Bob Blog 20 Feb

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 Sunday 20 February 2022
TC DOVI passed over Waikato to Gisborne on Sunday20 Feb
The storm brought waves to 7m as measured by a MetOcean buoy off Taranaki
See
metocean.co.nz/news/2022/2/15/drifting-wave-buoy-rides-the-waves-of-cyclone-
dovi
TROPICS
We have had a "quiet" time in the tropics since TC DOVI and indeed are now
"between MJO episodes".
In 1971 Roland Madden and Paul Julian discovered a pulse of extra energy
that forms in the Indian Ocean and then travels eastwards along the tropics
across Indonesia/Northern Australia to the Pacific Ocean, fading away near
180 degrees longitude. It is a regional scale coupling between atmospheric
circulation and tropical convection. Now called an MJO/Madden Julian
Oscillation, it is known to increase the risk of cyclone formation and can
be tracked by watching cloud and rain patterns, taking a week or two to
transit each area. So, each MJO lasts around 30 to 60 days.
A good site to see its extrapolated trend is
www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foregfs.shtml, scroll down
to Ensemble map of the OLR (outgoing long wave radiation) anomolies for the
next 15 days in 5-day steps. Here, blue is bubbly and yellow is mellow. At
present the next MJO is building in the Indian Ocean and expected to reach
Papua New Guinea in around 15 days near 8 March.

So, with some hand-waving, this shows that the next two weeks across the
South Pacific is likely to remain "quiet" and then by around mid-March the
risk of cyclone formation is likely to rise. The next two weeks is likely
to be a good time for those who are planning to do some Island hoping,
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

The Indian Ocean continues to bubble up cyclones and the latest is EMANATI
following two recent cyclones to Madagascar. ANA and BASTRATI.
A tropical low L1 s expected to form over Fiji/Tonga mid-week and then
deepen as it moves southeast out of the tropics by end of the week.

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
The SPCZ is less active than last week relaxing after a few heated weeks. m
Vanuatu/New Caledonia to Fiji. A trough forming over southern cooks and
south of there by mod-week is expected to drift westwards later in the week.

HIGHS and LOWS
High H1 moving across NZ on Monday and then east along 45S.
Low L2 in South Tasman Sea on Monday going southeast, and its associated
trough should cross NZ on Tuesday and Wednesday.
Then HIGH H2 is expected to travel east from South Australia along 45S to
reach the South Island this weekend.
Subtropical ridge is strong along 40 to 45S with trade winds north of 35S
making Trans-Tasman travel OK this week.
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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 64277762212
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