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Bob McDavitt's ideas for sailing weather around the South pacific

26 December 2020

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 27 Dec 2020

 

The calendar is about to turn from 2020 to 2021, and to mark the occasion many sing Auld Lang Syne

--- there is one verse with the English translation as follows:

 

We two have paddled in the stream,

from morning sun till dine;

But seas between us broad have roared

since auld lang syne.

 

So, here’s to a cup of kindness between us for the sake of the turn of the year.

 

Also, by way of a late Christmas present, here’s a way you can get access to the Fiji Meteorological Service’s latest Oceanic forecast (as a text messages) so those of you in the vulnerable zone and keep up-to-date:

Send an email to query@saildocs.com, no SUBJECT needed, with message

SEND http://www.met.gov.fj/aifs_prods/10140.txt

And for Tropical cyclone discussion use SEND https://www.met.gov.fj/aifs_prods/20036.txt

 

MJO

The MJO (Madden Julian Oscillation) is a wave of enhanced tropical activity that travels eastwards around the world. It is expected to be too weak to have much influence over the next few weeks.

The Tropics

TC CHALANE is about to make landfall over Madagascar.

There are also some zone s of high potential for tropical cyclone formation around eastern Indonesia/Papua New Guinea this week.

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ stretches from Solomon Islands to Vanuatu to between Fiji and Samoa.

A passing trough is expected to affect Tonga on Monday and move east onto Niue and maybe the southern cooks during the week.

Another tropical trough is expected to form off Queensland coast on Wednesday and move onto New Caledonia on Friday/Saturday.

 

Subtropical ridge (STR)

HIGH 1022 in Tasman Sea is expected to fade over northern NZ by Thursday.

HIGH south of Tasmania on Friday is expected to travel to south of NZ by early next week.

 

NZ/Tasman troughs

Low 10004 is expected to linger east of the North Island for much of this week.

Trough in western Tasman Sea today is expected to travel east and reach South Island from late Tuesday and fade over North Island on Wednesday.

Another front from the Southern Ocean is expected to reach South Island on Thursday and then deepen into a low over central NZ on Friday to Sunday.

 

Fiji/Tonga to NZ: Weather looks OK for a departure 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 6427 7762212

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20 December 2020

Bob Blog 20 Dec

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 20 Dec 2020

 

MJO

The MJO (Madden Julian Oscillation) is a wave of enhanced tropical activity that travels eastwards around the world. It takes a few weeks to a month to cross the Pacific. Its active (blue) has been over northern Australia and is expected to travel across the South Pacific over the next few weeks as shown in the attached plot of OLR (Outgoing Longwave Radiation).

 

Cyclone outlook:

Since YASA and ZAZU have disturbed the erm surface waters around Fiji and Tonga /Niue this REDUCES the risk of cyclone formation in these areas.

 

To check the latest tropical cyclone weather discussion from NZ MetService, click on

www.metservice.com/warnings/tropical-cyclone-activity

or from Fiji MetService

www.met.gov.fj/aifs_prods/20036.txt is a text file

This can be downloaded via an email to query@saildocs.com

No subject needed, with message

SEND https://www.met.gov.fj/aifs_prods/20036.txt

 

The Tropics

TC ZAZU went southeast over open water, but TC YASA build to category 5 and then made landfall over Vanua Levu, Fiji last Thursday night and travelled across the Lau group . It brought devasting damage, within a week of Christmas. Please remember the victims in your Christmas /New Year budget (fund raising is still being arranged).

 

There has aloe en flooding in Samoa, see

www.rnz.co.nz/international/pacific-news/433136/major-flooding-in-parts-of-samoa

YASA is now fading as it travels Southwest.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ stretches from Solomon Islands to Tuvalu/Samoa area whilst YASA does its own thing.

 

Subtropical ridge (STR)

HIGH 1022 east of NZ travelling along 40S extends a ridge back onto North island until Wednesday.

Another HIGH is expected to spread over Tasmania on Friday and reach northern NZ early next week.

