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Leg 1 - 2013, Update 1: Weather

From: "Commanders' Weather" <info@commandersweather.com>
Subject: Auckland to Rurutu forecast
Date: Wed, 8 May 2013 14:26:30 -0400

To: John Neal and crew of SY 'Mahina Tiare'
From: Commanders' Weather Corp, tel 603-882-6789
Route: Auckland to Rurutu
Depart: approx. 18utc Thu, May 9, 2013
Prepared: 1630utc, Wed, May 8, 2013

John, this trip looks interesting and somewhat challenging. Please stay in touch every few days and we can make sure you are moving to the correct spots for good wind.

Summary:

1) very active weather pattern continues in your region of the South Pacific

a) beginning with the complex low pressure area over North Island that is expected to move one low to the E of North Island around your departure time on the 9th
b) followed by another low that organizes on a strong cold front around your departure time just W of central South Island
c) this low and front will push to the NE, bringing the low near Cape Reinga around the time you near the tip of the Coromandel
d) then continues it off to the NE to be centered near 30S/175E by 00utc on the 11th
e) and helps to build some gusty SE-ESE winds for your first few days
away from NZ


2) by 00utc on the 12th, the strong cold front is forecast to extend N to near Rurutu

a) with a strong push of SW-S winds and swell from the E NZ coast to the cold front
b) routing right now takes you ENE near the ridgeline of the high that fills in behind the cold front
c) this 1034MB high is expected to be centered just W of the Cook Strait and, in combination with the lower pressure well to the E, will help to build your winds and seas out of the SE-ESE


3) we will be watching low pressure forming near Fiji around the 12th-13th'" over the past 24 hours there have been so many different scenarios for this low

a) it should slide to the SE or ESE into the middle of the week but also not sure how strong it will be (it was stronger in the forecasts yesterday vs today)
b) you may end up between the low to the N and the strong cold fronts to the S of your route
c) which could set you up traveling in light winds of high pressure squeezed between the two
d) we will monitor your progress and can recommend a change to your routing if this scenario happens

Routing:

1) recommend a rhumbline route right now for a better sailing angle on the ESE-SE winds during your first couple of days

a) then to take advantage of some expected S to SSE winds into the middle of next week
b) the later part of this routing could be affected by a low that is expected to form near Fiji around the 13th and generally travel off to the SE into next week
c) if the low looks like it will become a problem for your route, we will be in touch and recommend a change in your course to move around the low

2) routed you averaging closer to 120-130 nm/day for the first half of this forecast period

a) then getting to 150 nm/day by later in the forecast period

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

Thu, May 9
00: 240-260/6-12
06: 250-270/10-18
12: 260-280/12-18
18: 270-290/10-18 depart Auckland
Weather: Variably cloudy, a few showers/squalls
Seas: 2-4ft, light W swell

Fri, May 10
00: 280-300/10-15
06: 280-300/8-14 between Coromandel and Great Barrier Island
12: 300-320/10-16
18: light/variable
Weather: Variably to mostly cloudy, with increasing showers/squalls
Seas: up to 3-5ft, light NW swell

Sat, May 11
00: 110-130/20-28 g35 nr 35 30S/177 20E
06: 110-130/20-30 g40
12: 120-140/20-30 g40
18: 120-140/20-30
Weather: Variably to mostly cloudy, with showers/squalls
Seas: building quickly to 10-12ft, in choppy and confused conditions

Sun, May 12
00: 110-130/20-28 nr 34 50S/179 50E
06: 110-130/20-25
12: 110-130/15-20
18: 100-120/ 12-18
Weather: Variably to mostly cloudy, with showers/squalls
Seas: easing to 8-10ft, during the day, SE-S swell

Mon, May 13
00: 100-120/5-10 nr 34S/177 30W
12: 130-150/8-14
Weather: Variably cloudy, maybe a few showers/squalls
Seas: 8-10ft, in some SE windwave and increasing S-SW swell

Tue, May 14
00: 140-160/10-16 nr 33 10S/175W
12: 120-140/8-14
Weather: Variably cloudy, maybe a few showers/squalls
Seas: down to longer period 6-8ft, in some N and some SW swell

