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 05 October  2025

A review of last month's weather
Here is a link to a YouTube clip giving an animated loop of the isobars and
streamlines in the South Pacific for the last month youtu.be/l4EARdhOSlo
Lows crossed NZ on12 and 24-25, with several stormy fronts in-between
The Low on 12 September t was especially squally and thundery:
The 500hPa heights and anomalies shows these Lows.
at http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.shtml

Sea Surface temperature anomalies  from psl.noaa.gov/map/clim/sst.shtml
The North Pacific "blob" is no longer as intense as it was in August.  North
Atlantic has warmed.  The warm area between Java and West Australia is a
NEGATIVE IOD (Indian Ocean Dipole)  
This evening's satellite and radar imagery shows this negative IOD at work

There was a sudden stratospheric warning over that part of Antarctica south
of Australia during past few weeks and this is likely to trigger outbreaks
of cold air due to a weak polar vortex. The parameter I use to watch this is
not being updated by NOAA at present due to "US Government shutdown".

TROPICS

Tonight there are 5 named storms.

In the past few weeks…
• Typhoon Bualoi left 20 people dead in the Philippines before unleashing
days of heavy rain in Vietnam, killing an additional 29.
 • Remnants of Hurricane Gabrielle brought high winds to Portugal, then
triggered flash flooding in eastern and southern Spain.
 • Hurricane Imelda sent pounding surf into the U.S. East Coast, while
Tropical Storm Octavia formed briefly off western Mexico.
• An unnamed tropical storm drenched India's central Bay of Bengal coast.

WEATHER ZONES
 Rain accumulation this week from Windy.com below shows well defined SPCZ
between Solomon Islands and Samoa  and almost drifting south onto Fiji. 
Also a passing trough for Minerva .

Wind accumulation from windy.com below shows some squash zones in the
tropics one to north of Fiji and one in the Coral Sea.  The strong winds
southeast of French Polynesia are associated with a passing trough.  Ther
strong wind trails near Philippines and west of Mexico are associated with
tropical cyclones.

LOWS and HIGHS

Front associated with LOW L1 is crossing New Zealand on Monday and then
travelling off to the southeast.
 HIGH H1 is travelling east along around 30S and crossing northern NZ on
Tuesday/Wednesday.
A warm front is expected across Northern NZ on Sunday 12 Oct  followed by a
cold front around Wed 15 Oct.

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