 

NZ/Tasman troughs

Trough from Tasman Sea crossing South Island on Monday.

LOW offshore Sydney on Tuesday travelling east across Tasman reaching NZ on Wednesday /Thursday followed by a SW /S flow on Friday/Saturday.

 

Fiji/Tonga to NZ: Stay put until YASA fades 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

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12 December 2020

Bob Blog 13 Dec

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 13 Dec 2020

 

Outlook for PRADA Americas Cup AC75s World Series and PRADA Christmas Race on Hauraki Gulf 17-20 December.

There should be good racing and good variety of weather for the World Series with moderate SW wind on Thursday, light variable wind of Friday, and moderate NE winds on Saturday.

 

As for the Christmas racing on Sunday 20 December--- that may be exciting stuff, deepening on the progress of a system from the tropics-- weather forecast will need updating closer to the day.

 

MJO

The MJO (Madden Julian Oscillation) is a wave of enhanced tropical activity that travels eastwards around the world. It takes a few weeks to a month to cross the Pacific and is now over northern Australia.

 

The Tropics

Tropical Depression 01F is located around 350 bn N of Fiji and is very likely to deepen into the first tropical cyclone of the region for the season by Monday, between Vanuatu and Fiji. It is expected to travel slowly south this week. Its outlook is still uncertain but likely to go south and weaken in the Tasman Sea/NZ area from 18 to 21 December.

 

Tropical Depression 03F is located around 140nm south of Pagp Pago , It has a moderate chance of deepening into a tropical cyclone between Samoa and Niue by Monday and should travel southeastwards.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ stretches from Solomon Islands to Tuvalu/Samoa area whist the tropical cyclones do their own thing.

 

Subtropical ridge (STR)

HIGH 1028 in central Tasman Sea today is expected to weaken to 1018 as it crosses NZ on Thu 17 Dec and then join another High travelling east along 40 to 45S to east of South Island.

 

NZ/Tasman troughs

LOW offshore Brisbane area on Monday expected to turn into a trough and go inland on Tuesday.

Tropical feature from Fiji area is expected to come south and affect Tasman Sea /NZ area from 18 to 21 Dec.

 

Fiji/Tonga to NZ: Stay put 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 6427 7762212

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

 

05 December 2020

Bob Blog 6 Dec

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 06 Dec 2020

 

REVIEW OF THE LAST MONTH (November 2020)

La NINA (the cool eastern equatorial Pacific) is well marked, and there are warmer-than-normal seas over the Southwest Pacific. This means the cyclone season is likely to more active near the dateline.

The sub-tropical ridge in the southern hemisphere has weakened and the westerly isobars of the Southern Ocean have widened, deepened and shifted north.

Zooming into the NZ area, and comparing monthly anomalies from last month with now, the sub-tropical ridge has weakened - the 1015 isobar has drifted from 45/50S to 30S over Australia and New Zealand.

 

The Tropics

Things are quiet for now with no cyclones around but some potential areas for formation around Philippines/Indonesia/Northern Australia

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is in its normal position from Solomon Islands to Samoa to Southern Cooks.

A passing trough is expected over Southern Cooks area early in the week, and another over New Caledonia mid-week and again another over the weekend.

According to the GFS model, a tropical low is likely over northern Vanuatu from late in the week,,,, worth watching out for.

 

Subtropical ridge (STR)

HIGH 1018-1022 over northern NZ is expected to travel off to east along 30S.

Next HIGH is expected to enter Tasman Sea mid-week and travel east along 35S reaching northern NZ late in the week

 

NZ/Tasman troughs

LOW has deepened to 965 at 50S south of Tasmania and is expected to move off to southeast by Tuesday with associated troughs crossing South Island.

Low is expected to form off Sydney on local Monday and travel east southeast across the Tasman Sea reaching central New Zealand by mid-week 1002 hPa.

Another Low is expected to form in central Tasman Sea around the end of the week and move over South Island early next week.

