonga. Avoid.
Low L2 is expected to cross Tasmania on Tuesday and then stall over NZ from Thursday to Saturday..
HIGH H2 is expected to slowly spread across the Aussie Bight this week.

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