Bob Blog 5 March

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 5 Mar 2023

REVIEW OF THE LAST MONTH (February 2023)

Here is a link to a YouTube clip giving an animated loop of the isobars and
streamlines in the South Pacific for February 2023

youtu.be/G-N1Km9_pR4

Feb 2023 will be long remembered for Cyclone GABRIELLE (mid-month) over
Norfolk Island and Te Ika o Maui / North Island. The South Pacific
Convergence zone drifted south into the Coral Sea and formed GABRIELLE and
JUDY (then KEVIN in early March).

Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
The cool waters of La Nina continue to relax. A marine heat wave continues
to affect southern NZ, especially Fjordland, bleaching the coral there.
There is also a marine heat wave around the Falklands. Since these hotspots
are 180 deg longitude apart this suggests there may be a connection between
them and stalling of atmospheric wave 4.
Indeed this has been studied and seems to be valid . See
www.nature.com/articles/s41467-021-25160-y

Average isobars for past month (below)
From www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
The northern subtropical ridge has shifted north onto central Europe and
intensified in the North Pacific. The southern hemisphere pattern is much
the same as last month despite the daily drama. In February Canada is at its
coldest and storm paths encourage snow/ice storms across USA but in 2023
there were two dramatic storms.

Pressure anomolies for past month (below)
The anomaly pattern also shows the shift and intensification of the northern
subtropical ridge, as well as several subtle changes.

TROPICS

The positive boost of the MJO cycle that has been affecting the Western
Pacific over past few weeks is expected to fade away over next two weeks
allowing the South Pacific Convergence zone to return to normal.
FREDDY reformed over the sea and is expected to make another landfall onto
Mozambique this week.
JUDY and KEVIV ploughed thru Vanuatu last week,
and KEVIN is expected to sideswipe southern Tonga tonight.
The potential for development across the Coral Sea remains above normal, and
something just may brew there next weekend.

WEATHER ZONES
South Pacific Convergence zone SPCZ
The SPCZ is expected to remain active from Solomons to Fiji and another
convergence one is expected to remain active across Cook and Austral
Islands. A tropical low may form in the Coral Sea at the end of the week.

HIGHS and LOWS
TC KEVIN or L1 is expected to continue to the SE and remain this week as a
large low well east of NZ.
High H1 in the south Tasman Sea starts the week by feeding cooer SE winds
onto NZ,
and then travels slowly north across the country bringing a few sunny days,
and then moves off to the east along 30S
allowing a trough to reach NZ by Friday
preceded by NW winds and followed by southerlies.

Mainly easterly winds across the north Tasman Sea this week should help
voyages to the Brisbane area.

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If you would like more detail for your voyage, then check metbob.com to see
what I offer.
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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 64 277762212
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