 

Fiji/Tonga to NZ:

Looks Ok to head off this week, but need to reach NZ by Sun 20 Dec.

 

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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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28 November 2020

Bob Blog 29 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 Sun 29 Nov 2020

 

Australian Heat wave

A depression (low pressure centre) crossing inland Australia is expected to bring a five to six-day heatwave for millions of people in eastern Australia, with exceptional temperatures and duration.

See www.abc.net.au/news/2020-11-28/first-heatwave-of-australian-summer-2020/12928746

Despite the strong La Nia in the Pacific, rains have held off over northern Australia due to the recent dry phase of the MJO (Madden Julian Oscillation). However, the wet phase of the MJO is expected to move in for early to mid-December, bringing tropical rain to North Australia.

 

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

Things are quiet for now with no cyclones around but some potential areas for formation around Indonesia/Philippines.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is slightly north of its normal position from Solomon Islands to Samoa and extends further east than normal across French Polynesia.

A trough is moving east across s the Tongan/Niue area today/tomorrow, and another around mid-week.

 

Subtropical ridge (STR)

HIGH 1016 in north Tasman Sea is expected to travel east along 25S and fade to north of NZ on local Monday.

Another High is expected to cross Tasmania on Monday and then cross the Tasman Sea reaching central NZ on Wednesday then drifting off to north.

Another High should enter Tasman Sea on Thursday and cross northern NZ on Saturday.

 

NZ/Tasman troughs

LOW deepening to 986 off Tasmania tonight expected to travel across central NZ on local Monday and move off on Tuesday brining large swells and followed by vigorous southerly winds.

Low around 950hPa in Southern Ocean near 58S on Wednesday expected to travel east past south of NZ on Thursday/Friday with westerly gale for southern NZ.

 

Fiji/Tonga to NZ:

Avoid arriving on Monday 7 Dec, otherwise mostly OK.

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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

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

 

 

23 November 2020

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22 November 2020

Bob Blog 22 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 Sun 22 Nov 2020

 

LA NINA strengthens

La Nina is caused by cooler than normal seas along the equatorial eastern Pacific. It shifts the subtropical ridge away from the equator and strengthens the trade winds.

The Atmosphere:

The parameter we watch from the atmosphere is the Southern Oscillation Index SOI (30 day running mean) which is basically the (normalised) air pressure difference Tahiti-Darwin.  This entered La Nina territory last month and has relaxed a little in past few weeks.

 

The Ocean:

The parameter we use here is the average sea surface temperatures in the equatorial eastern Pacific zone NINO 3.4. This index has been steadily dropping for weeks and entered La Nina territory late November. The atmosphere and ocean have “coupled” in their behaviour, or are doing the same thing.

 

Sea temperature anomaly: Wwarmer than normal seas between New Caledonia and New Zealand are likely to enhance low pressure systems in the Tasma sea and increase the risk of tropical cyclone formation over next few months.

 

According to the International Research Institute of the Climate Prediction Centre, this La NINA should peak early in 2021 and has a 65% chance of lasting until May 2021.

 

The Tropics

TC IOTA brought more deluging rain to Central America in the past week.

Things seem to be quietening now, with a tropical depression about to make landfall onto the horn of Africa., and some potential areas for formation around Indonesia.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is in its normal position from Solomon Islands to Northern Vanuatu to between Fiji and Samoa..

A trough is expected to form over Samoa early in the week and travel over Niue/Southern Cooks around mid-week.

 

Subtropical ridge (STR)

HIGH/ridge is expected to travel east across the North island on Monday and then go east along 30 to 40South.

Next High is expected to arrive in Tasman Sea on Wednesday and linger there until the weekend, drifting northwards.

 

NZ/Tasman troughs

LOW 990hPa is expected to move from Tasman Sea onto North Island on Tuesday and off to the east on Wednesday followed by southerly flow.

Low below 960hpa is expected to travel east near 60South on Wed/Thu/Friday bringing vigorous west to SW wind flow to South Island.

