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Weather Updates Leg 7 - 2012


From: "Commanders' Weather" <info@commandersweather.com>
Subject: Weather Forecast 10/9/12
Date: Tue, 9 Oct 2012 10:44:32 -0400

To: John Neal and the crew of 'Mahina Tiare'
From: Commanders' Weather Corp, tel 603-882-6789
Route: Noumea, New Caledonia to Brisbane, Australia
Departure: 0000utc Wed, October 10, 2012
Prepared: 1445utc Tue, October 9, 2012


Summary It looks like a strong cold front to contend with on Fri with about a 24 hour period of rough conditions, otherwise much of this trip looks quiet and tranquil

1) The current weather map shows a broad and weak high pressure ridge running between New Caledonia and the east central coast of Australia.

2) A weak front or trough stretches from near northern New Zealand NW toward New Caledonia cutting through the high pressure ridge.

3) A weak area of low pressure is across the northern Tasman Sea tracking ESE.

4) You will have E trades to start your trip with the ridge to the S and SW of the area heading out today.

a) Wind speeds will be fairly light to start but will freshen well into the teens to possibly near 20 knots at times by late Wed.

5) A cold front will be getting organized and strengthening across eastern Australia with low pressure developing along the front and tracking SE Wed into Thu.

6) The high currently between New Caledonia and the east coast of Australia will shift to the SE and become better defined during this time as well.

a) Winds will back through the NE and into the N to NW as the cold front begins to approach your
route on Thu.

7) Will have some rough conditions to deal with on Fri as the cold front approaches with strong NNW winds up to the 20s to low 30s sustained along with squalls which could gust to 40-45 knots.

8) Following the cold front winds will back quickly into the W to SW and will be gusty initially behind the front but quickly diminish by early Sat.

a) So you will be forced on a more N to NW course for a time behind this cold front, more details in the routing section below.

9) Large high pressure building across south central Australia will ridge to the NE causing winds to back into a much more favorable SE to E direction this weekend into early next week to finish your trip.

a) Wind speeds will be on the light side as well with the high pressure ridge not far to the south.

10) Seas will start with a long period low end moderate SW to S swell, then this will diminish to slight levels before seas increase late Thu into Fri with the stronger period of winds and they could become quite rough during this time, then subsiding quickly this weekend and remaining low into early next week.

11) General weather looks quiet much of the time except for Fri with a band of showers and squalls coming through associated with the cold front.

a) Some squalls could be on the heavy side with brief gusts up to 40-45
knots.

12) Please keep us posted on your progress and let us know if you need an update en route.

Routing

1) Have you starting out on a rhumb line course.

2) Following the frontal passage you will be forced more to the N and NW for a time with the W to SW winds.

3) But you should be able to resume a direct course fairly quickly about 12-18 hours after the frontal passage as winds back into the S to SE.

4) Some estimated positions listed below.

Wind forecasts

Wind directions are true, wind speed in kts, and time is UTC

Tue, October 9 '" offshore Noumea
18: 060-080/10-15
Weather's Mostly cloudy with a few showers and possibly a squall
Seas 5-7 ft, long period SW swell

Wed, October 10
00: 090-110/ 6-12 departure
06: 090-110/11-17
12: 090-110/14-20
18: 080-100/12-18
Weather's Variably to partly cloudy
Seas 5-7 ft, long period SW to S swell

Thu, October 11
00: 060-080/13-19 near 23 30s/163 50e
06: 030-050/12-18
12: 360-020/11-17
18: 350-010/16-24
Weather's Fair to partly cloudy
Seas diminishing to 3-5 ft, S to SE swell, building some late with increasing wind wave chop

Fri, October 12 '" strong cold frontal passage
00: 330-350/22-32 g37 near 24 40s/161 10e
06: 240-260/20-30 g35
12: 230-250/15-25 g30
18: 220-240/12-18
Weather's Scattered showers and squalls early, then variable clouds with a few squally showers
Any heavier squall could briefly gust to 40-45 knots
Seas building to 8-12 ft, increasing NW-SW swell and wind wave chop, then diminishing to 7-9 ft late

Sat, October 13
00: 190-210/11-17 near 24s/159e
06: 180-200/ 7-14
12: 120-140/ 6-12
18: 120-150/ 5-10
Weather's Partly cloudy
Seas decreasing to 5-7 ft, longer period SW to S swell

