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 Sunday 28 Feb
Satellite view of recent rain
The Tropical rain Measuring Mission provided us with recent rain
measurements via satellite that could be viewed on Goggle earth via kml
until the mission was decommissioned in 2018.
It has been replaced by the GPM or Global precipitation Mission and data
from this satellite, sadly not available as a kml file, can be gleaned from
gpm.nasa.gov/data/visualization/global-viewer, with a choice of 7day, 24
hour or 30 minute timesteps.
Sadly, there is no latitude/longitude grid.
This data is also available from the nasa viewer website at
worldview.earthdata.nasa.gov/, in the Layer picker click "+Add layers"
(bottom left) and search for "GPM" or "IMERG" then select Rain rate
(Ascending) and Rain rate (Descending), then close the selection windows to
view the data.Sadly no coastal boundaries or lat/long grid.

The Tropics
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from http://www.ssd.noaa.gov/PS/TROP/TCFP/index.html
TC MARIAN is moving southwest across the South Indian Ocean.
A strong monsoonal trough lies across the South Pacific with several small
lows brining squally showers but these have a low likelihood of growing
further. There is a Tropical Depression 99P in the Coral Sea that has a high
potential of this system becoming a Tropical cyclone by Monday.

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
SPCZ is stretching southeast from Solomons to Tonga. TC is expected in the
Coral Sea.
A passing trough extends to southeast of French Polynesia and this may form
a low near the Austral Group by local Thursday that should travel off to the
South.
The rain accumulation map is starting to show a line of showers at 5S to
south of the Galapagos. This is the start of an annual system that is
sort-of-a-mirror-image of the ITCZ, due to the noon day being directly
overhead 5 degrees South latitude from around 5 to 10 March.

Subtropical ridge (STR)
HIGH 1022 east of South Island is expected to travel east along 47S and
build to over 1030 near 140West.
Next HIGH is expected to travel east across Tasmania on Saturday 6 March and
then travel northeast across the Tasman Sea and onto North Island early next
week.

NZ/Tasman troughs
Low 1005 in Tasman Sea is expected to travel off to the south. Another Low
is expected to form east of Tasmania on Monday and deepen to below 984 as it
passes by Campbell island on Wednesday with a few days of strong westerly
flow over NZ, turning SW on Thursday and Friday.
Start of America's Cup in Auckland has been delayed by a COVID lockdown.

Panama to Galapagos/Marquesas
Good northerly winds in Panama this week, but these may become light and
variable by mid-March. Wind flow over Galapagos is expected to turn to be
from the south from mid-arch. Current is expected to peel off to the north
of Galapagos, so way to go to Marquesas this week is via 3N 92W.
mailto:bob@metbob.com

Bob Blog 21 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 21 Feb

The Cause of the cold in Texas
Texas has been breaking many records for cold during the past week---
Basically the polar jet stream has been weak and allowed a burst of polar
air to break southwards as far as Texas.
The Arctic Oscillation index is a parameter that is positive when the polar
vortex is well contained, and has spent much of the northern winter NEGATIVE
with a big dive in early February ,see
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index.
html
One reason for the blackouts is that the electricity grid could not cope
with the increased demand. The cold weather froze natural gas wells and
blocked pipes. It also froze some wind turbines, but the main problem was
with natural gas which is the state's primary energy source. The network
engineers managed to stop a state-wide blackout by controlled overloading.
Also, Texas has insisted on having its own grid and has little
interconnection to the USA western or eastern interconnections. (Source:
http://www.theguardian.com/us-news/2021/feb/20/texas-power-grid-explainer-wi
nter-weather)

The Tropics
TC DUJUAN is moving onto the Philippines and TC GUAMBE is tracking southeast
from Mozambique channel.
There is a moderate potential for a Tropical Cyclone to form between Vanuatu
and Samoa..

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
SPCZ is north of its normal position and from Papua New Guinea to
Samoa/Southern Cooks
A tropical low over the Southern Cooks is expected to travel southeast and
deepen in the subtropics from Monday to Wednesday local dates.
Another tropical low is expected to deepen near Vanuatu by Mon 1 March.

Subtropical ridge (STR)
HIGH 1026 east of North Island is south of Tasmania on Monday is expected to
travel across central Tasman Sea this week and onto central NZ on
Friday/Saturday.
Next HIGH is expected to travel east across Tasmania on Wednesday and then
go southeast around southern NZ on Thursday.

NZ/Tasman troughs
Low 990hpa between Coffs harbour and Lord Howe is travelling south-southeast
and expected to zip past the south of the South Island on Wednesday.
Another Low is expected to form east of Eden by Friday and travel southeast
past south end of NZ by Tuesday 2 March.

Panama to Galapagos/Marquesas
Good northerly winds for starters. There is likely to be a good tail current
near EQ 85W, and a head current near 5-6N 85W so good idea to go direct, or
if heading for Marquesas go via south of Galapagos.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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 mailto:bob@metbob.com or txt 6427 7762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bob Blog 14 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.
Issued Sunday 14 Feb

The state of the ENSO
Our summer has peaked, La Nina continues but is declining.
La Nina and El Nino are tropical drivers of our weather patterns. 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 El Nino, with warmer than normal seas, draws the subtropical ridge
closer to the equator, weakening the trade winds, and allowing the westerly
winds of the roaring 40s to get further north. 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 Atmosphere:
ENSO = El Nino/Southern Oscillation. Early in the 1900s, Sir Gilbert Walker
from Britain was the Director-General of a met observatory in India, and he
searched thru world weather data looking for patterns on the weather map
across the Pacific and Indian Oceans. He found that the pressure difference
between Tahiti and Darwin helped describe the South Pacific weather pattern
in one number, and it could be used to forecast the intensity of the Indian
Monsoon (when negative, there is a drought in India). He called this
parameter the Southern Oscillation SOI. 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.