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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

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

14 November 2020

Bob Blog 15 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 Sun 15 Nov 2020

 

Why the Napier deluge?

On Monday 9 November, Napier City (east coast of North Island, NZ) got 242mm of rain ---463 per cent of its normal monthly rainfall -- in just a few hours. This was Napier’s second wettest day in 150 years. It caused floods and slips that left more than 100 homes uninhabitable.

This was due to a “collision” of warm moist air arriving from the north and cool air arriving from the south. These airflows combined and stayed in place like a hand-held-hose, bringing a stream of intense rain. Places north or south of this stream didn’t get the deluge.

The Low over northern NZ was “cut-off” - it had light variable winds above it and, lacking a steering field, was very slow-moving. This also allowed near vertical ascent in its clouds, accentuating the rain.

Moisture in the incoming northerly flow can be tracked back to Papua New Guinea, via Vanuatu. This is a weather pattern typical of our current LA NINA and should recur several times during next few months,

The intensity of this event also indicates how climate change is affecting us--- a warmer world allows these plumes of higher humidity and thus, when the moisture is cooled, zones of enhanced rainfall.

 

The Tropics

Cyclone ETA has moved offshore and weakened after leaving six dead in North Carolina and Florida, and is followed by IOTA now near central America.

Typhoon VAMCO brought extensive damage to Philippines, including Manila and is now making landfall over Vietnam.

Cyclone ALICIA in southern Indian Ocean is the first cyclone of the new Southern Hemisphere cyclone season.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is slowly shifting south to its normal position from Solomon Islands to Northern Vanuatu to between Fiji and Samoa, and is increasing in activity.

A trough is expected to linger about and south of the Tonga/Niue area early to mid-week.

 

Subtropical ridge (STR)

HIGH skirting around south of NZ today expected to travel NE to 40S 140W by mid-week and build to 1038hPa with enhanced trade winds on its northern side mainly around 20 to 30S.

Weak ridge of high pressure is expected to move into west Tasman Sea on local Tuesday and travel to NW of NZ by Friday/Saturday and then weaken away.

Another weak High should cross Tasmania on Friday and South Tasman Sea by 22 Nov.

 

NZ/Tasman troughs

Looks Ok to arrive in northern NZ any day this week/early next week, but avoid arriving around Fri 27/Sat 28 Nov.

Trough crossing South Island tonight and weakening over remainder of NZ on Monday.

LOW crossing South Tasman Sea on local Tuesday may deepen to 974 hPa then weaken and go southeast.

Associated trough expected to cross South Island on Tuesday night and North Island on Wednesday, and then deepen into a low 1004hpa east of North Island and move off to southeast from Thu to Sat.

Another trough expected to reach South Island by Saturday 21 Nov.

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

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

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

07 November 2020

Bob Blog 8 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 Sun 08 Nov 2020

 

The Tropics

Tropical Cyclone ETA  has been bringing damaging wind and rain to central America recently and is now heading to Cuba. In Guatemala a remote village has been buried by landslides and around 100 people are feared dead.  In Honduras, at least 23 deaths have been confirmed.

ATSANI is about to travelling southwestwards near Hong Kong.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is somewhat north of its normal position this week from Solomon islands to Samoa, with scattered activity around French Polynesia.

Another convergence zone or upper trough is expected to be over New Caledonia on Tuesday/Wednesday and Fiji on Wednesday/Thursday.

 

Subtropical ridge (STR)

HIGH 1028hpa easing to 1020 over Tasmania today should cross central Tasman Sea and then northern NZ Thursday/Friday

 

NZ/Tasman troughs

LOW 994 over central NZ tonight expected to move off to SE Monday.

However, trailing trough is expected to linger over northern NZ and deepen into low on Monday that travels slowly southeast over NE NZ on Tuesday and off to southeast on Wednesday and in Tasman sea moving slowly east along 30S should reach northern NZ by Friday.

NW flow over South Island on Friday 13th followed by a trough on Saturday.