Wed, May 15
00: 110-130/10-15 nr 32 10S/172 10W
12: 110-130/8-14
Weather: Variably cloudy, maybe a few showers/squalls
Seas: down to longer period 5-7ft, in some N and some SW swell

Best regards,
Brynn Campbell


Weather Update Leg 1 - Update 2

From: "Commanders' Weather" <info@commandersweather.com>
Subject: Weather Forecast 5/13/13
Date: Mon, 13 May 2013 09:40:46 -0400

To: John Neal and crew of SY 'Mahina Tiare'
From: Commanders' Weather Corp, tel 603-882-6789
Route: Auckland, NZ to Rurutu
Position: 33 15s/179 55e at 0300utc Mon, May13, 2013
Prepared: 1345utc Mon, May 13, 2013

Summary:

1) Large high pressure is currently across the western Tasman Sea and New Zealand and then stretches ENE toward Tahiti.

2) An area of low pressure is developing around 25s/176w along a low pressure trough.

3) The developing low and trough will be pressing southward toward the high pressure ridge and this will bring increasing E winds over the next 12-18 hours.

a) Wind speeds will increase to near 30 knots on average and gust to around 40 knots by late today.

b) This of course will make for tough going trying to continue on a course close to rhumb line, more details below in the routing section.

4) It looks best to head more north in these east winds and cut through the low pressure system to get on the north side of the low in the much more favorable following WSW to W winds, again see details below in the routing section.

a) As you head north winds will eventually veer into the SE, then S to SW for Wed.

b) Wind speeds will ease as you cross the low for a time with speeds dropping into the teens, then increasing into the 20s again on Wed as you get north of the low.

5) The various weather models are in decent agreement on the details of this low the next couple of days with most of them showing that the low will begin to slowly pull eastward later Tue and Wed and becoming rather elongated as this happens.

6) If you get north as outlined below, you will have mainly W to WSW winds for Thu and Fri with wind speeds slowly diminishing with time.

a) South of this elongated low, south of 33S or so there will be strong E or ENE winds with speeds in the 20s to low 30s later this week, so we will certainly want to avoid that.

b) Closer to 30S will be a zone of very light winds within the elongated low pressure axis.

c) So getting north is the best option for sure.

7) Also further north there will be another weaker high pressure ridge around 22-23S with lighter winds between 20-25S.

8) Seas will have a building E swell and wind wave chop over the next 12-24 hours with seas reaching 8-12 feet, then they will diminish to low end moderate levels Wed onward with swell eventually switching to the SW with diminishing chop.

9) General weather will trend unsettled with developing rain, showers and squalls today and it will remain unsettled for a couple of days due to the low in the vicinity, then a trend to quieter weather later in the week as you get away from the low and the low weakens to the south.

10) It is probably a good idea to get another update 48 hours from now but you can let us know if you would like it then.

Routing:

1) It looks best to begin heading more northward as winds increase over the next few hours from the E.

a) You will be headed toward the center of the low and the goal is to get on the north side of the low into the westerlies!

b) Did look at heading SE or SSE and that option does NOT look good in the longer term with strengthening E winds later this week into the weekend and early next week in that direction.

2) It looks like you will be able to resume a direct course toward Rurutu
on Wed or Thu as you get north of the low.

3) Some estimated positions listed below.

Wind forecasts

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

Mon, May 13

18: 080-100/16-24

Weather' Mostly cloudy with periods of rain, showers and squalls developing

Seas 5-7 ft, long period SE to S swell with increasing shorter/steeper E
seas

Tue, May 14

00: 070-090/18-25 g30 near 32s/178 30w

06: 080-100/25-35 g40

12: 080-100/25-35 g40

18: 110-130/25-35 g40

Weather' Cloudy with rain, showers and squalls

Seas building to 8-12 ft, increasing E swell with rough wind wave chop

Wed, May 15

00: 130-150/12-18 near 29 40s/177 25w

06: bcmg 220-250/10-18

12: 220-240/20-30 g35

18: 230-250/20-30 g35

Weather' Cloudy with rain showers and squalls early, then scattered squally showers late

