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

31 May 2015

BOB Blog 31 May 2015

WEATHERGRAM

YOTREPS

Issued 31 May 2015

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.

 

The Atmosphere:

The Southern Oscillation Index SOI sums up the weather pattern over the South Pacific as one number and is based on the standardized difference in the barometer readings between Tahiti and Darwin (30 day running mean).  It has dived very negative in the past few weeks, possibly due to troughs near Tahiti. We haven’t seen it this negative since Jan 2010.

SOI is shown at http://www.farmonlineweather.com.au/climate/indicator_enso.jsp?c=soi&p=weekly

If the next reading of this index remains lower than -10 then we have a fully- blown El Nino (both ocean and atmosphere). .

TROPICAL TOPICS

TC ANDRES is now well off the west coast of Mexico and slowly fading. There is another tropical depression already set to follow it this week.

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

In an El Nino year the Indian monsoon is usually late, slow, and not-so-wet. Well, this El Nino hasn't really got into the atmosphere yet, and the Indian Monsoon is starting up already and is maybe a day or so EARLY.

The Indian Monsoon is now about 5 days BEHIND schedule.  Its failure to bring ocean-moistened air into the heart of India has led to extremely high temperature to inland India:

From www.timeanddate.com  - last Friday’s reading was more likely to have been 41 rather than 14 (to err is human).  Human fatalities in India related to this pre-monsoon heat wave for 2015 are so far around 2000.—it is interesting to note that the previous high was 2541 in 1998  (the last mega El Nino).

Advance of Monsoon is seen at http://www.imd.gov.in/section/nhac/dynamic/Monsoon_frame.htm

 

The rain map for the last two weeks shows ANDRES blossoming the rain SW of Mexico and also a build-up of heavy rain over Papua New Guinea.

Weekly rain signatures for past two weeks, as seen at http://trmm.gsfc.nasa.gov/trmm_rain/Events/big_global_accumlation.gif

 

WEATHER ZONES

 Galapagos to Marquesas:

Poor light winds for departing on local Wed/Thu this week.

There is still signs of a good west-going current along around 5 to 6S from 100W to 125W, so use this if you can. There may be some convergence shower activity around the Marquesas until 6 June UTC. 

 

SPCZ=South Pacific Convergence zone.

SPCZ is expected to be weak again this week and well north of its normal position. A rare week of good weather for sailing from Tahiti to the west.

 

STR= Sub-tropical Ridge

STR is also north of normal—an El Nino trait.  IT is strong over dry Australia and the along 25S across the entire South Pacific.

Next HIGH is expected to move a cell into SOUTH Tasman Sea on Thursday and combine with a HIGH being knocked off Antarctica, there-by shovelling chilly winds onto NZ from the Southern ocean, with traceable trajectories off the ice shelf. The snow from this is expected to be mainly alpine.

 

Departing from Australia to the tropics this week:

LOW is expected to cross central Tasman Sea from Monday to Wednesday with strong SW winds and rough seas.  After Wednesday these winds ease and it should be Ok for sailing to Noumea again.

 

Departing from Northern NZ going north.

Front on Monday and LOW affects NZ weather with gales and heavy rain from Tuesday to Thursday. You can see its Thursday position in the above map, so forecast for Thursday in NZ is alpine snow.

Then it MAY be Ok for a departure on Friday from NZ to tropics—however there is likely to be a small low forming between Lord How and Norfolk Islands on Sat 6 June and then going SE .  This small low might affect those Friday departures—too far away to tell much detail at this stage.

 

See my yotpak at boatbooks.co.nz/weather.html for terms used.

Weathergram text only (and translator) is at weathergram.blogspot.co.nz

Weathergram with graphics is at metbob.wordpress.com, click FOLLOW at bottom right to subscribe.

My website is at metbob.com – Feedback to bob@metbob.com

To unsubscribe send a reply email saying LEAVE.