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

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

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

 

 

01 November 2020

Bob Blog 1 Nov 2020

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

REVIEW OF THE LAST MONTH (October 2020)

La NINA (the cool eastern equatorial Pacific) has intensified and widens during the past month. This means the coming cyclone season is likely to be less than normal for Cook Island s and French Polynesia, but it may be more active for New Caledonia. The South Pacific subtropical ridge line drifted south, bringing blockings Highs around northern NZ.

 

The monsoon is heading for Indonesia. The sub-tropical ridges in northern and southern hemisphere have shifted pole-wards and strengthened.

Zooming into the NZ area, and comparing monthly anomalies from last month with now, shows that

The 1015 isobar has drifted south over Queensland. The sub-tropical ridge is much the same intensity. The Antarctic high has weakened.

 

The Tropics

ZETA hit US Gulf Coast and inland hard last few days; nearly two million without power. That’s the Greek alphabet used up, but cyclones are still brewing and latest is called Twenty_Nine.

Super Typhoon GONI (local name ROLLY) is hitting Philippines tonight, one million people have been evacuated (so far) but maybe up to 31 million will be affected. ATSANI may hit the northern tip of the Philippines.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is expected to stretch from Solomon Islands to Vanuatu then Samoa with a tail southeast to south of French Polynesia

Trough over New Caledonia from Mon to Wednesday and then should go southeast to northern NZ by Friday. Also, a low may form south of French Polynesia late in the week and go south.

 

Subtropical ridge (STR)

HIGH 1030hpa is acting as a block east of north Island near 160W until Tuesday,

Another HIGH east of South Island on Monday should grow to 1032hPa as it travels east along 40 to 30S reaching 160W by end of the week. This is likely to enhance the trade winds on its northern side.

 

Tasman troughs

LOW 1010 in Tasman sea moving slowly east along 30S should reach northern NZ by Friday. Trough likely over NZ on Saturday, followed by a SW flow.

 

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

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

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

24 October 2020

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

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

17 October 2020

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.

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

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

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

10 October 2020

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.

04 October 2020

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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26 September 2020

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 27 Sep 2020

 

CAPE or Convective Available Potential energy, is the integrated (total) amount of work that the upward (positive) buoyancy force would perform on a given mass of air (called an air parcel) if it rose vertically through the entire atmosphere. Positive CAPE will cause the air parcel to rise and is an indicator of atmospheric instability in any given atmospheric sounding, while negative CAPE will cause the air parcel to sink.

 

Instability and rising motion in a cloud can cause a thunderstorm, CAPE values over 5Kj/Kg are significant in creating thunderstorms. This means that CAPE can be used as an indicator of the intensity of the South Pacific Convergence Zone. So I’m adding the mid-week CAPE map (from predictwind.com) to my illustrated edition of weathergram, as it shows another rview of the SPCZ..

 

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

Just two tropical depressions today. 15W and 14W (ex DOLPHIN at 40N 146E)

Also, some high potential for development off west Mexico coast., near Philippines, an d in the N NE Atlantic, off Africa

 

SPCZ=South Pacific Convergence zone.

SPCZ is moderate and in its normal position, from Solomon Islands to Samoa. The CAPE map also shows some convection along 15S.

Passing trough over Fiji /Tonga on Wednesday, and Southern Cooks on local Tuesday/Wednesday and Southern Cooks on Thursday.

Accumulated rainfall for next week from windyty.com

 

SubSubtropical  Ridge

HIGH 1024hPa over New South Wale on Tuesday and broaden as it crosses Tasman Sea , reaching North Island on Thursday and Friday, leaving a lingering ridge over North Island.

 

Tasman troughs

Low 966 hPa south of NZ moving south and deepening to below 050 hPa at 55S on Monday, then moving east., followed by vigorous S flow over NZ until Wed with huge swells. .

Front over South Island on Friday with NW winds followed by westerly winds.

