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Leg 3 - 2014, Forecast

From: "Rick Shema (WXGY)" <rick@weatherguy.com>
Subject: RE: Hello from Weatherguy.com
Date: Tue, 22 Jul 2014 10:37:18 -1000

Hi John:

You might want to head almost due north from 05N to 14N along 148W. Less ITCZ activity and less time in an area of maximum instability than a rhumbline course to Hilo. Expect first encountering low level clouds near 04N, then multilayered convective towering cu. Moderate to heavy rainshowers/squalls and possible thunderstorms. Winds become light and variable expect until about 11-12N. Then NE trades build to 20 kts.

As of 1100PST today, there was an area of tropical activity near 10N 120W or about 1125nm southwest of Cabo San Lucas. The system is moving westward at 13 kts. This area is concentrated with convective clouds, thunderstorms and heavy rain. It is likely the system will develop into a more organized circulation in about 5 days. This system may affect your passing through the ITCZ.

So suggest route as describe above at least 5.0 or greater as safest speed allows.

Best Regards,
Rick Shema, CCM


Original message follows.

From: "Rick Shema (WXGY)" <rick@weatherguy.com>
Subject: RE: Hello from Weatherguy.com
Date: Tue, 22 Jul 2014 23:36:08 -1000

Hi John:
Thank you for your note.
The highest winds I see right now outside of downdraft winds is NE 25 kts. I'm not too sure what you are seeing regarding the Pxxx warning box. However, there are two areas of concern.

At 0800 HST the NOAA discussions had this to say about them:

1. Showers and thunderstorms associated with an area of low pressure
located about 1200 miles southwest of the southern tip of the Baja
California peninsula have become better organized this evening.
Environmental conditions appear conducive for additional development
and this system is expected to become a tropical depression during
the next few days while it moves westward or west-northwestward at
10 to 15 mph.
* Formation chance through 48 hours...high...60 percent.
* Formation chance through 5 days...high...80 percent.

2. A tropical wave located about 1700 miles east-southeast of the Big
Island of Hawaii is producing disorganized showers and
thunderstorms. Some gradual development of this system is
possible during the next few days while it moves westward into the
central Pacific.
* Formation chance through 48 hours...low...near 10 percent.
* Formation chance through 5 days...medium...30 percent.

I'm a little concerned about the first system. But let's proceed northward and see how the situation develops.

BTW: Lee Chesneau sends his regards. He is sitting next to me in my office visiting this week from Seattle.

Best Regards,
Rick Shema, CCM


Original message follows.

From: "Rick Shema (WXGY)" <rick@weatherguy.com>
Subject: SV Mahina-Weather Update #1
Date: Thu, 24 Jul 2014 12:29:12 -1000

Hi John:

Thank you for your report this morning.

Here's how it's looking.
Weather Summary: As of 24July1200UTC. You are presently in a rather intense area of convective activity according to recent IR satellite imagery, relative to nearby surrounding areas. You should move north of the ITCZ and deep convection near 09N. Still mostly cloudy to overcast with lower level strato cu clouds and maybe still some heavy, non-convective rainshowers. This afternoon, wind direction should settle to more gradient winds of ENE about 15 kts outside of convective downdraft winds. Gradient winds increase to the 20 kt range moving north.

The tropical disturbance of concern is now located near 13 10N 134 45W or 840 nm to the ENE from your morning position. It has been given a slightly less chance of developing into an organized depression at 70% within two days and five days, which is down from 80% last NHC advisory. By the time you reach AP01, in about 37 hrs, the system should be about 675nm to the east of you. So I don't expect the tropical to affect you even if it does develop further.

Prior to reaching AP01, if ENE wind/sea conditions become too strong for comfortable sailing, then you can opt to head to Hilo early.

Significant wave heights should increase to about 10 ft range with increasing wind waves trade wind swell waves moving towards the subtropics.

Route: Based on your position, AP01 (Aim Point) was adjusted slightly west, then Rhumbline to Hilo
Adjusted AP01: 14 00N 148 40W
Average SOG since last night's position: 116nm over 15 Hr 30Min = 7.5 kts
Distance to Hilo: 782nm
ETE Hilo: 4 days 8 hours

Forecast:
Time UTC Winds Sig Wv
DD/HHHH Kts Ft
25/0000-25/1800 ENE 11-15 6-9
25/1800-26/0900 ENE 14-18 8-10
Passing AP01 about 0700
26/0900-26/1200 ENE 18-20 9-11
26/1200-27/0000 ENE 16-20 9-11
27/0000-28/0000 ENE-E 12-16 7-9
28/0000-28/0800 ENE-NE 13-16 6-8
28/0800-29/0000 NE 12-18 5-7

Please let me know when you need next update.

