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Leg 1, 2019

Weather Forecast


1. Weak front expected to cross Hauraki Gulf on Friday afternoon. Local forecast is for NW15 turning to SW10 knots with some rain. The models I'm using can't resolve this detail and have come out with light variable. Since we are mostly going east on Friday the passing front should be manageable, but may require some sail changes-- good exercises for Day 1. 

2. On Saturday, may be a foggy/low cloud start and motoring in light winds, a Northwest should l kick in and e can sail then , aim for 36S 178E

3. from 36S 178E go due east to 173:40W in prefrontal NW winds, they peak on Sunday night (NZ date) are briefly may get to 25gust 35 knots then ease as the rain arrives.

4. The frontal passage should bring us SW to S winds around 20 knots or less , and we can use these to get north. Two waypoints for getting thru the trades to Rurutu:.
33:15S 162:30W and 31S 158W then to Rurutu near 22:28S 151:23W--- but will need an update on these waypoint as you approacth173::40W 

5. OUTLOOK from 173:40W is for winds S to Se at first and increasing swell after the front. Peak 3.7m from South on 15 May (NZ date) but period 9 seconds so these should be well spaced waves, gentle giants. -- may need to fall off to the north on Tuesday night / Wed (NZ time) at time s in ESE head winds
and there may be another trough passing over on Wed night /Thu 15/16May NZ time, followed by SW winds --all that outlook will need updating,

To: John Neal and crew on SY "Mahina Tiare III"
From: Commanders’ Weather Corporation, tel: 603-882-6789, info@commandersweather.com
Route: Auckland, NZ to Rurutu, Austral Islands
Departure: 1000LT Fri, (2200utc Thu) May 10, 2019
Prepared: 1545utc Wed, May 8, 2019

Summary:

1) Overall things look pretty similar to yesterday with typical conditions for this part of the world – will have a strong cold front to contend with a few days out with favorable wind directions ahead of and behind it, but there will be a cold front moving by every few days and getting deeper into fall they will get stronger, so see no reason to delay.

2) High pressure will be centered around 41s/161w on Friday with a ridge axis stretching to the ENE and another one to the WNW to near Cape Reinga and into the far NE Tasman Sea.

3) A weak cold front will be crossing New Zealand to the S and SW of the high pressure ridge moving more SE than E or NE.

4) A stronger cold front with low pressure developing along it will be in the far western Tasman Sea just off the SE coast of Australia.

5) With the front to the S and SW and the high pressure ridge to the N and NE, winds will be mainly NW as you head out Fri.

a) Speeds will be mainly in the teens, nothing real strong since this front will be weak.

6) Heading into Sat, the high pressure ridge will pull/shift to the east with the western end of the ridge north of northern New Zealand and the weak cold front will move away to the SE and the low will continue developing and intensifying along the cold front as it moves east across the Tasman Sea.

a) It looks like the front will not pass you with winds remaining NW and veering more to the N later

in the day as the western end of the ridge approaches and speeds mainly in the teens again.

7) For Sunday, the high pressure ridge will continue to shift slowly eastward and the low and cold front will head toward New Zealand with the northern end of the front extending well NNW toward New Caledonia.

a) N to NNW winds will increase to the 20s to low 30s sustained with higher gusts Sunday as the cold front approaches.

b) If slower or delayed departing at all, winds will be stronger back to the W and SW closer to northern new Zealand with speeds in the 30s to near 40 knots sustained.

c) The strong winds will extend well to the N and NW of your route, so no good practical way to avoid having them come through.

8) Heading into Mon, the low and front will shift more E and SE with not a real big push to the NE and high pressure will build behind the front across the Tasman Sea and SE Australia.

a) The front will pass through early Mon with the strong NW winds quickly backing around into the S to SE with speeds in the 20s to near 30 knots for a time.

9) The high will build eastward and stretch out west-east between 30-40s for the middle of next week which may lead to winds backing more ESE and becoming lighter according to the U.S. GFS model while the Euro model develops a low on the cold front to your east leading to winds more SE to SSE and possibly stronger.

a) Will have to fine tune the long range as we get closer, but for now not planning on any big deviations to routing.

10) Seas will start out low with a bit of NW swell the first couple of days, then building to 8-12 feet ahead of and behind the cold front for Sunday and Mon, then diminishing steadily with longer period S to SE swell for the middle of next week.

11) General weather will have some variable clouds with a few showers from the weak cold front to start, then turning unsettled later Sunday into Mon with showers and squalls ahead of the cold front followed by a few scattered squally showers behind it, then turning fair and settled midweek with the high building in from the west.

12) Please keep us advised of your progress and let us know when you need any updates en route.

Routing:

1) It looks like a general ENE heading will be good avoiding rougher conditions further south but at the same time not getting too far north into possible head winds north of the subtropical high pressure ridge axis further out in time.

2) We may need to adjust more south or north further out in time once we are more certain of the weather pattern later next week and beyond.

3) Some estimated positions listed below.

Wind forecasts

Time is UTC: wind directions in TRUE/wind speed in KTS

Thu, May 9

22: 310-330/10-16 departure

Weather…Variable cloudiness with a few scattered showers

Seas 2-4 ft

Fri, May 10 – weak cold front moving away to the SE

00: 310-330/13-19

06: 310-330/11-17

12: 300-320/10-16

18: 290-310/10-15

Weather…Variable clouds with a chance of showers early, then becoming partly cloudy to fair

Seas 2-4 ft, NW swell

Sat, May 11 – winds stronger back to the west if you are slower

00: 300-320/12-18 near 36 10s/178 05e

06: 310-330/11-17

12: 330-350/13-19

18: 340-360/13-19

Weather…Partly cloudy to cloudy

Seas building to 4-6 ft, increasing NW swell

Sun, May 12 – strong cold front moving across NZ, rougher weather back to the west

00: 350-010/15-22 near 35 30s/178 31w

06: 350-010/18-25 g30

12: 330-350/20-30 g35

18: 320-340/22-30 g35

Weather…Mostly cloudy with scattered showers and squalls developing

Brief gusts up to 40-45 knots possible in any heavier squall

Seas building to 8-12 ft, increasing NW swell and wind waves

Mon, May 13 – cold front passing through

00: 310-330/20-30 g35 near 34 55s/175 20w

06: 250-280/20-30 g35

12: 170-190/18-25 g30

18: 160-180/20-30 g35

Weather…Showers and squalls early, then variable clouds with scattered squally showers

Brief gusts up to 40-45 knots possible in any heavier squall

Seas 8-12 ft, NW to SW-S swell and wind waves

Tue, May 14

00: 120-140/16-24 near 34 15s/172 25w

12: 120-140/15-22

Weather…Variably to partly cloudy, chance for a squally shower or two

Seas diminishing to 8-10 ft, longer period S to SE swell and diminishing wind waves

Wed, May 15 – forecast less certain, winds may be more SSE?

00: 110-130/15-22 near 33 15s/169 25w

12: 110-130/13-19

Weather…Partly cloudy

Seas down to 6-8 ft, S to SE swell

Thu, May 16 – forecast uncertain, could be another cold front approaching with NW winds?

00: 100-120/ 5-10 near 32 25s/166 25w

12: bcmg 320-350/10-16

Weather…Partly cloudy to cloudy

Seas down to 4-6 ft, leftover long period SE swells

Best regards,

Oliver Lucia

Commanders' Weather Corporation
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