 

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

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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20 September 2020

Bob's Blog 20 May

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 20 Sep 2020

 

LA Nina update

The main Met sites have confirmed that in the past week we have indeed started a new La Nina episode. It is expected to be a weak one, peaking around December and fading by March 2021. Should have a moderating effect on the number of cyclones, with the main ones forming WEST of 180.

 

Spring equinox and Daylight saving

The equinox is at 0130UTC on 22 September.

NZ switches to daylight time at 2am Sunday 27 Sep

In Australia Daylight saving is observed in New South Wales, Victoria, South Australia , Tasmania. Australia Capital Territory, and Norfolk Island

It starts on 2am on first Sunday of October.

Fiji starts 2am 8 Nov

French Polynesia doesn’t have daylight savings

Tonga is no longer (since 2017) having Daylight saving

 

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

Three Cyclones in the North Atlantic, TEDDY and WILFRED (+ Paulette’s remains north of 30 north, not shown ). But during the past week there were up to 7 systems worth watching. BETA in Gulf of Mexico--- so we have switched to the Greek Alphabet for names. NOUL is near Bangladesh. Also a high potential for development off west Mexico coast. And a rare ‘Medicane’ in Greece in the Mediterranean Sea with at least two fatalities, see https://www.bbc.com/news/world-europe-54219180

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is moderate and slightly north of normal from Solomon Islands to North of Vanuatu to Tuvalu /Samoa.

Passing trough over Southern Cooks on local Tuesday/Wednesday.

 

Subtropical ridge (STR)

HIGH 1028hPa over NZ moving east along 40S, but leaves a lingering ridge over North Island on Monday that may allow a new HIGH 1020pa to travel east along 30S to E of NZ from Tues to Sat.

 

Tasman troughs

Passing trough over NZ on Tuesday.

Low forming east of Tasmania on Thursday and crossing southern NZ on Friday at around 995hPa.

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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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13 September 2020

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 13 Sep 2020

 

LA Nina watch

ENSO (El Nino /Southern Oscillation) update

El Nino and La Nina are opposite ends of the swing of an identifiable tropical influence on our seasonal weather. The La Nina, caused by cooler than normal seas along the equatorial eastern pacific, shifts the subtropical ridge away from the equator and strengthens the trade winds

The El Nino, with warmer than normal seas, draws the subtropical ridge closer to the equator, weakening the trade winds. Their comings and goings can last several months, maybe over a year, and so their status can be used to help forecast the weather for the coming season.

 

The Atmosphere:

ENSO = El Nino/Southern Oscillation. The main parameter we watch from the atmosphere is the Southern Oscillation Index SOI (30 day running mean) as it sums up the whole weather pattern over the South Pacific in one number. It is based on the standardized difference in the barometer readings between Tahiti and Darwin, in other words it counts the average number of isobars between them on the weather map. When the SOI is more than plus one (standard deviation from its mean) for more than a month we call it a LA NINA event, and when it stays more than minus one we call it an EL NINO event.

There has been a positive trend I the SOI over the last few weeks , heading for the start of a La Nina event soon.

The SOI can be seen at www.farmonlineweather.com.au/climate/indicator_enso.jsp?c=soi&p=weekly

 

The Ocean:

The sea surface temperatures in the equatorial eastern Pacific has been showing a cooling (La Nina) trend . It looks like the Atmosphere and Ocean parameters are “coupled” or doing much the same thing, so a La Nina event may indeed soon be occurring.

Sea temperature anomaly, taken from

www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Waters just beneath the surface are slightly cooler than normal. These trends are towards a La Nina.

 

The International Research Institute of the Climate Prediction Centre compiles data from several ENSO prediction models. The model forecasts shows a 55% chance of weak La Nina for Sep Oct Nov. This is the trend of the average of the models.

CPC/IRI predictions from iri.columbia.edu/our-expertise/climate/forecasts/enso/current/

 

So, we are currently “neutral”, but we are on watch for La Nina trends.