Best Regards,
Rick Shema, CCM


Original message follows.

From: "Rick Shema (WXGY)" <rick@weatherguy.com>
Subject: SV Mahina-Weather Update #2
Date: Fri, 25 Jul 2014 12:58:05 -1000

Hi John:

Thank you for your report this morning. I think the possible convection will be staying around for a little while longer. Movement of a tropical disturbance westward is pushing instability over your track and further north.

Here's how it's looking.
Weather Summary: As of 25July1200UTC. As with yesterday, you are presently in a rather intense area of convective activity while in the ITCZ. You should be in and out of deep convection as bands of instability move north of the ITCZ to about 14N and possibly 16N. You may hit it lucky and pass between bands, but there remains the potential for deep convection. Winds maintain a NE gradient about 20 kts; up to 40kts in convective downdraft winds.

The tropical disturbance of concern has quickly been upgraded to Tropical Storm Genevieve. Genevieve is not expected to impact your route. TS Genevieve was centered near 12 12N 136 12W at 25/2100UTC. A recent satellite winds overpass confirms 40 kt winds. Expected gusts to 50 kt. Most of the convection is to the east of center. The TS is not expected to intensify much further and should gradually weaken during the next few days. Genevieve slowed down to 6 kts moving westward, which is a good thing. A strengthening ridge should keep the movement generally west to west-northwest for the next 5 days.

There is an area of concentrated convection located about 170 nm to your east. This area is of more concern than Genevieve because it is responsible for continued NE winds and deep convection you are experiencing. This system continued to produce widely scattered thunderstorms across a broad area. Convective bands of rainshowers, squalls, and thunderstorms extend out to 14N. Additional bands further north are possible with further system development. Tropical cyclone formation chance through 48 hours is 30 percent indicated by Central Pacific Hurricane Center. Prior to reaching AP01, NE winds may back to E-SE as this system moves westward and south of you.

Significant wave heights should increase to about 12 ft range with increasing wind waves trade wind swell waves moving towards the subtropics.

Route:
Suggest best comfortable speed
Have adjusted AP01 to 14N 150W
Average SOG since yesterday AM position: 135 nm over 22 Hr 30Min = 6.0 kts
Distance to Hilo: 605nm
ETE Hilo: 4 days 05 hours at 6.0 kts

Forecast:
Time UTC Winds Sig Wv
DD/HHHH Kts Ft
26/0000-26/0900 NE-ENE 18-23 8-10
Convective activity, squalls
Passing AP01 about 0800
26/0900-26/1200 ENE-E 20-25 10-12
26/1200-26/1800 E-ESE 20-25 10-12
26/1800-27/1200 E 20-25 10-12
27/1200-28/0300 E 25-30 9-11
Possible convective activity ending after 28/0000UTC
28/0300-28/1200 E-15-25 8-10

Please let me know if an update is needed tomorrow.

Best Regards,
Rick Shema, CCM


 

Original message follows.

From: "Rick Shema (WXGY)" <rick@weatherguy.com>
Subject: SV Mahina-Weather Update #3
Date: Sat, 26 Jul 2014 09:09:10 -1000

Good morning, John:

Convection has died off and tropical systems have weakened since yesterday indicating a more stable atmospheric environment. The worst is over.

Here's how it's looking.
Weather Summary: As of 26July1200UTC. You should be out of the deep convection and into more stable conditions leaving the threat of tropical systems behind. Down range, there is ENE trade winds in the 20-25 kt range and significant waves to 12 ft. Tropical squalls are replaced by trade wind squalls, which are less intense and no thunderstorms. Still expect down draft winds to 40 kts, however.

Genevieve has weakened to tropical depression since yesterday to max central winds of 30 kts. The center was near 12 12N 137 00W at 26/1200UTC. Gusts to 40 kt. Intensity maintaining next few days then dissipating. Genevieve moving westward at 6kts.

The area of concentrated convection discussed yesterday close by has also weakened.

Significant wave heights should abate to the 6-8 ft range.

Route:
Direct to Hilo. Suggest best comfortable course and speed to Hilo.
Distance: 510 nm
Average SOG: 7.5 kts (assumed)
ETE: 2 Days 20 Hours

Forecast:
Time UTC Winds Sig Wv
DD/HHHH Kts Ft
26/1600-27/0000 ENE 20-25 9-11
27/0000-27/1200 ENE 18-23 10-12
27/1200-28/0000 ENE 20-25 10-12
28/0000-28/1800 ENE 18-23 8-10
28/1800-28/1200 E-15-20 6-8

Please let me know if an update is needed tomorrow.

Best Regards,
Rick Shema, CCM

 

 

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