Sun, October 14
00: 130-150/ 6-12 near 25 20s/156 30e
12: 090-110/13-19
Weather's Partly cloudy
Seas 5-7 ft, S swell

Mon, October 15
00: 100-120/ 6-12 near 26 40s/154e
12: 060-080/ 8-15 near Brisbane
Weather's Partly cloudy to fair
Seas decreasing to 3-5 ft, S to SE swell

Tue, October 16 '" offshore Brisbane
00: 020-040/ 4-8
12: 360-020/ 5-9
Weather's Fair
Seas 2-4 ft

Kind regards,
Oliver Lucia

From: "Commanders' Weather" <info@commandersweather.com>
Subject: Noumea, New Caledonia to Brisbane, Australia update
Date: Thu, 11 Oct 2012 16:40:24 -0400

To: John Neal and the crew of 'Mahina Tiare'
From: Commanders' Weather Corp, tel 603-882-6789
Route: Noumea, New Caledonia to Brisbane, Australia
Position: 24 19S/162 13E, 1800utc Thu, October 11, 2012
Prepared: 1900utc Thu, October 11, 2012


Summary's

1) All is pretty much on schedule for the approach of the cold front during
the next 12 hours

a) currently, Lord Howe Island has winds building out of the W at 15-20kts, showing the intensification of the low E of Sydney
b) this strengthening low will help to intensify and push the cold front toward you
c) but it should also help to move the front quickly through your position by 00utc on the 13th
d) as you see winds back from the SW to the S and then SE during the 13th and 14th, utc time

2) by 00utc on the 13th, the low is forecast to be along the central W
coast of South Island, NZ

a) with the cold front extending from North Island, NZ to near Noumea,
New Caledonia
b) you should be far enough N that your gusty SW winds behind the front
will be short lived
c) with the NE corner of high pressure pushing across your position by
00utc on the 13th and backing your winds out of the SSW to S

3) as this high edges E through the weekend and into the beginning of next week, your winds are expected to remain mainly out of the SE-ESE on Sunday

a) then back out of the NE to N during Monday and Tuesday as you approach
Brisbane
b) with the high setting up between Lord Howe and Norfolk Islands to keep
you in the high's circulation
c) by later on Tuesday, the next cold front should be well removed from
Brisbane as it is forecast to stretch from near Sydney toward the NW into
central Australia

Routing:

1) continued your routing at 150-160 nm/day in the changing wind directions and speeds over the next few days

a) expect you will be able to stay on your WSW course for another 18
hours or so as the winds build out of the N and then NW
b) with your winds finally backing through the W to the SW, at 20-30kts,
around 12utc on the 12th
c) recommend you continue on a comfortable sailing angle for about the
next 6-12 hours, probably toward the N or NNW
d) then shift on a SW rhumbline course, probably around 00utc on the
13th, as the winds turn out of the S and then SE

Wind forecasts
Wind directions are true, wind speed in kts, and time is UTC

Fri, October 12
00: 330-350/20-28 g35 near 24 30S/161 40E
06: 270-290/20-25 g35
12: 230-250/20-30 g35 gusty push immediately behind the cold front
18: 200-220/14-20 g25
Weather's Scattered showers and squalls '" unstable, quickly shifting wind directions
Any heavier squall could briefly gust to 40-45 knots
Seas building to 8-12 ft, increasing NW-SW swell and wind wave chop, then diminishing to 7-9 ft late

Sat, October 13
00: 180-200/12-18 nr 23 50S/159 40E
06: 140-160/10-16
12: 130-150/ 10-15
18: 130-150/ 10-18
Weather's Variably to partly cloudy with chc of isolated showers
Seas decreasing to 5-7 ft, longer period SW to S swell

Sun, October 14
00: 120-140/ 14-20 nr 25S/157 30E
06: 110-130/ 10-18
12: 100-120/8-15
18: 090-110/7-14
Weather's Partly cloudy
Seas 5-7 ft, S swell

Mon, October 15
00: 080-100/8-14 nr 26 10S/155 10E
12: 040-060/6-13
Weather'ŚPartly cloudy
Seas decreasing to 3-5 ft, S to SE swell

Tue, October 16
00: 360-020/8-15 nr Brisbane
12: 340-360/6-12
Weather's Becoming variably cloudy, slight chc of a shower
Seas 2-4 ft

Kind regards,
Brynn Campbell

 

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