Bob Blog

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 Sun 25 Oct 2020

 

Southwest Pacific Tropical Cyclone Outlook

The NIWA and MetService assessment of named tropical cyclone (TC) activity indicates 8 to 10 named TCs could occur in the Southwest Pacific basin between November 2020 and April 2021.

We are having a La Nina. At present, sea surface temperature anomalies across the eastern equatorial Pacific Ocean are cool (negative) while the central equatorial Pacific Ocean has recently been trending toward cool conditions.

For the coming season, important differences are expected between the western and eastern halves of the Southwest Pacific basin and also for early and late season activity. Elevated TC presence is expected in and around the Coral Sea and north Tasman Sea, especially during the late season between February and April. Reduced TC activity is expected east of the International Dateline. The potential start to cyclone activity may occur close to or after the New Year.

New Caledonia is expected to get the greatest TC activity. Near normal activity is expected for Tokelau, Fiji, Vanuatu, the Solomon Islands and Papua New Guinea. Normal or slightly reduced activity is expected for Tonga, Wallis & Futuna, and Samoa.

For the coming season, the risk for an ex-tropical cyclone affecting New Zealand is considered above normal. If an ex-tropical cyclone comes close to the country, there is a near-equal probability of it tracking to either the east or west of the North Island, and landfall of a degrading ex-tropical cyclone is possible.

 

For more details, see

https://niwa.co.nz/climate/southwest-pacific-tropical-cyclone-outlook/southwest-pacific-tropical-cyclone-outlook-october-2020

 

The Tropics

Three active cyclones today, Saudel near China, Molave over Philippines, and Epsilon in North Atlantic. Zones of high potential for formation are around Micronesia and east-central America coastaround the Philippines and the Mexican East coast.

 

SPCZ is expected to stretch from Solomon Islands to Samoa then southeast to French Polynesia

Convergence zone/passing trough/low forming over Samoa by mid-week then travelling southeast to Sothern Cooks and maybe parts of French Polynesia.

 

HIGH 1030 to 1022hpa east of north Island near 160W drifting north and weakening away by mid week. Another High 1034 to 1026hPa travelling across South Tasman Sea at 50-S Monday to midweek, then weaker along east coast South Island, travelling to NE.

 

Front over South Island on Monday, weakening over North Island on Tuesday.

Low forming off Australian coast on Wednesday near 35S then going SSE to south of NZ by Fri, with a front over South Island on Friday.

 

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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 6427 7762212

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Bob Blog

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 Sun 18 Oct 2020

 

After 5 doses of radiology, I've been discharged from hospital and so I've returned to blog writing, for now. 😊

 

The Bureau of Meteorology, Australia, have issued their Outlook for the coming Cyclone season. Usually there are 11 cyclones in Australian waters with around four making landfall. However, more cyclones than average are likely for Australia during Nov 1 2020 to 30 April 2021. This is due to La Nina conditions in the tropical Pacific Ocean, and somewhat warmer than average ocean temperatures in Tasman Sea and to north of Australia. In La Nina years the first cyclone to develop around Australia usually occurs earlier than normal, around mid-December.

 

The Tropics

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

After a rush of cyclones in the past few weeks, it is currently quiet, but there are four areas of interest, and two zones of high potential for formation around the Philippines and the Mexican East coast.

 

SPCZ=South Pacific Convergence zone.

SPCZ is expected to stretch from Solomon Islands to norther Vanuatu to between Fiji and Samoa. Trough over Tonga/Niue area today moving off to SE and across Southern Cooks with some 3m swells tomorrow.

 

Subtropical ridge (STR)

HIGH 1020-22hPa northeast of northern Z on Mon travelling east-southeast to 35S by mid-week, when it joins with another High travelling along 45S to east of the South Island. And this is followed by Friday with a NW flow over NZ.

 

Tasman troughs

Low in south Tasman Sea today, travelling across the South Island on Monday at 1000hPa, followed by SW flow on Tuesday.

A trough is likely in northwest Tasman Sea on Tuesday/Wednesday, weakening away on Thursday.

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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 6427 7762212

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 

Bobblog/weather gram

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

DELTA made landfall in Louisiana yesterday and is now weakening inland.

LINFA is travelling across Vietnam

NORBERT is forming off the west coast of Mexico.

Several pockets of potential formation around Philippines

 

I’m in hospital now (complications with Bone Cancer) and may be in for a while,

so this brief blog may be it for a while from me. Bob for MetBob.

Bob Blog

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 Sun 4 Oct 2020

 

REVIEW OF THE LAST MONTH (September 2020)

Sea Surface temperature anomalies can be seen at www.weatherzone.com.au/climate/indicator_sst.jsp?lt=global&lc=global&c=ssta

La NINA kicked in mildly during September. Eastern equatorial Pacific continues a trend to COOL and the west of the South Pacific continues to be warmer than normal This means the coming cyclone season is likely to be less than normal for Coos Island s and French Polynesia, but it may be more active near 180 longitude (places such as Fiji).Also the South Pacific ridge line is likely to shift south.

The North Pacific and Atlantic have warmed between 30 and 50N but this may be seasonal.

 

To see how the annual weather cycle and the seasons are working out, we can check the average isobar maps for past 30 days and their anomaly from www.esrl.noaa.gov/psd/map/images/fnl/slp_30b.fnl.html

 

The monsoon is on schedule. The southern hemisphere sub-tropical ridges has strengthened, an d the northern hemisphere subtropical ridge has widened.

 

Zooming into the NZ area, and comparing monthly anomalies from last month with now, shows The ridge near NZ has strengthened to over 1020hPa and expanded south to 40S. The Antarctic high has weakened. .

 

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The Tropics

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

Two active tropical depressions today. GAMMA has made landfall in Mexico and MARIE is travelling NW in the North Pacific.

Also some high potential near Philippines, and medium potential around central America and mid-Atlantic.

 

SPCZ=South Pacific Convergence zone.

SPCZ is moderate and from Solomon Islands to Fiji to Samoa.

Passing trough over Fiji area on Mon /Tues, travelling off to SE on Thursday /Friday.

Squash zone on Mon/Tues between NZ and New Caledonia due to strong pressure gradient between a High (to south ) and low (to north) with main wind and swell at 30S from 180 to 170E.

 

Subtropical ridge (STR)

HIGH 1032hPa over northern Z on Mon travelling east along 30S on Tues/wed.

New High moving off Tasmania on wed and traveling E to central NZ on Friday, followed by a NW to W trough.

 

Tasman troughs

Front with strong westerlies over South Island on Mon. Another Front on Tues followed by SW winds Tuesday, and southerly on Wednesday/Thursday as that low from Fiji travels to SE of eastern NZ.

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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 6427 7762212

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