 

24 May 2015

Bob Blog

WEATHERGRAM
YOTREPS
Issued 24 May 2015

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. It was near and slightly southeast of the apex of a Jet
Stream as shown at the FL340 level map. At this position air may be sucked
upwards and outwards from the low in a process similar to how we can use a
hose to spray out garden chemicals. This causes the central air pressure (as
measured in hectoPascals) of the low to drop quickly, creating more and more
isobars near the centre, making for stronger winds around the system.
Many meteorologists monitor the 500 hPa (FL 160) map as it is in the
middle-atmosphere and combines the features of the upper air (jetstreams)
and the surface. The flow at this level is a good approximation of the
steering flow for surface features, and this map last Thursday showed strong
NW winds above the surface low, so that is was no great surprise that this
surface low travelled so quickly across northern New Zealand on Saturday.
The low has already been blown to the far SE of NZ and thus dislodged a
chunk of air out of the Southern ocean onto New Zealand as shown in the
latest plot of the current snow expected for the next 24 hours over NZ on
windyty.com

The Atmosphere:
The Southern Oscillation Index SOI is based on the standardized difference
in the barometer readings between Tahiti and Darwin (30 day running mean)
and sums up the weather pattern over the South Pacific as one number. It has
dived very negative in the past few weeks, possibly due to troughs near
Tahiti. We haven't seen it this negative since Jan 2010.
SOI is shown at
http://www.farmonlineweather.com.au/climate/indicator_enso.jsp?c=soi&p=weekl
y
If this index remains lower than -10 for four weeks in a row then we have a
fully-blown El Nino (both ocean and atmosphere). This is NOT a typical El
Nino. When compared to the past it seems to be mimicking the 1986-87 event
rather than the biggest ever 1997-1998 event: see
http://www.climate.gov/news-features/blogs/enso/may-2015-enso-forecast-will-
el-ni%C3%B1o-be-overachiever-or-peaked-high-school


The Ocean
Here is an interesting theory:
http://arstechnica.com/science/2015/05/how-the-indian-ocean-ended-up-stealin
g-the-atmospheres-heat/

Theory is that heat is being taken from atmosphere over the Pacific Ocean
and then driven by wind into the Indian Ocean. SO the Pacific Ocean
temperature indicators may take on the values of an El Nino, but might not
be delivering an atmospheric El Nino.

TROPICAL TOPICS
TC DOLPHIN has moved off to the NE of Japan, and at present we are having a
quiet period between cyclones. Next one is likely to form near 10N 105W by
Thursday, off the Southwest coast of Mexico.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
In an El Nino year the Indian monsoon is usually late, slow, and not-so-
wet. Well, this El Nino hasn't really got into the atmosphere yet, and the
Indian Monsoon is starting up already and is maybe a day or so EARLY.
Latest Indian Monsoon index is a few days early, and so far is wetter than
normal NOT a typical El Nino-Monsoon at all. See
http://apdrc.soest.hawaii.edu/projects/monsoon/realtime-monidx.html

The rain map for the last two weeks shows how quickly the South Pacific has
dropped in rainfall since that early May low over the Solomons. It also
shows maximums of rainfall in Southeast Asia as the Monsoon kicks in.
And troughs over southern French Polynesia. see:
http://trmm.gsfc.nasa.gov/trmm_rain/Events/big_global_accumlation.gif

WEATHER ZONES
Galapagos to Marquesas:
Better winds for departing are on local Monday/Tuesday this week.
There is still signs of a good west-going current along around 5 to 6S from
95W to 130W, so use this if you can. There may be some convergence shower
activity around the Marquesas this week.

SPCZ=South Pacific Convergence zone.
SPCZ is expected to be weak this week and stretch from Tuvalu to Suwarrow,
with a relaxation of the convergence zones that have been bothering French
Polynesia over last few week.
Late in the week a trough is expected to form between eastern Fiji and south
of Tonga (Minerva area). This trough is likely to have a squash zone of
strong easterly winds on its southern side.

STR= Sub-tropical Ridge
Next HIGH is expected to move east into central Tasman sea along 35S by
Wednesday and then across the North island on Thursday and off to the east
by Friday, and hug 35to 40S as it travels off to east of NZ next week.

Departing from Australia to the tropics his week:
Once that HIGH starts travelling east from Wednesday this will make for
strong SE winds in northern Tasman Sea, and there is a zone of light winds
within the HIGH for anyone motoring.
Big trough is expected to move into southern Tasman Sea from Thursday,
bringing strong SW winds and heavy swells as far north as Lord Howe Island
by Sun 31 May. Avoid.

Departing from Northern NZ going north.
Southerly blast is still strong on Monday and should ease on Tuesday.
Then easterly winds and light winds over northern NZ on Wednesday and
Thursday, and then the NE winds ahead of the next front are expected from
Friday. SO best day to depart is Tuesday 26 May.