 

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

Three Cyclones in the North Atlantic, PAULETTE, TD20 , and RENE,

and one inn Gulf of Mexico, SALLY. Also a high potential for development off west Mexico coast.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is moderate and slightly north of normal from Solomon Islands to North Vanuatu to Tuvalu /Samoa. Passing trough over Southern Cooks on local Sunday/Monday.

 

Subtropical ridge (STR)

HIGH 1028 to 1030 hPa crossing Tasman Sea Tues/Wed an d the travelling along 32S between Fiji an d NZ on Wed night/ Thursday, with a squash zone of rough weather over Fiji, easing from Friday.

Next High is expected to cross Tasmania on Friday and grow to 1032hPa in South Tasman on Friday/Saturday, crossing central NZ during the weekend.

 

Tasman troughs

Strengthening NW flow south of 40S on Monday, followed by a cold front on Tuesday with heavy rain for Southern Alps, then another front for all NZ on Thurs night/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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06 September 2020

Bob Blog 6 Sep

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 6  Sep 2020

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REVIEW OF THE LAST MONTH (August 2020)

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

A noticeable cooling of SST along eastern Pacific Equatorial zone, A sign that we are likely to have a La Nina. Soon, and this tends to bring the southern hemisphere’s subtropical ridge southwards, especially in the South Pacific.

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 much like last month. The northern hemisphere sub-tropical ridge has weekend and the southern hemisphere subtropical ridge is in much the same place, has shrunk a little, but for the High near western South America has intensified.

 

Zooming into the NZ area, and comparing monthly anomalies from last month with now, shows that the sub-tropical ridge has shifted north over NZ (as per a normal July), but strangely has intensified over Australia.

The 1015 line over NZ has shifted north, allowing more fronts to spread north over NZ.

The 1025 over Australia has weakened but the High near the Andes has intensified.

The Antarctic high has also intensified.

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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

MAYSAK last week affected Japan and South Korea and sunk a cattle ship .

HAISHEN follows , possibly stronger.

JULIO is moving offshore from west Mexico.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is moderate and in two bits, one from Solomon islands to Vanuatu to south of Fiji, t’other over Tuvalu to Samoa, briefly Tonga.

Passing trough over Fiji/Tonga mid-week, turning into a Low that goes Southeast.

 

Subtropical ridge (STR)

HIGH 1034hPa in Tasma Sea Monday travels onto central NZ 1028hPa on Tue/Wed then goes off to east.

Next HIGH expected to cross Tasmania on Thu 1032hPa , then ENE to Northern NZ 1022hPa by Sunday.

 

Tasman troughs

Trough is crossing NZ North Island tonight.

Next Tasman trough is expected to reach NZ South Island on Wednesday, lingering on Thu and developing into a Low over northern NZ on Friday, moving off to east on Sat.

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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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29 August 2020

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 30 Aug 2020

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The climate start to SPRING in  the Southern Hemisphere is 1 September, but I like to wait until the equinox on Sep 22 (this year).

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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

The latest death toll due to LAURA in Louisiana and Texas is 16 (many from Carbon Monoxide). At present there are two cyclones , ISELLE, west of Mexico, and MYSAk which seems to be heading for Korea. There are several areas of high potential for formation, especially in the Atlantic.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is moderate and in its normal position from PNG to Vanuatu/Tuvalu and, occasionally, Samoa.

Passing trough over Tonga on Wednesday (local) reaching Southern Cooks on (local) Friday, associated with a Low further south..

 

Subtropical ridge (STR)

RIDGE 1020hPa near 30S in north Tasman Sea, fading on Monday/Tuesday.

New High 1024hPa in Tasman Sea on Tues , travels along 35S crossing northern NZ on Fri/Sat.

 

Tasman troughs

Vigorous westerly winds south of 40S, then trough followed by cold southerly flow reaching South Island by Tuesday and north of North island on Wednesday.

Next trough over New South Wales by Friday, increasing the westerly flow over the south Tasman again.

