Interesting exchange between Dave and our professional weather router.

Lots of us offshore sailing fans use professional weather routers to help decipher much of the info that is available from the US government (NOAA: National Oceanic and Atmospheric Administration.)

Here is an exchange between Dave and the forecaster are using for this return delivery. This particular forecaster does a huge book of business on cross-pacific races, cruises and deliveries. But ultimately the final decision has to be made by the skipper on site.

SC

From Dave to the forecaster:

Thank you very much for the information and the detail that you provided to us in your earlier post. After digesting all the data, I made the decision to try to go south of the high and work my way up the coast about 500 miles offshore. My concerns were twofold. First, with our limited fuel supply, I was worried that we would expend most of our fuel motoring north to find the winds at 44-50N. We would then be limited on fuel and possibly food.

By going rhumb line to Astoria, I calculated that we would have to motor approx. 300 nm to get across the bottom of the high and into the northerly coastal flow east of the high. Riva is an excellent upwind boat and I took that into consideration when making my decision. It looks like the first winds we find will be from the NE quad and I would then make a decision to proceed on starboard or port tack, whichever will be favored. If all else fails, we would be positioned to beam reach into a port on the Oregon coast to resupply and refuel.

Presently, all the information we have shows that we should be in pretty calm air. We are presently at 1745 gmt we were at 36d39m N and 148d48 W proceeding at 7 knots under sail with wind of 8-10 knots from 150d T. As I thought we may be motoring at this time, having this wind is good for our progress and the morale is high with the crew. Our fuel situation is that we have approximately 90 gallons with a range of about 540 miles at 6 knots.

Any information that you could give us to improve on our decision would be very gratefully appreciated. This high seems to be very finicky and having a hard time getting consolidated.

Again, thank you for your help.

Dave Moran

And from the forecaster back to Dave:

Scott/Dave, understand your concern about fuel and sailing in the NE winds. We have found that the most efficient route out of Hawaii and to the US west coast is toward the center of the high then E in N-NW winds. This moveable high makes the routing much more difficult. We try to get you to a point far enough N and W that you can remain in favorable wind directions for this entire leg.

Summary…

1) the NE Pac high pressure is currently centered near 40N/140W and is fairly strong at 1031MB

a) into the beginning of next week, low pressure organizes over the S Aleutian Islands and moves into the E Bering Sea

b) in reaction to this, the NE Pacific high works it’s way further W

c) to be centered from 40-50N along 145W by midday on the 2nd

d) this high will continue to slide to the W during the 3rd and 4th, as the low in the Bering Sea is also pulled westward by a more complex low that develops N of Japan

3) by the evening of the 5th, the high is forecast to be centered near 43N/150W

a) with N to NW winds forecast between the center of the high and the Oregon coast

Routing…

1) routed you between 150-160 nm/day from your 1745utc position today toward 45N/145W

a) to remain on the W side of the center of the high in lightening and clocking SE to S to SSW winds

b) and away from the NNE to NE winds along the E side of the high

2) once you reach 45N/145W, you can head generally E toward Astoria along the E to ENE side of the high in building N to NW winds

a) expect you will get into some light air for around 400 nm as you approach the center of the high during the 2nd and the 3rd and then begin E from near 45N/145W

Wind forecasts

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

Sun, Aug 1

00: 150-170/8-10

12: 160-180/6-10 nr 38 30N/147 50W

Weather…Variably cloudy with chc of isolated showers/squalls

Seas 2-3ft

Mon, Aug 2

00: 170-190/5-10

12: 180-200/5-10 nr 41 10N/146 40W

Weather…Variably cloudy with chc of isolated showers/squalls

Seas 2-3ft

Tue, Aug 3

00: bcmg light and variable

12: bcmg 080-100/5-10 nr 43 40N/145 30W

Weather…Variably cloudy with chc of isolated showers/squalls

Seas 2-3 ft

Wed, Aug 4 – heading mainly E on rhumbline to Astoria

00: light and variable

12: light and variable nr 45N/144W

Weather…Variably cloudy

Seas 2-3ft, light NE swell

Thu, Aug 5

00: light and variable

12: bcmg 350-010/6-12 nr 45 30N/140 30W

Weather…Variably to mostly cloudy

Seas building to 4-6ft by later in the day with building NW-N swell

Fri, Aug 6

00: 340-360/8-14

12: 330-350/15-22 nr 45 50N/136 40W

Weather…Variably to mostly cloudy

Seas building to 5-7ft during the day, NW-N swell