See my yotpak at boatbooks.co.nz/weather.html for terms used.
Weathergram text only (and translator) is at weathergram.blogspot.co.nz
Weathergram with graphics is at metbob.wordpress.com, click FOLLOW at
bottom right to subscribe.
My website is at metbob.com
Feedback to bob@metbob.com
To unsubscribe: send a reply email saying LEAVE.

17 May 2015

Bob Blog

WEATHERGRAM
YOTREPS
Issued 17 May 2015
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.

Wellington and Kapiti s Thursday deluge:
As an active front rolled under a jet stream last Thursday it was able to
enjoy some enhanced upward motion. The arrangement of winds, with Jet
stream on top, prefrontal northwest winds underneath and converging winds
along the front, allowed rain to be collected from a wide area and then
focused so that it fell in a narrow zone. The rainfall occurred in narrow
bands, or as thunderstorms, and so some parts of the region were affected
far worse than others. MacKay s crossing had 145mm, and Otaki, just a
few miles further north, had insignificant rain. Avalon in the Hutt Valley
had 42mm in one hour.

The Tephigram for Paraparaumu (data from MetService and see display from
http://weather.uwyo.edu/upperair/sounding.html) around midnight during the
event it is a graph of the temperature and dew point trace as measured by a
weather balloon ascending through the atmosphere and is one of the main tool
s used by meteorologists to examine these sort of storms.
The winds are calculated by the actual drift of the weather balloon,
followed by GPS transponder, and are plotted on the right hand side of the
graph so that NW winds are drawn as coming from the top left. A barb is
worth 10 knots, half a barb is 5, and a pennant is 50. Notice how these
winds show a jet stream on top at 80 knot and winds curving with height so
they sculpt and focus the falling rain.


The Atmosphere:
The Southern Oscillation Index SOI is based on the standardized difference
in the barometer readings between Tahiti and Darwin (30 day running mean)
and sums up the weather pattern over the South Pacific as one number. It
went negative, to be -10 units for a few weeks in late March/early April,
then relaxed for a while. It has dived very negative in the past week, and
I think this is in response to a low that formed near Tahiti and has since
then moved off. Another trough of low pressure is expected to affect Tahiti
this week, and maybe this is going to be the trend as El Nino settles into
the atmosphere.
SOI is shown at
http://www.farmonlineweather.com.au/climate/indicator_enso.jsp?c=soi&p=weekl
y
If this index remains lower than -10 for four weeks in a row then we have a
fully- blown El Nino.

The Ocean
More than half of the world s oceans are warmer than they should be at
present, and this is true along the entire Pacific equator. This means the
ocean is storing extra energy, not just in the target area for El Nino, but
also in many other places. When this excess gets into the atmosphere we can
anticipate extreme storms. Sea surface temperature anomaly is shown at
http://www.ospo.noaa.gov/Products/ocean/sst/anomaly/index.html

TROPICAL TOPICS
Super Typhoon DOLPHIN is managing to stay offshore as it swings past the
Philippines this week. There has been a tropical Low over the Solomons for
the past week and we have been watching it wondering if it would develop
deeper. Well it now looks as if that system is now on its last legs and
should fade away in next few days.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
This year s Atlantic Hurricane Forecast: has now been issued. This region
has already had ANA, and the forecast is for BELOW NORMAL NUMBERS= 8 named
storms. 4 hurricanes and 1 major hurricane are predicted for the Atlantic
basin, with only 2 or 3 USA landfall.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
In an El Nino year the Indian monsoon is usually late, slow, and not-so-wet.
Well, this El Nino hasn't really got into the atmosphere yet, and the Indian
Monsoon is starting up already and is maybe a day or so EARLY. You can see
it as these SW winds in the Bay of Bengal on windyty.com, and when you
switch to rain and accumulation for next 10 days, then the
amount that is being predicted is indeed under-whelming.
( I like to check out the FL350/450 winds at this time of the year and
spot Easterly Jet Streams they are so weird and I'm sure there is a Phd
waiting for anyone who can dare try and explain them!)
If you would like a website to track this year s monsoon then try
http://www.imd.gov.in/section/nhac/dynamic/Monsoon_frame.htm

Weekly rain signatures are seen at
http://trmm.gsfc.nasa.gov/trmm_rain/Events/big_global_accumlation.gif
The rain map for the last two weeks shows heavy rain with DOLPHIN and that
low over the Solomons. Also rain from a low near Tahiti. And some bursts
of rain continuing from Nepal to the China coast.

