Bobgram 9 Nov

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 09 Nov 2025
Things missing from marine weather forecasts

Marine forecasts give a situation statement that lists the location o=and
movement of features seen on weather maps. Highs, Lows, Convergence zones
and fronts. The give warnings of areas with gales or stronger, heavy swells,
and freezing conditions.
There are two things they don't give, but sailors would like to know about.
to know about.

1) Lightning
2) Sunburn

1)If you have access to Internet and web sites then windy.com and
Predictwind.com do include lightning maps
The Predictwind map combines lightning and satellite imagery with the GMDSS
(Global Maritime Distress and Safety System) warning and situation maps

From forecast.predictwind.com/satellite-imagery/
Turn lightning on in the map options.

Windy.com offers several global models and displays their wind, isobars,
rain and lightning on the same map along with observations.
For people visiting the cruising grounds of New Zealand Weatherwatch have
compiled a special page for lightning
www.weatherwatch.co.nz/maps-radars/lightning/thunderstorm-risk
Combining observations from Blitzortung and MetService (coming soon) with
a CAPE
(Convective available potential energy) and SLI (Surface lifted index) and
the latest MetService Thunderstorm outlook.

This can be a useful place to check before sailing.

2). The NZ atmosphere has less haze that other places and thus higher UV.
As for the intensity of the sunburn, Earth Science NZ has put together the
following web page
niwa.co.nz/atmosphere/uv-and-ozone/uv-and-ozone/todays-uv-index

This can be used retrospectively. SO, if you do get sunburnt then check
this site and it shows the measured UV compared with the predicted UV cloud




TROPICS


Tonight there is 1 named storms, FUNG-WONG approaching Taiwan


In the past week.
. At least 140 people died during catastrophic flooding in the central
Philippines from Typhoon Kalmaegi, one of the strongest to hit the country
this year.
. Typhoon Fung-wong formed between the Pacific islands of Guam and Yap



WEATHER ZONES
Rain accumulation this week from Windy.com below shows well defined and
increasingly active SPCZ mainly in the north but visiting Fiji and Tonga at
times.

Wind accumulation from windy.com above shows even winds in the tropics, but
for a squash zone over southern parts of French Polynesia and wind
associated with L1.
Also, the Tasman Sea is windy, but elsewhere the wind zone is drifting to
the south.


LOWS and HIGHS
Low L1 East of Kermadecs is moving slowly to southeast whilst HIGH H1
travels quickly east along 43S.
The Trough and Low in the Tasman sea tonight is expected to travel east
across NZ on Monday and leave behind a low L2 that forms over Lord Howe area
on Tuesday and then travels east across NZ on Wednesday and Thursday.
HIGH H2 is expected to travel across Aussie Bight early this week and then
go northeast from New South Wales to northern NZ by the weekend with a
westerly flow on its southern side.
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If you would like more details about your voyage, check metbob.com
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 text 64277762212.
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