Seas diminishing to 5-7 ft, leftover E-SE swell with wind wave chop increasing late

Thu, May 16

00: 240-260/20-30 g35 near 28 10s/175 20w

06: 250-270/18-25 g30

12: 260-280/17-24

18: 260-280/15-22

Weather' Variable clouds with a few scattered squally showers

Seas 5-7 ft, W-SW swell and wind wave chop

Fri, May 17

00: 260-280/14-20 near 27 40s/172 45w

12: 260-280/13-19

Weather' Partly cloudy

Seas 5-7 ft, W to SW swell

Best regards,

Oliver Lucia

--
*
*Commanders' Weather Corporation
Tel: 603-882-6789
Email: info@commandersweather.com
Website: commandersweather.com
Normal hours of operation: 5am to 5pm US eastern time, 7 days a week


Weather Update Leg 1 - Update 3

To: John Neal and crew of SY 'Mahina Tiare'
From: Commanders' Weather Corp, tel 603-882-6789
Route: Auckland, NZ to Rurutu
Position: 29 15s/176 08e at 1600utc Wed, May 15, 2013
Prepared: 1730utc Wed, May 15, 2013

Summary:

1) low pressure centered near 31S/173W around 18utc on the 15th

a) to keep you in SW to WSW winds for the next few days in the NW corner of the low

b) satellite shows the main area of squalls and thunderstorms with this low are to the SE of the center and traveling away from you, as the low is heading SE

c) keeping you in some clouds with scattered showers and a few squalls

2) latest forecast models show the low moving to near 36S/157W by 12utc on the 17th

a) to put you into WSW to W winds for a time (about 18-24hours) before your winds begin to clock out of the WNW-NW in advance of the next cold front

b) this cold front is associated with a complex area of low pressure that should set up around NZ during the 17th and 18th, utc time

c) by 12utc on the 18th, the cold front is forecast to stretch from the S tip of New Caledonia toward the SE to near 40S/170W

d) to give you slowly building NW winds expected from the 18th through the 20th as the lows and cold front remain to your S and slide E

Routing:

1) took a look at a few different routes for you '" an ENE route to slowly work you toward Rurutu AND an E route

a) the ENE route brings you into the middle of the high that fills in N of the low and into building E winds along the N side of the high

b) the E route keeps you in following winds for the next 5 days

c) recommend we take one more look at your route this weekend to see where the high and cold front have set up to get you to Rurutu without headwinds

2) kept you averaging 150 nm/day in some gusty SW to WSW winds for the next few days

a) then down to about 140 nm/day in some lighter WNW to NW winds this weekend and into the beginning of next week

Wind forecasts

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

Thu, May 16
00: 240-260/16-23
06: 240-260/15-22
12: 230-250/15-20 nr 29S/173 30W
18: 230-250/16-22
Weather' Variably to mostly cloudy with a few scattered squally showers
Seas up to 8-10ft, in SW windwave and swell

Fri, May 17
00: 240-260/16-23
06: 250-270/15-20
12: 250-270/14-20 nr 29S/170 30W
18: 260-280/15-22
Weather' Variably to mostly cloudy with a few scattered squally showers
Seas 8-10ft, in SW windwave and swell

Sat, May 18
00: 270-290/17-22
06: 270-290/12-20
12: 280-300/10-16 nr 29S/167 30W
18: 290-310/10-18
Weather' Variable clouds with a few showers/squalls
Seas easing to 6-8ft in lighter windwave and swell

Sun, May 19
00: 290-310/10-18
06: 300-320/10-15
12: 310-330/10-14 nr 29S/164 30W
18: 310-330/10-15
Weather' Variable clouds with a few showers/squalls
Seas 6-8ft, light W swell

Mon, May 20
00: 310-330/10-18
06: 320-340/10-16
12: 320-340/10-15 nr 29S/161 50W
18: 320-340/10-15
Weather' Variably to mostly cloudy with a few scattered squally showers
Seas down to 5-7 ft, light W-WNW swell

Best regards,
Brynn Campbell

 

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