WEATHER ZONES
Galapagos to Marquesas?
Better winds for departing are on local Wednesday/Thursday this week. There
is now a counter-current to avoid near EQ to 4S at 95W so go to south of 4S
95W, then chase the west-going current which is still along about ^S from
100W to 130W a free ride. There may be some convergence shower activity
north of 5S, another reason to stay south of 5S.

SPCZ=South Pacific Convergence zone.
SPCZ is expected to relax this week over Solomons remain active across
Solomons and part of it may travel south cross Coral Sea and reach new
Caledonia by the end of the week. The main part of SPCZ is likely to stay in
the northern position from
Tuvalu to Samoa to the Cook Islands/ Australs. One friend from Bora Bora
has emailed me to say he hasn't seen the sun in weeks.

STR= Sub-tropical Ridge
HIGH in central Tasman Sea is expected to be a frosty one as it crosses NZ
on Tue/Wed/Thu. With its central pressure easing to 1022 or less it does
not have a squash zone of enhanced easterly winds on its north side. From
Thursday it is expected to move off the east along 25S.

Tasman Sea /NZ
Trough is expected to move onto South Island from Wednesday and develop a
LOW in central Tasman Sea by Thursday that is expected to deepen as it
crosses northern NZ on Fri/Sat 22/23 May.

Departing from Australia to the tropics this week?
May still be too much onshore wind over Queensland on Monday, but OK to go
on Tuesday/ Wednesday. Take care with the wind changes and rain from that
Low on Thursday, and the southerlies and big swells that follow it on
Friday. A squash zone of strong SE winds is expected in the Coral Sea by
end of the week.

Departing from Northern NZ going north?
As the HIGH goes East there are some SW/S/SE winds that are good for going
north Best departure date was today, and Monday departure is OK but likely
to be engulfed by Wed/Thu and then will need to contend with prefrontal
Northerly/NW winds on Friday and the FRONT on Saturday 23 May. FRONT
should be followed by OK SW/S/SE winds for the remainder of trip. By
Tuesday the current window closes. Next window might open around Sun 24
or Monday 25.

Departing from Northern NZ going east?
Good departures on Monday and Tuesday. After that it may be better to wait
until next Sunday or Monday.

See my yotpak at boatbooks.co.nz/weather.html for terms used.
Weathergram text only (and translator) is at weathergram.blogspot.co.nz
Weathergram with graphics is at metbob.wordpress.com, click FOLLOW at
bottom right to subscribe.
My website is at metbob.com Feedback to bob@metbob.com
To unsubscribe send a reply email saying LEAVE.

10 May 2015

Bob Blog

WEATHERGRAM
YOTREPS
Issued 10 May 2015
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.

For those thinking about landing at Tanna, Vanuatu:
The following notes have been sent to me by good-fella Eric Simmons from
Nelson.

1 Lenakel, on Tanna, isn't too bad as a Port of Entry, anchor in sand at
19 32.07S 169 15.91E, just behind the reef and you will have a comfortable
stay unless the wind moves to the South from Southeast and then it will be
rolly. Do not even try to use the concrete wharf!

2. It is possible to temporarily clear into Vanuatu at Port Resolution, SE
side of Tanna ,if you get advanced permission from Vanuatu Customs and
Inland Revenue, you need at least 24hours advanced noticed it can be two
months. This can be done on the "Contact Us" page of their website,
www.customsinlandrevenue.gov.vu/index.php/contact-us/advance-advice-of-
arrival-for-small-craft

You will need to let them know the place that you wish to arrive at in
Vanuatu, e.g. Port Resolution, Tanna, an approximate date of arrival, name
and description of boat, who is on it and documentation plus anything that
you are carrying that may need declaring, so basically copy all the
information on your advanced arrival form that you have completed and paste
it into the email when you are requesting approval. The fine men at the
Customs Department will get back to you with approval in short time
providing nothing is untoward. Once you have this and you arrive at Port
Resolution, Werry at the Yacht Club will contact Customs and Immigration who
will travel over to inspect and clear you. There is a fee of 5000vatu for
Customs and 5000vatu for Biosecurity for clearing in a port other than a
Port of Entry. There is also a charge of 15000vatu for travelling for 2hours
over the horrendous road from Lenakel and 2 hours back again. Just remember
they will help you if you play by the rules but woe betide those who don't.