 

From Panama: ITCZ 5N to 10N, SW winds in Panama, winds W/SW from 7N 80W to 90W.

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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

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

23 August 2020

Bob Blog 23 Aug

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 23 Aug 2020

 

Weather and climate drivers.

Seasonal and climate forecasting is more complicated than normal weather forecasting. The scope of the operation is wider and involves more variables. For Climate, one consideration is the amount of incoming energy (from the sun) and how this is distributed. As earth absorbs energy from the sun, it eventually emits an equal amount of energy to space Eventually. The (temporary) difference between incoming and outgoing can be measured and is given the name Radiative Forcing (RF). Volcanic dust is an example of one of the climate variables. Human-caused climate drivers, such as the amount of heat-trapping gases like CO2 and methane and the change in land-use have a trend, but at this stage, are not taken into account by seasonal forecasters. Seasonal forecasts use several regional based parameters to help decide what may happen in the next few months. ENSO, IPO, STR, SAM and MJO are the main parameters.

A comic way of reviewing and enjoying the effect of these on SE Australia is given at www.dpi.nsw.gov.au/climate-and-emergencies/seasonal-conditions/climatedogs

 

ENSO:

The El Niño–Southern Oscillation (ENSO) is currently neutral. However, in the OCEAN continued cooling of the tropical Pacific Ocean, changes in tropical weather patterns, and climate model outlooks shifting further towards La Niña, means that ENSO’s Outlook has moved to a La Niña ALERT.

The chance of La Niña forming in 2020 is around 70%— roughly three times the average likelihood. In the atmosphere, trade winds are stronger than average, while the Southern Oscillation Index (SOI) remains neutral but positive (indicating a La Nina trend). All international climate models surveyed suggest the tropical Pacific Ocean will cool further, with three of the eight models reaching La Niña thresholds in September, and two more in October.

For New Zealand this is likely to first bring the sub-tropical Ridge southwards with dry spells during the Spring, but it may encourage NE winds and wet spells in Northland during summer.

 

IPO:

The Indian Ocean Dipole (IOD) is currently neutral, despite the index dropping sharply recently. Large parts of the Indian Ocean are warmer than average, with some weak cool anomalies near the Horn of Africa. Half the six surveyed models indicate negative IOD thresholds could be met or exceeded during spring. This may increase the chance of rain in Australia but has little impact upon New Zealand.

 

SAM

The Southern Annular Mode (SAM) is currently negative and is expected to soon become weakly positive. A negative SM encourages southerly outbreaks.

 

MJO

The Madden–Julian Oscillation (MJO) is in the eastern Pacific and is expected to strengthen as it tracks eastwards towards Africa. At this time of year an MJO pulse in this region has little influence over NZ.

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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

There are two active storms in the Gulf of Mexico MARCO and LAURA and both seem to be heading to Louisiana, MRCO on local Sun/Mon then Laura on locl Tues/Wed Also BAVI is likely to make landfall over Korea. There are several areas of high potential for formation., especially west of central America.

 

WEATHER ZONES

SPCZ=South Pacific Convergence zone.

SPCZ is moderate and has shifted to north of normal near 10S from 150E to 160W.

Passing troughs over New Caledonia on Monday and over southern Tonga on Local Tuesday/ to Thursday.

 

Subtropical ridge (STR)

HIGH 1024hPa should get into Tasman sea at 30S n Thu and travel along 30S past northern NZ on Sunday over NZ at present is expected to travel east along 35S and build to 1040hP near 150W by mid-week, with a squash zone of enhanced trade winds along 25S with swells up to 4m from 145W to 155W.

 

Tasman troughs

Low off NSW likely to deepen to 988hPa over South Island on Mon wit a trough ove r North Island, then Low likely to go southeast and deepen to 980hPa. Low is followed by a vigorous West to SW flow over Tasman/NZ for remainder of the week with embedded weak troughs.

 

From Panama: ITCZ 5N to 10N, SW winds in Panama.W/SW winds from 7N 80W to 98W.

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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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