Bob Blog 7 Oct

WEATHERGRAM

YOTREPS

Compiled Sun 7 Oct 2018

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.

I know that I wrote last weekend telling you there may be not be a weathergram today,

but I managed to find time after a kava session this evening, washed down with Octopus and cassava .

TROPICS

The number of tropical features has decreased during the past week.

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Map of current storms is from tropic.ssec.wisc.edu/

The remains of LESLIE are heading for the UK.

SERIGO is heading to make landfall in Baja California.

And KONG-RAY is moving off to east of Japan.

Looking at the weekly rain maps, last week’s shows a drop in activity around Solomon Islands and Micronesia, otherwise little change.

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See: trmm.gsfc.nasa.gov/trmm_rain/Events/big_global_accumlation.gif

WEATHER ZONES

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Weather Zones (see text) as expected Wednesday 00UTC showing isobars, winds, waves(magenta), STR, and SPCZ. Pink area = lightning likely (high CAPE)

SPCZ=South Pacific Convergence zone.

The SPCZ is sitting over Solomon Islands and expected to spread SE towards northern Vanuatu on Monday and then across Fiji on Tuesday in a coming-and -going fashion, and linger there until next week. By late Wednesday a trough should form south of Fiji, to around 30S, and this is expected to travel southeast so that it merges with the eastern side of a low from the Tasman sea crossing NZ on Friday then moving off to east of NZ. The convergence zone is likely to linger over Fiji in a stop and go fashion.

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Accumulated rainfall for next week from windyty.com. CZ= convergence zone.

Subtropical ridge (STR)

HIGH weakening over northern NZ on Monday is expected to travel east along 30 to 35S reaching 140W/French Polynesia around Sat 15 local

This HIGH is NOT expected to have sufficient intensity to build a zone of strong easterly trade winds on it northern side. SO, note that is looks OK to venture from Tahiti to Tonga this week.

Next HIGH is expected to move in from west to south Taman Sea from Friday 12 Oct.

This should start to fade over northern NZ by Monday 15 Oct.

Between Tropics and Tasman/NZ/Aus.

Front/trough between Highs is expected to travel onto western South Island by Tuesday and deepen into a Low visiting northern NZ around Fri 12 Oct, and then move off to the East-south east. Avoid.

To avoid the southerly winds following this trough arrange departure from Tonga or Fiji to be after Fri 12 Oct.

  From New Caledonia to NZ a departure after 9 October may work OK.

From New Caledonia to Australia

Weather is looking OK for a voyage from New Caledonia to Australia this week.

From Tahiti to Tonga

With a HIGH travelling slowly just south of this route, this is a good week to do this voyage. Note that a departure after 11 Oct may have an encounter with a passing trough and a period of changing winds on west end of voyage.

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If you would like more detail for your voyage, then check metbob.com to see what I offer.

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 txt 6427 7762212

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