Bobgram 20 April

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 20 April 2025
Ten Tips for Weather Comms while Cruising South Pacific
TEN TIPS FOR CRUISING SAILORS
Now that cruising sailors are on their final preparations for
departing New Zealand for the warmth of the tropical Islands, 'tis is
a good time to review the ways to obtain weather forecasts and/or
provide position reports when at sea.
1. ZLM/Taupo Maritime Radio offer a continuous 7/24 Trip
reporting service, see
www.maritimenz.govt.nz/about/what-we-do/safety-and-response/maritime-r
adio.asp
The HIGH SEAS forecast for the area SUBTROPIC from MetService is read
out in English via ZLM at 0903hr, and 2103hr NZST/NZDT on 6224 and
12356KHz and repeated an hour later on 8297 and 16531 KHz.
(www.metservice.com/marine/radio-schedule)
NZ MetService ceased their ZKLF Radio fax 1 July 2023
Australia's Bureau of Meteorology still sends weather maps by HF Radio
fax. The nearest transmitter to the South Pacific is VMC in
Charleville, schedule is at
www.bom.gov.au/marine/radio-sat/radio-fax-schedule.shtml
2. Gulf Harbour Radio ZMH286 check in service with weather.
Patricia and David keep track of boats that listen to their
rollcall/weather service. Firstly, contact them via email or radio
with your details - boat name, MMSI, boat type and length. Then let
them know when you are about to take off and whether you will be on
air each night. They operate on 8752USB at 0515 UTC which is 5:15pm
NZST and an hour later during daylight saving, 6:15pm. Each broadcast
is live streamed so friends and family can hear your check in and
follow along. David gives a weather update each night for the passage
routes and the islands. And there are articles of general interest and
specifically on weather in their web site, www.ghradio.co.nz
ghradio@xtra.co.nz
3. Passage Guardian passageguardian.nz
peter@passageguardian.nz
Passage Monitoring is operated by Peter Mott and provides a global
free-of-charge service (donations welcome) that monitors the progress
of recreational vessels conducting ocean passages.
Peter uses a range of tools, including satellite trackers, AIS and
email, and multiple maritime radio frequencies to keep a constant
watch on yachts that have filed a float plan prior to departure. The
service has a formal policy for dealing with a missed check in.
Whilst available to all yachts, Passage Monitoring is especially
suited to shorthanded and solo sailors, in particular
circumnavigators.
4. AMATEUR RADIO/Ham net: PACSEANET pacseanet.gmail.com
The Pacific Seafarers Net is a ham (amateur radio) network providing a
free of charge check in service on amateur frequency 14300KHz USB in
the 20-metre band at 0300UTC. To participate, operator needs to hold
an Amateur Radio Operators Certificate (General class or above). In
the amateur radio service, the callsign is assigned to the licensed
operator, so this is a different callsign from using a maritime
callsign. Position reports are received and reported in the well-know
YOTREPS format (but missed calls may not be followed up). They have 12
listening station dotted between Australia and Alabama. See
pacseanet.blogspot.com
5. EMAIL via HF requires a PACTOR modem See
https://sailmail.com/

6. INTERNET via EMAIL
if you only have email, Saildocs (saildocs.com) relays details of a
TEXT BASED webpage. See weather.mailasail.com/Franks-Weather/Home
They allow you to download, e.g., the latest Fiji Met Service High
Seas by sending an email, no subject necessary, to query@saildocs.com
with message: SEND http://www.met.gov.fj/aifs_prods/10140.txt
For a list of useful links see https://www.y2ksail.com/meteo-link.html

7.. Fiji Fleet code. How to download a map via HF (thru email)
This is real old school stuff, but it still works if you need it.
To download the latest Nadi Fleet Code, send an email to
query@saildocs.com, no subject needed, saying SEND nadi-fleetcode
Or SEND https://tgftp.nws.noaa.gov/data/raw/as/asps20.nffn.txt
This can be viewed within the Fleet Code plug in OpenCPN.
Download this at opencpn.org/OpenCPN/info/downloadopencpn.html
Open the email and select and copy the data (right click, Contral A
then Control C on a PC). Then, in OpenCPN's Fleet code plugin, there
are 4 options: Files, Text, Raw and Downloads. Select Raw and then
<paste> or CTRL-V and Voila! the map appears.
I still have a copy of the old, no longer supported Fleet code viewing
program call Phys Plot. If you want to try it, let me know.
8. Smart phone apps: Some satellite phones now provide Wi-Fi that
allow nearby smart phones to use apps.
www.predictwind.com provides an app that supplies forecast model
data, observations and, at the Professional Account level, tools for
routing and comparing departure dates. It also has a position
tracking tool and can help with iridium Go! and some other GPS
devices. A moderate subscription gives access to its universal AIS
package with a regional search option.
9. The Windy.com App has a free basic option. It also has a
subscription option that can be used to compile route plots.
To make one: - "right click" anywhere on the map, this will open a
small context window. - choose "Distance & Planning"; - place your
points on the map; chose 'Boat' and enter your average likely speed,
click on "more options" bottom left and in the "table of points" you
just made, click the button label "share" in the bottom right corner;
- remember and use the short URL link provided or the long URL in the
top of your browser. You can also make one by building the URL
manually if you are familiar with this. Each time you plug this URL
in your browser, Windy will show the map and your planned route.
Shift the start time to see which gives the best voyage.
10. YiT, Yachts in Transit, at www.yit.nz or mike@yit.nz has a
smart phone app, and offers a subscription service to plot your
reports and blogs on the web and to request weather information via
coded emails. They also provide info on how to use iridium Go!, YB
Tracking, or Garmin inReach for communications. This site was closed
for a while but is back again this year.


TROPICS
The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is from
www.ospo.noaa.gov/products/ocean/tropical/tcfp/

There are no named Topical cyclones around at present. Tropical
Depression 31 is heading for top end of Queensland.
Cyclone Errol exploded in strength to Category-4 force between Bali
and northwestern Australia. It drifted southeast-ward and weakened
before striking the Australian coast near Broome during the following
week. Tropical Storm Tam drenched much of the Vanuatu archipelago
without inflicting significant damage. But its remnants later knocked
out power and triggered local flooding across New Zealand's North
Island.
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)




Wind accumulation shows a demarcation line along the SPCZ. Also, the
track of L1 leaves a wind trail.

Rain accumulation this week from Windy.com shows heaviest rain may be
near northern Australia and along the SPCZ. A dry slot between BZ and
Fiji/Tonga.


LOWS and HIGHS
The remains of Cyclone TAM are finally moving across N Z on Monday.

The High H1 south of Tahiti and near 35S is quasi-stationary this
week and shepherding a small Low L1 from near Kermadecs southwards
then southeast-wards bringing a southerly flow to NZ on Tuesday, an OK
pattern for departing Northland for Fiji/Tonga.

However, by mid-week small lows on the SPCZ may form, L2 near southern
Cooks and L3 near Vanuatu.
L3 can make for stronger E to NE winds in area north of NZ by the
weekend so if you are unable to make a Tuesday departure from NZ then
for comforts sake it may be better to wait for next agreeable pattern
High H2 from Aussie Bight is expected to cross southern Tasman Se and
central NZ on Thursday and Friday then build east of NZ this weekend
with a squash zone on its northern side.

Gulf of Panama: Light winds until local Monday then useful NE winds
for several days
5N to Galapagos: The convergence zone with squally showers and light
winds in-between them is from 6N to 2N. Light south to southeast winds
around Galapagos.
Current around Galapagos is mainly from SE. Avoid the HEAD current
near 5N 83W
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If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
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Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
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