The SOI has been positive since last August, reached a peak of 2 (standard
deviations above the mean) in January , and is now relaxing.

SOI can be seen at
http://www.farmonlineweather.com.au/climate/indicator_enso.jsp?c=soi&p=weekl
y

The Ocean:
Jacob Bjerknes (born in Sweden) was son of the well-known Norwegian
meteorologist Vilhelm Bjerknes (who helped develop the cyclone model as part
of the "Bergen School" in 1920s). Jacob founded the UCLA Department of Met
and in 1969 helped toward our understanding of El Nino by connecting it to
warmer than normal waters in the eastern equatorial Pacific. We now watch
SST (sea surface temperatures) in zone NINO3.4 to watch our oceanic
parameter.

This started going negative in May 2020 and reached a peak in coolness last
November and is now slowly relaxing.

According to the International Research Institute of the Climate Prediction
Centre,at iri.columbia.edu/our-expertise/climate/forecasts/enso/current/,
reviewing all the different models for forecasting the future of this La
Nina, it is expected to weaken to neutral by May 2021 (55% chance).

Impact on South Pacific
Trade winds should stretch further south than normal and may be more robust
than normal.
Tropical lows are likely to form in the Coral Sea area.

The Tropics
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from http://www.ssd.noaa.gov/PS/TROP/TCFP/index.html
TC FARAJI continues going westwards in the South Indian Ocean
There is a moderate potential for a Tropical Cyclone to form near
Micronesia, east of Philippines and around northern Australia Fiji on Monday
and move off to the south on Tuesday.

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
SPCZ is north of its normal position and from Papua New Guinea to
Tuvalu/Tokelau
A convergence zone is expected to linger between Southern Cooks and Tahiti.
A tropical low is expected to linger around the Coral Sea and pay deepen off
Queensland coast by end of the week and then travel south.


Subtropical ridge (STR)
HIGH 1026 south of Tasmania on Monday is expected to travel across central
Tasman Sea this week and onto central NZ on Friday/Saturday.

NZ/Tasman troughs
Low 1005 to north of North Island is expected to travel south over North
island on Monday and Tuesday, with rain and strong easterly/southeasterly
winds on its southern side (southerly thru Cook Strait). Low should weaken
on Wednesday, and easterly flow should ease on Thursday.
Looks like it will be too windy for the Prada Cup on Wednesday.

Panama to Galapagos/Marquesas
Good northerly winds for starters this week. There is likely to be a good
tail current near EQ 85W, and a head current near 5-6N 85W so good idea to
go direct, or if heading for Marquesas go via south of Galapagos.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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 mailto:bob@metbob.com or txt 6427 7762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bob Blog 7 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 Sun 7 February 2021

 

The way we look at things is changing. We need a more sustainable engagement with nature says the UK Government Dasgupta Review –Highlights are at

assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/957629/Dasgupta_Review_-_Headline_Messages.pdf

The Climate Change Commission of the NZ Government has issued a new report about how it hopes to decarbonise www.climatecommission.govt.nz/get-involved/our-advice-and-evidence/

People my age may remember the RV CALYPSO TV series on the undersea world with Jacques Cousteau back in the 1970s. This inspired my interest in nature and Oceanography. It has also inspired a NZ initiative into oceanic research see bluecradle.org/

 

REVIEW OF THE LAST MONTH (January 2021)

Sea Surface temperature anomalies as at

www.weatherzone.com.au/climate/indicator_sst.jsp?lt=global&lc=global&c=ssta

show La NINA (the cool eastern equatorial Pacific) seems to have peaked but is still continuing. The main change since last month is the intensification in the warm anomaly south of Tahiti. The seas between Fiji/New Caledonia and New Zealand are now slightly cooler than normal.

 

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 sub-tropical ridges in both hemisphere is much the same as it was last month

 

Zooming into the NZ area, the 1015 isobar near NZ has widened and shifted north. The 1010 isobar is much the same over the tropics (in spite of several tropical cyclones) and has spread eastwards across the equatorial Pacific. The Antarctic HIGH has weakened.

 

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

TC LUCAS travelled across New Caledonia as a Cat 2 cyclone last Wednesday as seen on the New Caledonian METEO web site. image

Tropical moisture from the remains of LUCAS should arrive over NZ mid-week along with a Tasman trough.

TC FARAJI is in the South Indian Ocean

There is a moderate potential for a Tropical Cyclone to form near Fiji on Monday and move off to the south on Tuesday.

 

SPCZ=South Pacific Convergence zone.

SPCZ is intense from Coral Sea to Vanuatu to Fiji. As part of a monsoonal trough.

A tropical low that is tonight north of Fiji is expected to drift southeast across the group on Monday, and then move off to the south on Tuesday, with a moderate to high potential to develop inti a cyclone.

Another cyclone may form over Vanuatu around Monday 15 Feb.

 

Subtropical ridge (STR)

HIGH 1022 east of South Island is moving off to the east.

New HIGH 1024 is expected to be south of Tasmanian on Tuesday and spread across North Island on Friday/Saturday.

 

NZ/Tasman troughs

Trough in the Tasman is expected to cross NZ on Tuesday and Wednesday, followed by a southerly flow on Thursday. .

For the start of the finals of the Prada Cup on Sat 13 Feb there should be OK easterly winds, but these are likely to be strong on Sunday 14th Feb.

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

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

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