If you need to know anything about Vanuatu you can refer to www.
vanuatucruising.info where you can download a free cruising guide for
Vanuatu or email us on cruising@vanuatutravel.info

The Atmosphere:
The Southern Oscillation Index SI sums up the weather pattern over the South
Pacific as one number and is based on the standardized difference in the
barometer readings between Tahiti and Darwin (30 day running mean).
It relaxed to zero in early March and then went negative, to be -10 units
for a few weeks in late March/early April, then relaxed in April and is now
steady.

If this index remains lower than -10 for four weeks in a row then we have a
fully- blown El Nino, but since it is now relaxing the trend is away from
an El Nino at present.

The Ocean
Last year at about this time, the Climate Prediction Center (CPC) predicted
a 70 percent chance of a weak to moderate El Niqo onset by last August, and
an 80 percent chance that it would occur by last November.
Well, we got a weak and stuttering El Nino instead.
The latest guidance from the CPC now indicates the current weak El Niqo
condition could strengthen to a moderate or even a strong event by mid or
late 2015.
In terms of Sea surface temperature: A weak El Niqo is classified as sea
surface temperatures in a selected area around the eastern equatorial
pacific (STEEP) for 3 consecutive months to be warmer than normal within a
0.5 to 1 degree Celsius range. A moderate El Niqo is classified as a 1 to
1.5 degree Celsius anomaly and a strong El Niqo is above 1.5 degrees
Celsius.

The latest CPC ensemble forecasts indicate that warmer than normal sea
surface temperature will continue through January 2016. Some of the model
solutions indicate as much as 2.5 degrees warmer than normal while the
consensus line indicates around 2 degrees.

TROPICAL TOPICS
Super typhoon NOUL is sideswiping the Philippines tonight. This is already
being followed by its successor DOLPHIN The equatorial westerly winds have
been very productive recently around Papua New Guinea.

The rain map for the last two weeks also show this build-up of activity. the
Solomons are in for a drenching this week, Weekly rain signatures for
week, is seen at
http://trmm.gsfc.nasa.gov/trmm_rain/Events/big_global_accumlation.gif \

WEATHER ZONES
Galapagos to Marquesas:
Best winds for departing are on local Thursday/Friday.
As last week the best strategy is as follows: First of all head for 5S 100W.
Then the middle leg is westwards along 5 to 6S as far as 125W enjoying a
west-ward going current. And then the third leg is to go direct in SE
winds. There now appears to be likely that a convergence zone may form
along 3 to 5S west of 125W next week.

SPCZ=South Pacific Convergence zone.
SPCZ is expected to remain active across Solomons and that LOW moves slowly
SW into the Coral Sea brining drenching rain and several squalls.
That LOW is likely to finally fade in the Coral Sea around early next week,
but from 20 May and new low may move slowly towards Vanuatu, so avoid
Solomons and the Coral Sea and keep on watching nearby.
Remainder of SPCZ spreads from Solomons to Tuvalu Samoa to Tahiti. This may
break into chunks during the week and a new zone may form across Southern
Cooks replacing the zone over Tahiti.

STR= Sub-tropical Ridge
STR is expected to remain north of NZ this week.
No Highs in Tasman Sea this week. Next big HIGH is expected to spread from
Australia into Tasman Sea from Sun 17 May (next week) and reach northern NZ
around Fri 22 May.

Departing from Northern NZ going north.
Trough is expected to cross NZ on Tuesday and another on Thursday followed
by a deepening Low on Friday/Saturday. The next likely looking weather
pattern for a possible departure north or northwest is Sat16/Sun 17/Mon 18th
May.

Departing from Northern NZ going east.
The long period of roaring 4os weather that NZ is now about to experience
is good for this voyage, but you need to be careful and try and run the
northern edge of the roaring 40s zone, maybe at 44S at times.
Email me at bob@metbob.com for more info.

See my yotpak at boatbooks.co.nz/weather.html for terms used.
Weathergram text only (and translator) is at weathergram.blogspot.co.nz
Weathergram with graphics is at metbob.wordpress.com, click FOLLOW at bottom
right to subscribe.
My website is at metbob.com Feedback to bob@metbob.com To unsubscribe
send a reply email saying LEAVE.

03 May 2015

Bob blog

WEATHERGRAM
YOTREPS
Issued 3 May 2015
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.

The Atmosphere:
The Southern Oscillation Index SOI sums up the weather pattern over the
South Pacific as one number and is based on the standardized difference in
the barometer readings between Tahiti and Darwin (30 day running mean).
It relaxed to zero in early March and then went negative, to be -10 units
for a few weeks in late March/early April, then relaxed in April and is now
steady.
SOI is shown at
http://www.farmonlineweather.com.au/climate/indicator_enso.jsp?c=soi&p=weekl
y

TROPICAL TOPICS
As we move into the month of May, the NW Pacific fires up. This region is
likely to produce a cyclone per week for the next 26weeks (that s an
alphabet of Cyclones). Currently this week s cyclone is numbered 06W which
is a number it gets from the computer models, but as you can see from this
forecast from JTWC its gales are on their way to Philippines region by 8
May.

The rain map for the last two weeks show not much change, but what is
apparent is an increase in extent and activity along the ITCZ, and a
decrease in activity around French Polynesia. The east Australian coast is
still a hot spot for rain.
Weekly rain signatures are seen at
http://trmm.gsfc.nasa.gov/trmm_rain/Events/big_global_accumlation.gif

WEATHER ZONES

Galapagos to Marquesas:
Best winds for departing are on local Wednesday, otherwise be prepared to
motor at the start.
As last week the best strategy is as follows: First of all head for 5S at
around 97 to 100W, even though this involves motoring into light SSE winds.
Then the middle leg is westwards along 5 to 6S as far as 125W enjoying a
west-ward going current. And then the third leg is to go direct in SE
winds.

SPCZ=South Pacific Convergence zone.
SPCZ is expected to remain active from Samoa to French Polynesia, triggering
a LOW just south of Australs Islands by Tues 05 May which is expected to
intensify a while as it goes southeast, finally weakening meat 40S.
SPCZ should also drift south across Vanuatu this week and may help form a
trough there on Thu/Fri/Sat. Strong NE/E winds on eastern and southern side
of this trough. Avoid.

STR= Sub-tropical Ridge
STR is expected to remain north of NZ this week. Also it is expected to
move into interior of Australia bring clear and therefore cold long nights
to their desserts. This allows the roaring 40s to spread north.
High over northern NZ this weekend is already travelling off to the east and
should do so along 35S for remainder of this week. Next significant HIGH to
reach Eastern Australia is NOT expected before 17 May, and may not reach NZ
until 20 May, so the Tasman Sea is being set up for a dose of disturbed
westerly winds.

Departing from Eastern Australia this week:
That LOW which was mentioned in last Weathergram to visit Brisbane area last
Thursday/Friday was a real damaging beast. It has already turned into an
area of slack winds which is crossing the north Tasman Sea from Monday
reaching 30S to north of NZ on Friday, and this might be a weather window
for motoring vessels to the tropics.
However, if you are intending to sail then beware of a series of fronts and
lows crossing the Tasman Sea, and filling up the Tasman with westerly gales
and heavy swells. One of these is expected on Tuesday to Thursday, another
from Friday to Sunday and a third on Sunday and Monday 10/11 May-followed by
several more the following week.

Departing from Northern NZ going north.
Those vessels which departed during the light winds of this passing HIGH
over the weekend should be able to pick a speed so that they arrive north of
25S after the squash zone of strong winds there finally ease by Thursday.
An approaching front is preceded by strong NW/N winds, so no good departing
between now and when that front passes on Thursday. Then Ok to go until next
front reaches northern NZ on Monday 11 May. Then a long period of strong
disturbed westerly winds is expected- stay and read a book unless you are
racing.

Departing from Northern NZ going east.
The long period of roaring 4os weather that NZ is now about to experience
is good for this voyage, but you need to be careful and try and run the
northern edge of the roaring 40s zone. Hard to do when this keeps buckling
with each passing Low and High. Email me at bob@metbob.com for more info.

See my yotpak at boatbooks.co.nz/weather.html for terms used.
Weathergram text only (and translator) is at weathergram.blogspot.co.nz
Weathergram with graphics is at metbob.wordpress.com, click FOLLOW at bottom
right to subscribe.
My website is at metbob.com Feedback to bob@metbob.com
To unsubscribe send a reply email saying LEAVE.

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